1649329200
Minimp3: Minimalistic MP3 Decoder Single Header Library
minimp3
Minimalistic, single-header library for decoding MP3. minimp3 is designed to be small, fast (with SSE and NEON support), and accurate (ISO conformant). You can find a rough benchmark below, measured using perf on an i7-6700K, IO included, no CPU heat to address speedstep:
| Vector | Hz | Samples | Sec | Clockticks | Clockticks per second | PSNR | Max diff |
|---|---|---|---|---|---|---|---|
| compl.bit | 48000 | 248832 | 5.184 | 14306684 | 2.759M | 124.22 | 1 |
| he_32khz.bit | 32000 | 172800 | 5.4 | 8426158 | 1.560M | 139.67 | 1 |
| he_44khz.bit | 44100 | 472320 | 10.710 | 21296300 | 1.988M | 144.04 | 1 |
| he_48khz.bit | 48000 | 172800 | 3.6 | 8453846 | 2.348M | 139.67 | 1 |
| hecommon.bit | 44100 | 69120 | 1.567 | 3169715 | 2.022M | 133.93 | 1 |
| he_free.bit | 44100 | 156672 | 3.552 | 5798418 | 1.632M | 137.48 | 1 |
| he_mode.bit | 44100 | 262656 | 5.955 | 9882314 | 1.659M | 118.00 | 1 |
| si.bit | 44100 | 135936 | 3.082 | 7170520 | 2.326M | 120.30 | 1 |
| si_block.bit | 44100 | 73728 | 1.671 | 4233136 | 2.533M | 125.18 | 1 |
| si_huff.bit | 44100 | 86400 | 1.959 | 4785322 | 2.442M | 107.98 | 1 |
| sin1k0db.bit | 44100 | 725760 | 16.457 | 24842977 | 1.509M | 111.03 | 1 |
Conformance test passed on all vectors (PSNR > 96db).
Comparison with keyj's minimp3
Comparison by features:
| Keyj minimp3 | Current |
|---|---|
| Fixed point | Floating point |
| source: 84kb | 70kb |
| binary: 34kb (20kb compressed) | 30kb (20kb) |
| no vector opts | SSE/NEON intrinsics |
| no free format | free format support |
Below, you can find the benchmark and conformance test for keyj's minimp3:
| Vector | Hz | Samples | Sec | Clockticks | Clockticks per second | PSNR | Max diff |
|---|---|---|---|---|---|---|---|
| compl.bit | 48000 | 248832 | 5.184 | 31849373 | 6.143M | 71.50 | 41 |
| he_32khz.bit | 32000 | 172800 | 5.4 | 26302319 | 4.870M | 71.63 | 24 |
| he_44khz.bit | 44100 | 472320 | 10.710 | 41628861 | 3.886M | 71.63 | 24 |
| he_48khz.bit | 48000 | 172800 | 3.6 | 25899527 | 7.194M | 71.63 | 24 |
| hecommon.bit | 44100 | 69120 | 1.567 | 20437779 | 13.039M | 71.58 | 25 |
| he_free.bit | 44100 | 0 | 0 | - | - | - | - |
| he_mode.bit | 44100 | 262656 | 5.955 | 30988984 | 5.203M | 71.78 | 27 |
| si.bit | 44100 | 135936 | 3.082 | 24096223 | 7.817M | 72.35 | 36 |
| si_block.bit | 44100 | 73728 | 1.671 | 20722017 | 12.394M | 71.84 | 26 |
| si_huff.bit | 44100 | 86400 | 1.959 | 21121376 | 10.780M | 27.80 | 65535 |
| sin1k0db.bit | 44100 | 730368 | 16.561 | 55569636 | 3.355M | 0.15 | 58814 |
Keyj minimp3 conformance test fails on all vectors (PSNR < 96db), and free format is unsupported. This caused some problems when it was used here, and was the main motivation for this work.
Usage
First, we need to initialize the decoder structure:
//#define MINIMP3_ONLY_MP3
//#define MINIMP3_ONLY_SIMD
//#define MINIMP3_NO_SIMD
//#define MINIMP3_NONSTANDARD_BUT_LOGICAL
//#define MINIMP3_FLOAT_OUTPUT
#define MINIMP3_IMPLEMENTATION
#include "minimp3.h"
...
static mp3dec_t mp3d;
mp3dec_init(&mp3d);
Note that you must define MINIMP3_IMPLEMENTATION in exactly one source file. You can #include minimp3.h in as many files as you like. Also you can use MINIMP3_ONLY_MP3 define to strip MP1/MP2 decoding code. MINIMP3_ONLY_SIMD define controls generic (non SSE/NEON) code generation (always enabled on x64/arm64 targets). In case you do not want any platform-specific SIMD optimizations, you can define MINIMP3_NO_SIMD. MINIMP3_NONSTANDARD_BUT_LOGICAL define saves some code bytes, and enforces non-standard but logical behaviour of mono-stereo transition (rare case). MINIMP3_FLOAT_OUTPUT makes mp3dec_decode_frame() output to be float instead of short and additional function mp3dec_f32_to_s16 will be available for float->short conversion if needed.
Then. we decode the input stream frame-by-frame:
/*typedef struct
{
int frame_bytes;
int channels;
int hz;
int layer;
int bitrate_kbps;
} mp3dec_frame_info_t;*/
mp3dec_frame_info_t info;
short pcm[MINIMP3_MAX_SAMPLES_PER_FRAME];
/*unsigned char *input_buf; - input byte stream*/
samples = mp3dec_decode_frame(&mp3d, input_buf, buf_size, pcm, &info);
The mp3dec_decode_frame() function decodes one full MP3 frame from the input buffer, which must be large enough to hold one full frame.
The decoder will analyze the input buffer to properly sync with the MP3 stream, and will skip ID3 data, as well as any data which is not valid. Short buffers may cause false sync and can produce 'squealing' artefacts. The bigger the size of the input buffer, the more reliable the sync procedure. We recommend having as many as 10 consecutive MP3 frames (~16KB) in the input buffer at a time.
At end of stream just pass rest of the buffer, sync procedure should work even with just 1 frame in stream (except for free format and garbage at the end can mess things up, so id3v1 and ape tags must be removed first).
For free format there minimum 3 frames needed to do proper sync: 2 frames to detect frame length and 1 next frame to check detect is good.
The size of the consumed MP3 data is returned in the mp3dec_frame_info_t field of the frame_bytes struct; you must remove the data corresponding to the frame_bytes field from the input buffer before the next decoder invocation.
The decoding function returns the number of decoded samples. The following cases are possible:
- 0: No MP3 data was found in the input buffer
- 384: Layer 1
- 576: MPEG 2 Layer 3
- 1152: Otherwise
The following is a description of the possible combinations of the number of samples and frame_bytes field values:
- More than 0 samples and
frame_bytes > 0: Succesful decode - 0 samples and
frame_bytes > 0: The decoder skipped ID3 or invalid data - 0 samples and
frame_bytes == 0: Insufficient data
If frame_bytes == 0, the other fields may be uninitialized or unchanged; if frame_bytes != 0, the other fields are available. The application may call mp3dec_init() when changing decode position, but this is not necessary.
As a special case, the decoder supports already split MP3 streams (for example, after doing an MP4 demux). In this case, the input buffer must contain exactly one non-free-format frame.
Seeking
You can seek to any byte in the stream and call mp3dec_decode_frame; this will work in almost all cases, but is not completely guaranteed. Probablility of sync procedure failure lowers when MAX_FRAME_SYNC_MATCHES value grows. Default MAX_FRAME_SYNC_MATCHES=10 and probablility of sync failure should be very low. If granule data is accidentally detected as a valid MP3 header, short audio artefacting is possible.
High-level mp3dec_ex_seek function supports precise seek to sample (MP3D_SEEK_TO_SAMPLE) using index and binary search.
Track length detect
If the file is known to be cbr, then all frames have equal size and lack ID3 tags, which allows us to decode the first frame and calculate all frame positions as frame_bytes * N. However, because of padding, frames can differ in size even in this case.
In general case whole stream scan is needed to calculate it's length. Scan can be omitted if vbr tag is present (added by encoders like lame and ffmpeg), which contains length info. High-level functions automatically use the vbr tag if present.
High-level API
If you need only decode file/buffer or use precise seek, you can use optional high-level API. Just #include minimp3_ex.h instead and use following additional functions:
#define MP3D_SEEK_TO_BYTE 0
#define MP3D_SEEK_TO_SAMPLE 1
#define MINIMP3_PREDECODE_FRAMES 2 /* frames to pre-decode and skip after seek (to fill internal structures) */
/*#define MINIMP3_SEEK_IDX_LINEAR_SEARCH*/ /* define to use linear index search instead of binary search on seek */
#define MINIMP3_IO_SIZE (128*1024) /* io buffer size for streaming functions, must be greater than MINIMP3_BUF_SIZE */
#define MINIMP3_BUF_SIZE (16*1024) /* buffer which can hold minimum 10 consecutive mp3 frames (~16KB) worst case */
#define MINIMP3_ENABLE_RING 0 /* enable hardware magic ring buffer if available, to make less input buffer memmove(s) in callback IO mode */
#define MP3D_E_MEMORY -1
#define MP3D_E_IOERROR -2
typedef struct
{
mp3d_sample_t *buffer;
size_t samples; /* channels included, byte size = samples*sizeof(mp3d_sample_t) */
int channels, hz, layer, avg_bitrate_kbps;
} mp3dec_file_info_t;
typedef size_t (*MP3D_READ_CB)(void *buf, size_t size, void *user_data);
typedef int (*MP3D_SEEK_CB)(uint64_t position, void *user_data);
typedef struct
{
MP3D_READ_CB read;
void *read_data;
MP3D_SEEK_CB seek;
void *seek_data;
} mp3dec_io_t;
typedef struct
{
uint64_t samples;
mp3dec_frame_info_t info;
int last_error;
...
} mp3dec_ex_t;
typedef int (*MP3D_ITERATE_CB)(void *user_data, const uint8_t *frame, int frame_size, int free_format_bytes, size_t buf_size, uint64_t offset, mp3dec_frame_info_t *info);
typedef int (*MP3D_PROGRESS_CB)(void *user_data, size_t file_size, uint64_t offset, mp3dec_frame_info_t *info);
/* decode whole buffer block */
int mp3dec_load_buf(mp3dec_t *dec, const uint8_t *buf, size_t buf_size, mp3dec_file_info_t *info, MP3D_PROGRESS_CB progress_cb, void *user_data);
int mp3dec_load_cb(mp3dec_t *dec, mp3dec_io_t *io, uint8_t *buf, size_t buf_size, mp3dec_file_info_t *info, MP3D_PROGRESS_CB progress_cb, void *user_data);
/* iterate through frames */
int mp3dec_iterate_buf(const uint8_t *buf, size_t buf_size, MP3D_ITERATE_CB callback, void *user_data);
int mp3dec_iterate_cb(mp3dec_io_t *io, uint8_t *buf, size_t buf_size, MP3D_ITERATE_CB callback, void *user_data);
/* streaming decoder with seeking capability */
int mp3dec_ex_open_buf(mp3dec_ex_t *dec, const uint8_t *buf, size_t buf_size, int seek_method);
int mp3dec_ex_open_cb(mp3dec_ex_t *dec, mp3dec_io_t *io, int seek_method);
void mp3dec_ex_close(mp3dec_ex_t *dec);
int mp3dec_ex_seek(mp3dec_ex_t *dec, uint64_t position);
size_t mp3dec_ex_read(mp3dec_ex_t *dec, mp3d_sample_t *buf, size_t samples);
#ifndef MINIMP3_NO_STDIO
/* stdio versions of file load, iterate and stream */
int mp3dec_load(mp3dec_t *dec, const char *file_name, mp3dec_file_info_t *info, MP3D_PROGRESS_CB progress_cb, void *user_data);
int mp3dec_iterate(const char *file_name, MP3D_ITERATE_CB callback, void *user_data);
int mp3dec_ex_open(mp3dec_ex_t *dec, const char *file_name, int seek_method);
#ifdef _WIN32
int mp3dec_load_w(mp3dec_t *dec, const wchar_t *file_name, mp3dec_file_info_t *info, MP3D_PROGRESS_CB progress_cb, void *user_data);
int mp3dec_iterate_w(const wchar_t *file_name, MP3D_ITERATE_CB callback, void *user_data);
int mp3dec_ex_open_w(mp3dec_ex_t *dec, const wchar_t *file_name, int seek_method);
#endif
#endif
Use MINIMP3_NO_STDIO define to exclude STDIO functions. MINIMP3_ALLOW_MONO_STEREO_TRANSITION allows mixing mono and stereo in same file. In that case mp3dec_frame_info_t->channels = 0 is reported on such files and correct channels number passed to progress_cb callback for each frame in mp3dec_frame_info_t structure. MP3D_PROGRESS_CB is optional and can be NULL, example of file decoding:
mp3dec_t mp3d;
mp3dec_file_info_t info;
if (mp3dec_load(&mp3d, input_file_name, &info, NULL, NULL))
{
/* error */
}
/* mp3dec_file_info_t contains decoded samples and info,
use free(info.buffer) to deallocate samples */
Example of file decoding with seek capability:
mp3dec_ex_t dec;
if (mp3dec_ex_open(&dec, input_file_name, MP3D_SEEK_TO_SAMPLE))
{
/* error */
}
/* dec.samples, dec.info.hz, dec.info.layer, dec.info.channels should be filled */
if (mp3dec_ex_seek(&dec, position))
{
/* error */
}
mp3d_sample_t *buffer = malloc(dec.samples*sizeof(mp3d_sample_t));
size_t readed = mp3dec_ex_read(&dec, buffer, dec.samples);
if (readed != dec.samples) /* normal eof or error condition */
{
if (dec.last_error)
{
/* error */
}
}
Bindings
- https://github.com/tosone/minimp3 - go bindings
- https://github.com/notviri/rmp3 - rust
no_stdbindings which don't allocate. - https://github.com/germangb/minimp3-rs - rust bindings
- https://github.com/johangu/node-minimp3 - NodeJS bindings
- https://github.com/pyminimp3/pyminimp3 - python bindings
- https://github.com/bashi/minimp3-wasm - wasm bindings
- https://github.com/DasZiesel/minimp3-delphi - delphi bindings
- https://github.com/mgeier/minimp3_ex-sys - low-level rust bindings to
minimp3_ex
Interesting links
- https://keyj.emphy.de/minimp3/
- https://github.com/technosaurus/PDMP3
- https://github.com/technosaurus/PDMP2
- https://github.com/packjpg/packMP3
- https://sites.google.com/a/kmlager.com/www/projects
- https://sourceforge.net/projects/mp3dec/
- http://blog.bjrn.se/2008/10/lets-build-mp3-decoder.html
- http://www.mp3-converter.com/mp3codec/
- http://www.multiweb.cz/twoinches/mp3inside.htm
- https://www.mp3-tech.org/
- https://id3.org/mp3Frame
- https://www.datavoyage.com/mpgscript/mpeghdr.htm
Download Details:
Author: lieff
Source Code: https://github.com/lieff/minimp3
License: CC0-1.0 License
#programming #developer #cplusplus #cpp
What is GEEK
Buddha Community
1652837384
Build a Single Page App with Laravel 9, Jetstream, Vuejs, Inertiajs, MySQL, Tailwind CSS and Docker
In this tutorial, you will learn how to build a single page application. I'll take you through the process step by step, using cutting edge technologies like Laravel 9, Jetstream, Vuejs, Inertiajs, MySQL, Tailwind CSS, and Docker.
Let's get started.
What you need to follow this guide:
To follow along you will need:
- a computer
- to know how to install software
- a basic understanding of HTML, CSS, JavaScript, and PHP
- knowledge of at least one JavaScript framework and an understanding of the MVC design pattern.
This guide is organized into 10 chapters and is based off a live coding series that I record. The live coding series is completely unscripted, so there will be bugs and gotchas there that you won't find in this guide.
You can find the complete playlist at the end of this article.
Everything here should just work, but if it doesn't feel free to ask for help by joining my community on Slack. There you can share code snippets and chat with me directly.
Table of Contents
- What Tech Are We Using?
- How to Setup Your Machine
- How to build the app with Laravel 9, Laravel Sail, Jetstram, Inertia and Vue3
- How to Refactor the Admin Dashboard and Create New Admin Pages
- How to Submit Forms with Files
- How to Add the Form to the Component
- How to Store Data
- How to Update Operations
- How to Delete a Resourse
- Wrap up and what's next
- Conclusion
Original article source at https://www.freecodecamp.org
What Tech Are We Using?
First, let's go over the different tools we'll be using in this project.
Docker
Docker is a set of platform as a service products that use OS-level virtualization to deliver software in packages called containers.
To simplify this concept, Docker lets you package applications and dependencies in a container.
A containerized application allows you to have a flexible development environment so that you can run different applications without worrying about dependencies, their requirements, and conflicts between different versions. You can easily run applications that, for instance, require two different versions of PHP and MySQL.
Each team member can quickly reproduce the same environment of your application by simply running the same container's configuration.
If you want to learn more about Docker, its Documentation is a great place to start.
Here's a Handbook on Docker essentials, as well, so you can practice your skills.
Mysql
MySQL is an open-source relational database management system. You can use it to organize data into one or more tables with data that may be related to each other.
We need to store data somewhere and here is where MySQL comes into play.
Here are the Docs if you want to read up more. Here's a full free course on MySQL if you want to dive deeper.
Laravel
Laravel is a free, open-source PHP web framework that helps you develop web applications following the model–view–controller architectural pattern.
Laravel is an amazing PHP framework that you can use to create bespoke web applications.
Here's the Laravel Documentation for more info, and here's a full project-based course to help you learn Laravel.
Laravel Sail
Laravel Sail is a lightweight command-line interface for interacting with Laravel's default Docker development environment.
Sail provides a great starting point for building a Laravel application using PHP, MySQL, and Redis without requiring prior Docker experience.
Usually, creating a development environment to build such applications means you have to install software, languages, and frameworks on your local machine – and that is time-consuming. Thanks to Docker and Laravel Sail we will be up and running in no time!
Laravel Sail is supported on macOS, Linux, and Windows via WSL2.
Here's the Documentation if you want to read up on it.
Laravel Jetstream
When building web applications, you likely want to let users register and log in to use your app. That is why we will use Jetstream.
Laravel Jetstream is a beautifully designed application starter kit for Laravel and provides the perfect starting point for your next Laravel application.
It uses Laravel Fortify to implement all the back end authentication logic.
Here are the Docs.
Vuejs
Vue.js is an open-source model–view–ViewModel front end JavaScript framework for building user interfaces and single-page applications.
Vue is a fantastic framework that you can use as a stand-alone to build single-page applications, but you can also use it with Laravel to build something amazing.
Here's the Vue Documentation if you want to read up. And here's a great Vue course to get you started.
Inertia JS
Inertia is the glue between Laravel and Vuejs that we will use to build modern single-page applications using classic server-side routing.
You can learn more about it in the Documentation here.
Tailwind
Tailwind CSS is a utility-first CSS framework packed with classes like flex, pt-4, text-center, and rotate-90 that you can use to build any design, directly in your markup
We'll use it in this project to build our design. Here's a quick guide to get you up and running if you aren't familiar with Tailwind.
How to Set Up Your Machine
To follow along with my live coding (and this tutorial), you will need to install Docker desktop on your machine. If you are using Windows, you will also need to enable WSL in your system settings.
Visit the Docker getting started page to install Docker Desktop.
If you are on Windows, enable WSL2 by following the steps here.
If you have any trouble, feel free to reach out or join my community on Slack to get help.
Laravel Installation with Sail
If you have successfully installed Docker Desktop on your machine, we can open the terminal and install Laravel 9.
Open a terminal window and browse to a folder where you want to keep your project. Then run the command below to download the latest Laravel files. The command will put all files inside a folder called my-example-app, which you can tweak as you like.
# Download laravel
curl -s "https://laravel.build/my-example-app" | bash
# Enter the laravel folder
cd my-example-app
Deploy Laravel on Docker using the sail up command
With Docker Desktop up and running, the next step is to start Laravel sail to build all the containers required to run our application locally.
Run the following command from the folder where all Laravel files have been downloaded:
vendor/bin/sail up
It will take a minute. Then visit http://localhost and you should see your Laravel application.
If you run sail up and you get the following error, it is likely that you need to update Docker Desktop:
ERROR: Service 'laravel.test' failed to build:
How to Build the App with Laravel 9, Laravel Sail, Jetstram, Inertia and Vue3
In this section, we will define a basic roadmap, install Laravel 9 with Laravel Sail, Run sail, and build the containers.
I will also take you on a tour of Laravel Sail and the sail commands.
Then we will install Jetstream and scaffold Vue and Inertia files and have a look at the files and available features.
Next, we will populate our database and add the front end provided by Jetstream to register an account and log into a fresh Laravel application.
Finally, we will have a look at the Jetstream dashboard, and the Inertia/Vue Components and then start playing around.
Along the way, we'll disable the registration, enable the Jetstream user profile picture feature, and then add our first Inertia page where we'll render some data taken from the database.
Here's the live coding video if you want to follow along that way:
And if you prefer following along in this written tutorial, here are all the steps.
Just a reminder – you should have Laravel installed with Sail and have Docker set up on your machine. You can follow the steps above to do so if you haven't already.
Laravel Sail Overview – Sail Commands
With Laravel Sail installed, our usual Laravel commands have sligtly changed.
For instance, instead of running the Laravel artisan command using PHP like php artisan, we now have to use Sail, like so: sail artisan.
The sail artisan command will return a list of all available Laravel commands.
Usually, when we work with Laravel, we also have to run the npm and composer commands.
Again, we need to prefix our commands with sail to make them run inside the container.
Below you'll find a list of some commands you will likely have to run:
# Interact with the database - run the migrations
sail artisan migrate # It was: php artisan migrate
# Use composer commands
sail composer require <packageName> # it was: composer require <packageName>
# Use npm commands
sail npm run dev # it was: npm run dev
You can read more in the Sail documentation.
Install Jetstream and Scaffold Vue and Inertia
Let's now install the Laravel Jetstream authentication package and use the Inertia scaffolding with Vue3.
cd my-example-app
sail composer require laravel/jetstream
Remember to prefix the composer command with sail.
The command above has added a new command to Laravel. Now we need to run it to install all the Jetstream components:
sail artisan jetstream:install inertia
Next we need to compile all static assets with npm:
sail npm install
sail npm run dev
Before we can actually see our application, we will need to run the database migrations so that the session table, required by Jetstream, is present.
sail artisan migrate
Done! Jetstream is now installed in our application. If you visit http://localhost in your browser you should see the Laravel application with two links at the top to register and log in.
Populate the Database and Create a User Account
Before creating a new user, let's have a quick look at the database configuration that Laravel Sail has created for us in the .env file.
DB_CONNECTION=mysql
DB_HOST=mysql
DB_PORT=3306
DB_DATABASE=my-example-app
DB_USERNAME=sail
DB_PASSWORD=password
As you can see, Laravel Sail configures everything we need to access the database container that is running on Docker. The DB_DATABASE is the name of the database and it is the same as the project folder. This is why in the previous step we were able to run the migrate command without issues.
Since we already migrated all database tables, we can now use the Laravel built-in user factory to create a new user then use its details to log in our user dashboard.
Let's open artisan tinker to interact with our application.
sail artisan tinker
The command above will open a command line interface that we can use to interact with our application. Let's create a new user.
User::factory()->create()
The command above will create a new user and save its data in our database. Then it will render the user data onto the screen. Make sure to copy the user email so we can use it later to log in. Then exit by typing exit;.
The default password for every user created with a factory is password.
Let's visit the login page and access our application dashboard.
Jetstream Dashboard
After login you are redirected to the Jetstream dashboard, which looks amazing by default. We can customize it as we like, but it is just a starting point.
Jetstream/Vue Components and Inertia Overview
The first thing you may notice after installing Jetstram is that there are a number of Vue components registered in our application. Not only that, also Inertia brings in Vue components.
To use Inertia, we need to get familiar with it when defining routes.
When we installed Jetstream, it created inside the resources/js directory a number of subfolders where all our Vue components live. There are not just simple components but also Pages components rendered by inertia as our Views.
The Jetstream inertia scaffolding created:
resources/js/JetstreamHere we have 27 components used by Jetstream, but we can use them in our application too if we want.resources/js/LayoutsIn this folder there is the layout component used by inertia to render the dashboard pageresources/js/PagesThis is where we will place all our Pages (views) components. You will find the Dashboard page as well as the Laravel Welcome page components here.
The power of Inertia mostly comes from how it connects Vue and Laravel, letting us pass data (Database Models and more) as props to our Vue Pages components.
When you open the routes/web.php file you will notice that we no longer return a view but instead we use Inertia to render a Page component.
Let's examine the / homepage route that renders the Welcome component.
Route::get('/', function () {
return Inertia::render('Welcome', [
'canLogin' => Route::has('login'),
'canRegister' => Route::has('register'),
'laravelVersion' => Application::VERSION,
'phpVersion' => PHP_VERSION,
]);
});
It looks like our usual Route definition, exept that in the closure we are returning an \Inertia\Response by calling the render method of the Inertia class Inertia::render().
This method accepts two parameters. The first is a component name. Here we passed the Welcome Page component, while the second parameter is an associative array that will turn into a list of props to pass to the component. Here is where the magic happens.
Looking inside the Welcome component, you will notice that in its script section, we simply define four props matching with the keys of our associative array. Then inertia will do the rest.
<script>
import { defineComponent } from 'vue'
import { Head, Link } from '@inertiajs/inertia-vue3';
export default defineComponent({
components: {
Head,
Link,
},
// 👇 Define the props
props: {
canLogin: Boolean,
canRegister: Boolean,
laravelVersion: String,
phpVersion: String,
}
})
</script>
We can then just call the props inside the template. If you look at the template section you will notice that laravelVersion and phpVersion are referenced in the code as you normally would do with props in Vuejs.
<div class="ml-4 text-center text-sm text-gray-500 sm:text-right sm:ml-0">
Laravel v{{ laravelVersion }} (PHP v{{ phpVersion }})
</div>
The dashboard component is a little different. In fact it uses the Layout defined under Layouts/AppLayout.vue and uses the Welcome component to render the Dashboard page content, which is the same as the laravel Welcome page.
<template>
<app-layout title="Dashboard">
<template #header>
<h2 class="font-semibold text-xl text-gray-800 leading-tight">
Dashboard
</h2>
</template>
<div class="py-12">
<div class="max-w-7xl mx-auto sm:px-6 lg:px-8">
<div class="bg-white overflow-hidden shadow-xl sm:rounded-lg">
<welcome />
</div>
</div>
</div>
</app-layout>
</template>
Inside the layout component you will notice the two inertia components Head and Link.
We can use the Head component to add head elements to our page, like meta tags, page title, and so on. The Link component is a wrapper aroud a standard anchor tag that incercepts click events and prevents full page reload as you can read in the Inertia documentation.
Disable the Registration Feature
If you are following along, the next step I'll take is to disable one on the features Jetstream provides – register an account.
To do that, we can navigate to config/fortify.php and comment out line 135 Features::registration() from the features array.
'features' => [
//Features::registration(),
Features::resetPasswords(),
// Features::emailVerification(),
Features::updateProfileInformation(),
Features::updatePasswords(),
Features::twoFactorAuthentication([
'confirmPassword' => true,
]),
],
If we visit the welcome page we will notice that the register link is gone. Also, the route is no longer listed when we run sail artisan route:list.
Enable Jetstream User Profile Picture
Now let's try to enable the Jetstream feature called ProfilePhotos. As you can guess, this will allow the user to add a profile picture.
To do that we need to visit config/jetstream.php and uncomment line 59 Features::profilePhoto.
'features' => [
// Features::termsAndPrivacyPolicy(),
Features::profilePhotos(), // 👈
// Features::api(),
// Features::teams(['invitations' => true]),
Features::accountDeletion(),
],
If you log in you will see that in the user profile, a new section is available to upload a profile picture.
But before doing anything else we need to run sail artisan storage:link so that Laravel creates a symlink to the storage/app/public folder where we will save all user profile images.
Now try to visit the user profile and update the profile picture. If you get a 404 on the image this is because by default Laravel sail assumes we are using Laravel valet and sets the app URL like so APP_URL=http://my-example-app.test in the .env file. Let's change it and use localhost instead.
APP_URL=http://localhost
Now we should be good to go and be able to see and change our profile image!🥳
How to Add our First Inertia Page and Render Records from the DB
Since we are rendering Vue components instead of blade views, it is wise to start sail npm run watch to watch and recompile our Vue components as we create or edit them. Next let's add a new Photos page.
I will start by creating a new Route inside web.php:
Route::get('photos', function () {
//dd(Photo::all());
return Inertia::render('Guest/Photos');
});
In the code above I defined a new GET route and then rendered a component that I will place inside the resources/js/Pages/Guest and call Photos. Let's create it.
Create a Guest folder:
cd resources/js/Pages
mkdir Guest
cd Guest
touch Photos.vue
Then let's define a basic component:
<template>
<h1>Photos Page</h1>
</template>
If we visit http://localhost/photos/ we will see our new page, cool! Let's copy over the page structure from the Welcome page so that we get the login and dashboard links as well.
The component will change to this:
<template>
<Head title="Phots" />
<div class="relative flex items-top justify-center min-h-screen bg-gray-100 dark:bg-gray-900 sm:items-center sm:pt-0">
<div v-if="canLogin" class="hidden fixed top-0 right-0 px-6 py-4 sm:block">
<Link v-if="$page.props.user" :href="route('admin.dashboard')" class="text-sm text-gray-700 underline">
Dashboard
</Link>
<template v-else>
<Link :href="route('login')" class="text-sm text-gray-700 underline">
Log in
</Link>
<Link v-if="canRegister" :href="route('register')" class="ml-4 text-sm text-gray-700 underline">
Register
</Link>
</template>
</div>
<div class="max-w-6xl mx-auto sm:px-6 lg:px-8">
<h1>Photos</h1>
</div>
</div>
</template>
<script>
import { defineComponent } from 'vue'
import { Head, Link } from '@inertiajs/inertia-vue3';
export default defineComponent({
components: {
Head,
Link,
},
props: {
canLogin: Boolean,
canRegister: Boolean,
}
})
</script>
The next step is to render a bunch of data onto this new page. For that we will build a Model and add some records to the database.
saild artisan make:model Photo -mfcr
This command creates a Model called Photo, plus a database migration table class, a factory, and a resource controller.
Now let's define the database table inside the migration we just creted. Visit the database/migrations folder and you should see a file with a name similar to this: 2022_02_13_215119_create_photos_table (yours will be sligly different).
Inside the migration file we can define a basic table like the following:
public function up()
{
Schema::create('photos', function (Blueprint $table) {
$table->id();
$table->string('path');
$table->text('description');
$table->timestamps();
});
}
For our table we defined just two new columns, path and description, plus the id, created_at and updated_at that will be created by the $table->id() and by the $table->timestamps() methods.
After the migration we will define a seeder and then run the migrations and seed the database.
At the top of the database/seeders/PhotoSeeder.php file we will import our Model and Faker:
use App\Models\Photo;
use Faker\Generator as Faker;
Next we will implement the run method using a for loop to create 10 records in the database.
public function run(Faker $faker)
{
for ($i = 0; $i < 10; $i++) {
$photo = new Photo();
$photo->path = $faker->imageUrl();
$photo->description = $faker->paragraphs(2, true);
$photo->save();
}
}
We are ready to run the migrations and seed the database.
sail artisan migrate
sail artisan db:seed --class PhotoSeeder
We are now ready to show the data on the Guest/Photos page component.
First update the route and pass a collection of Photos as props to the rendered component:
Route::get('photos', function () {
//dd(Photo::all());
return Inertia::render('Guest/Photos', [
'photos' => Photo::all(), ## 👈 Pass a collection of photos, the key will become our prop in the component
'canLogin' => Route::has('login'),
'canRegister' => Route::has('register'),
]);
});
Second, pass the prop to the props in the script section of the Guest/Photos component:
props: {
canLogin: Boolean,
canRegister: Boolean,
photos: Array // 👈 Here
}
Finally loop over the array and render all photos in the template section, just under the h1:
<section class="photos">
<div v-for="photo in photos" :key="photo.id" class="card" >
<img :src="photo.path" alt="">
</div>
</section>
Done! if you visit the /photos page you should see ten photos. 🥳
How to Refactor the Admin Dashboard and Create New Admin Pages
In this chapter we will Re-route the Jetstream dashboard and make a route group for all admin pages.
Then we will see how to add a new link to the dashboard and add a new admin page.
Finally we will take a collection of data from the db and render them in a basic table. The default table isn't cool enough, so for those reading this article, I decided to add a Tailwind table component.
Re-route the Jetstream Dashboard
If we look at the config/fortify.php file we can see that around line 64 there is a key called home. It is calling the Home constant of the Route service provider.
This means that we can tweek the constant and redirect the authenticated user to a different route.
Lets go through it step-by-step:
- update the HOME Constant
- make a route group and redirect logged in users to
admin/instead of '/dashboard'
Our application will have only a single user, so once they're logged in it is clearly the site admin – so makes sense to redirect to an admin URI.
Change the HOME constant in app/Providers/RouteServiceProvider.php around line 20 to match the following:
public const HOME = '/admin';
How to Add an Admin Pages Route Group
Next let's update our route inside web.php. We will change the route registered by Jetstream from this:
Route::middleware(['auth:sanctum', 'verified'])->get('/', function () {
return Inertia::render('Dashboard');
})->name('dashboard');
To this:
Route::middleware(['auth:sanctum', 'verified'])->prefix('admin')->name('admin.')->group(function () {
Route::get('/', function () {
return Inertia::render('Dashboard');
})->name('dashboard');
// other admin routes here
});
The route above is a route group that uses the auth:sanctum middleware for all routes within the group, a prefix of admin, and adds a admin suffix to each route name.
The end result is that we will be able to refer to the dashboard route by name, which now will be admin.dashboard. When we log in, we will be redirected to the admin route. Our dashboard route will respond since it's URI is just / but the goup prefix will prefix every route in the group and make their URI start with admin.
If you now run sail artisan route:list you will notice that the dashboard route has changed as we expected.
Before moving to the next step we need to update both the /layouts/AppLayout.vue and /Pages/Welcome.vue components.
Do you remeber that the dashboard route name is now admin.dashboard and not just dashboard?
Let's inspect the two components and update every reference of route('dahsboard') to this:
route('admin.dahsboard')
and also every reference of route().current('dashboard') to this:
route().current('admin.dashboard')
After all the changes, make sure to recompile the Vue components and watch changes by running sail npm run watch. Then visit the home page to check if everything is working.
How to Add a New Link to the Dashboard
Now, to add a new admin page where we can list all photos stored in the database, we need to add a new route to the group we created earlier. Let's hit the web.php file and make our changes.
In the Route group we will add a new route:
Route::middleware(['auth:sanctum', 'verified'])->prefix('admin')->name('admin.')->group(function () {
Route::get('/', function () {
return Inertia::render('Dashboard');
})->name('dashboard');
// 👇 other admin routes here 👇
Route::get('/photos', function () {
return inertia('Admin/Photos');
})->name('photos'); // This will respond to requests for admin/photos and have a name of admin.photos
});
In the new route above we used the inertia() helper function that does the same exact thing – returns an Inertia/Response and renders our Page component. We placed the component under an Admin folder inside Pages and we will call it Photos.vue.
Before we create the component, let's add a new link to the dashboard that points to our new route.
Inside AppLayout.vue, find the Navigation Links comment and copy/paste the jet-nav-link component that is actually displaing a link to the dashboard and make it point to our new route.
You will end up having something like this:
<!-- Navigation Links -->
<div class="hidden space-x-8 sm:-my-px sm:ml-10 sm:flex">
<jet-nav-link :href="route('admin.dashboard')" :active="route().current('admin.dashboard')">
Dashboard
</jet-nav-link>
<!-- 👇 here it is our new link -->
<jet-nav-link :href="route('admin.photos')" :active="route().current('admin.photos')">
Photos
</jet-nav-link>
</div>
Our link above uses route('admin.photos') to point to the correct route in the admin group.
If you visit localhost/dashboard and open the inspector, you should see an error:
Error: Cannot find module `./Photos.vue`
It is fine – we haven't created the Photos page component yet. So let's do it now!
How to Add a New Admin Page Component
Make a file named Photos.vue inside the Pages/Admin folder. Below are the bash commands to create the folder and the file via terminal, but you can do the same using your IDE's graphical interface.
cd resources/js/Pages
mkdir Admin
touch Admin/Photos.vue
To make this new page look like the Dashboard page, we will copy over its content. You should end up having something like this:
<template>
<app-layout title="Dashboard"> <!-- 👈 if you want you can update the page title -->
<template #header>
<h2 class="font-semibold text-xl text-gray-800 leading-tight">Photos</h2>
</template>
<div class="py-12">
<div class="max-w-7xl mx-auto sm:px-6 lg:px-8">
<div class="bg-white overflow-hidden shadow-xl sm:rounded-lg">
<!-- 👇 All photos for the Admin page down here -->
<h1 class="text-2xl">Photos</h1>
</div>
</div>
</div>
</app-layout>
</template>
<script>
import { defineComponent } from "vue";
import AppLayout from "@/Layouts/AppLayout.vue";
export default defineComponent({
components: {
AppLayout,
},
});
</script>
I removed a few pieces from the Dashboard template so make sure to double check the code above. The welcome component was removed from the template as it is not required in this page, and also its reference in the script section. The rest is identical.
Feel free to update the page title referenced as prop on the <app-layout title="Dashboard">.
Now when you visit localhost/admin you can click on the Photos menu item and see our Photos page component content. It's not much for now, just an h1.
How to Render Records in the Admin Page as a Table
Now it's time to render the data onto a table. To make things work let's first add our markup and fake that we already have access to as an array of objects and loop over them inside our table. Than we will figure out how to make things work for real.
<table class="table-auto w-full text-left">
<thead>
<tr>
<th>ID</th>
<th>Photo</th>
<th>Desciption</th>
<th>Actions</th>
</tr>
</thead>
<tbody>
<tr v-for="photo in photos">
<td>{{ photo.id }}</td>
<td><img width="60" :src="photo.path" alt="" /></td>
<td>{{photo.description}}</td>
<td>View - Edit - Delete</td>
</tr>
</tbody>
</table>
Ok, since we assumed that our component has access to a list of Photos, let's pass a new prop to the component from the Route.
Update the route in web.php and pass to the inertia() function a second argument that will be an associative array. It will have its keys passed as props to the Vue Page component.
In it we will call Photo::all() to have a collection to assign to a photos key, but you can use other eloquent methods if you want to paginate the results, for example.
Route::get('/photos', function () {
return inertia('Admin/Photos', [
'photos' => Photo::all()
]);
})->name('photos');
To connect the prop to our Page component we need to define the prop also inside the component.
<script>
import { defineComponent } from "vue";
import AppLayout from "@/Layouts/AppLayout.vue";
export default defineComponent({
components: {
AppLayout,
},
/* 👇 Pass the photos array as a props 👇 */
props: {
photos: Array,
},
});
</script>
Extra: How to use a Tailwind table component
Tailwind is a CSS framework similar to Bootstrap. There are a number of free to use components that we can grab from the documentation, tweak, and use.
This table component is free and looks nice:https://tailwindui.com/components/application-ui/lists/tables.
We can tweek the Photos page template and use the Tailwind table component to get a nice looking table like so:
<template>
<app-layout title="Dashboard">
<template #header>
<h2 class="font-semibold text-xl text-gray-800 leading-tight">Photos</h2>
</template>
<div class="py-12">
<div class="max-w-7xl mx-auto sm:px-6 lg:px-8">
<!-- All posts goes here -->
<h1 class="text-2xl">Photos</h1>
<a class="px-4 bg-sky-900 text-white rounded-md" href>Create</a>
<div class="flex flex-col">
<div class="-my-2 overflow-x-auto sm:-mx-6 lg:-mx-8">
<div class="py-2 align-middle inline-block min-w-full sm:px-6 lg:px-8">
<div class="shadow overflow-hidden border-b border-gray-200 sm:rounded-lg">
<table class="min-w-full divide-y divide-gray-200">
<thead class="bg-gray-50">
<tr>
<th
scope="col"
class="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase tracking-wider"
>ID</th>
<th
scope="col"
class="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase tracking-wider"
>Photos</th>
<th
scope="col"
class="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase tracking-wider"
>Description</th>
<th scope="col" class="relative px-6 py-3">
<span class="sr-only">Edit</span>
</th>
</tr>
</thead>
<tbody class="bg-white divide-y divide-gray-200">
<tr v-for="photo in photos" :key="photo.id">
<td class="px-6 py-4 whitespace-nowrap">
<div
class="text-sm text-gray-900"
>{{ photo.id }}</div>
</td>
<td class="px-6 py-4 whitespace-nowrap">
<div class="flex items-center">
<div class="flex-shrink-0 h-10 w-10">
<img
class="h-10 w-10 rounded-full"
:src="photo.path"
alt
/>
</div>
</div>
</td>
<td class="px-6 py-4 whitespace-nowrap">
<div class="text-sm text-gray-900">
{{ photo.description.slice(0, 100) + '...' }}
</div>
</td>
<!-- ACTIONS -->
<td class="px-6 py-4 whitespace-nowrap text-right text-sm font-medium">
<a href="#" class="text-indigo-600 hover:text-indigo-900">
View - Edit - Delete
</a>
</td>
</tr>
</tbody>
</table>
</div>
</div>
</div>
</div>
</div>
</div>
</app-layout>
</template>
How to Submit Forms with Files
For the next section we will look into how to submit a form so that we can add a new photo to the database.
- Add a create button
- Add a create route
- Define the PhotosCreate component
- Add a form
- Validate data
- Show validation errors
- Save the file to the filesystem
- Save the model
How to Create a New Photo
Add a link that points to a create route:
<a class="px-4 bg-sky-900 text-white rounded-md" :href="route('admin.photos.create')">Create</a>
Create the route within the admin group:
Route::get('/photos/create', function () {
return inertia('Admin/PhotosCreate');
})->name('photos.create');
Let's add also the route that will handle the form submission for later:
Route::post('/photos', function () {
dd('I will handle the form submission')
})->name('photos.store');
Create the Admin/PhotosCreate.vue component:
<template>
<app-layout title="Dashboard">
<template #header>
<h2 class="font-semibold text-xl text-gray-800 leading-tight">Photos</h2>
</template>
<div class="py-12">
<div class="max-w-7xl mx-auto sm:px-6 lg:px-8">
<h1 class="text-2xl">Add a new Photo</h1>
<!-- 👇 Photo creation form goes here -->
</div>
</div>
</app-layout>
</template>
<script>
import { defineComponent } from "vue";
import AppLayout from "@/Layouts/AppLayout.vue";
export default defineComponent({
components: {
AppLayout,
},
});
</script>
How to Add the Form to the Component
The next step is to add the form to the page and figure out how to submit it.
If you hit the Inertia documentation you will find out that there is a useForm class that we can use to simplify the process.
First, import the module inside the script tag of the Admin/PhotosCreate.vue component:
import { useForm } from '@inertiajs/inertia-vue3';
Next we can use it in the setup function (Vue 3 composition API):
setup () {
const form = useForm({
path: null,
description: null,
})
return { form }
}
In the code above we defined the function called setup() then a constant called form to have the useForm() class assigned to it.
Inside its parentheses we defined two properties, path and description which are the column names of our photos model.
Finally we returned the form variable for the setup function. This is to make the variable available inside our template.
Next we can add the form markup:
<form @submit.prevent="form.post(route('admin.photos.store'))">
<div>
<label for="description" class="block text-sm font-medium text-gray-700"> Description </label>
<div class="mt-1">
<textarea id="description" name="description" rows="3" class="shadow-sm focus:ring-indigo-500 focus:border-indigo-500 mt-1 block w-full sm:text-sm border border-gray-300 rounded-md" placeholder="lorem ipsum" v-model="form.description"/>
</div>
<p class="mt-2 text-sm text-gray-500">Brief description for your photo</p>
<div class="text-red-500" v-if="form.errors.description">{{form.errors.description}}</div>
</div>
<div>
<label class="block text-sm font-medium text-gray-700"> Photo </label>
<div class="mt-1 flex justify-center px-6 pt-5 pb-6 border-2 border-gray-300 border-dashed rounded-md">
<div class="space-y-1 text-center">
<svg class="mx-auto h-12 w-12 text-gray-400" stroke="currentColor" fill="none" viewBox="0 0 48 48" aria-hidden="true">
<path d="M28 8H12a4 4 0 00-4 4v20m32-12v8m0 0v8a4 4 0 01-4 4H12a4 4 0 01-4-4v-4m32-4l-3.172-3.172a4 4 0 00-5.656 0L28 28M8 32l9.172-9.172a4 4 0 015.656 0L28 28m0 0l4 4m4-24h8m-4-4v8m-12 4h.02" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" />
</svg>
<div class="flex text-sm text-gray-600">
<label for="path" class="relative cursor-pointer bg-white rounded-md font-medium text-indigo-600 hover:text-indigo-500 focus-within:outline-none focus-within:ring-2 focus-within:ring-offset-2 focus-within:ring-indigo-500">
<span>Upload a file</span>
<input id="path" name="path" type="file" class="sr-only" @input="form.path = $event.target.files[0]" />
</label>
<p class="pl-1">or drag and drop</p>
</div>
<p class="text-xs text-gray-500">PNG, JPG, GIF up to 10MB</p>
</div>
</div>
</div>
<div class="text-red-500" v-if="form.errors.path">{{form.errors.path}}</div>
<button type="submit" :disabled="form.processing" class="inline-flex justify-center py-2 px-4 border border-transparent shadow-sm text-sm font-medium rounded-md text-white bg-indigo-600 hover:bg-indigo-700 focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-indigo-500">Save</button>
</form>
The code above uses the Vue v-on directive short end syntax @submit.prevent="form.post(route('admin.photos.store'))" on the form tag, and the dom event submit with the prevent modifier.
Then it uses the form variable that we created earlier and a post method. This is available because we are using the useForm class.
Next we point the form to the route named admin.photos.store that we created earlier.
Inside the form we have two groups of inputs. First, we have the textarea that uses the v-model to bind it to the property form.description that we declared before.
The second group uses the form.path in a Tailwind component (showing the markup for a drop file area).
Right now we are allowing users to upload only a single photo using the v-on directive on the input DOM event @input="form.path = $event.target.files[0]".
The last two things to notice are the error handling done via <div class="text-red-500" v-if="form.errors.path">{{form.errors.path}}</div> for the path and also for the description.
Finally we use form.processing to disable the submit button while the form is processing.
The next step is to define the logic to save the data inside the database.
How to Store Data
To store the data, we can edit the route we defined earlier like so:
Route::post('/photos', function (Request $request) {
//dd('I will handle the form submission')
//dd(Request::all());
$validated_data = $request->validate([
'path' => ['required', 'image', 'max:2500'],
'description' => ['required']
]);
//dd($validated_data);
$path = Storage::disk('public')->put('photos', $request->file('path'));
$validated_data['path'] = $path;
//dd($validated_data);
Photo::create($validated_data);
return to_route('admin.photos');
})->name('photos.store');
The code above uses dependency injection to allow us to use the parameter $request inside the callback function.
We first validate the request and save the resulting array inside the variable $validated_data. Then we use the Storage facades to save the file in the filesystem and obtain the file path that we store inside the $path variable.
Finally we add a path key to the associative array and pass to it the $path variable. Next we create the resource in the database using the Photo::create method and redirect the user to the admin.photos page using the new to_route() helper function.
Make sure to import the Request class and the Storage facades at the top of the web.php file like so:
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Storage;
Now we can add a new photo in the database and show a list of photos for both the admin and standard visitors.
Next we need to complete the CRUD operations and allow the user to edit/update a photo and delete it.
How to Update Operations
Let's start by adding the routes responsible for showing the forms used to edit the resource and update its values onto the database.
Just under the other routes in the Admin group, let's add the following code:
Route::get('/photos/{photo}/edit', function(Photo $photo){
return inertia('Admin/PhotosEdit', [
'photo' => $photo
]);
})->name('photos.edit');
The route above uses dependency injection to inject inside the function the current post, selected by the URI /photos/{photo}/edit.
Next it returns the Inertia response via the inertia() function that accepts the Component name 'Admin/PhotosEdit' as its first parameter and an associative array as its second.
Doing ['photo' => $photo] will allow us to pass the $photo model as a prop to the component later.
Next let's add the new Page component under resources/js/Pages/Admin/PhotosEdit.vue
This will be its template:
<template>
<app-layout title="Edit Photo">
<template #header>
<h2 class="font-semibold text-xl text-gray-800 leading-tight">Edit Photo</h2>
</template>
<div class="py-12">
<div class="max-w-7xl mx-auto sm:px-6 lg:px-8">
<form @submit.prevent="form.post(route('admin.photos.update', photo.id))">
<div>
<label
for="description"
class="block text-sm font-medium text-gray-700"
>Description</label>
<div class="mt-1">
<textarea
id="description"
name="description"
rows="3"
class="shadow-sm focus:ring-indigo-500 focus:border-indigo-500 mt-1 block w-full sm:text-sm border border-gray-300 rounded-md"
placeholder="lorem ipsum"
v-model="form.description"
/>
</div>
<p class="mt-2 text-sm text-gray-500">Brief description for your photo</p>
<div
class="text-red-500"
v-if="form.errors.description"
>{{ form.errors.description }}</div>
</div>
<div class="grid grid-cols-2">
<div class="preview p-4">
<img :src="'/storage/' + photo.path" alt />
</div>
<div>
<label class="block text-sm font-medium text-gray-700">Photo</label>
<div
class="mt-1 flex justify-center px-6 pt-5 pb-6 border-2 border-gray-300 border-dashed rounded-md"
>
<div class="space-y-1 text-center">
<svg
class="mx-auto h-12 w-12 text-gray-400"
stroke="currentColor"
fill="none"
viewBox="0 0 48 48"
aria-hidden="true"
>
<path
d="M28 8H12a4 4 0 00-4 4v20m32-12v8m0 0v8a4 4 0 01-4 4H12a4 4 0 01-4-4v-4m32-4l-3.172-3.172a4 4 0 00-5.656 0L28 28M8 32l9.172-9.172a4 4 0 015.656 0L28 28m0 0l4 4m4-24h8m-4-4v8m-12 4h.02"
stroke-width="2"
stroke-linecap="round"
stroke-linejoin="round"
/>
</svg>
<div class="flex text-sm text-gray-600">
<label
for="path"
class="relative cursor-pointer bg-white rounded-md font-medium text-indigo-600 hover:text-indigo-500 focus-within:outline-none focus-within:ring-2 focus-within:ring-offset-2 focus-within:ring-indigo-500"
>
<span>Upload a file</span>
<input
id="path"
name="path"
type="file"
class="sr-only"
@input="form.path = $event.target.files[0]"
/>
</label>
<p class="pl-1">or drag and drop</p>
</div>
<p class="text-xs text-gray-500">PNG, JPG, GIF up to 10MB</p>
</div>
</div>
<div class="text-red-500" v-if="form.errors.path">{{ form.errors.path }}</div>
</div>
</div>
<button
type="submit"
:disabled="form.processing"
class="inline-flex justify-center py-2 px-4 border border-transparent shadow-sm text-sm font-medium rounded-md text-white bg-indigo-600 hover:bg-indigo-700 focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-indigo-500"
>Update</button>
</form>
</div>
</div>
</app-layout>
</template>
The template is actually identical to the Create component, except for a few things. The form points to a route that expects a paramenter that we pass as the second argument to the funtion route. It looks like this: <form @submit.prevent="form.post(route('admin.photos.update', photo.id))">.
There is a section where we can see the original photo next to the upload form group:
<div class="preview p-4">
<img :src="'/storage/' + photo.path" alt />
</div>
The rest is identical, and here we have the script section:
import { defineComponent } from "vue";
import AppLayout from "@/Layouts/AppLayout.vue";
import { useForm } from '@inertiajs/inertia-vue3';
export default defineComponent({
components: {
AppLayout,
},
props: {
photo: Object
},
setup(props) {
const form = useForm({
_method: "PUT",
path: null,
description: props.photo.description,
})
return { form }
},
});
Notice that we are passing a props object with the photo key, which allows us to reference the model in the template.
Next, this _method: "PUT", line of code is required to be able to submit a PUT request instead of the POST request called on the form tag.
Now let's implement the logic to handle the form submission inside the Route below.
In web.php just under the previous route, let's add one that responds to the PUT request submitted by our form.
Route::put('/photos/{photo}', function (Request $request, Photo $photo)
{
//dd(Request::all());
$validated_data = $request->validate([
'description' => ['required']
]);
if ($request->hasFile('path')) {
$validated_data['path'] = $request->validate([
'path' => ['required', 'image', 'max:1500'],
]);
// Grab the old image and delete it
// dd($validated_data, $photo->path);
$oldImage = $photo->path;
Storage::delete($oldImage);
$path = Storage::disk('public')->put('photos', $request->file('path'));
$validated_data['path'] = $path;
}
//dd($validated_data);
$photo->update($validated_data);
return to_route('admin.photos');
})->name('photos.update');
The route logic is straigthforward. First we validate the description, next we check if a file was uploaded and if so we validate it.
Then we delete the previously uploaded image Storage::delete($oldImage); before storing the new image onto the datadabse and update the resource using $photo->update($validated_data);.
As before with the store route, we redirect to the admin.photos route using return to_route('admin.photos');.
How to Delete a Resource
The last step we need to take is to write the logic to delete the photo. Let's start by adding the route.
Right below the previous route we can write:
Route::delete('/photos/{photo}', function (Photo $photo)
{
Storage::delete($photo->path);
$photo->delete();
return to_route('admin.photos');
})->name('photos.delete');
This route is also using a wildcard in its URI to identify the resource. Next, its second paramenter is the callback that uses the dependency injection as before. Inside the callback we first delete the image from the filesystem using Storage::delete($photo->path);.
Then we remove the resource from the database $photo->delete(); and redirect the user back return to_route('admin.photos'); like we did in the previous reoute.
Now we need to add a delete button to the table we created in one of the previous steps to show all photos.
Inside the template section of the component Admin/Photos.vue within the v-for, we can add this Jetstream button:
<jet-danger-button @click="delete_photo(photo)">
Delete
</jet-danger-button>
Find the table cell that has the ACTIONS comment and replace the DELETE text with the button above.
So the final code will be:
<td class="px-6 py-4 whitespace-nowrap text-right text-sm font-medium">
<a href="#" class="text-indigo-600 hover:text-indigo-900">
View - Edit -
<jet-danger-button @click="delete_photo(photo)">
Delete
</jet-danger-button>
</a>
</td>
As you can see there is a @click event listener on the button. It calls a method delete_photo(photo) that we need to define along with a bunch of other methods to have a nice modal opening to ask for confirmation from the user.
First import the Inertia helper function useForm:
// 0. Import the useForm class at the top of the script section along with all required components
import { useForm } from '@inertiajs/inertia-vue3';
import JetDangerButton from '@/Jetstream/DangerButton.vue'
import { ref } from "vue";
Remember to register the component JetDangerButton inside the components object before moving forward.
Next add the setup() function in the script section and implement the logic required to submit the form and show a modal. The comments in the code will guide you thorought all the steps.
// 1. add the setup function
setup() {
// 2. declare a form variable and assign to it the Inertia useForm() helper function
const form = useForm({
// 3. override the form method to make a DELETE request
_method: "DELETE",
});
// 4. define a reactive object with show_modal and photo property
// this will be used to figure out when to show the modal and the selected post values
const data = ref({
show_modal: false,
photo: {
id: null,
path: null,
description: null,
}
})
// 5. define the delete_photo function and update the values of the show_modal and photo properties
// of the reactive object defined above. This method is called by the delete button and will record the details
// of the selected post
const delete_photo = (photo) => {
//console.log(photo);
//console.log(photo.id, photo.path, photo.description);
data.value = {
photo: {
id: photo.id,
path: photo.path,
description: photo.description
},
show_modal: true
};
}
// 6. define the method that will be called when our delete form is submitted
// the form will be created next
const deleting_photo = (id) => {
form.post(route('admin.photos.delete', id))
closeModal();
}
// 7. delare a method to close the modal by setting the show_modal to false
const closeModal = () => {
data.value.show_modal = false;
}
// 8. remember to return from the setup function the all variables and methods that you want to expose
// to the template.
return { form, data, closeModal, delete_photo, deleting_photo }
}
Finally outside the v-for loop add the modal using the following code. You can place this where you want but not inside the loop.
<JetDialogModal :show="data.show_modal">
<template #title>
Photo {{ data.photo.description.slice(0, 20) + '...' }}
</template>
<template #content>
Are you sure you want to delete this photo?
</template>
<template #footer>
<button @click="closeModal" class="px-4 py-2">Close</button>
<form @submit.prevent="deleting_photo(data.photo.id)">
<jet-danger-button type="submit">Yes, I am sure!</jet-danger-button>
</form>
</template>
</JetDialogModal>
This is our final JavaScript code:
import { defineComponent } from "vue";
import AppLayout from "@/Layouts/AppLayout.vue";
import TableComponent from "@/Components/TableComponent.vue";
import { Link } from '@inertiajs/inertia-vue3';
import { useForm } from '@inertiajs/inertia-vue3';
import JetDialogModal from '@/Jetstream/DialogModal.vue';
import JetDangerButton from '@/Jetstream/DangerButton.vue'
import { ref } from "vue";
export default defineComponent({
components: {
AppLayout,
Link,
TableComponent,
JetDialogModal,
JetDangerButton
},
props: {
photos: Array,
},
setup() {
const form = useForm({
_method: "DELETE",
});
const data = ref({
show_modal: false,
photo: {
id: null,
path: null,
description: null,
}
})
const delete_photo = (photo) => {
//console.log(photo);
console.log(photo.id, photo.path, photo.description);
data.value = {
photo: {
id: photo.id,
path: photo.path,
description: photo.description
},
show_modal: true
};
}
const deleting_photo = (id) => {
form.post(route('admin.photos.delete', id))
closeModal();
}
const closeModal = () => {
data.value.show_modal = false;
}
return { form, data, closeModal, delete_photo, deleting_photo }
}
});
</script>
And here we have the HTML:
<template>
<app-layout title="Dashboard">
<template #header>
<h2 class="font-semibold text-xl text-gray-800 leading-tight">Photos</h2>
</template>
<div class="py-12">
<div class="max-w-7xl mx-auto sm:px-6 lg:px-8">
<!-- All posts goes here -->
<h1 class="text-2xl">Photos</h1>
<a class="px-4 bg-sky-900 text-white rounded-md" href>Create</a>
<div class="flex flex-col">
<div class="-my-2 overflow-x-auto sm:-mx-6 lg:-mx-8">
<div class="py-2 align-middle inline-block min-w-full sm:px-6 lg:px-8">
<div class="shadow overflow-hidden border-b border-gray-200 sm:rounded-lg">
<table class="min-w-full divide-y divide-gray-200">
<thead class="bg-gray-50">
<tr>
<th
scope="col"
class="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase tracking-wider"
>ID</th>
<th
scope="col"
class="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase tracking-wider"
>Photos</th>
<th
scope="col"
class="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase tracking-wider"
>Description</th>
<th scope="col" class="relative px-6 py-3">
<span class="sr-only">Edit</span>
</th>
</tr>
</thead>
<tbody class="bg-white divide-y divide-gray-200">
<tr v-for="photo in photos" :key="photo.id">
<td class="px-6 py-4 whitespace-nowrap">
<div
class="text-sm text-gray-900"
>{{ photo.id }}</div>
</td>
<td class="px-6 py-4 whitespace-nowrap">
<div class="flex items-center">
<div class="flex-shrink-0 h-10 w-10">
<img
class="h-10 w-10 rounded-full"
:src="photo.path"
alt
/>
</div>
</div>
</td>
<td class="px-6 py-4 whitespace-nowrap">
<div class="text-sm text-gray-900">
{{ photo.description.slice(0, 100) + '...' }}
</div>
</td>
<!-- ACTIONS -->
<td class="px-6 py-4 whitespace-nowrap text-right text-sm font-medium">
<a href="#" class="text-indigo-600 hover:text-indigo-900">
View - Edit -
<jet-danger-button @click="delete_photo(photo)">
Delete
</jet-danger-button>
</a>
</td>
</tr>
</tbody>
</table>
</div>
</div>
</div>
</div>
</div>
</div>
<JetDialogModal :show="data.show_modal">
<template #title>
Photo {{ data.photo.description.slice(0, 20) + '...' }}
</template>
<template #content>
Are you sure you want to delete this photo?
</template>
<template #footer>
<button @click="closeModal" class="px-4 py-2">Close</button>
<form @submit.prevent="deleting_photo(data.photo.id)">
<jet-danger-button type="submit">Yes, I am sure!</jet-danger-button>
</form>
</template>
</JetDialogModal>
</app-layout>
</template>
That's it. If you did everything correctly you should be able to see all photos, create new photos as well as edit and delete them.
I will leave you some home work. Can you figure out how to implement the view and edit links before the delete button in the section below?
<!-- ACTIONS -->
<td class="px-6 py-4 whitespace-nowrap text-right text-sm font-medium">
<a href="#" class="text-indigo-600 hover:text-indigo-900">
View - Edit -
<jet-danger-button @click="delete_photo(photo)">
Delete
</jet-danger-button>
</a>
</td>
Wrapup and What's next
During this guide we took our first steps and learned how to build a single page application using Laravel as our backend framework and Vue3 for the front end. We glued them together with Inertia js and built a simple photo application that lets a user manage photos.
We are just at the beginning of a fantastic journey. Learning new technologies isn't easy, but thanks to their exaustive documentations we can keep up and build awesome applications.
Your next step to master Laravel, Vue3, Inertia and all the tech we have been using so far is to hit their documentation and keep learning. Use the app we have build if you want, and improve it or start over from scratch.
Conclusion
This is just an overview of how I'd build a single page application using these technologies.
If you are familiar with server-side routing and Vuejs then you will enjoy bulding a single page application with Laravel, Inertia, and Vuejs. The learning curve isn't that steep plus you have great documentation to help you out.
You can find the source code for this guide here.
#laravel #laravel9 #jetstream #vuejs #inertiajs #mysql #tailwindcss #docker
1649473200
Understanding CSS's !important declaration
!important in CSS is a special notation that we can apply to a CSS declaration to override other conflicting rules for the matching selector.
When we work on web projects, it is natural that we have some style declarations that other styles overrule.
This is not an issue for an experienced developer who understands the core mechanism of CSS. However, it can be difficult for beginners to understand why the style declarations they expect are not applied by the browser.
So, instead of them focusing on resolving the issue naturally, they tend to go for the quick fix by adding the !important declaration to enforce the style they expect. While this approach might work for that moment, it can also initiate another complex problem.
In this guide, we will review the following, including how to use !important and when we should use it:
- The CSS core mechanism
- Understanding the
!importantdeclaration before we use it :is()and other related pseudo-class functions- When exactly can we use
!importantdeclaration?- Utility classes
- The style rules we cannot override
Enough said, let’s dive in.
The CSS core mechanism
Understanding the core principles of CSS will naturally enable us to know when it’s obvious to use the !important declaration. In this section, we will walk through some of these mechanisms.
Consider the HTML and CSS code below, what color do you think the heading text will be?
First, the HTML:
<h2 class="mytitle">This is heading text</h2>Then, the CSS:
h2 {
color: blue;
}
h2 {
color: green;
}The text will render green! This is basic CSS fundamental. With the CSS cascade algorithm, the ordering of CSS rules matters. In this case, the declaration that comes last in the source code wins.
Normally, this is logical. In the first place, we should not repeat the same selector as we did above. CSS does not want repetition, so it uses the last declaration rule.
However, there are cases whereby we create generic styles for the root elements, like the h2, and then add classes to style specific elements. Let’s consider the following example as well, starting with the HTML:
<h2>This is heading text</h2>
<h2 class="mytitle">This is heading text</h2>Then, let’s see the CSS:
.mytitle {
color: blue;
}
h2 {
color: green;
}In the above code, the first h2 element has no class applied, so it is obvious that it gets the green color of the h2 selector.
However, the second h2 element uses the rule for the class selector, .mytitle, even when the element selector rule comes last in the CSS code. The reason for that is that the class selector has a higher specificity when compared to the element selector.
In other words, the weight applied to the declaration in a class selector is more than element selector’s weight.
Similarly, the declaration in an ID selector is more than that of the class selector. In this case, the red color in the code below takes precedence:
<h2 id="maintitle" class="mytitle">This is heading text</h2> Followed by the CSS:
.mytitle {
color: blue;
}
#maintitle {
color: red;
}
h2 {
color: green;
}Furthermore, an inline style attribute takes precedence over the ID selector, starting with the HTML:
<h2 id="maintitle" style="color: black;" class="mytitle">This is heading text</h2>
Then followed by the CSS:
.mytitle {/*...*/}
#maintitle {/*...*/}
h2 {/*...*/}This is the ideal priority flow in CSS and must be maintained to avoid anomalies. The !important declaration most of the time comes when we are oblivious of these basic rules.
The inline style attribute and each of the selectors have values that browsers assign to them. That way, it knows which one has higher or lower priority. Think of this value as a number of four single digits with the style attribute assigned the strongest weight value of 1000.
This follows the ID with a value of 0100, then class with 0010, and finally the element selector with 0001.
Sometimes we can combine selectors targeting specific elements, as seen in the example below:
<h2 id="maintitle" class="mytitle">This is heading text</h2>
Followed by the CSS:
h2.mytitle {
color: blue;
}
#maintitle {
color: red;
}
h2 {
color: green;
}The specificity of the h2.mytitle selector in the CSS above is the addition of h2 and .mytitle. That is, 0001 + 0010 = 0011. This total value, however, is less than that of the #maintitle ID that is 0100.
So, the browser uses the declaration in the ID selector to override other conflicting rules. In a case of equal weight, the last rule declaration wins.
Now that we know which rules are most relevant and why the browser applies them, it will become naturally obvious whether or not to use this !important declaration.
Understanding the !important declaration before we use it
Before we consider using the !important notation, we must ensure that we follow the specificity rule and use the CSS cascade.
In the code below, we have the h2 and h3 elements styled to be a red color:
<h2 class="mytitle">This is heading II text</h2>
<h3 class="mytitle">This is heading III text</h3>Then, .mytitle in CSS:
.mytitle {
color: red;
}But, let’s say at some point, we want to give the h3 element a blue color. Adding a style rule like the one below would not change the color because the class has more weight and it’s more specific than the element selector, as we’ve learned:
.mytitle {...}
h3 {
color: blue;
}However, using the !important on the lesser weight makes the browser enforce that declaration over other conflicting rules:
.mytitle {...}
h3 {
color: blue !important;
}This is because the !important notation increases the weight of the declaration in the cascade order of precedence. What this means is that we’ve disrupted the normal priority flow. Hence, bad practice, and can lead to difficulties in code maintenance and debugging.
If at some other point, we want to override the above important rule, we can apply another !important notation on a declaration with higher specificity (or the same if it is lower down in the source). It can then lead to something like this:
h3 {
color: blue !important;
}
/* several lines of rules */
.mytitle {
color: green !important;
}This is bad and should be avoided. Instead, we should check if:
- Rearranging the rule or rewriting the selectors can solve the cascading issue
- Increasing the specificity of the target element can solve the issue
Well, let’s find out. Back to our style rules, we can enforce a blue color on the h3 element by increasing the specificity score.
As seen below, we can combine selectors until their specificity score supersedes the conflicting rule. The h3.mytitle selector gives a specificity score of 0011, which is more than the .mytitle of 0010 score:
.mytitle {...}
h3.mytitle {
color: blue;
}As we can see, instead of using the !important declaration to enforce a rule, we focus on increasing the specificity score.
:is() and other related pseudo-class functions
Sometimes, we may trace issues to a pseudo-class function. So, knowing how it works can save us a lot of stress. Let’s see another example.
Imagine we are working on a project and see the following code:
<h1 id="header">
heading <span>span it</span>
<a href="#">link it</a>
</h1>
<p class="paragraph">
paragraph <span>span it</span>
<a href="">link it</a>
</p>Using the following CSS rules gives us the output after:
:is(#header, p) span,
:is(#header, p) a {
color: red;
}
Now, let’s say we want to give the span and the link text in the paragraph another color of blue. We can do this by adding the following rule:
.paragraph span,
.paragraph a {
color: blue;
}The earlier rule will override the blue color despite being further down the line:
As a quick fix, we can enforce our blue color by using the !important notation like so:
:is(#header, p) span,
:is(#header, p) a {...}
.paragraph span,
.paragraph a {
color: blue !important;
}But, as you may guess, that is bad practice, so we must not be quick to use the !important notation. Instead, we can start by analyzing how every selector works. The :is() is used in the code is a pseudo-class function for writing mega selectors in a more compressed form.
So, here is the following rule in the above code:
:is(#header, p) span,
:is(#header, p) a {
color: red;
}Which is equivalent to the following:
#header span,
p span,
#header a,
p a {
color: red;
}So, why is .paragraph span and .paragraph a not overriding the color despite having a specificity score of 0011, which is higher than 0002 of the p span and p a.
Well, every selector in the :is() uses the highest specificity in the list of arguments. In that case, both the #header and the p in the :is(#header, p) uses the specificity score of the #header, which is 0100. Thus, the browser sticks to its value because it has a higher specificity.
Thus, anytime we see this type of conflict, we are better off not using the pseudo-class function and sticking to its equivalent like the following:
#header span,
p span,
#header a,
p a {
color: red;
}Now, we should be able to see the expected result without using the !important notation that disrupts cascade order.
You can see for yourself on CodeSandbox.
When exactly can we use !important declaration?
Below are a few occasions where using the !important notation is recommended.
Utility classes
Assuming we want to style all buttons on a page to look the same, we can write a CSS rule that can be reused across a page. Let’s take a look at the following markup and style below:
<p>Subscribe button : <a class="btn" href="#">Subscribe</a></p>
<section class="content">
<p>
This <a href="#" class="btn">button</a> style is affected by a higher
specificity value .
</p>
A link here: <a href="#">Dont click</a>
</section>Followed by the CSS:
.btn {
display: inline-block;
background: #99f2f5;
padding: 8px 10px;
border: 1px solid #99f2f5;
border-radius: 4px;
color: black;
font-weight: normal;
text-decoration: none;
}
.content a {
color: blue;
font-weight: bold;
text-decoration: underline;
}In the above code, we can see that the button link within the section element is targeted by both selectors in the CSS. And, we learned that for conflicting rules, the browser will use the most specific rule. As we expect, .content a has a score of 0011 while .btn has a score of 0010.
The page will look like this:
In this case, we can enforce the .btn rule by adding the !important notation to the conflicting declarations like this:
.btn {
/* ... */
color: black !important;
font-weight: normal !important;
text-decoration: none !important;
}The page now looks as we expect:
See for yourself on CodeSandbox.
The style rules we cannot override
This mostly happens when we don’t have total control over the working code. Sometimes, when we work with a content management system like WordPress, we may find that an inline CSS style in our WordPress theme is overruling our custom style.
In this case, the !important declaration is handy to override the theme inline style.
Conclusion
The !important declaration is never meant to be used as we desire. We must only use it if absolutely necessary, such as a situation where we have less control over the code or very extreme cases in our own code.
Whether or not we use it depends on how we understand the core CSS mechanism, and in this tutorial, we covered that as well.
I hope you enjoyed reading this post. If you have questions or contributions, share your thought in the comment section and remember to share this tutorial around the web.
Source: https://blog.logrocket.com/understanding-css-important-declaration/
1649426848
Comprender La Declaración !important De CSS
!importanten CSS es una notación especial que podemos aplicar a una declaración de CSS para anular otras reglas en conflicto para el selector coincidente.
Cuando trabajamos en proyectos web, es natural que tengamos algunas declaraciones de estilo que anulan otros estilos.
Este no es un problema para un desarrollador experimentado que comprende el mecanismo central de CSS. Sin embargo, puede ser difícil para los principiantes entender por qué el navegador no aplica las declaraciones de estilo que esperan.
Entonces, en lugar de enfocarse en resolver el problema de forma natural, tienden a buscar la solución rápida agregando la !importantdeclaración para hacer cumplir el estilo que esperan. Si bien este enfoque podría funcionar en ese momento, también puede iniciar otro problema complejo.
En esta guía, revisaremos lo siguiente, incluido cómo usarlo !importanty cuándo debemos usarlo:
- El mecanismo central de CSS
- Comprender la
!importantdeclaración antes de usarla :is()y otras funciones de pseudoclase relacionadas- ¿Cuándo exactamente podemos usar la
!importantdeclaración?- Clases de utilidad
- Las reglas de estilo que no podemos anular
Suficiente dicho, vamos a sumergirnos.
El mecanismo central de CSS
Comprender los principios básicos de CSS naturalmente nos permitirá saber cuándo es obvio usar la !importantdeclaración. En esta sección, analizaremos algunos de estos mecanismos.
Considere el código HTML y CSS a continuación, ¿de qué color cree que será el texto del encabezado?
Primero, el HTML:
<h2 class="mytitle">This is heading text</h2>Entonces, el CSS:
h2 {
color: blue;
}
h2 {
color: green;
}¡El texto se volverá verde! Esto es CSS básico fundamental. Con el algoritmo de cascada de CSS , el orden de las reglas de CSS importa. En este caso, gana la última declaración en el código fuente.
Normalmente, esto es lógico. En primer lugar, no debemos repetir el mismo selector que hicimos anteriormente. CSS no quiere repetición, por lo que usa la última regla de declaración.
Sin embargo, hay casos en los que creamos estilos genéricos para los elementos raíz, como el h2, y luego agregamos clases para diseñar elementos específicos. Consideremos también el siguiente ejemplo, comenzando con el HTML:
<h2>This is heading text</h2>
<h2 class="mytitle">This is heading text</h2>Entonces, veamos el CSS:
.mytitle {
color: blue;
}
h2 {
color: green;
}En el código anterior, el primer h2elemento no tiene clase aplicada, por lo que es obvio que obtiene el color verde del h2selector.
Sin embargo, el segundo h2elemento usa la regla para el selector de clase .mytitle, incluso cuando la regla del selector de elementos viene en último lugar en el código CSS. La razón de esto es que el selector de clase tiene una mayor especificidad en comparación con el selector de elementos.
En otras palabras, el peso aplicado a la declaración en un selector de clase es mayor que el peso del selector de elementos.
De manera similar, la declaración en un selector de ID es más que la del selector de clase. En este caso, el color rojo en el siguiente código tiene prioridad:
<h2 id="maintitle" class="mytitle">This is heading text</h2> Seguido por el CSS:
.mytitle {
color: blue;
}
#maintitle {
color: red;
}
h2 {
color: green;
}Además, un styleatributo en línea tiene prioridad sobre el selector de ID, comenzando con el HTML:
<h2 id="maintitle" style="color: black;" class="mytitle">This is heading text</h2>
Luego seguido por el CSS:
.mytitle {/*...*/}
#maintitle {/*...*/}
h2 {/*...*/}Este es el flujo de prioridad ideal en CSS y debe mantenerse para evitar anomalías. La !importantdeclaración la mayoría de las veces llega cuando nos olvidamos de estas reglas básicas.
El atributo de estilo en línea y cada uno de los selectores tienen valores que les asignan los navegadores. De esa manera, sabe cuál tiene mayor o menor prioridad. Piense en este valor como un número de cuatro dígitos individuales con el styleatributo asignado al valor de ponderación más fuerte de 1000.
Esto sigue al ID con un valor de 0100, luego a la clase con 0010, y finalmente al selector de elementos con 0001.
A veces podemos combinar selectores dirigidos a elementos específicos, como se ve en el siguiente ejemplo:
<h2 id="maintitle" class="mytitle">This is heading text</h2>
Seguido por el CSS:
h2.mytitle {
color: blue;
}
#maintitle {
color: red;
}
h2 {
color: green;
}La especificidad del h2.mytitleselector en el CSS anterior es la adición de h2y .mytitle. Es decir, 0001 + 0010 = 0011. Este valor total, sin embargo, es menor que el del #maintitleID que es 0100.
Entonces, el navegador usa la declaración en el selector de ID para anular otras reglas en conflicto. En un caso de igual peso, gana la declaración de la última regla.
Ahora que sabemos qué reglas son las más relevantes y por qué el navegador las aplica, será obvio si usar o no esta !importantdeclaración.
Comprender la !importantdeclaración antes de usarla
Antes de considerar el uso de la !importantnotación, debemos asegurarnos de que seguimos la regla de especificidad y usamos la cascada CSS.
En el siguiente código, tenemos los elementos h2y h3diseñados para ser un redcolor:
<h2 class="mytitle">This is heading II text</h2>
<h3 class="mytitle">This is heading III text</h3>Luego, .mytitleen CSS:
.mytitle {
color: red;
}Pero digamos que en algún momento queremos darle un color al h3elemento . blueAgregar una regla de estilo como la siguiente no cambiaría el color porque la clase tiene más peso y es más específica que el selector de elementos, como hemos aprendido:
.mytitle {...}
h3 {
color: blue;
}Sin embargo, usar !importanton the lesserweight hace que el navegador aplique esa declaración sobre otras reglas en conflicto:
.mytitle {...}
h3 {
color: blue !important;
}Esto se debe a que la !importantnotación aumenta el peso de la declaración en el orden de precedencia en cascada. Lo que esto significa es que hemos interrumpido el flujo de prioridad normal. Por lo tanto, es una mala práctica y puede generar dificultades en el mantenimiento y la depuración del código.
Si en algún otro punto, queremos anular la regla importante anterior, podemos aplicar otra !importantnotación en una declaración con mayor especificidad (o lo mismo si está más abajo en la fuente). Entonces puede conducir a algo como esto:
h3 {
color: blue !important;
}
/* several lines of rules */
.mytitle {
color: green !important;
}Esto es malo y debe evitarse. En su lugar, debemos comprobar si:
- Reorganizar la regla o reescribir los selectores puede resolver el problema en cascada
- El aumento de la especificidad del elemento de destino puede resolver el problema
Bueno, averigüémoslo. Volviendo a nuestras reglas de estilo, podemos imponer un bluecolor en el h3elemento aumentando la puntuación de especificidad.
Como se ve a continuación, podemos combinar selectores hasta que su puntaje de especificidad reemplace la regla en conflicto. El h3.mytitleselector otorga una puntuación de especificidad de 0011, que es mayor que la puntuación .mytitlede :0010
.mytitle {...}
h3.mytitle {
color: blue;
}Como podemos ver, en lugar de usar la !importantdeclaración para hacer cumplir una regla, nos enfocamos en aumentar el puntaje de especificidad.
:is()y otras funciones de pseudoclase relacionadas
A veces, podemos rastrear problemas hasta una función de pseudoclase. Entonces, saber cómo funciona puede ahorrarnos mucho estrés. Veamos otro ejemplo.
Imagina que estamos trabajando en un proyecto y vemos el siguiente código:
<h1 id="header">
heading <span>span it</span>
<a href="#">link it</a>
</h1>
<p class="paragraph">
paragraph <span>span it</span>
<a href="">link it</a>
</p>El uso de las siguientes reglas CSS nos da el resultado después:
:is(#header, p) span,
:is(#header, p) a {
color: red;
}
Ahora, digamos que queremos darle al spany al texto del enlace en el párrafo otro color de blue. Podemos hacer esto agregando la siguiente regla:
.paragraph span,
.paragraph a {
color: blue;
}La regla anterior anulará el bluecolor a pesar de estar más abajo en la línea:
Como una solución rápida, podemos hacer cumplir nuestro bluecolor usando la !importantnotación de esta manera:
:is(#header, p) span,
:is(#header, p) a {...}
.paragraph span,
.paragraph a {
color: blue !important;
}Pero, como puede suponer, esa es una mala práctica, por lo que no debemos apresurarnos a usar la !importantnotación. En cambio, podemos comenzar analizando cómo funciona cada selector. La :is()que se usa en el código es una función de pseudoclase para escribir megaselectores en una forma más comprimida.
Entonces, aquí está la siguiente regla en el código anterior:
:is(#header, p) span,
:is(#header, p) a {
color: red;
}Lo cual es equivalente a lo siguiente:
#header span,
p span,
#header a,
p a {
color: red;
}Entonces, ¿por qué .paragraph spany .paragraph ano anula el color a pesar de tener un puntaje de especificidad de 0011, que es más alto que 0002el de p spany p a.
Bueno, cada selector en :is()usa la especificidad más alta en la lista de argumentos. En ese caso, tanto the #headercomo the pin the :is(#header, p)usan la puntuación de especificidad de #header, que es 0100. Por lo tanto, el navegador mantiene su valor porque tiene una mayor especificidad.
Por lo tanto, cada vez que vemos este tipo de conflicto, es mejor no usar la función de pseudoclase y apegarnos a su equivalente como el siguiente:
#header span,
p span,
#header a,
p a {
color: red;
}Ahora, deberíamos poder ver el resultado esperado sin usar la !importantnotación que interrumpe el orden en cascada.
Puedes verlo por ti mismo en CodeSandbox .
¿Cuándo exactamente podemos usar la !importantdeclaración?
A continuación se presentan algunas ocasiones en las !importantque se recomienda usar la notación.
Clases de utilidad
Suponiendo que queremos diseñar todos los botones de una página para que tengan el mismo aspecto, podemos escribir una regla CSS que se puede reutilizar en una página. Echemos un vistazo al siguiente marcado y estilo a continuación:
<p>Subscribe button : <a class="btn" href="#">Subscribe</a></p>
<section class="content">
<p>
This <a href="#" class="btn">button</a> style is affected by a higher
specificity value .
</p>
A link here: <a href="#">Dont click</a>
</section>Seguido por el CSS:
.btn {
display: inline-block;
background: #99f2f5;
padding: 8px 10px;
border: 1px solid #99f2f5;
border-radius: 4px;
color: black;
font-weight: normal;
text-decoration: none;
}
.content a {
color: blue;
font-weight: bold;
text-decoration: underline;
}En el código anterior, podemos ver que el enlace del botón dentro del sectionelemento está dirigido por ambos selectores en el CSS. Y aprendimos que para las reglas en conflicto, el navegador usará la regla más específica. Como esperábamos, .content atiene una puntuación de 0011while .btntiene una puntuación de 0010.
La página se verá así:
En este caso, podemos hacer cumplir la .btnregla agregando la !importantnotación a las declaraciones en conflicto como esta:
.btn {
/* ... */
color: black !important;
font-weight: normal !important;
text-decoration: none !important;
}La página ahora se ve como esperamos:
Compruébelo usted mismo en CodeSandbox .
Las reglas de estilo que no podemos anular
Esto sucede principalmente cuando no tenemos control total sobre el código de trabajo. A veces, cuando trabajamos con un sistema de administración de contenido como WordPress, podemos encontrar que un estilo CSS en línea en nuestro tema de WordPress anula nuestro estilo personalizado.
En este caso, la !importantdeclaración es útil para anular el estilo en línea del tema.
Conclusión
La !importantdeclaración nunca está destinada a ser utilizada como deseamos. Solo debemos usarlo si es absolutamente necesario, como una situación en la que tenemos menos control sobre el código o casos muy extremos en nuestro propio código.
Si lo usamos o no depende de cómo entendamos el mecanismo central de CSS, y en este tutorial también cubrimos eso.
Espero que hayas disfrutado leyendo esta publicación. Si tiene preguntas o contribuciones, comparta su opinión en la sección de comentarios y recuerde compartir este tutorial en la web.
Fuente: https://blog.logrocket.com/understanding-css-important-declaration/
1649426640
CSSの！important宣言を理解する
!importantCSSでは、CSS宣言に適用して、一致するセレクターの他の競合するルールをオーバーライドできる特別な表記法です。
Webプロジェクトで作業する場合、他のスタイルが無効にするスタイル宣言があるのは当然です。
これは、CSSのコアメカニズムを理解している経験豊富な開発者にとっては問題ではありません。ただし、初心者にとって、期待するスタイル宣言がブラウザによって適用されない理由を理解するのは難しい場合があります。
そのため、問題を自然に解決することに集中するのではなく、!important宣言を追加して期待するスタイルを適用することで、迅速な修正を行う傾向があります。このアプローチはその瞬間は機能するかもしれませんが、別の複雑な問題を引き起こす可能性もあります。
このガイドでは、使用方法と使用!important時期を含め、以下を確認します。
- CSSコアメカニズム
!important使用する前に宣言を理解する:is()およびその他の関連する疑似クラス関数- いつ正確に
!important宣言を使用できますか？- ユーティリティクラス
- オーバーライドできないスタイルルール
十分に言った、飛び込みましょう。
CSSコアメカニズム
!importantCSSのコア原則を理解することで、宣言を使用することが明らかな時期を自然に知ることができます。このセクションでは、これらのメカニズムのいくつかについて説明します。
以下のHTMLおよびCSSコードを検討してください。見出しのテキストはどのような色になると思いますか？
まず、HTML：
<h2 class="mytitle">This is heading text</h2>次に、CSS：
h2 {
color: blue;
}
h2 {
color: green;
}テキストが緑色になります！これは基本的なCSSの基本です。CSSカスケードアルゴリズムでは、CSSルールの順序が重要です。この場合、ソースコードの最後にある宣言が優先されます。
通常、これは論理的です。そもそも、上記と同じセレクターを繰り返すべきではありません。CSSは繰り返しを望まないため、最後の宣言ルールを使用します。
ただし、のようなルート要素のジェネリックスタイルを作成してh2から、特定の要素のスタイルにクラスを追加する場合があります。HTMLから始めて、次の例も考えてみましょう。
<h2>This is heading text</h2>
<h2 class="mytitle">This is heading text</h2>次に、CSSを見てみましょう。
.mytitle {
color: blue;
}
h2 {
color: green;
}上記のコードでは、最初の要素にはクラスが適用されていないため、セレクターh2の緑色を取得していることは明らかです。h2
ただし、2番目の要素は、要素セレクタールールがCSSコードの最後にある場合でもh2、クラスセレクターのルールを使用します。.mytitleその理由は、要素セレクターと比較した場合、クラスセレクターの特異性が高いためです。
つまり、クラスセレクターの宣言に適用される重みは、要素セレクターの重みよりも大きくなります。
同様に、IDセレクターでの宣言は、クラスセレクターの宣言よりも多くなります。この場合、以下のコードの赤い色が優先されます。
<h2 id="maintitle" class="mytitle">This is heading text</h2> CSSが続きます：
.mytitle {
color: blue;
}
#maintitle {
color: red;
}
h2 {
color: green;
}さらに、インラインstyle属性は、HTMLから始まるIDセレクターよりも優先されます。
<h2 id="maintitle" style="color: black;" class="mytitle">This is heading text</h2>
次にCSSが続きます。
.mytitle {/*...*/}
#maintitle {/*...*/}
h2 {/*...*/}これはCSSの理想的な優先フローであり、異常を回避するために維持する必要があります。ほとんどの!important場合、宣言は、これらの基本的なルールを知らないときに行われます。
インラインスタイル属性と各セレクターには、ブラウザーが割り当てる値があります。そうすれば、どちらが優先度が高いか低いかがわかります。styleこの値は、属性に最も強い重み値が割り当てられた4桁の数字と考えてください1000。
これは、値が。のID 0100、次にクラス0010、最後に。の要素セレクターの後に続きます0001。
以下の例に示すように、特定の要素をターゲットとするセレクターを組み合わせることができる場合があります。
<h2 id="maintitle" class="mytitle">This is heading text</h2>
CSSが続きます：
h2.mytitle {
color: blue;
}
#maintitle {
color: red;
}
h2 {
color: green;
}h2.mytitle上記のCSSのセレクターの特異性は、h2との追加です.mytitle。つまり、0001 + 0010 = 0011。ただし、この合計値は、#maintitleIDの合計値よりも小さくなります0100。
そのため、ブラウザはIDセレクタの宣言を使用して、他の競合するルールを上書きします。重みが等しい場合は、最後のルール宣言が優先されます。
!importantどのルールが最も関連性があり、ブラウザがそれらを適用する理由がわかったので、この宣言を使用するかどうかは当然明らかになります。
使用する前に宣言を理解する!important
表記法の使用を検討する前に!important、特異性ルールに従い、CSSカスケードを使用していることを確認する必要があります。
以下のコードでは、h2とh3要素がred色になるようにスタイル設定されています。
<h2 class="mytitle">This is heading II text</h2>
<h3 class="mytitle">This is heading III text</h3>次に、.mytitleCSSで：
.mytitle {
color: red;
}h3しかし、ある時点で、要素にblue色を付けたいとしましょう。以下のようなスタイルルールを追加しても、クラスの重みが大きく、要素セレクターよりも具体的であるため、色は変更されません。
.mytitle {...}
h3 {
color: blue;
}ただし、!importantより小さな重みでを使用すると、ブラウザは他の競合するルールに対してその宣言を強制します。
.mytitle {...}
h3 {
color: blue !important;
}これは、!important表記によって宣言の重みがカスケード優先順位で増加するためです。これが意味するのは、通常の優先フローを中断したということです。したがって、悪い習慣であり、コードの保守とデバッグが困難になる可能性があります。
他の時点で、上記の重要なルールをオーバーライドしたい場合は、!importantより高い特異性を持つ宣言に別の表記法を適用できます（または、ソースの下位にある場合は同じ）。次に、次のような結果になる可能性があります。
h3 {
color: blue !important;
}
/* several lines of rules */
.mytitle {
color: green !important;
}これは悪いことであり、避けるべきです。代わりに、次のことを確認する必要があります。
- ルールを再配置したり、セレクターを書き直したりすると、カスケードの問題を解決できます
- ターゲット要素の特異性を高めることで問題を解決できます
さて、調べてみましょう。スタイルルールに戻ると、特異性スコアを上げることblueで要素に色を適用できます。h3
以下に示すように、セレクターの特異性スコアが競合するルールに優先するまで、セレクターを組み合わせることができます。h3.mytitleセレクターは、スコアの0011よりも大きい特異.mytitle性スコアを与え0010ます。
.mytitle {...}
h3.mytitle {
color: blue;
}ご覧のとおり、!important宣言を使用してルールを適用するのではなく、特異性スコアを上げることに重点を置いています。
:is()およびその他の関連する疑似クラス関数
場合によっては、問題を疑似クラス関数にトレースすることがあります。したがって、それがどのように機能するかを知ることは、私たちに多くのストレスを節約することができます。別の例を見てみましょう。
プロジェクトに取り組んでいて、次のコードが表示されているとします。
<h1 id="header">
heading <span>span it</span>
<a href="#">link it</a>
</h1>
<p class="paragraph">
paragraph <span>span it</span>
<a href="">link it</a>
</p>次のCSSルールを使用すると、次の出力が得られます。
:is(#header, p) span,
:is(#header, p) a {
color: red;
}
spanここで、段落内のとリンクテキストに別の色を付けたいとしましょうblue。これを行うには、次のルールを追加します。
.paragraph span,
.paragraph a {
color: blue;
}以前のルールは、blueさらに下にあるにもかかわらず、色をオーバーライドします。
簡単な修正として、次のような表記blueを使用して色を適用できます。!important
:is(#header, p) span,
:is(#header, p) a {...}
.paragraph span,
.paragraph a {
color: blue !important;
}!importantしかし、ご想像のとおり、これは悪い習慣です。そのため、この表記をすぐに使用してはなりません。代わりに、すべてのセレクターがどのように機能するかを分析することから始めることができます。コードで使用されているの:is()は、メガセレクターをより圧縮された形式で記述するための疑似クラス関数です。
したがって、上記のコードには次のルールがあります。
:is(#header, p) span,
:is(#header, p) a {
color: red;
}これは、次と同等です。
#header span,
p span,
#header a,
p a {
color: red;
}したがって、とのよりも高い特異性スコアを持っているにもかかわらず、なぜ色をオーバーライド.paragraph spanしないのですか。.paragraph a00110002p spanp a
さて、のすべてのセレクターは、:is()引数のリストで最も高い特異性を使用します。その場合、のとの両方が#header、pの:is(#header, p)特異性スコアを使用します。#headerこれは0100です。したがって、ブラウザはより高い特異性を持っているため、その値に固執します。
したがって、このタイプの競合が発生した場合は、疑似クラス関数を使用せず、次のような同等の関数を使用することをお勧めします。
#header span,
p span,
#header a,
p a {
color: red;
}!importantこれで、カスケード順序を乱す表記を使用せずに、期待される結果を確認できるはずです。
CodeSandboxで自分の目で確かめることができます。
いつ正確に!important宣言を使用できますか？
!important以下は、表記の使用が推奨されるいくつかの機会です。
ユーティリティクラス
ページ上のすべてのボタンのスタイルを同じにしたいと仮定すると、ページ全体で再利用できるCSSルールを記述できます。以下のマークアップとスタイルを見てみましょう。
<p>Subscribe button : <a class="btn" href="#">Subscribe</a></p>
<section class="content">
<p>
This <a href="#" class="btn">button</a> style is affected by a higher
specificity value .
</p>
A link here: <a href="#">Dont click</a>
</section>CSSが続きます：
.btn {
display: inline-block;
background: #99f2f5;
padding: 8px 10px;
border: 1px solid #99f2f5;
border-radius: 4px;
color: black;
font-weight: normal;
text-decoration: none;
}
.content a {
color: blue;
font-weight: bold;
text-decoration: underline;
}上記のコードでは、section要素内のボタンリンクがCSSの両方のセレクターのターゲットになっていることがわかります。また、競合するルールについては、ブラウザーが最も具体的なルールを使用することを学びました。予想どおり、.content aスコアは0011while.btnで、スコアは0010。です。
ページは次のようになります。
この場合、次のように競合する宣言に表記を.btn追加することで、ルールを適用できます。!important
.btn {
/* ... */
color: black !important;
font-weight: normal !important;
text-decoration: none !important;
}ページは期待どおりに表示されます。
CodeSandboxで自分の目で確かめてください。
オーバーライドできないスタイルルール
これは主に、動作するコードを完全に制御できない場合に発生します。WordPressのようなコンテンツ管理システムを使用している場合、WordPressテーマのインラインCSSスタイルがカスタムスタイルを覆していることに気付くことがあります。
この場合、!important宣言はテーマのインラインスタイルを上書きするのに便利です。
結論
宣言は、!important私たちが望むように使用されることを意図したものではありません。コードを制御できない状況や、独自のコードの非常に極端な場合など、絶対に必要な場合にのみ使用する必要があります。
使用するかどうかは、コアCSSメカニズムをどのように理解しているかによって異なります。このチュートリアルでは、それについても説明しました。
この投稿を楽しんでいただけたでしょうか。質問や貢献がある場合は、コメントセクションで考えを共有し、このチュートリアルをWeb上で共有することを忘れないでください。
ソース：https ：//blog.logrocket.com/understanding-css-important-declaration/
1649329200
Minimp3: Minimalistic MP3 Decoder Single Header Library
minimp3
Minimalistic, single-header library for decoding MP3. minimp3 is designed to be small, fast (with SSE and NEON support), and accurate (ISO conformant). You can find a rough benchmark below, measured using perf on an i7-6700K, IO included, no CPU heat to address speedstep:
| Vector | Hz | Samples | Sec | Clockticks | Clockticks per second | PSNR | Max diff |
|---|---|---|---|---|---|---|---|
| compl.bit | 48000 | 248832 | 5.184 | 14306684 | 2.759M | 124.22 | 1 |
| he_32khz.bit | 32000 | 172800 | 5.4 | 8426158 | 1.560M | 139.67 | 1 |
| he_44khz.bit | 44100 | 472320 | 10.710 | 21296300 | 1.988M | 144.04 | 1 |
| he_48khz.bit | 48000 | 172800 | 3.6 | 8453846 | 2.348M | 139.67 | 1 |
| hecommon.bit | 44100 | 69120 | 1.567 | 3169715 | 2.022M | 133.93 | 1 |
| he_free.bit | 44100 | 156672 | 3.552 | 5798418 | 1.632M | 137.48 | 1 |
| he_mode.bit | 44100 | 262656 | 5.955 | 9882314 | 1.659M | 118.00 | 1 |
| si.bit | 44100 | 135936 | 3.082 | 7170520 | 2.326M | 120.30 | 1 |
| si_block.bit | 44100 | 73728 | 1.671 | 4233136 | 2.533M | 125.18 | 1 |
| si_huff.bit | 44100 | 86400 | 1.959 | 4785322 | 2.442M | 107.98 | 1 |
| sin1k0db.bit | 44100 | 725760 | 16.457 | 24842977 | 1.509M | 111.03 | 1 |
Conformance test passed on all vectors (PSNR > 96db).
Comparison with keyj's minimp3
Comparison by features:
| Keyj minimp3 | Current |
|---|---|
| Fixed point | Floating point |
| source: 84kb | 70kb |
| binary: 34kb (20kb compressed) | 30kb (20kb) |
| no vector opts | SSE/NEON intrinsics |
| no free format | free format support |
Below, you can find the benchmark and conformance test for keyj's minimp3:
| Vector | Hz | Samples | Sec | Clockticks | Clockticks per second | PSNR | Max diff |
|---|---|---|---|---|---|---|---|
| compl.bit | 48000 | 248832 | 5.184 | 31849373 | 6.143M | 71.50 | 41 |
| he_32khz.bit | 32000 | 172800 | 5.4 | 26302319 | 4.870M | 71.63 | 24 |
| he_44khz.bit | 44100 | 472320 | 10.710 | 41628861 | 3.886M | 71.63 | 24 |
| he_48khz.bit | 48000 | 172800 | 3.6 | 25899527 | 7.194M | 71.63 | 24 |
| hecommon.bit | 44100 | 69120 | 1.567 | 20437779 | 13.039M | 71.58 | 25 |
| he_free.bit | 44100 | 0 | 0 | - | - | - | - |
| he_mode.bit | 44100 | 262656 | 5.955 | 30988984 | 5.203M | 71.78 | 27 |
| si.bit | 44100 | 135936 | 3.082 | 24096223 | 7.817M | 72.35 | 36 |
| si_block.bit | 44100 | 73728 | 1.671 | 20722017 | 12.394M | 71.84 | 26 |
| si_huff.bit | 44100 | 86400 | 1.959 | 21121376 | 10.780M | 27.80 | 65535 |
| sin1k0db.bit | 44100 | 730368 | 16.561 | 55569636 | 3.355M | 0.15 | 58814 |
Keyj minimp3 conformance test fails on all vectors (PSNR < 96db), and free format is unsupported. This caused some problems when it was used here, and was the main motivation for this work.
Usage
First, we need to initialize the decoder structure:
//#define MINIMP3_ONLY_MP3
//#define MINIMP3_ONLY_SIMD
//#define MINIMP3_NO_SIMD
//#define MINIMP3_NONSTANDARD_BUT_LOGICAL
//#define MINIMP3_FLOAT_OUTPUT
#define MINIMP3_IMPLEMENTATION
#include "minimp3.h"
...
static mp3dec_t mp3d;
mp3dec_init(&mp3d);
Note that you must define MINIMP3_IMPLEMENTATION in exactly one source file. You can #include minimp3.h in as many files as you like. Also you can use MINIMP3_ONLY_MP3 define to strip MP1/MP2 decoding code. MINIMP3_ONLY_SIMD define controls generic (non SSE/NEON) code generation (always enabled on x64/arm64 targets). In case you do not want any platform-specific SIMD optimizations, you can define MINIMP3_NO_SIMD. MINIMP3_NONSTANDARD_BUT_LOGICAL define saves some code bytes, and enforces non-standard but logical behaviour of mono-stereo transition (rare case). MINIMP3_FLOAT_OUTPUT makes mp3dec_decode_frame() output to be float instead of short and additional function mp3dec_f32_to_s16 will be available for float->short conversion if needed.
Then. we decode the input stream frame-by-frame:
/*typedef struct
{
int frame_bytes;
int channels;
int hz;
int layer;
int bitrate_kbps;
} mp3dec_frame_info_t;*/
mp3dec_frame_info_t info;
short pcm[MINIMP3_MAX_SAMPLES_PER_FRAME];
/*unsigned char *input_buf; - input byte stream*/
samples = mp3dec_decode_frame(&mp3d, input_buf, buf_size, pcm, &info);
The mp3dec_decode_frame() function decodes one full MP3 frame from the input buffer, which must be large enough to hold one full frame.
The decoder will analyze the input buffer to properly sync with the MP3 stream, and will skip ID3 data, as well as any data which is not valid. Short buffers may cause false sync and can produce 'squealing' artefacts. The bigger the size of the input buffer, the more reliable the sync procedure. We recommend having as many as 10 consecutive MP3 frames (~16KB) in the input buffer at a time.
At end of stream just pass rest of the buffer, sync procedure should work even with just 1 frame in stream (except for free format and garbage at the end can mess things up, so id3v1 and ape tags must be removed first).
For free format there minimum 3 frames needed to do proper sync: 2 frames to detect frame length and 1 next frame to check detect is good.
The size of the consumed MP3 data is returned in the mp3dec_frame_info_t field of the frame_bytes struct; you must remove the data corresponding to the frame_bytes field from the input buffer before the next decoder invocation.
The decoding function returns the number of decoded samples. The following cases are possible:
- 0: No MP3 data was found in the input buffer
- 384: Layer 1
- 576: MPEG 2 Layer 3
- 1152: Otherwise
The following is a description of the possible combinations of the number of samples and frame_bytes field values:
- More than 0 samples and
frame_bytes > 0: Succesful decode - 0 samples and
frame_bytes > 0: The decoder skipped ID3 or invalid data - 0 samples and
frame_bytes == 0: Insufficient data
If frame_bytes == 0, the other fields may be uninitialized or unchanged; if frame_bytes != 0, the other fields are available. The application may call mp3dec_init() when changing decode position, but this is not necessary.
As a special case, the decoder supports already split MP3 streams (for example, after doing an MP4 demux). In this case, the input buffer must contain exactly one non-free-format frame.
Seeking
You can seek to any byte in the stream and call mp3dec_decode_frame; this will work in almost all cases, but is not completely guaranteed. Probablility of sync procedure failure lowers when MAX_FRAME_SYNC_MATCHES value grows. Default MAX_FRAME_SYNC_MATCHES=10 and probablility of sync failure should be very low. If granule data is accidentally detected as a valid MP3 header, short audio artefacting is possible.
High-level mp3dec_ex_seek function supports precise seek to sample (MP3D_SEEK_TO_SAMPLE) using index and binary search.
Track length detect
If the file is known to be cbr, then all frames have equal size and lack ID3 tags, which allows us to decode the first frame and calculate all frame positions as frame_bytes * N. However, because of padding, frames can differ in size even in this case.
In general case whole stream scan is needed to calculate it's length. Scan can be omitted if vbr tag is present (added by encoders like lame and ffmpeg), which contains length info. High-level functions automatically use the vbr tag if present.
High-level API
If you need only decode file/buffer or use precise seek, you can use optional high-level API. Just #include minimp3_ex.h instead and use following additional functions:
#define MP3D_SEEK_TO_BYTE 0
#define MP3D_SEEK_TO_SAMPLE 1
#define MINIMP3_PREDECODE_FRAMES 2 /* frames to pre-decode and skip after seek (to fill internal structures) */
/*#define MINIMP3_SEEK_IDX_LINEAR_SEARCH*/ /* define to use linear index search instead of binary search on seek */
#define MINIMP3_IO_SIZE (128*1024) /* io buffer size for streaming functions, must be greater than MINIMP3_BUF_SIZE */
#define MINIMP3_BUF_SIZE (16*1024) /* buffer which can hold minimum 10 consecutive mp3 frames (~16KB) worst case */
#define MINIMP3_ENABLE_RING 0 /* enable hardware magic ring buffer if available, to make less input buffer memmove(s) in callback IO mode */
#define MP3D_E_MEMORY -1
#define MP3D_E_IOERROR -2
typedef struct
{
mp3d_sample_t *buffer;
size_t samples; /* channels included, byte size = samples*sizeof(mp3d_sample_t) */
int channels, hz, layer, avg_bitrate_kbps;
} mp3dec_file_info_t;
typedef size_t (*MP3D_READ_CB)(void *buf, size_t size, void *user_data);
typedef int (*MP3D_SEEK_CB)(uint64_t position, void *user_data);
typedef struct
{
MP3D_READ_CB read;
void *read_data;
MP3D_SEEK_CB seek;
void *seek_data;
} mp3dec_io_t;
typedef struct
{
uint64_t samples;
mp3dec_frame_info_t info;
int last_error;
...
} mp3dec_ex_t;
typedef int (*MP3D_ITERATE_CB)(void *user_data, const uint8_t *frame, int frame_size, int free_format_bytes, size_t buf_size, uint64_t offset, mp3dec_frame_info_t *info);
typedef int (*MP3D_PROGRESS_CB)(void *user_data, size_t file_size, uint64_t offset, mp3dec_frame_info_t *info);
/* decode whole buffer block */
int mp3dec_load_buf(mp3dec_t *dec, const uint8_t *buf, size_t buf_size, mp3dec_file_info_t *info, MP3D_PROGRESS_CB progress_cb, void *user_data);
int mp3dec_load_cb(mp3dec_t *dec, mp3dec_io_t *io, uint8_t *buf, size_t buf_size, mp3dec_file_info_t *info, MP3D_PROGRESS_CB progress_cb, void *user_data);
/* iterate through frames */
int mp3dec_iterate_buf(const uint8_t *buf, size_t buf_size, MP3D_ITERATE_CB callback, void *user_data);
int mp3dec_iterate_cb(mp3dec_io_t *io, uint8_t *buf, size_t buf_size, MP3D_ITERATE_CB callback, void *user_data);
/* streaming decoder with seeking capability */
int mp3dec_ex_open_buf(mp3dec_ex_t *dec, const uint8_t *buf, size_t buf_size, int seek_method);
int mp3dec_ex_open_cb(mp3dec_ex_t *dec, mp3dec_io_t *io, int seek_method);
void mp3dec_ex_close(mp3dec_ex_t *dec);
int mp3dec_ex_seek(mp3dec_ex_t *dec, uint64_t position);
size_t mp3dec_ex_read(mp3dec_ex_t *dec, mp3d_sample_t *buf, size_t samples);
#ifndef MINIMP3_NO_STDIO
/* stdio versions of file load, iterate and stream */
int mp3dec_load(mp3dec_t *dec, const char *file_name, mp3dec_file_info_t *info, MP3D_PROGRESS_CB progress_cb, void *user_data);
int mp3dec_iterate(const char *file_name, MP3D_ITERATE_CB callback, void *user_data);
int mp3dec_ex_open(mp3dec_ex_t *dec, const char *file_name, int seek_method);
#ifdef _WIN32
int mp3dec_load_w(mp3dec_t *dec, const wchar_t *file_name, mp3dec_file_info_t *info, MP3D_PROGRESS_CB progress_cb, void *user_data);
int mp3dec_iterate_w(const wchar_t *file_name, MP3D_ITERATE_CB callback, void *user_data);
int mp3dec_ex_open_w(mp3dec_ex_t *dec, const wchar_t *file_name, int seek_method);
#endif
#endif
Use MINIMP3_NO_STDIO define to exclude STDIO functions. MINIMP3_ALLOW_MONO_STEREO_TRANSITION allows mixing mono and stereo in same file. In that case mp3dec_frame_info_t->channels = 0 is reported on such files and correct channels number passed to progress_cb callback for each frame in mp3dec_frame_info_t structure. MP3D_PROGRESS_CB is optional and can be NULL, example of file decoding:
mp3dec_t mp3d;
mp3dec_file_info_t info;
if (mp3dec_load(&mp3d, input_file_name, &info, NULL, NULL))
{
/* error */
}
/* mp3dec_file_info_t contains decoded samples and info,
use free(info.buffer) to deallocate samples */
Example of file decoding with seek capability:
mp3dec_ex_t dec;
if (mp3dec_ex_open(&dec, input_file_name, MP3D_SEEK_TO_SAMPLE))
{
/* error */
}
/* dec.samples, dec.info.hz, dec.info.layer, dec.info.channels should be filled */
if (mp3dec_ex_seek(&dec, position))
{
/* error */
}
mp3d_sample_t *buffer = malloc(dec.samples*sizeof(mp3d_sample_t));
size_t readed = mp3dec_ex_read(&dec, buffer, dec.samples);
if (readed != dec.samples) /* normal eof or error condition */
{
if (dec.last_error)
{
/* error */
}
}
Bindings
- https://github.com/tosone/minimp3 - go bindings
- https://github.com/notviri/rmp3 - rust
no_stdbindings which don't allocate. - https://github.com/germangb/minimp3-rs - rust bindings
- https://github.com/johangu/node-minimp3 - NodeJS bindings
- https://github.com/pyminimp3/pyminimp3 - python bindings
- https://github.com/bashi/minimp3-wasm - wasm bindings
- https://github.com/DasZiesel/minimp3-delphi - delphi bindings
- https://github.com/mgeier/minimp3_ex-sys - low-level rust bindings to
minimp3_ex
Interesting links
- https://keyj.emphy.de/minimp3/
- https://github.com/technosaurus/PDMP3
- https://github.com/technosaurus/PDMP2
- https://github.com/packjpg/packMP3
- https://sites.google.com/a/kmlager.com/www/projects
- https://sourceforge.net/projects/mp3dec/
- http://blog.bjrn.se/2008/10/lets-build-mp3-decoder.html
- http://www.mp3-converter.com/mp3codec/
- http://www.multiweb.cz/twoinches/mp3inside.htm
- https://www.mp3-tech.org/
- https://id3.org/mp3Frame
- https://www.datavoyage.com/mpgscript/mpeghdr.htm
Download Details:
Author: lieff
Source Code: https://github.com/lieff/minimp3
License: CC0-1.0 License
#programming #developer #cplusplus #cpp