1604773020
Vue 3 is the up and coming version of Vue front end framework.
It builds on the popularity and ease of use of Vue 2.
In this article, we’ll look at how to add transitions with Vue 3.
We can add transitions to our Vue app with various components
The transition
component helps us add enter and leave transitions which are triggered by v-if
.
Transition modes let us change the ordering of a transition.
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msgpack.php
A pure PHP implementation of the MessagePack serialization format.
The recommended way to install the library is through Composer:
composer require rybakit/msgpack
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.
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,Map
andBin
. 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);
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
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) {...}
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.
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.
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.
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.
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.
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
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
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.
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
1600583123
In this article, we are going to list out the most popular websites using Vue JS as their frontend framework.
Vue JS is one of those elite progressive JavaScript frameworks that has huge demand in the web development industry. Many popular websites are developed using Vue in their frontend development because of its imperative features.
This framework was created by Evan You and still it is maintained by his private team members. Vue is of course an open-source framework which is based on MVVM concept (Model-view view-Model) and used extensively in building sublime user-interfaces and also considered a prime choice for developing single-page heavy applications.
Released in February 2014, Vue JS has gained 64,828 stars on Github, making it very popular in recent times.
Evan used Angular JS on many operations while working for Google and integrated many features in Vue to cover the flaws of Angular.
“I figured, what if I could just extract the part that I really liked about Angular and build something really lightweight." - Evan You
#vuejs #vue #vue-with-laravel #vue-top-story #vue-3 #build-vue-frontend #vue-in-laravel #vue.js
1677907260
Node.js client for the official ChatGPT API.
This package is a Node.js wrapper around ChatGPT by OpenAI. TS batteries included. ✨
March 1, 2023
The official OpenAI chat completions API has been released, and it is now the default for this package! 🔥
Method | Free? | Robust? | Quality? |
---|---|---|---|
ChatGPTAPI | ❌ No | ✅ Yes | ✅️ Real ChatGPT models |
ChatGPTUnofficialProxyAPI | ✅ Yes | ☑️ Maybe | ✅ 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 the gpt-3.5-turbo-0301
model 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)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
npm install chatgpt
Make sure you're using node >= 18
so fetch
is available (or node >= 14
if you install a fetch polyfill).
To use this module from Node.js, you need to pick between two methods:
Method | Free? | Robust? | Quality? |
---|---|---|---|
ChatGPTAPI | ❌ No | ✅ Yes | ✅️ Real ChatGPT models |
ChatGPTUnofficialProxyAPI | ✅ Yes | ☑️ Maybe | ✅ 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.
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)
}
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.ts
ChatGPTUnofficialProxyAPI
messages also contain a conversationid
in addition to parentMessageId
, since the ChatGPT webapp can't reference messages across
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.
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:
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.
See the auto-generated docs for more info on methods and parameters.
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:
OPENAI_API_KEY
in .envA basic demo is included for testing purposes:
npx tsx demos/demo.ts
A demo showing on progress handler:
npx tsx demos/demo-on-progress.ts
The on progress demo uses the optional onProgress
parameter to sendMessage
to receive intermediary results as ChatGPT is "typing".
npx tsx demos/demo-conversation.ts
A persistence demo shows how to store messages in Redis for persistence:
npx tsx demos/demo-persistence.ts
Any 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.
All of these awesome projects are built using the chatgpt
package. 🤯
If you create a cool integration, feel free to open a PR and add it to the list.
node >= 14
.fetch
is installed.chatgpt
, we recommend using it only from your backend APIPrevious 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 | ❌ No | ✅ Yes | ☑️ Mimics ChatGPT |
ChatGPTUnofficialProxyAPI | ✅ Yes | ☑️ Maybe | ✅ Real ChatGPT |
ChatGPTAPIBrowser (v3) | ✅ Yes | ❌ No | ✅ Real ChatGPT |
Note: I recommend that you use either ChatGPTAPI
or ChatGPTUnofficialProxyAPI
.
ChatGPTAPI
- Uses text-davinci-003
to 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 – it is now using the official OpenAI completions API with a leaked model that ChatGPT uses under the hood. 🔥
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
Author: Transitive-bullshit
Source Code: https://github.com/transitive-bullshit/chatgpt-api
License: MIT license
1630743562
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. FHIR® 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.
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.
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');
FHIR® is a registered trademark of Health Level Seven International (HL7) and its use does not constitute an endorsement of products by HL7®
Run this command:
With Flutter:
$ flutter pub add fhir_db
This will add a line like this to your package's pubspec.yaml (and run an implicit flutter pub get):
dependencies:
fhir_db: ^0.4.3
Alternatively, your editor might support or flutter pub get. Check the docs for your editor to learn more.
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
1669952228
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.
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 – 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.
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 | ∞ |
B | ∞ |
C | ∞ |
D | ∞ |
E | ∞ |
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 (∞). This is because we don't know the shortest distance yet.
We also have two arrays – 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.
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 | ∞ |
C | ∞ |
D | ∞ |
E | ∞ |
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 | ∞ |
E | ∞ |
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:
Step #1 - Pick an unvisited node
We have four unvisited nodes — [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 | ∞ |
E | ∞ |
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,
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 | ∞ |
E | ∞ |
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]
Step #1 - Pick an unvisited node
We're down to three unvisited nodes — [B,D,E]. From the array, B has the shortest known distance.
To restate what is going on in the diagram above:
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]
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]
Step #1 - Pick an unvisited node
We're currently left with one node in the unvisited array — 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.
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] ← INFINITY
5 prev[v] ← UNDEFINED
6 add v to Q
7 dist[source] ← 0
8
9 while Q is not empty:
10 u ← 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 ← dist[u] + Graph.Edges(u, v)
15 if alt < dist[v]:
16 dist[v] ← alt
17 prev[v] ← u
18
19 return dist[], prev[]
Here are some of the common applications of Dijkstra's algorithm:
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
#algorithm #datastructures