1666940978
3 Ways to Open an XML File
XML stands for eXtensible Markup Language. XML files are readable files that describe the structure of data. You store XML files with the .xml extension.
An XML file contains tags that specify how the document should be structured and how it should be stored and transmitted over the internet.
It is no longer the preferred method for organizing and transmitting data, but many legacy systems still use it. Also, both RSS and SVG are based on the XML format.
This is how XML appears:
<?xml version="1.0" encoding="UTF-8"?>
<catalog>
<book id="bk1">
<author>Corets, Eva</author>
<title>Maeve Ascendant</title>
<genre>Fantasy</genre>
<price>5.95</price>
</book>
<book id="bk2">
<author>Corets, Eva</author>
<title>Oberon's Legacy</title>
<genre>Fantasy</genre>
<price>5.95</price>
</book>
<book id="bk3">
<author>Corets, Eva</author>
<title>The Sundered Grail</title>
<genre>Fantasy</genre>
<price>5.95</price>
</book>
</catalog>
In this article, you will learn the various ways you can open an XML file, either on your computer or online.
- How to Open an XML File Using a Text Editor
- How to Open an XML File Using a Browser
- How to Open an XML File Online
How to Open an XML File Using a Text Editor
You must have an XML file you are trying to open, either to view only or to view and edit.
If you want to open an XML file and edit it, you can use a text editor. You can use default text editors, which come with your computer, like Notepad on Windows or TextEdit on Mac.
All you have to do is locate the XML file, right-click the XML file, and select the "Open With" option. This will display a list of programs to open the file.
Select Notepad if it is a Windows computer or TextEdit if it is a Mac computer, as shown in the image above. These two are pre-installed text editors for each operating system and should already be on the list. Any basic text editor will work.
You can use other text editors like VSCode (which is suggested on the image above), Atom, Sublime Text and others. But it is always best to use default editors for basic tasks like this, as text editors like VSCode, Atom, and Sublime Text are pretty heavy programs.
How to Open an XML File Using a Browser
If you only want to view the file, you can use any web browser such as Safari, Chrome, and lots more with similar procedures.
The first step is to locate the XML file you want to open, right-click the file, and select the โopen withโ option. A list of options will appear, including some browsers.
Click on your preferred browser, and then your XML will load up.
Another option would be to open your browser and then drag the XML file to the browser. This also works for text editors.
How to Open an XML File Online
On the internet, dozens of XML viewers and even converters help convert XML files to other formats like JSON. Here are some of the most popular online XML viewers/editors:
Each one works similarly, allowing you to upload the XML file from your computer.
Chrome has an XML Viewer extension, which works like all these online XML viewers. All you have to do is download the extension. Then click on it whenever you want to open an XML file.
Once you click on it, an interface that is easy to navigate will appear with two major options you can use to upload your XML file: From your PC or From your Google Drive.
When you select an option, you can search for the file, and within a few milliseconds, your XML file will open in the plain section.
Ta-da ๐
In this short article, you have learned how to open an XML file. I hope this will help you.
Have fun coding!
Original article source at https://www.freecodecamp.org
#xml
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1653475560
A Pure PHP Implementation Of The MessagePack Serialization Format
msgpack.php
A pure PHP implementation of the MessagePack serialization format.
Features
- Fully compliant with the latest MessagePack specification
- Supports streaming unpacking
- Supports unsigned 64-bit integers handling
- Supports object serialization
- Fully tested
- Relatively fast
Installation
The recommended way to install the library is through Composer:
composer require rybakit/msgpack
Usage
Packing
To pack values you can either use an instance of a Packer:
$packer = new Packer();
$packed = $packer->pack($value);
or call a static method on the MessagePack class:
$packed = MessagePack::pack($value);
In the examples above, the method pack automatically packs a value depending on its type. However, not all PHP types can be uniquely translated to MessagePack types. For example, the MessagePack format defines map and array types, which are represented by a single array type in PHP. By default, the packer will pack a PHP array as a MessagePack array if it has sequential numeric keys, starting from 0 and as a MessagePack map otherwise:
$mpArr1 = $packer->pack([1, 2]); // MP array [1, 2]
$mpArr2 = $packer->pack([0 => 1, 1 => 2]); // MP array [1, 2]
$mpMap1 = $packer->pack([0 => 1, 2 => 3]); // MP map {0: 1, 2: 3}
$mpMap2 = $packer->pack([1 => 2, 2 => 3]); // MP map {1: 2, 2: 3}
$mpMap3 = $packer->pack(['a' => 1, 'b' => 2]); // MP map {a: 1, b: 2}
However, sometimes you need to pack a sequential array as a MessagePack map. To do this, use the packMap method:
$mpMap = $packer->packMap([1, 2]); // {0: 1, 1: 2}
Here is a list of type-specific packing methods:
$packer->packNil(); // MP nil
$packer->packBool(true); // MP bool
$packer->packInt(42); // MP int
$packer->packFloat(M_PI); // MP float (32 or 64)
$packer->packFloat32(M_PI); // MP float 32
$packer->packFloat64(M_PI); // MP float 64
$packer->packStr('foo'); // MP str
$packer->packBin("\x80"); // MP bin
$packer->packArray([1, 2]); // MP array
$packer->packMap(['a' => 1]); // MP map
$packer->packExt(1, "\xaa"); // MP ext
Check the "Custom types" section below on how to pack custom types.
Packing options
The Packer object supports a number of bitmask-based options for fine-tuning the packing process (defaults are in bold):
| Name | Description |
|---|---|
FORCE_STR | Forces PHP strings to be packed as MessagePack UTF-8 strings |
FORCE_BIN | Forces PHP strings to be packed as MessagePack binary data |
DETECT_STR_BIN | Detects MessagePack str/bin type automatically |
FORCE_ARR | Forces PHP arrays to be packed as MessagePack arrays |
FORCE_MAP | Forces PHP arrays to be packed as MessagePack maps |
DETECT_ARR_MAP | Detects MessagePack array/map type automatically |
FORCE_FLOAT32 | Forces PHP floats to be packed as 32-bits MessagePack floats |
FORCE_FLOAT64 | Forces PHP floats to be packed as 64-bits MessagePack floats |
The type detection mode (
DETECT_STR_BIN/DETECT_ARR_MAP) adds some overhead which can be noticed when you pack large (16- and 32-bit) arrays or strings. However, if you know the value type in advance (for example, you only work with UTF-8 strings or/and associative arrays), you can eliminate this overhead by forcing the packer to use the appropriate type, which will save it from running the auto-detection routine. Another option is to explicitly specify the value type. The library provides 2 auxiliary classes for this,MapandBin. Check the "Custom types" section below for details.
Examples:
// detect str/bin type and pack PHP 64-bit floats (doubles) to MP 32-bit floats
$packer = new Packer(PackOptions::DETECT_STR_BIN | PackOptions::FORCE_FLOAT32);
// these will throw MessagePack\Exception\InvalidOptionException
$packer = new Packer(PackOptions::FORCE_STR | PackOptions::FORCE_BIN);
$packer = new Packer(PackOptions::FORCE_FLOAT32 | PackOptions::FORCE_FLOAT64);
Unpacking
To unpack data you can either use an instance of a BufferUnpacker:
$unpacker = new BufferUnpacker();
$unpacker->reset($packed);
$value = $unpacker->unpack();
or call a static method on the MessagePack class:
$value = MessagePack::unpack($packed);
If the packed data is received in chunks (e.g. when reading from a stream), use the tryUnpack method, which attempts to unpack data and returns an array of unpacked messages (if any) instead of throwing an InsufficientDataException:
while ($chunk = ...) {
$unpacker->append($chunk);
if ($messages = $unpacker->tryUnpack()) {
return $messages;
}
}
If you want to unpack from a specific position in a buffer, use seek:
$unpacker->seek(42); // set position equal to 42 bytes
$unpacker->seek(-8); // set position to 8 bytes before the end of the buffer
To skip bytes from the current position, use skip:
$unpacker->skip(10); // set position to 10 bytes ahead of the current position
To get the number of remaining (unread) bytes in the buffer:
$unreadBytesCount = $unpacker->getRemainingCount();
To check whether the buffer has unread data:
$hasUnreadBytes = $unpacker->hasRemaining();
If needed, you can remove already read data from the buffer by calling:
$releasedBytesCount = $unpacker->release();
With the read method you can read raw (packed) data:
$packedData = $unpacker->read(2); // read 2 bytes
Besides the above methods BufferUnpacker provides type-specific unpacking methods, namely:
$unpacker->unpackNil(); // PHP null
$unpacker->unpackBool(); // PHP bool
$unpacker->unpackInt(); // PHP int
$unpacker->unpackFloat(); // PHP float
$unpacker->unpackStr(); // PHP UTF-8 string
$unpacker->unpackBin(); // PHP binary string
$unpacker->unpackArray(); // PHP sequential array
$unpacker->unpackMap(); // PHP associative array
$unpacker->unpackExt(); // PHP MessagePack\Type\Ext object
Unpacking options
The BufferUnpacker object supports a number of bitmask-based options for fine-tuning the unpacking process (defaults are in bold):
| Name | Description |
|---|---|
BIGINT_AS_STR | Converts overflowed integers to strings [1] |
BIGINT_AS_GMP | Converts overflowed integers to GMP objects [2] |
BIGINT_AS_DEC | Converts overflowed integers to Decimal\Decimal objects [3] |
1. The binary MessagePack format has unsigned 64-bit as its largest integer data type, but PHP does not support such integers, which means that an overflow can occur during unpacking.
2. Make sure the GMP extension is enabled.
3. Make sure the Decimal extension is enabled.
Examples:
$packedUint64 = "\xcf"."\xff\xff\xff\xff"."\xff\xff\xff\xff";
$unpacker = new BufferUnpacker($packedUint64);
var_dump($unpacker->unpack()); // string(20) "18446744073709551615"
$unpacker = new BufferUnpacker($packedUint64, UnpackOptions::BIGINT_AS_GMP);
var_dump($unpacker->unpack()); // object(GMP) {...}
$unpacker = new BufferUnpacker($packedUint64, UnpackOptions::BIGINT_AS_DEC);
var_dump($unpacker->unpack()); // object(Decimal\Decimal) {...}
Custom types
In addition to the basic types, the library provides functionality to serialize and deserialize arbitrary types. This can be done in several ways, depending on your use case. Let's take a look at them.
Type objects
If you need to serialize an instance of one of your classes into one of the basic MessagePack types, the best way to do this is to implement the CanBePacked interface in the class. A good example of such a class is the Map type class that comes with the library. This type is useful when you want to explicitly specify that a given PHP array should be packed as a MessagePack map without triggering an automatic type detection routine:
$packer = new Packer();
$packedMap = $packer->pack(new Map([1, 2, 3]));
$packedArray = $packer->pack([1, 2, 3]);
More type examples can be found in the src/Type directory.
Type transformers
As with type objects, type transformers are only responsible for serializing values. They should be used when you need to serialize a value that does not implement the CanBePacked interface. Examples of such values could be instances of built-in or third-party classes that you don't own, or non-objects such as resources.
A transformer class must implement the CanPack interface. To use a transformer, it must first be registered in the packer. Here is an example of how to serialize PHP streams into the MessagePack bin format type using one of the supplied transformers, StreamTransformer:
$packer = new Packer(null, [new StreamTransformer()]);
$packedBin = $packer->pack(fopen('/path/to/file', 'r+'));
More type transformer examples can be found in the src/TypeTransformer directory.
Extensions
In contrast to the cases described above, extensions are intended to handle extension types and are responsible for both serialization and deserialization of values (types).
An extension class must implement the Extension interface. To use an extension, it must first be registered in the packer and the unpacker.
The MessagePack specification divides extension types into two groups: predefined and application-specific. Currently, there is only one predefined type in the specification, Timestamp.
Timestamp
The Timestamp extension type is a predefined type. Support for this type in the library is done through the TimestampExtension class. This class is responsible for handling Timestamp objects, which represent the number of seconds and optional adjustment in nanoseconds:
$timestampExtension = new TimestampExtension();
$packer = new Packer();
$packer = $packer->extendWith($timestampExtension);
$unpacker = new BufferUnpacker();
$unpacker = $unpacker->extendWith($timestampExtension);
$packedTimestamp = $packer->pack(Timestamp::now());
$timestamp = $unpacker->reset($packedTimestamp)->unpack();
$seconds = $timestamp->getSeconds();
$nanoseconds = $timestamp->getNanoseconds();
When using the MessagePack class, the Timestamp extension is already registered:
$packedTimestamp = MessagePack::pack(Timestamp::now());
$timestamp = MessagePack::unpack($packedTimestamp);
Application-specific extensions
In addition, the format can be extended with your own types. For example, to make the built-in PHP DateTime objects first-class citizens in your code, you can create a corresponding extension, as shown in the example. Please note, that custom extensions have to be registered with a unique extension ID (an integer from 0 to 127).
More extension examples can be found in the examples/MessagePack directory.
To learn more about how extension types can be useful, check out this article.
Exceptions
If an error occurs during packing/unpacking, a PackingFailedException or an UnpackingFailedException will be thrown, respectively. In addition, an InsufficientDataException can be thrown during unpacking.
An InvalidOptionException will be thrown in case an invalid option (or a combination of mutually exclusive options) is used.
Tests
Run tests as follows:
vendor/bin/phpunit
Also, if you already have Docker installed, you can run the tests in a docker container. First, create a container:
./dockerfile.sh | docker build -t msgpack -
The command above will create a container named msgpack with PHP 8.1 runtime. You may change the default runtime by defining the PHP_IMAGE environment variable:
PHP_IMAGE='php:8.0-cli' ./dockerfile.sh | docker build -t msgpack -
See a list of various images here.
Then run the unit tests:
docker run --rm -v $PWD:/msgpack -w /msgpack msgpack
Fuzzing
To ensure that the unpacking works correctly with malformed/semi-malformed data, you can use a testing technique called Fuzzing. The library ships with a help file (target) for PHP-Fuzzer and can be used as follows:
php-fuzzer fuzz tests/fuzz_buffer_unpacker.php
Performance
To check performance, run:
php -n -dzend_extension=opcache.so \
-dpcre.jit=1 -dopcache.enable=1 -dopcache.enable_cli=1 \
tests/bench.php
Example output
Filter: MessagePack\Tests\Perf\Filter\ListFilter
Rounds: 3
Iterations: 100000
=============================================
Test/Target Packer BufferUnpacker
---------------------------------------------
nil .................. 0.0030 ........ 0.0139
false ................ 0.0037 ........ 0.0144
true ................. 0.0040 ........ 0.0137
7-bit uint #1 ........ 0.0052 ........ 0.0120
7-bit uint #2 ........ 0.0059 ........ 0.0114
7-bit uint #3 ........ 0.0061 ........ 0.0119
5-bit sint #1 ........ 0.0067 ........ 0.0126
5-bit sint #2 ........ 0.0064 ........ 0.0132
5-bit sint #3 ........ 0.0066 ........ 0.0135
8-bit uint #1 ........ 0.0078 ........ 0.0200
8-bit uint #2 ........ 0.0077 ........ 0.0212
8-bit uint #3 ........ 0.0086 ........ 0.0203
16-bit uint #1 ....... 0.0111 ........ 0.0271
16-bit uint #2 ....... 0.0115 ........ 0.0260
16-bit uint #3 ....... 0.0103 ........ 0.0273
32-bit uint #1 ....... 0.0116 ........ 0.0326
32-bit uint #2 ....... 0.0118 ........ 0.0332
32-bit uint #3 ....... 0.0127 ........ 0.0325
64-bit uint #1 ....... 0.0140 ........ 0.0277
64-bit uint #2 ....... 0.0134 ........ 0.0294
64-bit uint #3 ....... 0.0134 ........ 0.0281
8-bit int #1 ......... 0.0086 ........ 0.0241
8-bit int #2 ......... 0.0089 ........ 0.0225
8-bit int #3 ......... 0.0085 ........ 0.0229
16-bit int #1 ........ 0.0118 ........ 0.0280
16-bit int #2 ........ 0.0121 ........ 0.0270
16-bit int #3 ........ 0.0109 ........ 0.0274
32-bit int #1 ........ 0.0128 ........ 0.0346
32-bit int #2 ........ 0.0118 ........ 0.0339
32-bit int #3 ........ 0.0135 ........ 0.0368
64-bit int #1 ........ 0.0138 ........ 0.0276
64-bit int #2 ........ 0.0132 ........ 0.0286
64-bit int #3 ........ 0.0137 ........ 0.0274
64-bit int #4 ........ 0.0180 ........ 0.0285
64-bit float #1 ...... 0.0134 ........ 0.0284
64-bit float #2 ...... 0.0125 ........ 0.0275
64-bit float #3 ...... 0.0126 ........ 0.0283
fix string #1 ........ 0.0035 ........ 0.0133
fix string #2 ........ 0.0094 ........ 0.0216
fix string #3 ........ 0.0094 ........ 0.0222
fix string #4 ........ 0.0091 ........ 0.0241
8-bit string #1 ...... 0.0122 ........ 0.0301
8-bit string #2 ...... 0.0118 ........ 0.0304
8-bit string #3 ...... 0.0119 ........ 0.0315
16-bit string #1 ..... 0.0150 ........ 0.0388
16-bit string #2 ..... 0.1545 ........ 0.1665
32-bit string ........ 0.1570 ........ 0.1756
wide char string #1 .. 0.0091 ........ 0.0236
wide char string #2 .. 0.0122 ........ 0.0313
8-bit binary #1 ...... 0.0100 ........ 0.0302
8-bit binary #2 ...... 0.0123 ........ 0.0324
8-bit binary #3 ...... 0.0126 ........ 0.0327
16-bit binary ........ 0.0168 ........ 0.0372
32-bit binary ........ 0.1588 ........ 0.1754
fix array #1 ......... 0.0042 ........ 0.0131
fix array #2 ......... 0.0294 ........ 0.0367
fix array #3 ......... 0.0412 ........ 0.0472
16-bit array #1 ...... 0.1378 ........ 0.1596
16-bit array #2 ........... S ............. S
32-bit array .............. S ............. S
complex array ........ 0.1865 ........ 0.2283
fix map #1 ........... 0.0725 ........ 0.1048
fix map #2 ........... 0.0319 ........ 0.0405
fix map #3 ........... 0.0356 ........ 0.0665
fix map #4 ........... 0.0465 ........ 0.0497
16-bit map #1 ........ 0.2540 ........ 0.3028
16-bit map #2 ............. S ............. S
32-bit map ................ S ............. S
complex map .......... 0.2372 ........ 0.2710
fixext 1 ............. 0.0283 ........ 0.0358
fixext 2 ............. 0.0291 ........ 0.0371
fixext 4 ............. 0.0302 ........ 0.0355
fixext 8 ............. 0.0288 ........ 0.0384
fixext 16 ............ 0.0293 ........ 0.0359
8-bit ext ............ 0.0302 ........ 0.0439
16-bit ext ........... 0.0334 ........ 0.0499
32-bit ext ........... 0.1845 ........ 0.1888
32-bit timestamp #1 .. 0.0337 ........ 0.0547
32-bit timestamp #2 .. 0.0335 ........ 0.0560
64-bit timestamp #1 .. 0.0371 ........ 0.0575
64-bit timestamp #2 .. 0.0374 ........ 0.0542
64-bit timestamp #3 .. 0.0356 ........ 0.0533
96-bit timestamp #1 .. 0.0362 ........ 0.0699
96-bit timestamp #2 .. 0.0381 ........ 0.0701
96-bit timestamp #3 .. 0.0367 ........ 0.0687
=============================================
Total 2.7618 4.0820
Skipped 4 4
Failed 0 0
Ignored 0 0
With JIT:
php -n -dzend_extension=opcache.so \
-dpcre.jit=1 -dopcache.jit_buffer_size=64M -dopcache.jit=tracing -dopcache.enable=1 -dopcache.enable_cli=1 \
tests/bench.php
Example output
Filter: MessagePack\Tests\Perf\Filter\ListFilter
Rounds: 3
Iterations: 100000
=============================================
Test/Target Packer BufferUnpacker
---------------------------------------------
nil .................. 0.0005 ........ 0.0054
false ................ 0.0004 ........ 0.0059
true ................. 0.0004 ........ 0.0059
7-bit uint #1 ........ 0.0010 ........ 0.0047
7-bit uint #2 ........ 0.0010 ........ 0.0046
7-bit uint #3 ........ 0.0010 ........ 0.0046
5-bit sint #1 ........ 0.0025 ........ 0.0046
5-bit sint #2 ........ 0.0023 ........ 0.0046
5-bit sint #3 ........ 0.0024 ........ 0.0045
8-bit uint #1 ........ 0.0043 ........ 0.0081
8-bit uint #2 ........ 0.0043 ........ 0.0079
8-bit uint #3 ........ 0.0041 ........ 0.0080
16-bit uint #1 ....... 0.0064 ........ 0.0095
16-bit uint #2 ....... 0.0064 ........ 0.0091
16-bit uint #3 ....... 0.0064 ........ 0.0094
32-bit uint #1 ....... 0.0085 ........ 0.0114
32-bit uint #2 ....... 0.0077 ........ 0.0122
32-bit uint #3 ....... 0.0077 ........ 0.0120
64-bit uint #1 ....... 0.0085 ........ 0.0159
64-bit uint #2 ....... 0.0086 ........ 0.0157
64-bit uint #3 ....... 0.0086 ........ 0.0158
8-bit int #1 ......... 0.0042 ........ 0.0080
8-bit int #2 ......... 0.0042 ........ 0.0080
8-bit int #3 ......... 0.0042 ........ 0.0081
16-bit int #1 ........ 0.0065 ........ 0.0095
16-bit int #2 ........ 0.0065 ........ 0.0090
16-bit int #3 ........ 0.0056 ........ 0.0085
32-bit int #1 ........ 0.0067 ........ 0.0107
32-bit int #2 ........ 0.0066 ........ 0.0106
32-bit int #3 ........ 0.0063 ........ 0.0104
64-bit int #1 ........ 0.0072 ........ 0.0162
64-bit int #2 ........ 0.0073 ........ 0.0174
64-bit int #3 ........ 0.0072 ........ 0.0164
64-bit int #4 ........ 0.0077 ........ 0.0161
64-bit float #1 ...... 0.0053 ........ 0.0135
64-bit float #2 ...... 0.0053 ........ 0.0135
64-bit float #3 ...... 0.0052 ........ 0.0135
fix string #1 ....... -0.0002 ........ 0.0044
fix string #2 ........ 0.0035 ........ 0.0067
fix string #3 ........ 0.0035 ........ 0.0077
fix string #4 ........ 0.0033 ........ 0.0078
8-bit string #1 ...... 0.0059 ........ 0.0110
8-bit string #2 ...... 0.0063 ........ 0.0121
8-bit string #3 ...... 0.0064 ........ 0.0124
16-bit string #1 ..... 0.0099 ........ 0.0146
16-bit string #2 ..... 0.1522 ........ 0.1474
32-bit string ........ 0.1511 ........ 0.1483
wide char string #1 .. 0.0039 ........ 0.0084
wide char string #2 .. 0.0073 ........ 0.0123
8-bit binary #1 ...... 0.0040 ........ 0.0112
8-bit binary #2 ...... 0.0075 ........ 0.0123
8-bit binary #3 ...... 0.0077 ........ 0.0129
16-bit binary ........ 0.0096 ........ 0.0145
32-bit binary ........ 0.1535 ........ 0.1479
fix array #1 ......... 0.0008 ........ 0.0061
fix array #2 ......... 0.0121 ........ 0.0165
fix array #3 ......... 0.0193 ........ 0.0222
16-bit array #1 ...... 0.0607 ........ 0.0479
16-bit array #2 ........... S ............. S
32-bit array .............. S ............. S
complex array ........ 0.0749 ........ 0.0824
fix map #1 ........... 0.0329 ........ 0.0431
fix map #2 ........... 0.0161 ........ 0.0189
fix map #3 ........... 0.0205 ........ 0.0262
fix map #4 ........... 0.0252 ........ 0.0205
16-bit map #1 ........ 0.1016 ........ 0.0927
16-bit map #2 ............. S ............. S
32-bit map ................ S ............. S
complex map .......... 0.1096 ........ 0.1030
fixext 1 ............. 0.0157 ........ 0.0161
fixext 2 ............. 0.0175 ........ 0.0183
fixext 4 ............. 0.0156 ........ 0.0185
fixext 8 ............. 0.0163 ........ 0.0184
fixext 16 ............ 0.0164 ........ 0.0182
8-bit ext ............ 0.0158 ........ 0.0207
16-bit ext ........... 0.0203 ........ 0.0219
32-bit ext ........... 0.1614 ........ 0.1539
32-bit timestamp #1 .. 0.0195 ........ 0.0249
32-bit timestamp #2 .. 0.0188 ........ 0.0260
64-bit timestamp #1 .. 0.0207 ........ 0.0281
64-bit timestamp #2 .. 0.0212 ........ 0.0291
64-bit timestamp #3 .. 0.0207 ........ 0.0295
96-bit timestamp #1 .. 0.0222 ........ 0.0358
96-bit timestamp #2 .. 0.0228 ........ 0.0353
96-bit timestamp #3 .. 0.0210 ........ 0.0319
=============================================
Total 1.6432 1.9674
Skipped 4 4
Failed 0 0
Ignored 0 0
You may change default benchmark settings by defining the following environment variables:
| Name | Default |
|---|---|
| MP_BENCH_TARGETS | pure_p,pure_u, see a list of available targets |
| MP_BENCH_ITERATIONS | 100_000 |
| MP_BENCH_DURATION | not set |
| MP_BENCH_ROUNDS | 3 |
| MP_BENCH_TESTS | -@slow, see a list of available tests |
For example:
export MP_BENCH_TARGETS=pure_p
export MP_BENCH_ITERATIONS=1000000
export MP_BENCH_ROUNDS=5
# a comma separated list of test names
export MP_BENCH_TESTS='complex array, complex map'
# or a group name
# export MP_BENCH_TESTS='-@slow' // @pecl_comp
# or a regexp
# export MP_BENCH_TESTS='/complex (array|map)/'
Another example, benchmarking both the library and the PECL extension:
MP_BENCH_TARGETS=pure_p,pure_u,pecl_p,pecl_u \
php -n -dextension=msgpack.so -dzend_extension=opcache.so \
-dpcre.jit=1 -dopcache.enable=1 -dopcache.enable_cli=1 \
tests/bench.php
Example output
Filter: MessagePack\Tests\Perf\Filter\ListFilter
Rounds: 3
Iterations: 100000
===========================================================================
Test/Target Packer BufferUnpacker msgpack_pack msgpack_unpack
---------------------------------------------------------------------------
nil .................. 0.0031 ........ 0.0141 ...... 0.0055 ........ 0.0064
false ................ 0.0039 ........ 0.0154 ...... 0.0056 ........ 0.0053
true ................. 0.0038 ........ 0.0139 ...... 0.0056 ........ 0.0044
7-bit uint #1 ........ 0.0061 ........ 0.0110 ...... 0.0059 ........ 0.0046
7-bit uint #2 ........ 0.0065 ........ 0.0119 ...... 0.0042 ........ 0.0029
7-bit uint #3 ........ 0.0054 ........ 0.0117 ...... 0.0045 ........ 0.0025
5-bit sint #1 ........ 0.0047 ........ 0.0103 ...... 0.0038 ........ 0.0022
5-bit sint #2 ........ 0.0048 ........ 0.0117 ...... 0.0038 ........ 0.0022
5-bit sint #3 ........ 0.0046 ........ 0.0102 ...... 0.0038 ........ 0.0023
8-bit uint #1 ........ 0.0063 ........ 0.0174 ...... 0.0039 ........ 0.0031
8-bit uint #2 ........ 0.0063 ........ 0.0167 ...... 0.0040 ........ 0.0029
8-bit uint #3 ........ 0.0063 ........ 0.0168 ...... 0.0039 ........ 0.0030
16-bit uint #1 ....... 0.0092 ........ 0.0222 ...... 0.0049 ........ 0.0030
16-bit uint #2 ....... 0.0096 ........ 0.0227 ...... 0.0042 ........ 0.0046
16-bit uint #3 ....... 0.0123 ........ 0.0274 ...... 0.0059 ........ 0.0051
32-bit uint #1 ....... 0.0136 ........ 0.0331 ...... 0.0060 ........ 0.0048
32-bit uint #2 ....... 0.0130 ........ 0.0336 ...... 0.0070 ........ 0.0048
32-bit uint #3 ....... 0.0127 ........ 0.0329 ...... 0.0051 ........ 0.0048
64-bit uint #1 ....... 0.0126 ........ 0.0268 ...... 0.0055 ........ 0.0049
64-bit uint #2 ....... 0.0135 ........ 0.0281 ...... 0.0052 ........ 0.0046
64-bit uint #3 ....... 0.0131 ........ 0.0274 ...... 0.0069 ........ 0.0044
8-bit int #1 ......... 0.0077 ........ 0.0236 ...... 0.0058 ........ 0.0044
8-bit int #2 ......... 0.0087 ........ 0.0244 ...... 0.0058 ........ 0.0048
8-bit int #3 ......... 0.0084 ........ 0.0241 ...... 0.0055 ........ 0.0049
16-bit int #1 ........ 0.0112 ........ 0.0271 ...... 0.0048 ........ 0.0045
16-bit int #2 ........ 0.0124 ........ 0.0292 ...... 0.0057 ........ 0.0049
16-bit int #3 ........ 0.0118 ........ 0.0270 ...... 0.0058 ........ 0.0050
32-bit int #1 ........ 0.0137 ........ 0.0366 ...... 0.0058 ........ 0.0051
32-bit int #2 ........ 0.0133 ........ 0.0366 ...... 0.0056 ........ 0.0049
32-bit int #3 ........ 0.0129 ........ 0.0350 ...... 0.0052 ........ 0.0048
64-bit int #1 ........ 0.0145 ........ 0.0254 ...... 0.0034 ........ 0.0025
64-bit int #2 ........ 0.0097 ........ 0.0214 ...... 0.0034 ........ 0.0025
64-bit int #3 ........ 0.0096 ........ 0.0287 ...... 0.0059 ........ 0.0050
64-bit int #4 ........ 0.0143 ........ 0.0277 ...... 0.0059 ........ 0.0046
64-bit float #1 ...... 0.0134 ........ 0.0281 ...... 0.0057 ........ 0.0052
64-bit float #2 ...... 0.0141 ........ 0.0281 ...... 0.0057 ........ 0.0050
64-bit float #3 ...... 0.0144 ........ 0.0282 ...... 0.0057 ........ 0.0050
fix string #1 ........ 0.0036 ........ 0.0143 ...... 0.0066 ........ 0.0053
fix string #2 ........ 0.0107 ........ 0.0222 ...... 0.0065 ........ 0.0068
fix string #3 ........ 0.0116 ........ 0.0245 ...... 0.0063 ........ 0.0069
fix string #4 ........ 0.0105 ........ 0.0253 ...... 0.0083 ........ 0.0077
8-bit string #1 ...... 0.0126 ........ 0.0318 ...... 0.0075 ........ 0.0088
8-bit string #2 ...... 0.0121 ........ 0.0295 ...... 0.0076 ........ 0.0086
8-bit string #3 ...... 0.0125 ........ 0.0293 ...... 0.0130 ........ 0.0093
16-bit string #1 ..... 0.0159 ........ 0.0368 ...... 0.0117 ........ 0.0086
16-bit string #2 ..... 0.1547 ........ 0.1686 ...... 0.1516 ........ 0.1373
32-bit string ........ 0.1558 ........ 0.1729 ...... 0.1511 ........ 0.1396
wide char string #1 .. 0.0098 ........ 0.0237 ...... 0.0066 ........ 0.0065
wide char string #2 .. 0.0128 ........ 0.0291 ...... 0.0061 ........ 0.0082
8-bit binary #1 ........... I ............. I ........... F ............. I
8-bit binary #2 ........... I ............. I ........... F ............. I
8-bit binary #3 ........... I ............. I ........... F ............. I
16-bit binary ............. I ............. I ........... F ............. I
32-bit binary ............. I ............. I ........... F ............. I
fix array #1 ......... 0.0040 ........ 0.0129 ...... 0.0120 ........ 0.0058
fix array #2 ......... 0.0279 ........ 0.0390 ...... 0.0143 ........ 0.0165
fix array #3 ......... 0.0415 ........ 0.0463 ...... 0.0162 ........ 0.0187
16-bit array #1 ...... 0.1349 ........ 0.1628 ...... 0.0334 ........ 0.0341
16-bit array #2 ........... S ............. S ........... S ............. S
32-bit array .............. S ............. S ........... S ............. S
complex array ............. I ............. I ........... F ............. F
fix map #1 ................ I ............. I ........... F ............. I
fix map #2 ........... 0.0345 ........ 0.0391 ...... 0.0143 ........ 0.0168
fix map #3 ................ I ............. I ........... F ............. I
fix map #4 ........... 0.0459 ........ 0.0473 ...... 0.0151 ........ 0.0163
16-bit map #1 ........ 0.2518 ........ 0.2962 ...... 0.0400 ........ 0.0490
16-bit map #2 ............. S ............. S ........... S ............. S
32-bit map ................ S ............. S ........... S ............. S
complex map .......... 0.2380 ........ 0.2682 ...... 0.0545 ........ 0.0579
fixext 1 .................. I ............. I ........... F ............. F
fixext 2 .................. I ............. I ........... F ............. F
fixext 4 .................. I ............. I ........... F ............. F
fixext 8 .................. I ............. I ........... F ............. F
fixext 16 ................. I ............. I ........... F ............. F
8-bit ext ................. I ............. I ........... F ............. F
16-bit ext ................ I ............. I ........... F ............. F
32-bit ext ................ I ............. I ........... F ............. F
32-bit timestamp #1 ....... I ............. I ........... F ............. F
32-bit timestamp #2 ....... I ............. I ........... F ............. F
64-bit timestamp #1 ....... I ............. I ........... F ............. F
64-bit timestamp #2 ....... I ............. I ........... F ............. F
64-bit timestamp #3 ....... I ............. I ........... F ............. F
96-bit timestamp #1 ....... I ............. I ........... F ............. F
96-bit timestamp #2 ....... I ............. I ........... F ............. F
96-bit timestamp #3 ....... I ............. I ........... F ............. F
===========================================================================
Total 1.5625 2.3866 0.7735 0.7243
Skipped 4 4 4 4
Failed 0 0 24 17
Ignored 24 24 0 7
With JIT:
MP_BENCH_TARGETS=pure_p,pure_u,pecl_p,pecl_u \
php -n -dextension=msgpack.so -dzend_extension=opcache.so \
-dpcre.jit=1 -dopcache.jit_buffer_size=64M -dopcache.jit=tracing -dopcache.enable=1 -dopcache.enable_cli=1 \
tests/bench.php
Example output
Filter: MessagePack\Tests\Perf\Filter\ListFilter
Rounds: 3
Iterations: 100000
===========================================================================
Test/Target Packer BufferUnpacker msgpack_pack msgpack_unpack
---------------------------------------------------------------------------
nil .................. 0.0001 ........ 0.0052 ...... 0.0053 ........ 0.0042
false ................ 0.0007 ........ 0.0060 ...... 0.0057 ........ 0.0043
true ................. 0.0008 ........ 0.0060 ...... 0.0056 ........ 0.0041
7-bit uint #1 ........ 0.0031 ........ 0.0046 ...... 0.0062 ........ 0.0041
7-bit uint #2 ........ 0.0021 ........ 0.0043 ...... 0.0062 ........ 0.0041
7-bit uint #3 ........ 0.0022 ........ 0.0044 ...... 0.0061 ........ 0.0040
5-bit sint #1 ........ 0.0030 ........ 0.0048 ...... 0.0062 ........ 0.0040
5-bit sint #2 ........ 0.0032 ........ 0.0046 ...... 0.0062 ........ 0.0040
5-bit sint #3 ........ 0.0031 ........ 0.0046 ...... 0.0062 ........ 0.0040
8-bit uint #1 ........ 0.0054 ........ 0.0079 ...... 0.0062 ........ 0.0050
8-bit uint #2 ........ 0.0051 ........ 0.0079 ...... 0.0064 ........ 0.0044
8-bit uint #3 ........ 0.0051 ........ 0.0082 ...... 0.0062 ........ 0.0044
16-bit uint #1 ....... 0.0077 ........ 0.0094 ...... 0.0065 ........ 0.0045
16-bit uint #2 ....... 0.0077 ........ 0.0094 ...... 0.0063 ........ 0.0045
16-bit uint #3 ....... 0.0077 ........ 0.0095 ...... 0.0064 ........ 0.0047
32-bit uint #1 ....... 0.0088 ........ 0.0119 ...... 0.0063 ........ 0.0043
32-bit uint #2 ....... 0.0089 ........ 0.0117 ...... 0.0062 ........ 0.0039
32-bit uint #3 ....... 0.0089 ........ 0.0118 ...... 0.0063 ........ 0.0044
64-bit uint #1 ....... 0.0097 ........ 0.0155 ...... 0.0063 ........ 0.0045
64-bit uint #2 ....... 0.0095 ........ 0.0153 ...... 0.0061 ........ 0.0045
64-bit uint #3 ....... 0.0096 ........ 0.0156 ...... 0.0063 ........ 0.0047
8-bit int #1 ......... 0.0053 ........ 0.0083 ...... 0.0062 ........ 0.0044
8-bit int #2 ......... 0.0052 ........ 0.0080 ...... 0.0062 ........ 0.0044
8-bit int #3 ......... 0.0052 ........ 0.0080 ...... 0.0062 ........ 0.0043
16-bit int #1 ........ 0.0089 ........ 0.0097 ...... 0.0069 ........ 0.0046
16-bit int #2 ........ 0.0075 ........ 0.0093 ...... 0.0063 ........ 0.0043
16-bit int #3 ........ 0.0075 ........ 0.0094 ...... 0.0062 ........ 0.0046
32-bit int #1 ........ 0.0086 ........ 0.0122 ...... 0.0063 ........ 0.0044
32-bit int #2 ........ 0.0087 ........ 0.0120 ...... 0.0066 ........ 0.0046
32-bit int #3 ........ 0.0086 ........ 0.0121 ...... 0.0060 ........ 0.0044
64-bit int #1 ........ 0.0096 ........ 0.0149 ...... 0.0060 ........ 0.0045
64-bit int #2 ........ 0.0096 ........ 0.0157 ...... 0.0062 ........ 0.0044
64-bit int #3 ........ 0.0096 ........ 0.0160 ...... 0.0063 ........ 0.0046
64-bit int #4 ........ 0.0097 ........ 0.0157 ...... 0.0061 ........ 0.0044
64-bit float #1 ...... 0.0079 ........ 0.0153 ...... 0.0056 ........ 0.0044
64-bit float #2 ...... 0.0079 ........ 0.0152 ...... 0.0057 ........ 0.0045
64-bit float #3 ...... 0.0079 ........ 0.0155 ...... 0.0057 ........ 0.0044
fix string #1 ........ 0.0010 ........ 0.0045 ...... 0.0071 ........ 0.0044
fix string #2 ........ 0.0048 ........ 0.0075 ...... 0.0070 ........ 0.0060
fix string #3 ........ 0.0048 ........ 0.0086 ...... 0.0068 ........ 0.0060
fix string #4 ........ 0.0050 ........ 0.0088 ...... 0.0070 ........ 0.0059
8-bit string #1 ...... 0.0081 ........ 0.0129 ...... 0.0069 ........ 0.0062
8-bit string #2 ...... 0.0086 ........ 0.0128 ...... 0.0069 ........ 0.0065
8-bit string #3 ...... 0.0086 ........ 0.0126 ...... 0.0115 ........ 0.0065
16-bit string #1 ..... 0.0105 ........ 0.0137 ...... 0.0128 ........ 0.0068
16-bit string #2 ..... 0.1510 ........ 0.1486 ...... 0.1526 ........ 0.1391
32-bit string ........ 0.1517 ........ 0.1475 ...... 0.1504 ........ 0.1370
wide char string #1 .. 0.0044 ........ 0.0085 ...... 0.0067 ........ 0.0057
wide char string #2 .. 0.0081 ........ 0.0125 ...... 0.0069 ........ 0.0063
8-bit binary #1 ........... I ............. I ........... F ............. I
8-bit binary #2 ........... I ............. I ........... F ............. I
8-bit binary #3 ........... I ............. I ........... F ............. I
16-bit binary ............. I ............. I ........... F ............. I
32-bit binary ............. I ............. I ........... F ............. I
fix array #1 ......... 0.0014 ........ 0.0059 ...... 0.0132 ........ 0.0055
fix array #2 ......... 0.0146 ........ 0.0156 ...... 0.0155 ........ 0.0148
fix array #3 ......... 0.0211 ........ 0.0229 ...... 0.0179 ........ 0.0180
16-bit array #1 ...... 0.0673 ........ 0.0498 ...... 0.0343 ........ 0.0388
16-bit array #2 ........... S ............. S ........... S ............. S
32-bit array .............. S ............. S ........... S ............. S
complex array ............. I ............. I ........... F ............. F
fix map #1 ................ I ............. I ........... F ............. I
fix map #2 ........... 0.0148 ........ 0.0180 ...... 0.0156 ........ 0.0179
fix map #3 ................ I ............. I ........... F ............. I
fix map #4 ........... 0.0252 ........ 0.0201 ...... 0.0214 ........ 0.0167
16-bit map #1 ........ 0.1027 ........ 0.0836 ...... 0.0388 ........ 0.0510
16-bit map #2 ............. S ............. S ........... S ............. S
32-bit map ................ S ............. S ........... S ............. S
complex map .......... 0.1104 ........ 0.1010 ...... 0.0556 ........ 0.0602
fixext 1 .................. I ............. I ........... F ............. F
fixext 2 .................. I ............. I ........... F ............. F
fixext 4 .................. I ............. I ........... F ............. F
fixext 8 .................. I ............. I ........... F ............. F
fixext 16 ................. I ............. I ........... F ............. F
8-bit ext ................. I ............. I ........... F ............. F
16-bit ext ................ I ............. I ........... F ............. F
32-bit ext ................ I ............. I ........... F ............. F
32-bit timestamp #1 ....... I ............. I ........... F ............. F
32-bit timestamp #2 ....... I ............. I ........... F ............. F
64-bit timestamp #1 ....... I ............. I ........... F ............. F
64-bit timestamp #2 ....... I ............. I ........... F ............. F
64-bit timestamp #3 ....... I ............. I ........... F ............. F
96-bit timestamp #1 ....... I ............. I ........... F ............. F
96-bit timestamp #2 ....... I ............. I ........... F ............. F
96-bit timestamp #3 ....... I ............. I ........... F ............. F
===========================================================================
Total 0.9642 1.0909 0.8224 0.7213
Skipped 4 4 4 4
Failed 0 0 24 17
Ignored 24 24 0 7
Note that the msgpack extension (v2.1.2) doesn't support ext, bin and UTF-8 str types.
License
The library is released under the MIT License. See the bundled LICENSE file for details.
Author: rybakit
Source Code: https://github.com/rybakit/msgpack.php
License: MIT License
1630743562
A Wrapper for Sembast and SQFlite to Enable Easy
FHIR_DB
This is really just a wrapper around Sembast_SQFLite - so all of the heavy lifting was done by Alex Tekartik. I highly recommend that if you have any questions about working with this package that you take a look at Sembast. He's also just a super nice guy, and even answered a question for me when I was deciding which sembast version to use. As usual, ResoCoder also has a good tutorial.
I have an interest in low-resource settings and thus a specific reason to be able to store data offline. To encourage this use, there are a number of other packages I have created based around the data format FHIR. FHIRยฎ is the registered trademark of HL7 and is used with the permission of HL7. Use of the FHIR trademark does not constitute endorsement of this product by HL7.
Using the Db
So, while not absolutely necessary, I highly recommend that you use some sort of interface class. This adds the benefit of more easily handling errors, plus if you change to a different database in the future, you don't have to change the rest of your app, just the interface.
I've used something like this in my projects:
class IFhirDb {
IFhirDb();
final ResourceDao resourceDao = ResourceDao();
Future<Either<DbFailure, Resource>> save(Resource resource) async {
Resource resultResource;
try {
resultResource = await resourceDao.save(resource);
} catch (error) {
return left(DbFailure.unableToSave(error: error.toString()));
}
return right(resultResource);
}
Future<Either<DbFailure, List<Resource>>> returnListOfSingleResourceType(
String resourceType) async {
List<Resource> resultList;
try {
resultList =
await resourceDao.getAllSortedById(resourceType: resourceType);
} catch (error) {
return left(DbFailure.unableToObtainList(error: error.toString()));
}
return right(resultList);
}
Future<Either<DbFailure, List<Resource>>> searchFunction(
String resourceType, String searchString, String reference) async {
List<Resource> resultList;
try {
resultList =
await resourceDao.searchFor(resourceType, searchString, reference);
} catch (error) {
return left(DbFailure.unableToObtainList(error: error.toString()));
}
return right(resultList);
}
}
I like this because in case there's an i/o error or something, it won't crash your app. Then, you can call this interface in your app like the following:
final patient = Patient(
resourceType: 'Patient',
name: [HumanName(text: 'New Patient Name')],
birthDate: Date(DateTime.now()),
);
final saveResult = await IFhirDb().save(patient);
This will save your newly created patient to the locally embedded database.
IMPORTANT: this database will expect that all previously created resources have an id. When you save a resource, it will check to see if that resource type has already been stored. (Each resource type is saved in it's own store in the database). It will then check if there is an ID. If there's no ID, it will create a new one for that resource (along with metadata on version number and creation time). It will save it, and return the resource. If it already has an ID, it will copy the the old version of the resource into a _history store. It will then update the metadata of the new resource and save that version into the appropriate store for that resource. If, for instance, we have a previously created patient:
{
"resourceType": "Patient",
"id": "fhirfli-294057507-6811107",
"meta": {
"versionId": "1",
"lastUpdated": "2020-10-16T19:41:28.054369Z"
},
"name": [
{
"given": ["New"],
"family": "Patient"
}
],
"birthDate": "2020-10-16"
}
And we update the last name to 'Provider'. The above version of the patient will be kept in _history, while in the 'Patient' store in the db, we will have the updated version:
{
"resourceType": "Patient",
"id": "fhirfli-294057507-6811107",
"meta": {
"versionId": "2",
"lastUpdated": "2020-10-16T19:45:07.316698Z"
},
"name": [
{
"given": ["New"],
"family": "Provider"
}
],
"birthDate": "2020-10-16"
}
This way we can keep track of all previous version of all resources (which is obviously important in medicine).
For most of the interactions (saving, deleting, etc), they work the way you'd expect. The only difference is search. Because Sembast is NoSQL, we can search on any of the fields in a resource. If in our interface class, we have the following function:
Future<Either<DbFailure, List<Resource>>> searchFunction(
String resourceType, String searchString, String reference) async {
List<Resource> resultList;
try {
resultList =
await resourceDao.searchFor(resourceType, searchString, reference);
} catch (error) {
return left(DbFailure.unableToObtainList(error: error.toString()));
}
return right(resultList);
}
You can search for all immunizations of a certain patient:
searchFunction(
'Immunization', 'patient.reference', 'Patient/$patientId');
This function will search through all entries in the 'Immunization' store. It will look at all 'patient.reference' fields, and return any that match 'Patient/$patientId'.
The last thing I'll mention is that this is a password protected db, using AES-256 encryption (although it can also use Salsa20). Anytime you use the db, you have the option of using a password for encryption/decryption. Remember, if you setup the database using encryption, you will only be able to access it using that same password. When you're ready to change the password, you will need to call the update password function. If we again assume we created a change password method in our interface, it might look something like this:
class IFhirDb {
IFhirDb();
final ResourceDao resourceDao = ResourceDao();
...
Future<Either<DbFailure, Unit>> updatePassword(String oldPassword, String newPassword) async {
try {
await resourceDao.updatePw(oldPassword, newPassword);
} catch (error) {
return left(DbFailure.unableToUpdatePassword(error: error.toString()));
}
return right(Unit);
}
You don't have to use a password, and in that case, it will save the db file as plain text. If you want to add a password later, it will encrypt it at that time.
General Store
After using this for a while in an app, I've realized that it needs to be able to store data apart from just FHIR resources, at least on occasion. For this, I've added a second class for all versions of the database called GeneralDao. This is similar to the ResourceDao, but fewer options. So, in order to save something, it would look like this:
await GeneralDao().save('password', {'new':'map'});
await GeneralDao().save('password', {'new':'map'}, 'key');
The difference between these two options is that the first one will generate a key for the map being stored, while the second will store the map using the key provided. Both will return the key after successfully storing the map.
Other functions available include:
// deletes everything in the general store
await GeneralDao().deleteAllGeneral('password');
// delete specific entry
await GeneralDao().delete('password','key');
// returns map with that key
await GeneralDao().find('password', 'key');
FHIRยฎ is a registered trademark of Health Level Seven International (HL7) and its use does not constitute an endorsement of products by HL7ยฎ
Use this package as a library
Depend on it
Run this command:
With Flutter:
$ flutter pub add fhir_dbThis will add a line like this to your package's pubspec.yaml (and run an implicit flutter pub get):
dependencies:
fhir_db: ^0.4.3Alternatively, your editor might support or flutter pub get. Check the docs for your editor to learn more.
Import it
Now in your Dart code, you can use:
import 'package:fhir_db/dstu2.dart';
import 'package:fhir_db/dstu2/fhir_db.dart';
import 'package:fhir_db/dstu2/general_dao.dart';
import 'package:fhir_db/dstu2/resource_dao.dart';
import 'package:fhir_db/encrypt/aes.dart';
import 'package:fhir_db/encrypt/salsa.dart';
import 'package:fhir_db/r4.dart';
import 'package:fhir_db/r4/fhir_db.dart';
import 'package:fhir_db/r4/general_dao.dart';
import 'package:fhir_db/r4/resource_dao.dart';
import 'package:fhir_db/r5.dart';
import 'package:fhir_db/r5/fhir_db.dart';
import 'package:fhir_db/r5/general_dao.dart';
import 'package:fhir_db/r5/resource_dao.dart';
import 'package:fhir_db/stu3.dart';
import 'package:fhir_db/stu3/fhir_db.dart';
import 'package:fhir_db/stu3/general_dao.dart';
import 'package:fhir_db/stu3/resource_dao.dart'; import 'package:fhir/r4.dart';
import 'package:fhir_db/r4.dart';
import 'package:flutter/material.dart';
import 'package:test/test.dart';
Future<void> main() async {
WidgetsFlutterBinding.ensureInitialized();
final resourceDao = ResourceDao();
// await resourceDao.updatePw('newPw', null);
await resourceDao.deleteAllResources(null);
group('Playing with passwords', () {
test('Playing with Passwords', () async {
final patient = Patient(id: Id('1'));
final saved = await resourceDao.save(null, patient);
await resourceDao.updatePw(null, 'newPw');
final search1 = await resourceDao.find('newPw',
resourceType: R4ResourceType.Patient, id: Id('1'));
expect(saved, search1[0]);
await resourceDao.updatePw('newPw', 'newerPw');
final search2 = await resourceDao.find('newerPw',
resourceType: R4ResourceType.Patient, id: Id('1'));
expect(saved, search2[0]);
await resourceDao.updatePw('newerPw', null);
final search3 = await resourceDao.find(null,
resourceType: R4ResourceType.Patient, id: Id('1'));
expect(saved, search3[0]);
await resourceDao.deleteAllResources(null);
});
});
final id = Id('12345');
group('Saving Things:', () {
test('Save Patient', () async {
final humanName = HumanName(family: 'Atreides', given: ['Duke']);
final patient = Patient(id: id, name: [humanName]);
final saved = await resourceDao.save(null, patient);
expect(saved.id, id);
expect((saved as Patient).name?[0], humanName);
});
test('Save Organization', () async {
final organization = Organization(id: id, name: 'FhirFli');
final saved = await resourceDao.save(null, organization);
expect(saved.id, id);
expect((saved as Organization).name, 'FhirFli');
});
test('Save Observation1', () async {
final observation1 = Observation(
id: Id('obs1'),
code: CodeableConcept(text: 'Observation #1'),
effectiveDateTime: FhirDateTime(DateTime(1981, 09, 18)),
);
final saved = await resourceDao.save(null, observation1);
expect(saved.id, Id('obs1'));
expect((saved as Observation).code.text, 'Observation #1');
});
test('Save Observation1 Again', () async {
final observation1 = Observation(
id: Id('obs1'),
code: CodeableConcept(text: 'Observation #1 - Updated'));
final saved = await resourceDao.save(null, observation1);
expect(saved.id, Id('obs1'));
expect((saved as Observation).code.text, 'Observation #1 - Updated');
expect(saved.meta?.versionId, Id('2'));
});
test('Save Observation2', () async {
final observation2 = Observation(
id: Id('obs2'),
code: CodeableConcept(text: 'Observation #2'),
effectiveDateTime: FhirDateTime(DateTime(1981, 09, 18)),
);
final saved = await resourceDao.save(null, observation2);
expect(saved.id, Id('obs2'));
expect((saved as Observation).code.text, 'Observation #2');
});
test('Save Observation3', () async {
final observation3 = Observation(
id: Id('obs3'),
code: CodeableConcept(text: 'Observation #3'),
effectiveDateTime: FhirDateTime(DateTime(1981, 09, 18)),
);
final saved = await resourceDao.save(null, observation3);
expect(saved.id, Id('obs3'));
expect((saved as Observation).code.text, 'Observation #3');
});
});
group('Finding Things:', () {
test('Find 1st Patient', () async {
final search = await resourceDao.find(null,
resourceType: R4ResourceType.Patient, id: id);
final humanName = HumanName(family: 'Atreides', given: ['Duke']);
expect(search.length, 1);
expect((search[0] as Patient).name?[0], humanName);
});
test('Find 3rd Observation', () async {
final search = await resourceDao.find(null,
resourceType: R4ResourceType.Observation, id: Id('obs3'));
expect(search.length, 1);
expect(search[0].id, Id('obs3'));
expect((search[0] as Observation).code.text, 'Observation #3');
});
test('Find All Observations', () async {
final search = await resourceDao.getResourceType(
null,
resourceTypes: [R4ResourceType.Observation],
);
expect(search.length, 3);
final idList = [];
for (final obs in search) {
idList.add(obs.id.toString());
}
expect(idList.contains('obs1'), true);
expect(idList.contains('obs2'), true);
expect(idList.contains('obs3'), true);
});
test('Find All (non-historical) Resources', () async {
final search = await resourceDao.getAll(null);
expect(search.length, 5);
final patList = search.toList();
final orgList = search.toList();
final obsList = search.toList();
patList.retainWhere(
(resource) => resource.resourceType == R4ResourceType.Patient);
orgList.retainWhere(
(resource) => resource.resourceType == R4ResourceType.Organization);
obsList.retainWhere(
(resource) => resource.resourceType == R4ResourceType.Observation);
expect(patList.length, 1);
expect(orgList.length, 1);
expect(obsList.length, 3);
});
});
group('Deleting Things:', () {
test('Delete 2nd Observation', () async {
await resourceDao.delete(
null, null, R4ResourceType.Observation, Id('obs2'), null, null);
final search = await resourceDao.getResourceType(
null,
resourceTypes: [R4ResourceType.Observation],
);
expect(search.length, 2);
final idList = [];
for (final obs in search) {
idList.add(obs.id.toString());
}
expect(idList.contains('obs1'), true);
expect(idList.contains('obs2'), false);
expect(idList.contains('obs3'), true);
});
test('Delete All Observations', () async {
await resourceDao.deleteSingleType(null,
resourceType: R4ResourceType.Observation);
final search = await resourceDao.getAll(null);
expect(search.length, 2);
final patList = search.toList();
final orgList = search.toList();
patList.retainWhere(
(resource) => resource.resourceType == R4ResourceType.Patient);
orgList.retainWhere(
(resource) => resource.resourceType == R4ResourceType.Organization);
expect(patList.length, 1);
expect(patList.length, 1);
});
test('Delete All Resources', () async {
await resourceDao.deleteAllResources(null);
final search = await resourceDao.getAll(null);
expect(search.length, 0);
});
});
group('Password - Saving Things:', () {
test('Save Patient', () async {
await resourceDao.updatePw(null, 'newPw');
final humanName = HumanName(family: 'Atreides', given: ['Duke']);
final patient = Patient(id: id, name: [humanName]);
final saved = await resourceDao.save('newPw', patient);
expect(saved.id, id);
expect((saved as Patient).name?[0], humanName);
});
test('Save Organization', () async {
final organization = Organization(id: id, name: 'FhirFli');
final saved = await resourceDao.save('newPw', organization);
expect(saved.id, id);
expect((saved as Organization).name, 'FhirFli');
});
test('Save Observation1', () async {
final observation1 = Observation(
id: Id('obs1'),
code: CodeableConcept(text: 'Observation #1'),
effectiveDateTime: FhirDateTime(DateTime(1981, 09, 18)),
);
final saved = await resourceDao.save('newPw', observation1);
expect(saved.id, Id('obs1'));
expect((saved as Observation).code.text, 'Observation #1');
});
test('Save Observation1 Again', () async {
final observation1 = Observation(
id: Id('obs1'),
code: CodeableConcept(text: 'Observation #1 - Updated'));
final saved = await resourceDao.save('newPw', observation1);
expect(saved.id, Id('obs1'));
expect((saved as Observation).code.text, 'Observation #1 - Updated');
expect(saved.meta?.versionId, Id('2'));
});
test('Save Observation2', () async {
final observation2 = Observation(
id: Id('obs2'),
code: CodeableConcept(text: 'Observation #2'),
effectiveDateTime: FhirDateTime(DateTime(1981, 09, 18)),
);
final saved = await resourceDao.save('newPw', observation2);
expect(saved.id, Id('obs2'));
expect((saved as Observation).code.text, 'Observation #2');
});
test('Save Observation3', () async {
final observation3 = Observation(
id: Id('obs3'),
code: CodeableConcept(text: 'Observation #3'),
effectiveDateTime: FhirDateTime(DateTime(1981, 09, 18)),
);
final saved = await resourceDao.save('newPw', observation3);
expect(saved.id, Id('obs3'));
expect((saved as Observation).code.text, 'Observation #3');
});
});
group('Password - Finding Things:', () {
test('Find 1st Patient', () async {
final search = await resourceDao.find('newPw',
resourceType: R4ResourceType.Patient, id: id);
final humanName = HumanName(family: 'Atreides', given: ['Duke']);
expect(search.length, 1);
expect((search[0] as Patient).name?[0], humanName);
});
test('Find 3rd Observation', () async {
final search = await resourceDao.find('newPw',
resourceType: R4ResourceType.Observation, id: Id('obs3'));
expect(search.length, 1);
expect(search[0].id, Id('obs3'));
expect((search[0] as Observation).code.text, 'Observation #3');
});
test('Find All Observations', () async {
final search = await resourceDao.getResourceType(
'newPw',
resourceTypes: [R4ResourceType.Observation],
);
expect(search.length, 3);
final idList = [];
for (final obs in search) {
idList.add(obs.id.toString());
}
expect(idList.contains('obs1'), true);
expect(idList.contains('obs2'), true);
expect(idList.contains('obs3'), true);
});
test('Find All (non-historical) Resources', () async {
final search = await resourceDao.getAll('newPw');
expect(search.length, 5);
final patList = search.toList();
final orgList = search.toList();
final obsList = search.toList();
patList.retainWhere(
(resource) => resource.resourceType == R4ResourceType.Patient);
orgList.retainWhere(
(resource) => resource.resourceType == R4ResourceType.Organization);
obsList.retainWhere(
(resource) => resource.resourceType == R4ResourceType.Observation);
expect(patList.length, 1);
expect(orgList.length, 1);
expect(obsList.length, 3);
});
});
group('Password - Deleting Things:', () {
test('Delete 2nd Observation', () async {
await resourceDao.delete(
'newPw', null, R4ResourceType.Observation, Id('obs2'), null, null);
final search = await resourceDao.getResourceType(
'newPw',
resourceTypes: [R4ResourceType.Observation],
);
expect(search.length, 2);
final idList = [];
for (final obs in search) {
idList.add(obs.id.toString());
}
expect(idList.contains('obs1'), true);
expect(idList.contains('obs2'), false);
expect(idList.contains('obs3'), true);
});
test('Delete All Observations', () async {
await resourceDao.deleteSingleType('newPw',
resourceType: R4ResourceType.Observation);
final search = await resourceDao.getAll('newPw');
expect(search.length, 2);
final patList = search.toList();
final orgList = search.toList();
patList.retainWhere(
(resource) => resource.resourceType == R4ResourceType.Patient);
orgList.retainWhere(
(resource) => resource.resourceType == R4ResourceType.Organization);
expect(patList.length, 1);
expect(patList.length, 1);
});
test('Delete All Resources', () async {
await resourceDao.deleteAllResources('newPw');
final search = await resourceDao.getAll('newPw');
expect(search.length, 0);
await resourceDao.updatePw('newPw', null);
});
});
} Download Details:
Author: MayJuun
Source Code: https://github.com/MayJuun/fhir/tree/main/fhir_db
1661577180
Swift Tips: A Collection Useful Tips for The Swift Language
SwiftTips
The following is a collection of tips I find to be useful when working with the Swift language. More content is available on my Twitter account!
Property Wrappers as Debugging Tools
Property Wrappers allow developers to wrap properties with specific behaviors, that will be seamlessly triggered whenever the properties are accessed.
While their primary use case is to implement business logic within our apps, it's also possible to use Property Wrappers as debugging tools!
For example, we could build a wrapper called @History, that would be added to a property while debugging and would keep track of all the values set to this property.
import Foundation
@propertyWrapper
struct History<Value> {
private var value: Value
private(set) var history: [Value] = []
init(wrappedValue: Value) {
self.value = wrappedValue
}
var wrappedValue: Value {
get { value }
set {
history.append(value)
value = newValue
}
}
var projectedValue: Self {
return self
}
}
// We can then decorate our business code
// with the `@History` wrapper
struct User {
@History var name: String = ""
}
var user = User()
// All the existing call sites will still
// compile, without the need for any change
user.name = "John"
user.name = "Jane"
// But now we can also access an history of
// all the previous values!
user.$name.history // ["", "John"]
Localization through String interpolation
Swift 5 gave us the possibility to define our own custom String interpolation methods.
This feature can be used to power many use cases, but there is one that is guaranteed to make sense in most projects: localizing user-facing strings.
import Foundation
extension String.StringInterpolation {
mutating func appendInterpolation(localized key: String, _ args: CVarArg...) {
let localized = String(format: NSLocalizedString(key, comment: ""), arguments: args)
appendLiteral(localized)
}
}
/*
Let's assume that this is the content of our Localizable.strings:
"welcome.screen.greetings" = "Hello %@!";
*/
let userName = "John"
print("\(localized: "welcome.screen.greetings", userName)") // Hello John!
Implementing pseudo-inheritance between structs
If youโve always wanted to use some kind of inheritance mechanism for your structs, Swift 5.1 is going to make you very happy!
Using the new KeyPath-based dynamic member lookup, you can implement some pseudo-inheritance, where a type inherits the API of another one ๐
(However, be careful, Iโm definitely not advocating inheritance as a go-to solution ๐)
import Foundation
protocol Inherits {
associatedtype SuperType
var `super`: SuperType { get }
}
extension Inherits {
subscript<T>(dynamicMember keyPath: KeyPath<SuperType, T>) -> T {
return self.`super`[keyPath: keyPath]
}
}
struct Person {
let name: String
}
@dynamicMemberLookup
struct User: Inherits {
let `super`: Person
let login: String
let password: String
}
let user = User(super: Person(name: "John Appleseed"), login: "Johnny", password: "1234")
user.name // "John Appleseed"
user.login // "Johnny"
Composing NSAttributedString through a Function Builder
Swift 5.1 introduced Function Builders: a great tool for building custom DSL syntaxes, like SwiftUI. However, one doesn't need to be building a full-fledged DSL in order to leverage them.
For example, it's possible to write a simple Function Builder, whose job will be to compose together individual instances of NSAttributedString through a nicer syntax than the standard API.
import UIKit
@_functionBuilder
class NSAttributedStringBuilder {
static func buildBlock(_ components: NSAttributedString...) -> NSAttributedString {
let result = NSMutableAttributedString(string: "")
return components.reduce(into: result) { (result, current) in result.append(current) }
}
}
extension NSAttributedString {
class func composing(@NSAttributedStringBuilder _ parts: () -> NSAttributedString) -> NSAttributedString {
return parts()
}
}
let result = NSAttributedString.composing {
NSAttributedString(string: "Hello",
attributes: [.font: UIFont.systemFont(ofSize: 24),
.foregroundColor: UIColor.red])
NSAttributedString(string: " world!",
attributes: [.font: UIFont.systemFont(ofSize: 20),
.foregroundColor: UIColor.orange])
}
Using switch and if as expressions
Contrary to other languages, like Kotlin, Swift does not allow switch and if to be used as expressions. Meaning that the following code is not valid Swift:
let constant = if condition {
someValue
} else {
someOtherValue
}
A common solution to this problem is to wrap the if or switch statement within a closure, that will then be immediately called. While this approach does manage to achieve the desired goal, it makes for a rather poor syntax.
To avoid the ugly trailing () and improve on the readability, you can define a resultOf function, that will serve the exact same purpose, in a more elegant way.
import Foundation
func resultOf<T>(_ code: () -> T) -> T {
return code()
}
let randomInt = Int.random(in: 0...3)
let spelledOut: String = resultOf {
switch randomInt {
case 0:
return "Zero"
case 1:
return "One"
case 2:
return "Two"
case 3:
return "Three"
default:
return "Out of range"
}
}
print(spelledOut)
Avoiding double negatives within guard statements
A guard statement is a very convenient way for the developer to assert that a condition is met, in order for the execution of the program to keep going.
However, since the body of a guard statement is meant to be executed when the condition evaluates to false, the use of the negation (!) operator within the condition of a guard statement can make the code hard to read, as it becomes a double negative.
A nice trick to avoid such double negatives is to encapsulate the use of the ! operator within a new property or function, whose name does not include a negative.
import Foundation
extension Collection {
var hasElements: Bool {
return !isEmpty
}
}
let array = Bool.random() ? [1, 2, 3] : []
guard array.hasElements else { fatalError("array was empty") }
print(array)
Defining a custom init without loosing the compiler-generated one
It's common knowledge for Swift developers that, when you define a struct, the compiler is going to automatically generate a memberwise init for you. That is, unless you also define an init of your own. Because then, the compiler won't generate any memberwise init.
Yet, there are many instances where we might enjoy the opportunity to get both. As it turns out, this goal is quite easy to achieve: you just need to define your own init in an extension rather than inside the type definition itself.
import Foundation
struct Point {
let x: Int
let y: Int
}
extension Point {
init() {
x = 0
y = 0
}
}
let usingDefaultInit = Point(x: 4, y: 3)
let usingCustomInit = Point()
Implementing a namespace through an empty enum
Swift does not really have an out-of-the-box support of namespaces. One could argue that a Swift module can be seen as a namespace, but creating a dedicated Framework for this sole purpose can legitimately be regarded as overkill.
Some developers have taken the habit to use a struct which only contains static fields to implement a namespace. While this does the job, it requires us to remember to implement an empty private init(), because it wouldn't make sense for such a struct to be instantiated.
It's actually possible to take this approach one step further, by replacing the struct with an enum. While it might seem weird to have an enum with no case, it's actually a very idiomatic way to declare a type that cannot be instantiated.
import Foundation
enum NumberFormatterProvider {
static var currencyFormatter: NumberFormatter {
let formatter = NumberFormatter()
formatter.numberStyle = .currency
formatter.roundingIncrement = 0.01
return formatter
}
static var decimalFormatter: NumberFormatter {
let formatter = NumberFormatter()
formatter.numberStyle = .decimal
formatter.decimalSeparator = ","
return formatter
}
}
NumberFormatterProvider() // โ impossible to instantiate by mistake
NumberFormatterProvider.currencyFormatter.string(from: 2.456) // $2.46
NumberFormatterProvider.decimalFormatter.string(from: 2.456) // 2,456
Using Never to represent impossible code paths
Never is quite a peculiar type in the Swift Standard Library: it is defined as an empty enum enum Never { }.
While this might seem odd at first glance, it actually yields a very interesting property: it makes it a type that cannot be constructed (i.e. it possesses no instances).
This way, Never can be used as a generic parameter to let the compiler know that a particular feature will not be used.
import Foundation
enum Result<Value, Error> {
case success(value: Value)
case failure(error: Error)
}
func willAlwaysSucceed(_ completion: @escaping ((Result<String, Never>) -> Void)) {
completion(.success(value: "Call was successful"))
}
willAlwaysSucceed( { result in
switch result {
case .success(let value):
print(value)
// the compiler knows that the `failure` case cannot happen
// so it doesn't require us to handle it.
}
})
Providing a default value to a Decodable enum
Swift's Codable framework does a great job at seamlessly decoding entities from a JSON stream. However, when we integrate web-services, we are sometimes left to deal with JSONs that require behaviors that Codable does not provide out-of-the-box.
For instance, we might have a string-based or integer-based enum, and be required to set it to a default value when the data found in the JSON does not match any of its cases.
We might be tempted to implement this via an extensive switch statement over all the possible cases, but there is a much shorter alternative through the initializer init?(rawValue:):
import Foundation
enum State: String, Decodable {
case active
case inactive
case undefined
init(from decoder: Decoder) throws {
let container = try decoder.singleValueContainer()
let decodedString = try container.decode(String.self)
self = State(rawValue: decodedString) ?? .undefined
}
}
let data = """
["active", "inactive", "foo"]
""".data(using: .utf8)!
let decoded = try! JSONDecoder().decode([State].self, from: data)
print(decoded) // [State.active, State.inactive, State.undefined]
Another lightweight dependency injection through default values for function parameters
Dependency injection boils down to a simple idea: when an object requires a dependency, it shouldn't create it by itself, but instead it should be given a function that does it for him.
Now the great thing with Swift is that, not only can a function take another function as a parameter, but that parameter can also be given a default value.
When you combine both those features, you can end up with a dependency injection pattern that is both lightweight on boilerplate, but also type safe.
import Foundation
protocol Service {
func call() -> String
}
class ProductionService: Service {
func call() -> String {
return "This is the production"
}
}
class MockService: Service {
func call() -> String {
return "This is a mock"
}
}
typealias Provider<T> = () -> T
class Controller {
let service: Service
init(serviceProvider: Provider<Service> = { return ProductionService() }) {
self.service = serviceProvider()
}
func work() {
print(service.call())
}
}
let productionController = Controller()
productionController.work() // prints "This is the production"
let mockedController = Controller(serviceProvider: { return MockService() })
mockedController.work() // prints "This is a mock"
Lightweight dependency injection through protocol-oriented programming
Singletons are pretty bad. They make your architecture rigid and tightly coupled, which then results in your code being hard to test and refactor. Instead of using singletons, your code should rely on dependency injection, which is a much more architecturally sound approach.
But singletons are so easy to use, and dependency injection requires us to do extra-work. So maybe, for simple situations, we could find an in-between solution?
One possible solution is to rely on one of Swift's most know features: protocol-oriented programming. Using a protocol, we declare and access our dependency. We then store it in a private singleton, and perform the injection through an extension of said protocol.
This way, our code will indeed be decoupled from its dependency, while at the same time keeping the boilerplate to a minimum.
import Foundation
protocol Formatting {
var formatter: NumberFormatter { get }
}
private let sharedFormatter: NumberFormatter = {
let sharedFormatter = NumberFormatter()
sharedFormatter.numberStyle = .currency
return sharedFormatter
}()
extension Formatting {
var formatter: NumberFormatter { return sharedFormatter }
}
class ViewModel: Formatting {
var displayableAmount: String?
func updateDisplay(to amount: Double) {
displayableAmount = formatter.string(for: amount)
}
}
let viewModel = ViewModel()
viewModel.updateDisplay(to: 42000.45)
viewModel.displayableAmount // "$42,000.45"
Getting rid of overabundant [weak self] and guard
Callbacks are a part of almost all iOS apps, and as frameworks such as RxSwift keep gaining in popularity, they become ever more present in our codebase.
Seasoned Swift developers are aware of the potential memory leaks that @escaping callbacks can produce, so they make real sure to always use [weak self], whenever they need to use self inside such a context. And when they need to have self be non-optional, they then add a guard statement along.
Consequently, this syntax of a [weak self] followed by a guard rapidly tends to appear everywhere in the codebase. The good thing is that, through a little protocol-oriented trick, it's actually possible to get rid of this tedious syntax, without loosing any of its benefits!
import Foundation
import PlaygroundSupport
PlaygroundPage.current.needsIndefiniteExecution = true
protocol Weakifiable: class { }
extension Weakifiable {
func weakify(_ code: @escaping (Self) -> Void) -> () -> Void {
return { [weak self] in
guard let self = self else { return }
code(self)
}
}
func weakify<T>(_ code: @escaping (T, Self) -> Void) -> (T) -> Void {
return { [weak self] arg in
guard let self = self else { return }
code(arg, self)
}
}
}
extension NSObject: Weakifiable { }
class Producer: NSObject {
deinit {
print("deinit Producer")
}
private var handler: (Int) -> Void = { _ in }
func register(handler: @escaping (Int) -> Void) {
self.handler = handler
DispatchQueue.main.asyncAfter(deadline: .now() + 1.0, execute: { self.handler(42) })
}
}
class Consumer: NSObject {
deinit {
print("deinit Consumer")
}
let producer = Producer()
func consume() {
producer.register(handler: weakify { result, strongSelf in
strongSelf.handle(result)
})
}
private func handle(_ result: Int) {
print("๐ \(result)")
}
}
var consumer: Consumer? = Consumer()
consumer?.consume()
DispatchQueue.main.asyncAfter(deadline: .now() + 2.0, execute: { consumer = nil })
// This code prints:
// ๐ 42
// deinit Consumer
// deinit Producer
Solving callback hell with function composition
Asynchronous functions are a big part of iOS APIs, and most developers are familiar with the challenge they pose when one needs to sequentially call several asynchronous APIs.
This often results in callbacks being nested into one another, a predicament often referred to as callback hell.
Many third-party frameworks are able to tackle this issue, for instance RxSwift or PromiseKit. Yet, for simple instances of the problem, there is no need to use such big guns, as it can actually be solved with simple function composition.
import Foundation
typealias CompletionHandler<Result> = (Result?, Error?) -> Void
infix operator ~>: MultiplicationPrecedence
func ~> <T, U>(_ first: @escaping (CompletionHandler<T>) -> Void, _ second: @escaping (T, CompletionHandler<U>) -> Void) -> (CompletionHandler<U>) -> Void {
return { completion in
first({ firstResult, error in
guard let firstResult = firstResult else { completion(nil, error); return }
second(firstResult, { (secondResult, error) in
completion(secondResult, error)
})
})
}
}
func ~> <T, U>(_ first: @escaping (CompletionHandler<T>) -> Void, _ transform: @escaping (T) -> U) -> (CompletionHandler<U>) -> Void {
return { completion in
first({ result, error in
guard let result = result else { completion(nil, error); return }
completion(transform(result), nil)
})
}
}
func service1(_ completionHandler: CompletionHandler<Int>) {
completionHandler(42, nil)
}
func service2(arg: String, _ completionHandler: CompletionHandler<String>) {
completionHandler("๐ \(arg)", nil)
}
let chainedServices = service1
~> { int in return String(int / 2) }
~> service2
chainedServices({ result, _ in
guard let result = result else { return }
print(result) // Prints: ๐ 21
})
Transform an asynchronous function into a synchronous one
Asynchronous functions are a great way to deal with future events without blocking a thread. Yet, there are times where we would like them to behave in exactly such a blocking way.
Think about writing unit tests and using mocked network calls. You will need to add complexity to your test in order to deal with asynchronous functions, whereas synchronous ones would be much easier to manage.
Thanks to Swift proficiency in the functional paradigm, it is possible to write a function whose job is to take an asynchronous function and transform it into a synchronous one.
import Foundation
func makeSynchrone<A, B>(_ asyncFunction: @escaping (A, (B) -> Void) -> Void) -> (A) -> B {
return { arg in
let lock = NSRecursiveLock()
var result: B? = nil
asyncFunction(arg) {
result = $0
lock.unlock()
}
lock.lock()
return result!
}
}
func myAsyncFunction(arg: Int, completionHandler: (String) -> Void) {
completionHandler("๐ \(arg)")
}
let syncFunction = makeSynchrone(myAsyncFunction)
print(syncFunction(42)) // prints ๐ 42
Using KeyPaths instead of closures
Closures are a great way to interact with generic APIs, for instance APIs that allow to manipulate data structures through the use of generic functions, such as filter() or sorted().
The annoying part is that closures tend to clutter your code with many instances of {, } and $0, which can quickly undermine its readably.
A nice alternative for a cleaner syntax is to use a KeyPath instead of a closure, along with an operator that will deal with transforming the provided KeyPath in a closure.
import Foundation
prefix operator ^
prefix func ^ <Element, Attribute>(_ keyPath: KeyPath<Element, Attribute>) -> (Element) -> Attribute {
return { element in element[keyPath: keyPath] }
}
struct MyData {
let int: Int
let string: String
}
let data = [MyData(int: 2, string: "Foo"), MyData(int: 4, string: "Bar")]
data.map(^\.int) // [2, 4]
data.map(^\.string) // ["Foo", "Bar"]
Bringing some type-safety to a userInfo Dictionary
Many iOS APIs still rely on a userInfo Dictionary to handle use-case specific data. This Dictionary usually stores untyped values, and is declared as follows: [String: Any] (or sometimes [AnyHashable: Any].
Retrieving data from such a structure will involve some conditional casting (via the as? operator), which is prone to both errors and repetitions. Yet, by introducing a custom subscript, it's possible to encapsulate all the tedious logic, and end-up with an easier and more robust API.
import Foundation
typealias TypedUserInfoKey<T> = (key: String, type: T.Type)
extension Dictionary where Key == String, Value == Any {
subscript<T>(_ typedKey: TypedUserInfoKey<T>) -> T? {
return self[typedKey.key] as? T
}
}
let userInfo: [String : Any] = ["Foo": 4, "Bar": "forty-two"]
let integerTypedKey = TypedUserInfoKey(key: "Foo", type: Int.self)
let intValue = userInfo[integerTypedKey] // returns 4
type(of: intValue) // returns Int?
let stringTypedKey = TypedUserInfoKey(key: "Bar", type: String.self)
let stringValue = userInfo[stringTypedKey] // returns "forty-two"
type(of: stringValue) // returns String?
Lightweight data-binding for an MVVM implementation
MVVM is a great pattern to separate business logic from presentation logic. The main challenge to make it work, is to define a mechanism for the presentation layer to be notified of model updates.
RxSwift is a perfect choice to solve such a problem. Yet, some developers don't feel confortable with leveraging a third-party library for such a central part of their architecture.
For those situation, it's possible to define a lightweight Variable type, that will make the MVVM pattern very easy to use!
import Foundation
class Variable<Value> {
var value: Value {
didSet {
onUpdate?(value)
}
}
var onUpdate: ((Value) -> Void)? {
didSet {
onUpdate?(value)
}
}
init(_ value: Value, _ onUpdate: ((Value) -> Void)? = nil) {
self.value = value
self.onUpdate = onUpdate
self.onUpdate?(value)
}
}
let variable: Variable<String?> = Variable(nil)
variable.onUpdate = { data in
if let data = data {
print(data)
}
}
variable.value = "Foo"
variable.value = "Bar"
// prints:
// Foo
// Bar
Using typealias to its fullest
The keyword typealias allows developers to give a new name to an already existing type. For instance, Swift defines Void as a typealias of (), the empty tuple.
But a less known feature of this mechanism is that it allows to assign concrete types for generic parameters, or to rename them. This can help make the semantics of generic types much clearer, when used in specific use cases.
import Foundation
enum Either<Left, Right> {
case left(Left)
case right(Right)
}
typealias Result<Value> = Either<Value, Error>
typealias IntOrString = Either<Int, String>
Writing an interruptible overload of forEach
Iterating through objects via the forEach(_:) method is a great alternative to the classic for loop, as it allows our code to be completely oblivious of the iteration logic. One limitation, however, is that forEach(_:) does not allow to stop the iteration midway.
Taking inspiration from the Objective-C implementation, we can write an overload that will allow the developer to stop the iteration, if needed.
import Foundation
extension Sequence {
func forEach(_ body: (Element, _ stop: inout Bool) throws -> Void) rethrows {
var stop = false
for element in self {
try body(element, &stop)
if stop {
return
}
}
}
}
["Foo", "Bar", "FooBar"].forEach { element, stop in
print(element)
stop = (element == "Bar")
}
// Prints:
// Foo
// Bar
Optimizing the use of reduce()
Functional programing is a great way to simplify a codebase. For instance, reduce is an alternative to the classic for loop, without most the boilerplate. Unfortunately, simplicity often comes at the price of performance.
Consider that you want to remove duplicate values from a Sequence. While reduce() is a perfectly fine way to express this computation, the performance will be sub optimal, because of all the unnecessary Array copying that will happen every time its closure gets called.
That's when reduce(into:_:) comes into play. This version of reduce leverages the capacities of copy-on-write type (such as Array or Dictionnary) in order to avoid unnecessary copying, which results in a great performance boost.
import Foundation
func time(averagedExecutions: Int = 1, _ code: () -> Void) {
let start = Date()
for _ in 0..<averagedExecutions { code() }
let end = Date()
let duration = end.timeIntervalSince(start) / Double(averagedExecutions)
print("time: \(duration)")
}
let data = (1...1_000).map { _ in Int(arc4random_uniform(256)) }
// runs in 0.63s
time {
let noDuplicates: [Int] = data.reduce([], { $0.contains($1) ? $0 : $0 + [$1] })
}
// runs in 0.15s
time {
let noDuplicates: [Int] = data.reduce(into: [], { if !$0.contains($1) { $0.append($1) } } )
}
Avoiding hardcoded reuse identifiers
UI components such as UITableView and UICollectionView rely on reuse identifiers in order to efficiently recycle the views they display. Often, those reuse identifiers take the form of a static hardcoded String, that will be used for every instance of their class.
Through protocol-oriented programing, it's possible to avoid those hardcoded values, and instead use the name of the type as a reuse identifier.
import Foundation
import UIKit
protocol Reusable {
static var reuseIdentifier: String { get }
}
extension Reusable {
static var reuseIdentifier: String {
return String(describing: self)
}
}
extension UITableViewCell: Reusable { }
extension UITableView {
func register<T: UITableViewCell>(_ class: T.Type) {
register(`class`, forCellReuseIdentifier: T.reuseIdentifier)
}
func dequeueReusableCell<T: UITableViewCell>(for indexPath: IndexPath) -> T {
return dequeueReusableCell(withIdentifier: T.reuseIdentifier, for: indexPath) as! T
}
}
class MyCell: UITableViewCell { }
let tableView = UITableView()
tableView.register(MyCell.self)
let myCell: MyCell = tableView.dequeueReusableCell(for: [0, 0])
Defining a union type
The C language has a construct called union, that allows a single variable to hold values from different types. While Swift does not provide such a construct, it provides enums with associated values, which allows us to define a type called Either that implements a union of two types.
import Foundation
enum Either<A, B> {
case left(A)
case right(B)
func either(ifLeft: ((A) -> Void)? = nil, ifRight: ((B) -> Void)? = nil) {
switch self {
case let .left(a):
ifLeft?(a)
case let .right(b):
ifRight?(b)
}
}
}
extension Bool { static func random() -> Bool { return arc4random_uniform(2) == 0 } }
var intOrString: Either<Int, String> = Bool.random() ? .left(2) : .right("Foo")
intOrString.either(ifLeft: { print($0 + 1) }, ifRight: { print($0 + "Bar") })
If you're interested by this kind of data structure, I strongly recommend that you learn more about Algebraic Data Types.
Asserting that classes have associated NIBs and vice-versa
Most of the time, when we create a .xib file, we give it the same name as its associated class. From that, if we later refactor our code and rename such a class, we run the risk of forgetting to rename the associated .xib.
While the error will often be easy to catch, if the .xib is used in a remote section of its app, it might go unnoticed for sometime. Fortunately it's possible to build custom test predicates that will assert that 1) for a given class, there exists a .nib with the same name in a given Bundle, 2) for all the .nib in a given Bundle, there exists a class with the same name.
import XCTest
public func XCTAssertClassHasNib(_ class: AnyClass, bundle: Bundle, file: StaticString = #file, line: UInt = #line) {
let associatedNibURL = bundle.url(forResource: String(describing: `class`), withExtension: "nib")
XCTAssertNotNil(associatedNibURL, "Class \"\(`class`)\" has no associated nib file", file: file, line: line)
}
public func XCTAssertNibHaveClasses(_ bundle: Bundle, file: StaticString = #file, line: UInt = #line) {
guard let bundleName = bundle.infoDictionary?["CFBundleName"] as? String,
let basePath = bundle.resourcePath,
let enumerator = FileManager.default.enumerator(at: URL(fileURLWithPath: basePath),
includingPropertiesForKeys: nil,
options: [.skipsHiddenFiles, .skipsSubdirectoryDescendants]) else { return }
var nibFilesURLs = [URL]()
for case let fileURL as URL in enumerator {
if fileURL.pathExtension.uppercased() == "NIB" {
nibFilesURLs.append(fileURL)
}
}
nibFilesURLs.map { $0.lastPathComponent }
.compactMap { $0.split(separator: ".").first }
.map { String($0) }
.forEach {
let associatedClass: AnyClass? = bundle.classNamed("\(bundleName).\($0)")
XCTAssertNotNil(associatedClass, "File \"\($0).nib\" has no associated class", file: file, line: line)
}
}
XCTAssertClassHasNib(MyFirstTableViewCell.self, bundle: Bundle(for: AppDelegate.self))
XCTAssertClassHasNib(MySecondTableViewCell.self, bundle: Bundle(for: AppDelegate.self))
XCTAssertNibHaveClasses(Bundle(for: AppDelegate.self))
Many thanks Benjamin Lavialle for coming up with the idea behind the second test predicate.
Small footprint type-erasing with functions
Seasoned Swift developers know it: a protocol with associated type (PAT) "can only be used as a generic constraint because it has Self or associated type requirements". When we really need to use a PAT to type a variable, the goto workaround is to use a type-erased wrapper.
While this solution works perfectly, it requires a fair amount of boilerplate code. In instances where we are only interested in exposing one particular function of the PAT, a shorter approach using function types is possible.
import Foundation
import UIKit
protocol Configurable {
associatedtype Model
func configure(with model: Model)
}
typealias Configurator<Model> = (Model) -> ()
extension UILabel: Configurable {
func configure(with model: String) {
self.text = model
}
}
let label = UILabel()
let configurator: Configurator<String> = label.configure
configurator("Foo")
label.text // "Foo"
Performing animations sequentially
UIKit exposes a very powerful and simple API to perform view animations. However, this API can become a little bit quirky to use when we want to perform animations sequentially, because it involves nesting closure within one another, which produces notoriously hard to maintain code.
Nonetheless, it's possible to define a rather simple class, that will expose a really nicer API for this particular use case ๐
import Foundation
import UIKit
class AnimationSequence {
typealias Animations = () -> Void
private let current: Animations
private let duration: TimeInterval
private var next: AnimationSequence? = nil
init(animations: @escaping Animations, duration: TimeInterval) {
self.current = animations
self.duration = duration
}
@discardableResult func append(animations: @escaping Animations, duration: TimeInterval) -> AnimationSequence {
var lastAnimation = self
while let nextAnimation = lastAnimation.next {
lastAnimation = nextAnimation
}
lastAnimation.next = AnimationSequence(animations: animations, duration: duration)
return self
}
func run() {
UIView.animate(withDuration: duration, animations: current, completion: { finished in
if finished, let next = self.next {
next.run()
}
})
}
}
var firstView = UIView()
var secondView = UIView()
firstView.alpha = 0
secondView.alpha = 0
AnimationSequence(animations: { firstView.alpha = 1.0 }, duration: 1)
.append(animations: { secondView.alpha = 1.0 }, duration: 0.5)
.append(animations: { firstView.alpha = 0.0 }, duration: 2.0)
.run()
Debouncing a function call
Debouncing is a very useful tool when dealing with UI inputs. Consider a search bar, whose content is used to query an API. It wouldn't make sense to perform a request for every character the user is typing, because as soon as a new character is entered, the result of the previous request has become irrelevant.
Instead, our code will perform much better if we "debounce" the API call, meaning that we will wait until some delay has passed, without the input being modified, before actually performing the call.
import Foundation
func debounced(delay: TimeInterval, queue: DispatchQueue = .main, action: @escaping (() -> Void)) -> () -> Void {
var workItem: DispatchWorkItem?
return {
workItem?.cancel()
workItem = DispatchWorkItem(block: action)
queue.asyncAfter(deadline: .now() + delay, execute: workItem!)
}
}
let debouncedPrint = debounced(delay: 1.0) { print("Action performed!") }
debouncedPrint()
debouncedPrint()
debouncedPrint()
// After a 1 second delay, this gets
// printed only once to the console:
// Action performed!
Providing useful operators for Optional booleans
When we need to apply the standard boolean operators to Optional booleans, we often end up with a syntax unnecessarily crowded with unwrapping operations. By taking a cue from the world of three-valued logics, we can define a couple operators that make working with Bool? values much nicer.
import Foundation
func && (lhs: Bool?, rhs: Bool?) -> Bool? {
switch (lhs, rhs) {
case (false, _), (_, false):
return false
case let (unwrapLhs?, unwrapRhs?):
return unwrapLhs && unwrapRhs
default:
return nil
}
}
func || (lhs: Bool?, rhs: Bool?) -> Bool? {
switch (lhs, rhs) {
case (true, _), (_, true):
return true
case let (unwrapLhs?, unwrapRhs?):
return unwrapLhs || unwrapRhs
default:
return nil
}
}
false && nil // false
true && nil // nil
[true, nil, false].reduce(true, &&) // false
nil || true // true
nil || false // nil
[true, nil, false].reduce(false, ||) // true
Removing duplicate values from a Sequence
Transforming a Sequence in order to remove all the duplicate values it contains is a classic use case. To implement it, one could be tempted to transform the Sequence into a Set, then back to an Array. The downside with this approach is that it will not preserve the order of the sequence, which can definitely be a dealbreaker. Using reduce() it is possible to provide a concise implementation that preserves ordering:
import Foundation
extension Sequence where Element: Equatable {
func duplicatesRemoved() -> [Element] {
return reduce([], { $0.contains($1) ? $0 : $0 + [$1] })
}
}
let data = [2, 5, 2, 3, 6, 5, 2]
data.duplicatesRemoved() // [2, 5, 3, 6]
Shorter syntax to deal with optional strings
Optional strings are very common in Swift code, for instance many objects from UIKit expose the text they display as a String?. Many times you will need to manipulate this data as an unwrapped String, with a default value set to the empty string for nil cases.
While the nil-coalescing operator (e.g. ??) is a perfectly fine way to a achieve this goal, defining a computed variable like orEmpty can help a lot in cleaning the syntax.
import Foundation
import UIKit
extension Optional where Wrapped == String {
var orEmpty: String {
switch self {
case .some(let value):
return value
case .none:
return ""
}
}
}
func doesNotWorkWithOptionalString(_ param: String) {
// do something with `param`
}
let label = UILabel()
label.text = "This is some text."
doesNotWorkWithOptionalString(label.text.orEmpty)
Encapsulating background computation and UI update
Every seasoned iOS developers knows it: objects from UIKit can only be accessed from the main thread. Any attempt to access them from a background thread is a guaranteed crash.
Still, running a costly computation on the background, and then using it to update the UI can be a common pattern.
In such cases you can rely on asyncUI to encapsulate all the boilerplate code.
import Foundation
import UIKit
func asyncUI<T>(_ computation: @autoclosure @escaping () -> T, qos: DispatchQoS.QoSClass = .userInitiated, _ completion: @escaping (T) -> Void) {
DispatchQueue.global(qos: qos).async {
let value = computation()
DispatchQueue.main.async {
completion(value)
}
}
}
let label = UILabel()
func costlyComputation() -> Int { return (0..<10_000).reduce(0, +) }
asyncUI(costlyComputation()) { value in
label.text = "\(value)"
}
Retrieving all the necessary data to build a debug view
A debug view, from which any controller of an app can be instantiated and pushed on the navigation stack, has the potential to bring some real value to a development process. A requirement to build such a view is to have a list of all the classes from a given Bundle that inherit from UIViewController. With the following extension, retrieving this list becomes a piece of cake ๐ฐ
import Foundation
import UIKit
import ObjectiveC
extension Bundle {
func viewControllerTypes() -> [UIViewController.Type] {
guard let bundlePath = self.executablePath else { return [] }
var size: UInt32 = 0
var rawClassNames: UnsafeMutablePointer<UnsafePointer<Int8>>!
var parsedClassNames = [String]()
rawClassNames = objc_copyClassNamesForImage(bundlePath, &size)
for index in 0..<size {
let className = rawClassNames[Int(index)]
if let name = NSString.init(utf8String:className) as String?,
NSClassFromString(name) is UIViewController.Type {
parsedClassNames.append(name)
}
}
return parsedClassNames
.sorted()
.compactMap { NSClassFromString($0) as? UIViewController.Type }
}
}
// Fetch all view controller types in UIKit
Bundle(for: UIViewController.self).viewControllerTypes()
I share the credit for this tip with Benoรฎt Caron.
Defining a function to map over dictionaries
Update As it turns out, map is actually a really bad name for this function, because it does not preserve composition of transformations, a property that is required to fit the definition of a real map function.
Surprisingly enough, the standard library doesn't define a map() function for dictionaries that allows to map both keys and values into a new Dictionary. Nevertheless, such a function can be helpful, for instance when converting data across different frameworks.
import Foundation
extension Dictionary {
func map<T: Hashable, U>(_ transform: (Key, Value) throws -> (T, U)) rethrows -> [T: U] {
var result: [T: U] = [:]
for (key, value) in self {
let (transformedKey, transformedValue) = try transform(key, value)
result[transformedKey] = transformedValue
}
return result
}
}
let data = [0: 5, 1: 6, 2: 7]
data.map { ("\($0)", $1 * $1) } // ["2": 49, "0": 25, "1": 36]
A shorter syntax to remove nil values
Swift provides the function compactMap(), that can be used to remove nil values from a Sequence of optionals when calling it with an argument that just returns its parameter (i.e. compactMap { $0 }). Still, for such use cases it would be nice to get rid of the trailing closure.
The implementation isn't as straightforward as your usual extension, but once it has been written, the call site definitely gets cleaner ๐
import Foundation
protocol OptionalConvertible {
associatedtype Wrapped
func asOptional() -> Wrapped?
}
extension Optional: OptionalConvertible {
func asOptional() -> Wrapped? {
return self
}
}
extension Sequence where Element: OptionalConvertible {
func compacted() -> [Element.Wrapped] {
return compactMap { $0.asOptional() }
}
}
let data = [nil, 1, 2, nil, 3, 5, nil, 8, nil]
data.compacted() // [1, 2, 3, 5, 8]
Dealing with expirable values
It might happen that your code has to deal with values that come with an expiration date. In a game, it could be a score multiplier that will only last for 30 seconds. Or it could be an authentication token for an API, with a 15 minutes lifespan. In both instances you can rely on the type Expirable to encapsulate the expiration logic.
import Foundation
struct Expirable<T> {
private var innerValue: T
private(set) var expirationDate: Date
var value: T? {
return hasExpired() ? nil : innerValue
}
init(value: T, expirationDate: Date) {
self.innerValue = value
self.expirationDate = expirationDate
}
init(value: T, duration: Double) {
self.innerValue = value
self.expirationDate = Date().addingTimeInterval(duration)
}
func hasExpired() -> Bool {
return expirationDate < Date()
}
}
let expirable = Expirable(value: 42, duration: 3)
sleep(2)
expirable.value // 42
sleep(2)
expirable.value // nil
I share the credit for this tip with Benoรฎt Caron.
Using parallelism to speed-up map()
Almost all Apple devices able to run Swift code are powered by a multi-core CPU, consequently making a good use of parallelism is a great way to improve code performance. map() is a perfect candidate for such an optimization, because it is almost trivial to define a parallel implementation.
import Foundation
extension Array {
func parallelMap<T>(_ transform: (Element) -> T) -> [T] {
let res = UnsafeMutablePointer<T>.allocate(capacity: count)
DispatchQueue.concurrentPerform(iterations: count) { i in
res[i] = transform(self[i])
}
let finalResult = Array<T>(UnsafeBufferPointer(start: res, count: count))
res.deallocate(capacity: count)
return finalResult
}
}
let array = (0..<1_000).map { $0 }
func work(_ n: Int) -> Int {
return (0..<n).reduce(0, +)
}
array.parallelMap { work($0) }
๐จ Make sure to only use parallelMap() when the transform function actually performs some costly computations. Otherwise performances will be systematically slower than using map(), because of the multithreading overhead.
Measuring execution time with minimum boilerplate
During development of a feature that performs some heavy computations, it can be helpful to measure just how much time a chunk of code takes to run. The time() function is a nice tool for this purpose, because of how simple it is to add and then to remove when it is no longer needed.
import Foundation
func time(averagedExecutions: Int = 1, _ code: () -> Void) {
let start = Date()
for _ in 0..<averagedExecutions { code() }
let end = Date()
let duration = end.timeIntervalSince(start) / Double(averagedExecutions)
print("time: \(duration)")
}
time {
(0...10_000).map { $0 * $0 }
}
// time: 0.183973908424377
Running two pieces of code in parallel
Concurrency is definitely one of those topics were the right encapsulation bears the potential to make your life so much easier. For instance, with this piece of code you can easily launch two computations in parallel, and have the results returned in a tuple.
import Foundation
func parallel<T, U>(_ left: @autoclosure () -> T, _ right: @autoclosure () -> U) -> (T, U) {
var leftRes: T?
var rightRes: U?
DispatchQueue.concurrentPerform(iterations: 2, execute: { id in
if id == 0 {
leftRes = left()
} else {
rightRes = right()
}
})
return (leftRes!, rightRes!)
}
let values = (1...100_000).map { $0 }
let results = parallel(values.map { $0 * $0 }, values.reduce(0, +))
Making good use of #file, #line and #function
Swift exposes three special variables #file, #line and #function, that are respectively set to the name of the current file, line and function. Those variables become very useful when writing custom logging functions or test predicates.
import Foundation
func log(_ message: String, _ file: String = #file, _ line: Int = #line, _ function: String = #function) {
print("[\(file):\(line)] \(function) - \(message)")
}
func foo() {
log("Hello world!")
}
foo() // [MyPlayground.playground:8] foo() - Hello world!
Comparing Optionals through Conditional Conformance
Swift 4.1 has introduced a new feature called Conditional Conformance, which allows a type to implement a protocol only when its generic type also does.
With this addition it becomes easy to let Optional implement Comparable only when Wrapped also implements Comparable:
import Foundation
extension Optional: Comparable where Wrapped: Comparable {
public static func < (lhs: Optional, rhs: Optional) -> Bool {
switch (lhs, rhs) {
case let (lhs?, rhs?):
return lhs < rhs
case (nil, _?):
return true // anything is greater than nil
case (_?, nil):
return false // nil in smaller than anything
case (nil, nil):
return true // nil is not smaller than itself
}
}
}
let data: [Int?] = [8, 4, 3, nil, 12, 4, 2, nil, -5]
data.sorted() // [nil, nil, Optional(-5), Optional(2), Optional(3), Optional(4), Optional(4), Optional(8), Optional(12)]
Safely subscripting a Collection
Any attempt to access an Array beyond its bounds will result in a crash. While it's possible to write conditions such as if index < array.count { array[index] } in order to prevent such crashes, this approach will rapidly become cumbersome.
A great thing is that this condition can be encapsulated in a custom subscript that will work on any Collection:
import Foundation
extension Collection {
subscript (safe index: Index) -> Element? {
return indices.contains(index) ? self[index] : nil
}
}
let data = [1, 3, 4]
data[safe: 1] // Optional(3)
data[safe: 10] // nil
Easier String slicing using ranges
Subscripting a string with a range can be very cumbersome in Swift 4. Let's face it, no one wants to write lines like someString[index(startIndex, offsetBy: 0)..<index(startIndex, offsetBy: 10)] on a regular basis.
Luckily, with the addition of one clever extension, strings can be sliced as easily as arrays ๐
import Foundation
extension String {
public subscript(value: CountableClosedRange<Int>) -> Substring {
get {
return self[index(startIndex, offsetBy: value.lowerBound)...index(startIndex, offsetBy: value.upperBound)]
}
}
public subscript(value: CountableRange<Int>) -> Substring {
get {
return self[index(startIndex, offsetBy: value.lowerBound)..<index(startIndex, offsetBy: value.upperBound)]
}
}
public subscript(value: PartialRangeUpTo<Int>) -> Substring {
get {
return self[..<index(startIndex, offsetBy: value.upperBound)]
}
}
public subscript(value: PartialRangeThrough<Int>) -> Substring {
get {
return self[...index(startIndex, offsetBy: value.upperBound)]
}
}
public subscript(value: PartialRangeFrom<Int>) -> Substring {
get {
return self[index(startIndex, offsetBy: value.lowerBound)...]
}
}
}
let data = "This is a string!"
data[..<4] // "This"
data[5..<9] // "is a"
data[10...] // "string!"
Concise syntax for sorting using a KeyPath
By using a KeyPath along with a generic type, a very clean and concise syntax for sorting data can be implemented:
import Foundation
extension Sequence {
func sorted<T: Comparable>(by attribute: KeyPath<Element, T>) -> [Element] {
return sorted(by: { $0[keyPath: attribute] < $1[keyPath: attribute] })
}
}
let data = ["Some", "words", "of", "different", "lengths"]
data.sorted(by: \.count) // ["of", "Some", "words", "lengths", "different"]
If you like this syntax, make sure to checkout KeyPathKit!
Manufacturing cache-efficient versions of pure functions
By capturing a local variable in a returned closure, it is possible to manufacture cache-efficient versions of pure functions. Be careful though, this trick only works with non-recursive function!
import Foundation
func cached<In: Hashable, Out>(_ f: @escaping (In) -> Out) -> (In) -> Out {
var cache = [In: Out]()
return { (input: In) -> Out in
if let cachedValue = cache[input] {
return cachedValue
} else {
let result = f(input)
cache[input] = result
return result
}
}
}
let cachedCos = cached { (x: Double) in cos(x) }
cachedCos(.pi * 2) // value of cos for 2ฯ is now cached
Simplifying complex conditions with pattern matching
When distinguishing between complex boolean conditions, using a switch statement along with pattern matching can be more readable than the classic series of if {} else if {}.
import Foundation
let expr1: Bool
let expr2: Bool
let expr3: Bool
if expr1 && !expr3 {
functionA()
} else if !expr2 && expr3 {
functionB()
} else if expr1 && !expr2 && expr3 {
functionC()
}
switch (expr1, expr2, expr3) {
case (true, _, false):
functionA()
case (_, false, true):
functionB()
case (true, false, true):
functionC()
default:
break
}
Easily generating arrays of data
Using map() on a range makes it easy to generate an array of data.
import Foundation
func randomInt() -> Int { return Int(arc4random()) }
let randomArray = (1...10).map { _ in randomInt() }
Using @autoclosure for cleaner call sites
Using @autoclosure enables the compiler to automatically wrap an argument within a closure, thus allowing for a very clean syntax at call sites.
import UIKit
extension UIView {
class func animate(withDuration duration: TimeInterval, _ animations: @escaping @autoclosure () -> Void) {
UIView.animate(withDuration: duration, animations: animations)
}
}
let view = UIView()
UIView.animate(withDuration: 0.3, view.backgroundColor = .orange)
Observing new and old value with RxSwift
When working with RxSwift, it's very easy to observe both the current and previous value of an observable sequence by simply introducing a shift using skip().
import RxSwift
let values = Observable.of(4, 8, 15, 16, 23, 42)
let newAndOld = Observable.zip(values, values.skip(1)) { (previous: $0, current: $1) }
.subscribe(onNext: { pair in
print("current: \(pair.current) - previous: \(pair.previous)")
})
//current: 8 - previous: 4
//current: 15 - previous: 8
//current: 16 - previous: 15
//current: 23 - previous: 16
//current: 42 - previous: 23
Implicit initialization from literal values
Using protocols such as ExpressibleByStringLiteral it is possible to provide an init that will be automatically when a literal value is provided, allowing for nice and short syntax. This can be very helpful when writing mock or test data.
import Foundation
extension URL: ExpressibleByStringLiteral {
public init(stringLiteral value: String) {
self.init(string: value)!
}
}
let url: URL = "http://www.google.fr"
NSURLConnection.canHandle(URLRequest(url: "http://www.google.fr"))
Achieving systematic validation of data
Through some clever use of Swift private visibility it is possible to define a container that holds any untrusted value (such as a user input) from which the only way to retrieve the value is by making it successfully pass a validation test.
import Foundation
struct Untrusted<T> {
private(set) var value: T
}
protocol Validator {
associatedtype T
static func validation(value: T) -> Bool
}
extension Validator {
static func validate(untrusted: Untrusted<T>) -> T? {
if self.validation(value: untrusted.value) {
return untrusted.value
} else {
return nil
}
}
}
struct FrenchPhoneNumberValidator: Validator {
static func validation(value: String) -> Bool {
return (value.count) == 10 && CharacterSet(charactersIn: value).isSubset(of: CharacterSet.decimalDigits)
}
}
let validInput = Untrusted(value: "0122334455")
let invalidInput = Untrusted(value: "0123")
FrenchPhoneNumberValidator.validate(untrusted: validInput) // returns "0122334455"
FrenchPhoneNumberValidator.validate(untrusted: invalidInput) // returns nil
Implementing the builder pattern with keypaths
With the addition of keypaths in Swift 4, it is now possible to easily implement the builder pattern, that allows the developer to clearly separate the code that initializes a value from the code that uses it, without the burden of defining a factory method.
import UIKit
protocol With {}
extension With where Self: AnyObject {
@discardableResult
func with<T>(_ property: ReferenceWritableKeyPath<Self, T>, setTo value: T) -> Self {
self[keyPath: property] = value
return self
}
}
extension UIView: With {}
let view = UIView()
let label = UILabel()
.with(\.textColor, setTo: .red)
.with(\.text, setTo: "Foo")
.with(\.textAlignment, setTo: .right)
.with(\.layer.cornerRadius, setTo: 5)
view.addSubview(label)
๐จ The Swift compiler does not perform OS availability checks on properties referenced by keypaths. Any attempt to use a KeyPath for an unavailable property will result in a runtime crash.
I share the credit for this tip with Marion Curtil.
Storing functions rather than values
When a type stores values for the sole purpose of parametrizing its functions, itโs then possible to not store the values but directly the function, with no discernable difference at the call site.
import Foundation
struct MaxValidator {
let max: Int
let strictComparison: Bool
func isValid(_ value: Int) -> Bool {
return self.strictComparison ? value < self.max : value <= self.max
}
}
struct MaxValidator2 {
var isValid: (_ value: Int) -> Bool
init(max: Int, strictComparison: Bool) {
self.isValid = strictComparison ? { $0 < max } : { $0 <= max }
}
}
MaxValidator(max: 5, strictComparison: true).isValid(5) // false
MaxValidator2(max: 5, strictComparison: false).isValid(5) // true
Defining operators on function types
Functions are first-class citizen types in Swift, so it is perfectly legal to define operators for them.
import Foundation
let firstRange = { (0...3).contains($0) }
let secondRange = { (5...6).contains($0) }
func ||(_ lhs: @escaping (Int) -> Bool, _ rhs: @escaping (Int) -> Bool) -> (Int) -> Bool {
return { value in
return lhs(value) || rhs(value)
}
}
(firstRange || secondRange)(2) // true
(firstRange || secondRange)(4) // false
(firstRange || secondRange)(6) // true
Typealiases for functions
Typealiases are great to express function signatures in a more comprehensive manner, which then enables us to easily define functions that operate on them, resulting in a nice way to write and use some powerful API.
import Foundation
typealias RangeSet = (Int) -> Bool
func union(_ left: @escaping RangeSet, _ right: @escaping RangeSet) -> RangeSet {
return { left($0) || right($0) }
}
let firstRange = { (0...3).contains($0) }
let secondRange = { (5...6).contains($0) }
let unionRange = union(firstRange, secondRange)
unionRange(2) // true
unionRange(4) // false
Encapsulating state within a function
By returning a closure that captures a local variable, it's possible to encapsulate a mutable state within a function.
import Foundation
func counterFactory() -> () -> Int {
var counter = 0
return {
counter += 1
return counter
}
}
let counter = counterFactory()
counter() // returns 1
counter() // returns 2
Generating all cases for an Enum
โ ๏ธ Since Swift 4.2,
allCasescan now be synthesized at compile-time by simply conforming to the protocolCaseIterable. The implementation below should no longer be used in production code.
Through some clever leveraging of how enums are stored in memory, it is possible to generate an array that contains all the possible cases of an enum. This can prove particularly useful when writing unit tests that consume random data.
import Foundation
enum MyEnum { case first; case second; case third; case fourth }
protocol EnumCollection: Hashable {
static var allCases: [Self] { get }
}
extension EnumCollection {
public static var allCases: [Self] {
var i = 0
return Array(AnyIterator {
let next = withUnsafePointer(to: &i) {
$0.withMemoryRebound(to: Self.self, capacity: 1) { $0.pointee }
}
if next.hashValue != i { return nil }
i += 1
return next
})
}
}
extension MyEnum: EnumCollection { }
MyEnum.allCases // [.first, .second, .third, .fourth]
Using map on optional values
The if-let syntax is a great way to deal with optional values in a safe manner, but at times it can prove to be just a little bit to cumbersome. In such cases, using the Optional.map() function is a nice way to achieve a shorter code while retaining safeness and readability.
import UIKit
let date: Date? = Date() // or could be nil, doesn't matter
let formatter = DateFormatter()
let label = UILabel()
if let safeDate = date {
label.text = formatter.string(from: safeDate)
}
label.text = date.map { return formatter.string(from: $0) }
label.text = date.map(formatter.string(from:)) // even shorter, tough less readable
๐ฃ NEW ๐ฃ Swift Tips are now available on YouTube ๐
Summary
- #57 Property Wrappers as Debugging Tools
- #56 Localization through
Stringinterpolation - #55 Implementing pseudo-inheritance between
structs - #54 Composing
NSAttributedStringthrough a Function Builder - #53 Using
switchandifas expressions - #52 Avoiding double negatives within
guardstatements - #51 Defining a custom
initwithout loosing the compiler-generated one - #50 Implementing a namespace through an empty
enum - #49 Using
Neverto represent impossible code paths - #48 Providing a default value to a
Decodableenum - #47 Another lightweight dependency injection through default values for function parameters
- #46 Lightweight dependency injection through protocol-oriented programming
- #45 Getting rid of overabundant
[weak self]andguard - #44 Solving callback hell with function composition
- #43 Transform an asynchronous function into a synchronous one
- #42 Using KeyPaths instead of closures
- #41 Bringing some type-safety to a
userInfoDictionary - #40 Lightweight data-binding for an MVVM implementation
- #39 Using
typealiasto its fullest - #38 Writing an interruptible overload of
forEach - #37 Optimizing the use of
reduce() - #36 Avoiding hardcoded reuse identifiers
- #35 Defining a union type
- #34 Asserting that classes have associated NIBs and vice-versa
- #33 Small footprint type-erasing with functions
- #32 Performing animations sequentially
- #31 Debouncing a function call
- #30 Providing useful operators for
Optionalbooleans - #29 Removing duplicate values from a
Sequence - #28 Shorter syntax to deal with optional strings
- #27 Encapsulating background computation and UI update
- #26 Retrieving all the necessary data to build a debug view
- #25 Defining a function to map over dictionaries
- #24 A shorter syntax to remove
nilvalues - #23 Dealing with expirable values
- #22 Using parallelism to speed-up
map() - #21 Measuring execution time with minimum boilerplate
- #20 Running two pieces of code in parallel
- #19 Making good use of #file, #line and #function
- #18 Comparing Optionals through Conditional Conformance
- #17 Safely subscripting a Collection
- #16 Easier String slicing using ranges
- #15 Concise syntax for sorting using a KeyPath
- #14 Manufacturing cache-efficient versions of pure functions
- #13 Simplifying complex condition with pattern matching
- #12 Easily generating arrays of data
- #11 Using @autoclosure for cleaner call sites
- #10 Observing new and old value with RxSwift
- #09 Implicit initialization from literal values
- #08 Achieving systematic validation of data
- #07 Implementing the builder pattern with keypaths
- #06 Storing functions rather than values
- #05 Defining operators on function types
- #04 Typealiases for functions
- #03 Encapsulating state within a function
- #02 Generating all cases for an Enum
- #01 Using map on optional values
Tips
Download Details:
Author: vincent-pradeilles
Source code: https://github.com/vincent-pradeilles/swift-tips
License: MIT license
#swift
1677907260
Chatgpt-api: Node.js client for the official ChatGPT API
ChatGPT API
Node.js client for the official ChatGPT API.
Intro
This package is a Node.js wrapper around ChatGPT by OpenAI. TS batteries included. โจ
Updates
March 1, 2023
The official OpenAI chat completions API has been released, and it is now the default for this package! ๐ฅ
| Method | Free? | Robust? | Quality? |
|---|---|---|---|
ChatGPTAPI | โ No | โ Yes | โ ๏ธ Real ChatGPT models |
ChatGPTUnofficialProxyAPI | โ Yes | โ๏ธ Maybe | โ Real ChatGPT |
Note: We strongly recommend using ChatGPTAPI since it uses the officially supported API from OpenAI. We may remove support for ChatGPTUnofficialProxyAPI in a future release.
ChatGPTAPI- Uses thegpt-3.5-turbo-0301model with the official OpenAI chat completions API (official, robust approach, but it's not free)ChatGPTUnofficialProxyAPI- Uses an unofficial proxy server to access ChatGPT's backend API in a way that circumvents Cloudflare (uses the real ChatGPT and is pretty lightweight, but relies on a third-party server and is rate-limited)
CLI
To run the CLI, you'll need an OpenAI API key:
export OPENAI_API_KEY="sk-TODO"
npx chatgpt "your prompt here"By default, the response is streamed to stdout, the results are stored in a local config file, and every invocation starts a new conversation. You can use -c to continue the previous conversation and --no-stream to disable streaming.
Under the hood, the CLI uses ChatGPTAPI with text-davinci-003 to mimic ChatGPT.
Usage:
$ chatgpt <prompt>
Commands:
<prompt> Ask ChatGPT a question
rm-cache Clears the local message cache
ls-cache Prints the local message cache path
For more info, run any command with the `--help` flag:
$ chatgpt --help
$ chatgpt rm-cache --help
$ chatgpt ls-cache --help
Options:
-c, --continue Continue last conversation (default: false)
-d, --debug Enables debug logging (default: false)
-s, --stream Streams the response (default: true)
-s, --store Enables the local message cache (default: true)
-t, --timeout Timeout in milliseconds
-k, --apiKey OpenAI API key
-n, --conversationName Unique name for the conversation
-h, --help Display this message
-v, --version Display version number
Install
npm install chatgptMake sure you're using node >= 18 so fetch is available (or node >= 14 if you install a fetch polyfill).
Usage
To use this module from Node.js, you need to pick between two methods:
| Method | Free? | Robust? | Quality? |
|---|---|---|---|
ChatGPTAPI | โ No | โ Yes | โ ๏ธ Real ChatGPT models |
ChatGPTUnofficialProxyAPI | โ Yes | โ๏ธ Maybe | โ Real ChatGPT |
ChatGPTAPI - Uses the gpt-3.5-turbo-0301 model with the official OpenAI chat completions API (official, robust approach, but it's not free). You can override the model, completion params, and system message to fully customize your assistant.
ChatGPTUnofficialProxyAPI - Uses an unofficial proxy server to access ChatGPT's backend API in a way that circumvents Cloudflare (uses the real ChatGPT and is pretty lightweight, but relies on a third-party server and is rate-limited)
Both approaches have very similar APIs, so it should be simple to swap between them.
Note: We strongly recommend using ChatGPTAPI since it uses the officially supported API from OpenAI. We may remove support for ChatGPTUnofficialProxyAPI in a future release.
Usage - ChatGPTAPI
Sign up for an OpenAI API key and store it in your environment.
import { ChatGPTAPI } from 'chatgpt'
async function example() {
const api = new ChatGPTAPI({
apiKey: process.env.OPENAI_API_KEY
})
const res = await api.sendMessage('Hello World!')
console.log(res.text)
}You can override the default model (gpt-3.5-turbo-0301) and any OpenAI chat completion params using completionParams:
const api = new ChatGPTAPI({
apiKey: process.env.OPENAI_API_KEY,
completionParams: {
temperature: 0.5,
top_p: 0.8
}
})If you want to track the conversation, you'll need to pass the parentMessageId like this:
const api = new ChatGPTAPI({ apiKey: process.env.OPENAI_API_KEY })
// send a message and wait for the response
let res = await api.sendMessage('What is OpenAI?')
console.log(res.text)
// send a follow-up
res = await api.sendMessage('Can you expand on that?', {
parentMessageId: res.id
})
console.log(res.text)
// send another follow-up
res = await api.sendMessage('What were we talking about?', {
parentMessageId: res.id
})
console.log(res.text)You can add streaming via the onProgress handler:
const res = await api.sendMessage('Write a 500 word essay on frogs.', {
// print the partial response as the AI is "typing"
onProgress: (partialResponse) => console.log(partialResponse.text)
})
// print the full text at the end
console.log(res.text)You can add a timeout using the timeoutMs option:
// timeout after 2 minutes (which will also abort the underlying HTTP request)
const response = await api.sendMessage(
'write me a really really long essay on frogs',
{
timeoutMs: 2 * 60 * 1000
}
)If you want to see more info about what's actually being sent to OpenAI's chat completions API, set the debug: true option in the ChatGPTAPI constructor:
const api = new ChatGPTAPI({
apiKey: process.env.OPENAI_API_KEY,
debug: true
})We default to a basic systemMessage. You can override this in either the ChatGPTAPI constructor or sendMessage:
const res = await api.sendMessage('what is the answer to the universe?', {
systemMessage: `You are ChatGPT, a large language model trained by OpenAI. You answer as concisely as possible for each responseIf you are generating a list, do not have too many items.
Current date: ${new Date().toISOString()}\n\n`
})Note that we automatically handle appending the previous messages to the prompt and attempt to optimize for the available tokens (which defaults to 4096).
Usage in CommonJS (Dynamic import)
async function example() {
// To use ESM in CommonJS, you can use a dynamic import
const { ChatGPTAPI } = await import('chatgpt')
const api = new ChatGPTAPI({ apiKey: process.env.OPENAI_API_KEY })
const res = await api.sendMessage('Hello World!')
console.log(res.text)
}Usage - ChatGPTUnofficialProxyAPI
The API for ChatGPTUnofficialProxyAPI is almost exactly the same. You just need to provide a ChatGPT accessToken instead of an OpenAI API key.
import { ChatGPTUnofficialProxyAPI } from 'chatgpt'
async function example() {
const api = new ChatGPTUnofficialProxyAPI({
accessToken: process.env.OPENAI_ACCESS_TOKEN
})
const res = await api.sendMessage('Hello World!')
console.log(res.text)
}See demos/demo-reverse-proxy for a full example:
npx tsx demos/demo-reverse-proxy.tsChatGPTUnofficialProxyAPI messages also contain a conversationid in addition to parentMessageId, since the ChatGPT webapp can't reference messages across
Reverse Proxy
You can override the reverse proxy by passing apiReverseProxyUrl:
const api = new ChatGPTUnofficialProxyAPI({
accessToken: process.env.OPENAI_ACCESS_TOKEN,
apiReverseProxyUrl: 'https://your-example-server.com/api/conversation'
})Known reverse proxies run by community members include:
| Reverse Proxy URL | Author | Rate Limits | Last Checked |
|---|---|---|---|
https://chat.duti.tech/api/conversation | @acheong08 | 120 req/min by IP | 2/19/2023 |
https://gpt.pawan.krd/backend-api/conversation | @PawanOsman | ? | 2/19/2023 |
Note: info on how the reverse proxies work is not being published at this time in order to prevent OpenAI from disabling access.
Access Token
To use ChatGPTUnofficialProxyAPI, you'll need an OpenAI access token from the ChatGPT webapp. To do this, you can use any of the following methods which take an email and password and return an access token:
- Node.js libs
- Python libs
These libraries work with email + password accounts (e.g., they do not support accounts where you auth via Microsoft / Google).
Alternatively, you can manually get an accessToken by logging in to the ChatGPT webapp and then opening https://chat.openai.com/api/auth/session, which will return a JSON object containing your accessToken string.
Access tokens last for days.
Note: using a reverse proxy will expose your access token to a third-party. There shouldn't be any adverse effects possible from this, but please consider the risks before using this method.
Docs
See the auto-generated docs for more info on methods and parameters.
Demos
Most of the demos use ChatGPTAPI. It should be pretty easy to convert them to use ChatGPTUnofficialProxyAPI if you'd rather use that approach. The only thing that needs to change is how you initialize the api with an accessToken instead of an apiKey.
To run the included demos:
- clone repo
- install node deps
- set
OPENAI_API_KEYin .env
A basic demo is included for testing purposes:
npx tsx demos/demo.tsA demo showing on progress handler:
npx tsx demos/demo-on-progress.tsThe on progress demo uses the optional onProgress parameter to sendMessage to receive intermediary results as ChatGPT is "typing".
npx tsx demos/demo-conversation.tsA persistence demo shows how to store messages in Redis for persistence:
npx tsx demos/demo-persistence.tsAny keyv adaptor is supported for persistence, and there are overrides if you'd like to use a different way of storing / retrieving messages.
Note that persisting message is required for remembering the context of previous conversations beyond the scope of the current Node.js process, since by default, we only store messages in memory. Here's an external demo of using a completely custom database solution to persist messages.
Note: Persistence is handled automatically when using ChatGPTUnofficialProxyAPI because it is connecting indirectly to ChatGPT.
Projects
All of these awesome projects are built using the chatgpt package. ๐คฏ
- Twitter Bot powered by ChatGPT โจ
- Mention @ChatGPTBot on Twitter with your prompt to try it out
- ChatGPT API Server - API server for this package with support for multiple OpenAI accounts, proxies, and load-balancing requests between accounts.
- ChatGPT Prompts - A collection of 140+ of the best ChatGPT prompts from the community.
- Lovelines.xyz
- Chrome Extension (demo)
- VSCode Extension #1 (demo, updated version, marketplace)
- VSCode Extension #2 (marketplace)
- VSCode Extension #3 (marketplace)
- VSCode Extension #4 (marketplace)
- Raycast Extension #1 (demo)
- Raycast Extension #2
- Telegram Bot #1
- Telegram Bot #2
- Telegram Bot #3 (group privacy mode, ID-based auth)
- Telegram Bot #4 (queue system, ID-based chat thread)
- Deno Telegram Bot
- Go Telegram Bot
- Telegram Bot for YouTube Summaries
- GitHub ProBot
- Discord Bot #1
- Discord Bot #2
- Discord Bot #3
- Discord Bot #4 (selfbot)
- Discord Bot #5
- Discord Bot #6 (Shakespeare bot)
- WeChat Bot #1
- WeChat Bot #2
- WeChat Bot #3 (
- WeChat Bot #4
- WeChat Bot #5
- QQ Bot (plugin for Yunzai-bot)
- QQ Bot (plugin for KiviBot)
- QQ Bot (oicq)
- QQ Bot (oicq + RabbitMQ)
- QQ Bot (go-cqhttp)
- EXM smart contracts
- Flutter ChatGPT API
- Carik Bot
- Github Action for reviewing PRs
- WhatsApp Bot #1 (DALL-E + Whisper support ๐ช)
- WhatsApp Bot #2
- WhatsApp Bot #3 (multi-user support)
- WhatsApp Bot #4 (schedule periodic messages)
- WhatsApp Bot #5 (RaspberryPi + ngrok + Twilio)
- WhatsApp Bot #6 (Session and chat history storage with MongoStore)
- Matrix Bot
- Rental Cover Letter Generator
- Assistant CLI
- Teams Bot
- Askai
- TalkGPT
- ChatGPT With Voice
- iOS Shortcut
- Slack Bot #1
- Slack Bot #2 (with queueing mechanism)
- Slack Bot #3
- Slack Bot #4 ( Serverless AWS Lambda )
- Electron Bot
- Kodyfire CLI
- Twitch Bot
- Continuous Conversation
- Figma plugin
- NestJS server
- NestJS ChatGPT Starter Boilerplate
- Wordsmith: Add-in for Microsoft Word
- QuizGPT: Create Kahoot quizzes with ChatGPT
- openai-chatgpt: Talk to ChatGPT from the terminal
- Clippy the Saleforce chatbot ClippyJS joke bot
- ai-assistant Chat assistant
- Feishu Bot
- DomainGPT: Discover available domain names
- AI Poem Generator
- Next.js ChatGPT With Firebase
- ai-commit โ GPT-3 Commit Message Generator
If you create a cool integration, feel free to open a PR and add it to the list.
Compatibility
- This package is ESM-only.
- This package supports
node >= 14. - This module assumes that
fetchis installed. - If you want to build a website using
chatgpt, we recommend using it only from your backend API
Credits
- Huge thanks to @waylaidwanderer, @abacaj, @wong2, @simon300000, @RomanHotsiy, @ElijahPepe, and all the other contributors ๐ช
- The original browser version was inspired by this Go module by Daniel Gross
- OpenAI for creating ChatGPT ๐ฅ
Previous Updates
Feb 19, 2023
We now provide three ways of accessing the unofficial ChatGPT API, all of which have tradeoffs:
| Method | Free? | Robust? | Quality? |
|---|---|---|---|
ChatGPTAPI | โ No | โ Yes | โ๏ธ Mimics ChatGPT |
ChatGPTUnofficialProxyAPI | โ Yes | โ๏ธ Maybe | โ Real ChatGPT |
ChatGPTAPIBrowser (v3) | โ Yes | โ No | โ Real ChatGPT |
Note: I recommend that you use either ChatGPTAPI or ChatGPTUnofficialProxyAPI.
ChatGPTAPI- Usestext-davinci-003to mimic ChatGPT via the official OpenAI completions API (most robust approach, but it's not free and doesn't use a model fine-tuned for chat)ChatGPTUnofficialProxyAPI- Uses an unofficial proxy server to access ChatGPT's backend API in a way that circumvents Cloudflare (uses the real ChatGPT and is pretty lightweight, but relies on a third-party server and is rate-limited)ChatGPTAPIBrowser- (deprecated; v3.5.1 of this package) Uses Puppeteer to access the official ChatGPT webapp (uses the real ChatGPT, but very flaky, heavyweight, and error prone)
Feb 5, 2023
OpenAI has disabled the leaked chat model we were previously using, so we're now defaulting to text-davinci-003, which is not free.
We've found several other hidden, fine-tuned chat models, but OpenAI keeps disabling them, so we're searching for alternative workarounds.
Feb 1, 2023
This package no longer requires any browser hacks โ it is now using the official OpenAI completions API with a leaked model that ChatGPT uses under the hood. ๐ฅ
import { ChatGPTAPI } from 'chatgpt'
const api = new ChatGPTAPI({
apiKey: process.env.OPENAI_API_KEY
})
const res = await api.sendMessage('Hello World!')
console.log(res.text)Please upgrade to chatgpt@latest (at least v4.0.0). The updated version is significantly more lightweight and robust compared with previous versions. You also don't have to worry about IP issues or rate limiting.
Huge shoutout to @waylaidwanderer for discovering the leaked chat model!
If you run into any issues, we do have a pretty active Discord with a bunch of ChatGPT hackers from the Node.js & Python communities.
Lastly, please consider starring this repo and following me on twitter to help support the project.
Thanks && cheers, Travis
Download Details:
Author: Transitive-bullshit
Source Code: https://github.com/transitive-bullshit/chatgpt-api
License: MIT license
1669952228
Dijkstra's Algorithm Explained with Examples
In this tutorial, you'll learn: What is Dijkstra's Algorithm and how Dijkstra's algorithm works with the help of visual guides.
You can use algorithms in programming to solve specific problems through a set of precise instructions or procedures.
Dijkstra's algorithm is one of many graph algorithms you'll come across. It is used to find the shortest path from a fixed node to all other nodes in a graph.
There are different representations of Dijkstra's algorithm. You can either find the shortest path between two nodes, or the shortest path from a fixed node to the rest of the nodes in a graph.
In this article, you'll learn how Dijkstra's algorithm works with the help of visual guides.
How Does Dijkstraโs Algorithm Work?
Before we dive into more detailed visual examples, you need to understand how Dijkstra's algorithm works.
Although the theoretical explanation may seem a bit abstract, it'll help you understand the practical aspect better.
In a given graph containing different nodes, we are required to get the shortest path from a given node to the rest of the nodes.
These nodes can represent any object like the names of cities, letters, and so on.
Between each node is a number denoting the distance between two nodes, as you can see in the image below:
We usually work with two arrays โ one for visited nodes, and another for unvisited nodes. You'll learn more about the arrays in the next section.
When a node is visited, the algorithm calculates how long it took to get to the node and stores the distance. If a shorter path to a node is found, the initial value assigned for the distance is updated.
Note that a node cannot be visited twice.
The algorithm runs recursively until all the nodes have been visited.
Dijkstra's Algorithm Example
In this section, we'll take a look at a practical example that shows how Dijkstra's algorithm works.
Here's the graph we'll be working with:
We'll use the table below to put down the visited nodes and their distance from the fixed node:
| NODE | SHORTEST DISTANCE FROM FIXED NODE |
|---|---|
| A | โ |
| B | โ |
| C | โ |
| D | โ |
| E | โ |
Visited nodes = []
Unvisited nodes = [A,B,C,D,E]
Above, we have a table showing each node and the shortest distance from the that node to the fixed node. We are yet to choose the fixed node.
Note that the distance for each node in the table is currently denoted as infinity (โ). This is because we don't know the shortest distance yet.
We also have two arrays โ visited and unvisited. Whenever a node is visited, it is added to the visited nodes array.
Let's get started!
To simplify things, I'll break the process down into iterations. You'll see what happens in each step with the aid of diagrams.
Iteration #1
The first iteration might seem confusing, but that's totally fine. Once we start repeating the process in each iteration, you'll have a clearer picture of how the algorithm works.
Step #1 - Pick an unvisited node
We'll choose A as the fixed node. So we'll find the shortest distance from A to every other node in the graph.
We're going to give A a distance of 0 because it is the initial node. So the table would look like this:
| NODE | SHORTEST DISTANCE FROM FIXED NODE |
|---|---|
| A | 0 |
| B | โ |
| C | โ |
| D | โ |
| E | โ |
Step #2 - Find the distance from current node
The next thing to do after choosing a node is to find the distance from it to the unvisited nodes around it.
The two unvisited nodes directly linked to A are B and C.
To get the distance from A to B:
0 + 4 = 4
0 being the value of the current node (A), and 4 being the distance between A and B in the graph.
To get the distance from A to C:
0 + 2 = 2
Step #3 - Update table with known distances
In the last step, we got 4 and 2 as the values of B and C respectively. So we'll update the table with those values:
| NODE | SHORTEST DISTANCE FROM FIXED NODE |
|---|---|
| A | 0 |
| B | 4 |
| C | 2 |
| D | โ |
| E | โ |
Step #4 - Update arrays
At this point, the first iteration is complete. We'll move node A to the visited nodes array:
Visited nodes = [A]
Unvisited nodes = [B,C,D,E]
Before we proceed to the next iteration, you should know the following:
- Once a node has been visited, it cannot be linked to the current node. Refer to step #2 in the iteration above and step #2 in the next iteration.
- A node cannot be visited twice.
- You can only update the shortest known distance if you get a value smaller than the recorded distance.
Iteration #2
Step #1 - Pick an unvisited node
We have four unvisited nodes โ [B,C,D,E]. So how do you know which node to pick for the next iteration?
Well, we pick the node with the smallest known distance recorded in the table. Here's the table:
| NODE | SHORTEST DISTANCE FROM FIXED NODE |
|---|---|
| A | 0 |
| B | 4 |
| C | 2 |
| D | โ |
| E | โ |
So we're going with node C.
Step #2 - Find the distance from current node
To find the distance from the current node to the fixed node, we have to consider the nodes linked to the current node.
The nodes linked to the current node are A and B.
But A has been visited in the previous iteration so it will not be linked to the current node. That is:
From the diagram above,
- The green color denotes the current node.
- The blue color denotes the visited nodes. We cannot link to them or visit them again.
- The red color shows the link from the unvisited nodes to the current node.
To find the distance from C to B:
2 + 1 = 3
2 above is recorded distance for node C while 1 is the distance between C and B in the graph.
Step #3 - Update table with known distances
In the last step, we got the value of B to be 3. In the first iteration, it was 4.
We're going to update the distance in the table to 3.
| NODE | SHORTEST DISTANCE FROM FIXED NODE |
|---|---|
| A | 0 |
| B | 3 |
| C | 2 |
| D | โ |
| E | โ |
So, A --> B = 4 (First iteration).
A --> C --> B = 3 (Second iteration).
The algorithm has helped us find the shortest path to B from A.
Step #4 - Update arrays
We're done with the last visited node. Let's add it to the visited nodes array:
Visited nodes = [A,C]
Unvisited nodes = [B,D,E]
Iteration #3
Step #1 - Pick an unvisited node
We're down to three unvisited nodes โ [B,D,E]. From the array, B has the shortest known distance.
To restate what is going on in the diagram above:
- The green color denotes the current node.
- The blue color denotes the visited nodes. We cannot link to them or visit them again.
- The red color shows the link from the unvisited nodes to the current node.
Step #2 - Find the distance from current node
The nodes linked to the current node are D and E.
B (the current node) has a value of 3. Therefore,
For node D, 3 + 3 = 6.
For node E, 3 + 2 = 5.
Step #3 - Update table with known distances
| NODE | SHORTEST DISTANCE FROM FIXED NODE |
|---|---|
| A | 0 |
| B | 3 |
| C | 2 |
| D | 6 |
| E | 5 |
Step #4 - Update arrays
Visited nodes = [A,C,B]
Unvisited nodes = [D,E]
Iteration #4
Step #1 - Pick an unvisited node
Like other iterations, we'll go with the unvisited node with the shortest known distance. That is E.
Step #2 - Find the distance from current node
According to our table, E has a value of 5.
For D in the current iteration,
5 + 5 = 10.
The value gotten for D here is 10, which is greater than the recorded value of 6 in the previous iteration. For this reason, we'll not update the table.
Step #3 - Update table with known distances
Our table remains the same:
| NODE | SHORTEST DISTANCE FROM FIXED NODE |
|---|---|
| A | 0 |
| B | 3 |
| C | 2 |
| D | 6 |
| E | 5 |
Step #4 - Update arrays
Visited nodes = [A,C,B,E]
Unvisited nodes = [D]
Iteration #5
Step #1 - Pick an unvisited node
We're currently left with one node in the unvisited array โ D.
Step #2 - Find the distance from current node
The algorithm has gotten to the last iteration. This is because all nodes linked to the current node have been visited already so we can't link to them.
Step #3 - Update table with known distances
Our table remains the same:
| NODE | SHORTEST DISTANCE FROM FIXED NODE |
|---|---|
| A | 0 |
| B | 3 |
| C | 2 |
| D | 6 |
| E | 5 |
At this point, we have updated the table with the shortest distance from the fixed node to every other node in the graph.
Step #4 - Update arrays
Visited nodes = [A,C,B,E,D]
Unvisited nodes = []
As can be seen above, we have no nodes left to visit. Using Dijkstra's algorithm, we've found the shortest distance from the fixed node to others nodes in the graph.
Dijkstra's Algorithm Pseudocode Example
The pseudocode example in this section was gotten from Wikipedia. Here it is:
1 function Dijkstra(Graph, source):
2
3 for each vertex v in Graph.Vertices:
4 dist[v] โ INFINITY
5 prev[v] โ UNDEFINED
6 add v to Q
7 dist[source] โ 0
8
9 while Q is not empty:
10 u โ vertex in Q with min dist[u]
11 remove u from Q
12
13 for each neighbor v of u still in Q:
14 alt โ dist[u] + Graph.Edges(u, v)
15 if alt < dist[v]:
16 dist[v] โ alt
17 prev[v] โ u
18
19 return dist[], prev[]Applications of Dijkstra's Algorithm
Here are some of the common applications of Dijkstra's algorithm:
- In maps to get the shortest distance between locations. An example is Google Maps.
- In telecommunications to determine transmission rate.
- In robotic design to determine shortest path for automated robots.
Summary
In this article, we talked about Dijkstra's algorithm. It is used to find the shortest distance from a fixed node to all other nodes in a graph.
We started by giving a brief summary of how the algorithm works.
We then had a look at an example that further explained Dijkstra's algorithm in steps using visual guides.
We concluded with a pseudocode example and some of the applications of Dijkstra's algorithm.
Happy coding!
Original article source at https://www.freecodecamp.org
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