Yii 2

https://github.com/yiisoft/yii2
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### Setup ZSH completion

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/tutorial-console.md

Commands to install ZSH completion, add the directory to fpath, initialize completion, and reload the shell.

```bash
mkdir -p ~/.zsh/completion
curl -L https://raw.githubusercontent.com/yiisoft/yii2/master/contrib/completion/zsh/_yii -o ~/.zsh/completion/_yii
```

```bash
fpath=(~/.zsh/completion $fpath)
```

```bash
autoload -Uz compinit && compinit -i
```

```bash
exec $SHELL -l
```

--------------------------------

### Example migrate/up command

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/tutorial-console.md

Example of calling MigrateController::actionUp() with a limit of 5 and setting the migrationTable option to 'migrations'.

```text
yii migrate/up 5 --migrationTable=migrations
```

--------------------------------

### Install fxp/composer-asset-plugin globally

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/structure-assets.md

Run this command to install the composer-asset-plugin globally, enabling Bower and NPM support for all projects.

```bash
composer global require "fxp/composer-asset-plugin:^1.4.1"
```

--------------------------------

### Install an application with dev/app

Source: https://github.com/yiisoft/yii2/blob/master/docs/internals/release.md

Installs an application template (e.g., basic) under /apps/ using the dev/app command. This ensures the application uses the same framework code as the current repository state.

```bash
./build/build dev/app basic
```

--------------------------------

### Install an extension with dev/ext

Source: https://github.com/yiisoft/yii2/blob/master/docs/internals/release.md

Installs an extension (e.g., authclient) under /extensions/ using the dev/ext command. This ensures the extension uses the same framework code as the current repository state.

```bash
./build/build dev/ext authclient
```

--------------------------------

### Module config.php file example

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide-zh-CN/structure-modules.md

Example content of a module's config.php file. It returns an array with 'components' and 'params' sections, similar to an application configuration.

```php
<?php
return [
    'components' => [
        // list of component configurations
    ],
    'params' => [
        // list of parameters
    ],
];

```

--------------------------------

### Examples of Url::toRoute() usage

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/helper-url.md

Various examples demonstrating route generation, including aliases, absolute URLs, and schemes.

```php
// /index.php?r=site%2Findex
echo Url::toRoute('site/index');

// /index.php?r=site%2Findex&src=ref1#name
echo Url::toRoute(['site/index', 'src' => 'ref1', '#' => 'name']);

// /index.php?r=post%2Fedit&id=100     assume the alias "@postEdit" is defined as "post/edit"
echo Url::toRoute(['@postEdit', 'id' => 100]);

// https://www.example.com/index.php?r=site%2Findex
echo Url::toRoute('site/index', true);

// https://www.example.com/index.php?r=site%2Findex
echo Url::toRoute('site/index', 'https');
```

--------------------------------

### Enable RunProcess extension in Acceptance.suite.yml

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/test-environment-setup.md

This YAML configuration lets Codeception start and stop the web server automatically. It requires the symfony/process package, installable with 'composer require --dev symfony/process'. The 'sleep: 1' gives the server time to start.

```yaml
extensions:
    enabled:
        - Codeception\Extension\RunProcess:
            0: php -S localhost:8080 -t web
            sleep: 1
```

--------------------------------

### Usage examples for Url::to()

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/helper-url.md

Examples showing how Url::to() handles routes, aliases, and absolute URL schemes.

```php
// /index.php?r=site%2Findex
echo Url::to(['site/index']);

// /index.php?r=site%2Findex&src=ref1#name
echo Url::to(['site/index', 'src' => 'ref1', '#' => 'name']);

// /index.php?r=post%2Fedit&id=100     assume the alias "@postEdit" is defined as "post/edit"
echo Url::to(['@postEdit', 'id' => 100]);

// the currently requested URL
echo Url::to();

// /images/logo.gif
echo Url::to('@web/images/logo.gif');

// images/logo.gif
echo Url::to('images/logo.gif');

// https://www.example.com/images/logo.gif
echo Url::to('@web/images/logo.gif', true);

// https://www.example.com/images/logo.gif
echo Url::to('@web/images/logo.gif', 'https');
```

--------------------------------

### Configure log targets in application configuration

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/runtime-logging.md

Shows how to register multiple log targets via the 'log' component in the application configuration. The 'log' component must be loaded during bootstrapping time, and the 'timeZone' is set to ensure correct timestamps. The example includes a DbTarget for error and warning levels, and an EmailTarget for error messages in categories starting with 'yii\db\*', sending emails to specified addresses.

```php
return [
    // the "log" component must be loaded during bootstrapping time
    'bootstrap' => ['log'],
    // the "log" component process messages with timestamp. Set PHP timezone to create correct timestamp
    'timeZone' => 'America/Los_Angeles',
    'components' => [
        'log' => [
            'targets' => [
                [
                    'class' => 'yii\log\DbTarget',
                    'levels' => ['error', 'warning'],
                ],
                [
                    'class' => 'yii\log\EmailTarget',
                    'levels' => ['error'],
                    'categories' => ['yii\db\*'],
                    'message' => [
                       'from' => ['log@example.com'],
                       'to' => ['admin@example.com', 'developer@example.com'],
                       'subject' => 'Database errors at example.com',
                    ],
                ],
            ],
        ],
    ],
];
```

--------------------------------

### Build application with extension

Source: https://github.com/yiisoft/yii2/blob/master/docs/internals/git-workflow.md

Run this command to install the extension and its dependencies and create a symlink to the extension directory.

```bash
php build/build dev/app basic <fork>
```

--------------------------------

### Start PHP built-in web server

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/test-environment-setup.md

Starts PHP's built-in web server on localhost:8080 with the web directory as document root. Run this manually before executing acceptance tests.

```bash
php -S localhost:8080 -t web
```

--------------------------------

### Install Composer on Linux and Mac OS X

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/start-installation.md

Commands to download and install Composer globally on Linux and Mac OS X. The first command downloads the installer and runs it with PHP, the second moves the composer.phar file to /usr/local/bin/composer.

```bash
curl -sS https://getcomposer.org/installer | php
sudo mv composer.phar /usr/local/bin/composer
```

--------------------------------

### Start services in background

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/tutorial-docker.md

Starts all services defined in the stack in the background.

```bash
docker-compose up -d
```

--------------------------------

### Configure fxp-asset installer paths

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/structure-assets.md

Add these lines to your project's composer.json to customize the installation directories for Bower and NPM packages.

```json
"config": {
    "fxp-asset": {
        "installer-paths": {
            "npm-asset-library": "vendor/npm",
            "bower-asset-library": "vendor/bower"
        }
    }
}
```

--------------------------------

### Guide link syntax

Source: https://github.com/yiisoft/yii2/blob/master/docs/internals/core-code-style.md

Markdown syntax to link to the Guide, with optional subsection anchor.

```markdown
[link to guide](guide:file-name.md)
[link to guide](guide:file-name.md#subsection)
```

--------------------------------

### Start built-in PHP web server

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/start-installation.md

Run this console command in the project root directory to start the built-in PHP web server. By default it listens on port 8080.

```bash
php yii serve
```

--------------------------------

### Start a transaction on the master connection

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/db-dao.md

By default, transactions use the master connection, and all DB operations within the transaction also use the master. This example shows a transaction that performs a SELECT and an UPDATE on the master, with proper rollback on exceptions.

```php
$db = Yii::$app->db;
// the transaction is started on the master connection
$transaction = $db->beginTransaction();

try {
    // both queries are performed against the master
    $rows = $db->createCommand('SELECT * FROM user LIMIT 10')->queryAll();
    $db->createCommand("UPDATE user SET username='demo' WHERE id=1")->execute();

    $transaction->commit();
} catch(\Exception $e) {
    $transaction->rollBack();
    throw $e;
} catch(\Throwable $e) {
    $transaction->rollBack();
    throw $e;
}
```

--------------------------------

### Install Composer autoloader and include Yii

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/tutorial-yii-integration.md

Place these lines in the entry script to install the Composer autoloader and include the Yii class file, enabling autoloading for installed Composer packages.

```php
// install Composer autoloader
require __DIR__ . '/../vendor/autoload.php';

// include Yii class file
require __DIR__ . '/../vendor/yiisoft/yii2/Yii.php';
```

--------------------------------

### Run application with yii serve

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/tutorial-yii-as-micro-framework.md

Starts the PHP built-in web server from the micro-app directory.

```bash
vendor/bin/yii serve --docroot=./web
```

--------------------------------

### Install Codeception and modules via Composer

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/test-environment-setup.md

Run this console command to install Codeception 5 and its modules as development dependencies. The command installs codeception/codeception:^5.0, codeception/module-yii2, codeception/module-asserts, codeception/module-filesystem, codeception/module-phpbrowser, and codeception/verify. Note that Codeception 5 requires PHP 8.0 or higher; for PHP 7.4, change the version constraint to ^4.0.

```bash
composer require --dev 'codeception/codeception:^5.0' codeception/module-yii2 codeception/module-asserts codeception/module-filesystem codeception/module-phpbrowser codeception/verify
```

--------------------------------

### Example Log Message Format

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/runtime-logging.md

A sample log message as it appears in the runtime/log/app.log file.

```text
2014-10-04 18:10:15 [::1][][-][trace][yii\base\Module::getModule] Loading module: debug
```

--------------------------------

### Install composer-asset-plugin and configure asset paths

Source: https://github.com/yiisoft/yii2/blob/master/framework/UPGRADE.md

Before upgrading Yii with Composer, install the composer-asset-plugin globally, add the asset-installer-paths configuration to composer.json, and optionally upgrade Composer itself.

```bash
php composer.phar global require "fxp/composer-asset-plugin:~1.3.1"
```

```json
"extra": {
    "asset-installer-paths": {
        "npm-asset-library": "vendor/npm",
        "bower-asset-library": "vendor/bower"
    }
}
```

```bash
composer self-update
```

--------------------------------

### Example output of object to array conversion

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/helper-array.md

Shows the resulting array structure for a single model after applying the mapping defined in the previous example.

```php
[
    'id' => 123,
    'title' => 'test',
    'createTime' => '2013-01-01 12:00AM',
    'length' => 301,
]
```

--------------------------------

### Running Migrations with Command Line Options

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/db-migrations.md

Example of running the migration command for a specific module path in non-interactive mode.

```bash
# migrate the migrations in a forum module non-interactively
yii migrate --migrationPath=@app/modules/forum/migrations --interactive=0
```

--------------------------------

### Advanced Dependency Classes

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/concept-di-container.md

Example classes demonstrating constructor dependencies for advanced DI scenarios.

```php
class FileStorage
{
    public function __construct($root) {
        // whatever
    }
}

class DocumentsReader
{
    public function __construct(FileStorage $fs) {
        // whatever
    }
}
```

--------------------------------

### Create a specific migration named create_news_table

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/db-migrations.md

Example of running the migration creation command for a specific table name.

```bash
yii migrate/create create_news_table
```

--------------------------------

### PHPDoc example with PHPDoc, PHPStan, and Psalm annotations

Source: https://github.com/yiisoft/yii2/blob/master/docs/internals/git-workflow.md

Example of PHPDoc annotations using PHPStan types. Shows how to specify a different type for Psalm using @phpstan-return and @psalm-return annotations.

```php
<?php
/**
 * @return Action<covariant static>|null
 * @phpstan-return Action<covariant static>|null
 * @psalm-return Action<self>|null
 */
public function createAction($id)
{
...
}
```

--------------------------------

### Configuration with properties, events, and behaviors

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/concept-configurations.md

Example configuration that sets initial property values, attaches an event handler, and adds a behavior.

```php
[
    'class' => 'app\components\SearchEngine',
    'apiKey' => 'xxxxxxxx',
    'on search' => function ($event) {
        Yii::info("Keyword searched: " . $event->keyword);
    },
    'as indexer' => [
        'class' => 'app\components\IndexerBehavior',
        // ... property init values ...
    ],
]
```

--------------------------------

### GET Query Filter Request

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/rest-filtering-collections.md

Example of providing the same filtering conditions as a part of a GET query string.

```text
?filter[id][in][]=2&filter[id][in][]=5&filter[id][in][]=9&filter[title][like]=cheese
```

--------------------------------

### Verify Docker installation

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/tutorial-docker.md

Run this command to confirm the Docker daemon is active and running.

```bash
docker ps
```

--------------------------------

### Initialize project directory

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/tutorial-yii-as-micro-framework.md

Commands to create and enter the project directory.

```bash
mkdir micro-app
cd micro-app
```

--------------------------------

### Install Bash completion

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/tutorial-console.md

Download the Yii2 Bash completion script to the system directory for command auto-completion.

```bash
curl -L https://raw.githubusercontent.com/yiisoft/yii2/master/contrib/completion/bash/yii -o /etc/bash_completion.d/yii
```

--------------------------------

### Composer require for yiisoft/yii2-imagine

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/structure-extensions.md

Add the extension to the 'require' section of composer.json to install it via Composer. The version is specified as '*' to get the latest version.

```json
{
    // ...

    "require": {
        // ... other dependencies

        "yiisoft/yii2-imagine": "*"
    }
}
```

--------------------------------

### Generate namespaced migration for CreateBANANATable

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/db-migrations.md

Example of generating a migration to create a table with an all-caps name.

```bash
yii migrate/create app\\migrations\\CreateBANANATable
```

--------------------------------

### URL to display static page via ViewAction

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/structure-views.md

Example URL that requests the 'about' view using the ViewAction. The 'view' GET parameter specifies which view to render.

```text
http://localhost/index.php?r=site%2Fpage&view=about
```

--------------------------------

### Bootstrap configuration with log component and closures

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/structure-application-components.md

This configuration example shows how to use the 'bootstrap' property to ensure the 'log' component is always loaded, and demonstrates using closures to return a new component or run code after application instantiation.

```php
[
    'bootstrap' => [
        'log',
        function($app){
            return new ComponentX();
        },
        function($app){
            // some code
           return;
        }
    ],
    'components' => [
        'log' => [
            // configuration for "log" component
        ],
    ],
]
```

--------------------------------

### FilterValidator configuration examples

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/tutorial-core-validators.md

Demonstrates how to configure the FilterValidator using trim, anonymous functions, and class methods.

```php
[
    // trim "username" and "email" inputs
    [['username', 'email'], 'filter', 'filter' => 'trim', 'skipOnArray' => true],

    // normalize "phone" input
    ['phone', 'filter', 'filter' => function ($value) {
        // normalize phone input here
        return $value;
    }],
    
    // normalize "phone" using the function "normalizePhone"
    ['phone', 'filter', 'filter' => [$this, 'normalizePhone']],
    
    public function normalizePhone($value) {
        return $value;
    }
]
```

--------------------------------

### Create Mail View File

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/tutorial-mailing.md

Example content for a mail view file located at @app/mail.

```php
<?php
use yii\helpers\Html;
use yii\helpers\Url;

/**
 * @var \yii\web\View $this view component instance
 * @var \yii\mail\BaseMessage $message instance of newly created mail message
 */

?>
<h2>This message allows you to visit our site home page by one click</h2>
<?= Html::a('Go to home page', Url::home('http')) ?>
```

--------------------------------

### Initialize environment configuration

Source: https://github.com/yiisoft/yii2/blob/master/tests/README.md

Copy the environment distribution file to create a local .env file.

```bash
cd tests
cp .env-dist .env
```

--------------------------------

### UrlValidator configuration example

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/tutorial-core-validators.md

Configures the 'website' attribute to be validated as a URL, prepending 'http://' if no scheme is present.

```php
[
    // checks if "website" is a valid URL. Prepend "http://" to the "website" attribute
    // if it does not have a URI scheme
    ['website', 'url', 'defaultScheme' => 'http'],
]
```

--------------------------------

### Configure SqlDataProvider

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/output-data-providers.md

Example of initializing SqlDataProvider with a raw SQL query, parameters, total count, pagination settings, and sortable attributes.

```php
use yii\data\SqlDataProvider;

$count = Yii::$app->db->createCommand('
    SELECT COUNT(*) FROM post WHERE status=:status
', [':status' => 1])->queryScalar();

$provider = new SqlDataProvider([
    'sql' => 'SELECT * FROM post WHERE status=:status',
    'params' => [':status' => 1],
    'totalCount' => $count,
    'pagination' => [
        'pageSize' => 10,
    ],
    'sort' => [
        'attributes' => [
            'title',
            'view_count',
            'created_at',
        ],
    ],
]);

// returns an array of data rows
$models = $provider->getModels();
```

--------------------------------

### Prevent asset installation via Composer in composer.json

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/start-installation.md

Add these lines to 'composer.json' to bypass asset installation via Composer. You become responsible for installing assets and resolving version collisions.

```json
"replace": {
    "bower-asset/jquery": ">=1.11.0",
    "bower-asset/inputmask": ">=3.2.0",
    "bower-asset/punycode": ">=1.3.0",
    "bower-asset/yii2-pjax": ">=2.0.0"
},
```

--------------------------------

### Code examples in docblocks (correct vs incorrect)

Source: https://github.com/yiisoft/yii2/blob/master/docs/internals/core-code-style.md

Shows that code examples in docblocks should use Markdown fences without specifying a language. The correct example omits 'php', the incorrect one includes it.

```php
/**
 * Correct code example:
 * 
 * ```
 * $object->doMagic();
 * ```
 */
function doMagic()
{
}

/**
 * Incorrect code example:
 * 
 * ```php
 * $object->doMagic();
 * ```
 */
function doMagic()
{
}
```

--------------------------------

### Show version overview

Source: https://github.com/yiisoft/yii2/blob/master/docs/internals/release.md

Displays an overview of framework and extension versions. Use --update to fetch tags for all repos to get the newest information.

```bash
./build/build release/info
```

--------------------------------

### Example shared host directory structure

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/tutorial-shared-hosting.md

Typical directory structure found on a shared hosting server via FTP.

```text
config
logs
www
```

--------------------------------

### Verify Docker Compose installation

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/tutorial-docker.md

Run this command to check the installed version of Docker Compose.

```bash
docker-compose version
```

--------------------------------

### Registering components with ServiceLocator::set()

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/concept-service-locator.md

Demonstrates various methods to register components using class names, configuration arrays, anonymous functions, or existing instances.

```php
use yii\di\ServiceLocator;
use yii\caching\FileCache;

$locator = new ServiceLocator;

// register "cache" using a class name that can be used to create a component
$locator->set('cache', 'yii\caching\ApcCache');

// register "db" using a configuration array that can be used to create a component
$locator->set('db', [
    'class' => 'yii\db\Connection',
    'dsn' => 'mysql:host=localhost;dbname=demo',
    'username' => 'root',
    'password' => '',
]);

// register "search" using an anonymous function that builds a component
$locator->set('search', function () {
    return new app\components\SolrService;
});

// register "pageCache" using a component
$locator->set('pageCache', new FileCache);
```

--------------------------------

### Resolving dependencies with get()

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/concept-di-container.md

Retrieves object instances from the container, optionally providing constructor parameters and configuration.

```php
// "db" is a previously registered alias name
$db = $container->get('db');

// equivalent to: $engine = new \app\components\SearchEngine($apiKey, $apiSecret, ['type' => 1]);
$engine = $container->get('app\components\SearchEngine', [$apiKey, $apiSecret], ['type' => 1]);

// equivalent to: $api = new \app\components\Api($host, $apiKey);
$api = $container->get('app\components\Api', ['host' => $host, 'apiKey' => $apiKey]);
```

--------------------------------

### Access installed Yii application

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/start-installation.md

Use this URL in your browser to access the installed Yii application.

```text
http://localhost:8080/
```

--------------------------------

### composer.json for yiisoft/yii2-imagine

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/structure-extensions.md

Example configuration file for a Yii2 extension, defining metadata, dependencies, and PSR-4 autoloading specifications.

```json
{
    // package name
    "name": "yiisoft/yii2-imagine",

    // package type
    "type": "yii2-extension",

    "description": "The Imagine integration for the Yii framework",
    "keywords": ["yii2", "imagine", "image", "helper"],
    "license": "BSD-3-Clause",
    "support": {
        "issues": "https://github.com/yiisoft/yii2/issues?labels=ext%3Aimagine",
        "forum": "https://forum.yiiframework.com/",
        "wiki": "https://www.yiiframework.com/wiki/",
        "irc": "ircs://irc.libera.chat:6697/yii",
        "source": "https://github.com/yiisoft/yii2"
    },
    "authors": [
        {
            "name": "Antonio Ramirez",
            "email": "amigo.cobos@gmail.com"
        }
    ],

    // package dependencies
    "require": {
        "yiisoft/yii2": "~2.0.0",
        "imagine/imagine": "v0.5.0"
    },

    // class autoloading specs
    "autoload": {
        "psr-4": {
            "yii\\imagine\\": ""
        }
    }
}
```

--------------------------------

### Run composer install in container

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/tutorial-docker.md

Runs the composer installation command inside a new PHP container.

```bash
docker-compose run --rm php composer install
```

--------------------------------

### Run Database Migration Commands

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/tutorial-yii-as-micro-framework.md

Use the console commands to create a migration file for the post table and apply it to the database.

```bash
vendor/bin/yii migrate/create --appconfig=config.php create_post_table --fields="title:string,body:text"
vendor/bin/yii migrate/up --appconfig=config.php
```

--------------------------------

### Registering dependencies with set()

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/concept-di-container.md

Demonstrates various ways to register dependencies using the set() method, including class names, interfaces, aliases, configurations, and callables.

```php
$container = new \yii\di\Container;

// register a class name as is. This can be skipped.
$container->set('yii\db\Connection');

// register an interface
// When a class depends on the interface, the corresponding class
// will be instantiated as the dependent object
$container->set('yii\mail\MailInterface', 'yii\symfonymailer\Mailer');

// register an alias name. You can use $container->get('foo')
// to create an instance of Connection
$container->set('foo', 'yii\db\Connection');

// register an alias with `Instance::of`
$container->set('bar', Instance::of('foo'));

// register a class with configuration. The configuration
// will be applied when the class is instantiated by get()
$container->set('yii\db\Connection', [
    'dsn' => 'mysql:host=127.0.0.1;dbname=demo',
    'username' => 'root',
    'password' => '',
    'charset' => 'utf8',
]);

// register an alias name with class configuration
// In this case, a "class" or "__class" element is required to specify the class
$container->set('db', [
    'class' => 'yii\db\Connection',
    'dsn' => 'mysql:host=127.0.0.1;dbname=demo',
    'username' => 'root',
    'password' => '',
    'charset' => 'utf8',
]);

// register callable closure or array
// The callable will be executed each time when $container->get('db') is called
$container->set('db', function ($container, $params, $config) {
    return new \yii\db\Connection($config);
});
$container->set('db', ['app\db\DbFactory', 'create']);

// register a component instance
// $container->get('pageCache') will return the same instance each time it is called
$container->set('pageCache', new FileCache);
```

--------------------------------

### Function/method docblock

Source: https://github.com/yiisoft/yii2/blob/master/docs/internals/core-code-style.md

Example of a method docblock with @param, @return, and @throws tags, including an inline code example.

```php
/**
 * Returns the list of attached event handlers for an event.
 * You may manipulate the returned [[Vector]] object by adding or removing handlers.
 * For example,
 *
 * ```
 * $component->getEventHandlers($eventName)->insertAt(0, $eventHandler);
 * ```
 *
 * @param string $name the event name
 * @return Vector list of attached event handlers for the event
 * @throws Exception if the event is not defined
 */
public function getEventHandlers($name)
{
    if (!isset($this->_e[$name])) {
        $this->_e[$name] = new Vector;
    }
    $this->ensureBehaviors();
    return $this->_e[$name];
}
```

--------------------------------

### Start a transaction on the slave connection

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/db-dao.md

To start a transaction on a slave connection, you must explicitly call beginTransaction() on the slave property.

```php
$transaction = Yii::$app->db->slave->beginTransaction();
```

--------------------------------

### ExistValidator Configuration Examples

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/tutorial-core-validators.md

Demonstrates various ways to configure the ExistValidator, including single and multi-column checks, target class mapping, and relation usage.

```php
[
    // a1 needs to exist in the column represented by the "a1" attribute
    // i.e. a1 = 1, valid if there is value 1 in column "a1"
    ['a1', 'exist'],
    // equivalent of
    ['a1', 'exist', 'targetAttribute' => 'a1'],
    ['a1', 'exist', 'targetAttribute' => ['a1' => 'a1']],

    // a1 needs to exist, but its value will use a2 to check for the existence
    // i.e. a1 = 2, valid if there is value 2 in column "a2"
    ['a1', 'exist', 'targetAttribute' => 'a2'],
    // equivalent of
    ['a1', 'exist', 'targetAttribute' => ['a1' => 'a2']],
    
    // a2 needs to exist, its value will use a2 to check for the existence, a1 will receive error message
    // i.e. a2 = 2, valid if there is value 2 in column "a2"
    ['a1', 'exist', 'targetAttribute' => ['a2']],
    // equivalent of
    ['a1', 'exist', 'targetAttribute' => ['a2' => 'a2']],

    // a1 and a2 need to exist together, and the first attribute without errors will receive error message
    // i.e. a1 = 3, a2 = 4, valid if there is value 3 in column "a1" and value 4 in column "a2"
    [['a1', 'a2'], 'exist', 'targetAttribute' => ['a1', 'a2']],
    // equivalent of
    [['a1', 'a2'], 'exist', 'targetAttribute' => ['a1' => 'a1', 'a2' => 'a2']],

    // a1 and a2 need to exist together, only a1 will receive error message
    // i.e. a1 = 5, a2 = 6, valid if there is value 5 in column "a1" and value 6 in column "a2"
    ['a1', 'exist', 'targetAttribute' => ['a1', 'a2']],
    // equivalent of
    ['a1', 'exist', 'targetAttribute' => ['a1' => 'a1', 'a2' => 'a2']],

    // a1 needs to exist by checking the existence of both a2 and a3 (using a1 value)
    // i.e. a1 = 7, a2 = 8, valid if there is value 7 in column "a3" and value 8 in column "a2"
    ['a1', 'exist', 'targetAttribute' => ['a2', 'a1' => 'a3']],
    // equivalent of
    ['a1', 'exist', 'targetAttribute' => ['a2' => 'a2', 'a1' => 'a3']],

    // a1 needs to exist. If a1 is an array, then every element of it must exist.
    // i.e. a1 = 9, valid if there is value 9 in column "a1"
    //      a1 = [9, 10], valid if there are values 9 and 10 in column "a1"
    ['a1', 'exist', 'allowArray' => true],
    
    // type_id needs to exist in the column "id" in the table defined in ProductType class
    // i.e. type_id = 1, valid if there is value 1 in column "id" of ProductType's table
    ['type_id', 'exist', 'targetClass' => ProductType::class, 'targetAttribute' => ['type_id' => 'id']],    
    
    // the same as the previous, but using already defined relation "type"
    ['type_id', 'exist', 'targetRelation' => 'type'],
]
```

--------------------------------

### Application Entry Script Initialization

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/concept-configurations.md

Shows how the application configuration array is passed to the application constructor in the entry script.

```php
(new yii\web\Application($config))->run();
```

--------------------------------

### Configure assetManager for CDN usage

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/structure-assets.md

Example of overriding the default JqueryAsset to use a CDN-hosted version by setting sourcePath to null.

```php
return [
    // ...
    'components' => [
        'assetManager' => [
            'bundles' => [
                'yii\web\JqueryAsset' => [
                    'sourcePath' => null,   // do not publish the bundle
                    'js' => [
                        '//ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js',
                    ]
                ],
            ],
        ],
    ],
];
```

--------------------------------

### Create command to inspect SQL and parameters

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/db-query-builder.md

Shows how to create a Command object from a Query to examine the generated SQL statement and bound parameters, and then execute it to fetch all rows.

```php
$command = (new \yii\db\Query())
    ->select(['id', 'email'])
    ->from('user')
    ->where(['last_name' => 'Smith'])
    ->limit(10)
    ->createCommand();
    
// show the SQL statement
echo $command->sql;
// show the parameters to be bound
print_r($command->params);

// returns all rows of the query result
$rows = $command->queryAll();
```

--------------------------------

### Get home URL with Url::home()

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/helper-url.md

Use Url::home() to get the home URL. Without parameters, it returns a relative URL. Pass true to get an absolute URL for the current schema, or specify a schema explicitly like 'https' or 'http'.

```php
$relativeHomeUrl = Url::home();
$absoluteHomeUrl = Url::home(true);
$httpsAbsoluteHomeUrl = Url::home('https');
```

--------------------------------

### PHP Callable Injection Example

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/concept-di-container.md

Demonstrates defining interfaces, classes, and configuring the DI container to resolve dependencies, showing the equivalence between container-based instantiation and manual instantiation.

```php
namespace app\models;

use yii\base\BaseObject;
use yii\db\Connection;
use yii\di\Container;

interface UserFinderInterface
{
    function findUser();
}

class UserFinder extends BaseObject implements UserFinderInterface
{
    public $db;

    public function __construct(Connection $db, $config = [])
    {
        $this->db = $db;
        parent::__construct($config);
    }

    public function findUser()
    {
    }
}

class UserLister extends BaseObject
{
    public $finder;

    public function __construct(UserFinderInterface $finder, $config = [])
    {
        $this->finder = $finder;
        parent::__construct($config);
    }
}

$container = new Container;
$container->set('yii\db\Connection', [
    'dsn' => '...',
]);
$container->set('app\models\UserFinderInterface', [
    'class' => 'app\models\UserFinder',
]);
$container->set('userLister', 'app\models\UserLister');

$lister = $container->get('userLister');

// which is equivalent to:

$db = new \yii\db\Connection(['dsn' => '...']);
$finder = new UserFinder($db);
$lister = new UserLister($finder);
```

--------------------------------

### Russian Plural Rules Example

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/tutorial-i18n.md

Example of a Russian translation string using specific plural categories like one, few, and many.

```text
Здесь {n,plural,=0{котов нет} =1{есть один кот} one{# кот} few{# кота} many{# котов} other{# кота}}!
```

--------------------------------

### Use the configured connection for read and write queries

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/db-dao.md

After configuring the connection, create a Connection instance and perform a read query (SELECT) against a slave and a write query (UPDATE) against the master.

```php
// create a Connection instance using the above configuration
Yii::$app->db = Yii::createObject($config);

// query against one of the slaves
$rows = Yii::$app->db->createCommand('SELECT * FROM user LIMIT 10')->queryAll();

// query against the master
Yii::$app->db->createCommand("UPDATE user SET username='demo' WHERE id=1")->execute();
```

--------------------------------

### Register dependencies as singletons

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/concept-di-container.md

Optimizes performance by registering stateless classes as singletons using setSingletons.

```php
$container->setSingletons([
    'tempFileStorage' => [
        'class' => 'app\storage\FileStorage',
        '__construct()' => ['/var/tempfiles']
    ],
]);

$container->setDefinitions([
    'app\storage\DocumentsReader' => [
        'class' => 'app\storage\DocumentsReader',
        '__construct()' => [Instance::of('tempFileStorage')],
    ],
    'app\storage\DocumentsWriter' => [
        'class' => 'app\storage\DocumentsWriter',
        '__construct()' => [Instance::of('tempFileStorage')],
    ]
]);

$reader = $container->get('app\storage\DocumentsReader');
```

--------------------------------

### Using Cache as ArrayAccess

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/caching-data.md

Demonstrates how to use a cache component like an array to set and get values, which is equivalent to calling set() and get() methods.

```php
$cache['var1'] = $value1;  // equivalent to: $cache->set('var1', $value1);
$value2 = $cache['var2'];  // equivalent to: $value2 = $cache->get('var2');
```

--------------------------------

### Show release command help

Source: https://github.com/yiisoft/yii2/blob/master/docs/internals/release.md

Run this command in the framework repo root to see the help for the release command. The --dryRun option can be used to preview actions without making changes.

```bash
./build/build help release  # run in framework repo root
```

--------------------------------

### Execute RBAC initialization command

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/security-authorization.md

Run the console command to initialize the authorization data.

```bash
yii rbac/init
```

--------------------------------

### Start built-in PHP web server with custom port

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/start-installation.md

Use the --port argument to specify a different port if 8080 is already in use or you want to serve multiple applications.

```bash
php yii serve --port=8888
```

--------------------------------

### Install Composer and Yii autoloaders

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/concept-autoloading.md

Entry script code that installs the Composer autoloader first, then the Yii autoloader. This ensures Yii's autoloader is the first to respond.

```php
require __DIR__ . '/../vendor/autoload.php';
require __DIR__ . '/../vendor/yiisoft/yii2/Yii.php';
```

--------------------------------

### Inject constructor parameters with Instance::of

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/concept-di-container.md

Shows how to use the __construct() option and Instance::of to manage dependencies and avoid code duplication.

```php
$container->setDefinitions([
    'tempFileStorage' => [ // we've created an alias for convenience
        'class' => 'app\storage\FileStorage',
        '__construct()' => ['/var/tempfiles'], // could be extracted from some config files
    ],
    'app\storage\DocumentsReader' => [
        'class' => 'app\storage\DocumentsReader',
        '__construct()' => [Instance::of('tempFileStorage')],
    ],
    'app\storage\DocumentsWriter' => [
        'class' => 'app\storage\DocumentsWriter',
        '__construct()' => [Instance::of('tempFileStorage')]
    ]
]);

$reader = $container->get('app\storage\DocumentsReader'); 
// Will behave exactly the same as in the previous example.
```

--------------------------------

### Create and configure an object using Yii::createObject

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/intro-upgrade-from-v1.md

Demonstrates how to instantiate a configured object using Yii::createObject with a configuration array and constructor parameters. The configuration array must include the 'class' key and property values.

```php
$object = Yii::createObject([
    'class' => 'MyClass',
    'property1' => 'abc',
    'property2' => 'cde',
], [$param1, $param2]);
```

--------------------------------

### Anonymous function spacing (good vs bad)

Source: https://github.com/yiisoft/yii2/blob/master/docs/internals/core-code-style.md

Shows correct spacing between function/use tokens and open parenthesis. The good example uses spaces, the bad example omits them.

```php
// good
$n = 100;
$sum = array_reduce($numbers, function ($r, $x) use ($n) {
    $this->doMagic();
    $r += $x * $n;
    return $r;
});
```

```php
// bad
$n = 100;
$mul = array_reduce($numbers, function($r, $x) use($n) {
    $this->doMagic();
    $r *= $x * $n;
    return $r;
});
```

--------------------------------

### Module directory structure example

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide-zh-CN/structure-modules.md

Shows the typical directory layout for a module named 'forum', including the Module.php class file, controllers, models, and views subdirectories. Use this as a reference when creating a new module structure.

```text
forum/
    Module.php                   模块类文件
    controllers/                 包含控制器类文件
        DefaultController.php    default 控制器类文件
    models/                      包含模型类文件
    views/                       包含控制器视图文件和布局文件
        layouts/                 包含布局文件
        default/                 包含 DefaultController 控制器视图文件
            index.php            index 视图文件

```

--------------------------------

### Create web/index.php entry point

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/tutorial-yii-as-micro-framework.md

The entry script that initializes the Yii application and loads the configuration.

```php
<?php

// comment out the following two lines when deployed to production
defined('YII_DEBUG') or define('YII_DEBUG', true);
defined('YII_ENV') or define('YII_ENV', 'dev');

require(__DIR__ . '/../vendor/autoload.php');
require(__DIR__ . '/../vendor/yiisoft/yii2/Yii.php');

$config = require __DIR__ . '/../config.php';
(new yiiase
un());
```

--------------------------------

### Basic Application Configuration

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/concept-configurations.md

An example of an application configuration array defining components like cache, mailer, log, and database connection.

```php
$config = [
    'id' => 'basic',
    'basePath' => dirname(__DIR__),
    'extensions' => require __DIR__ . '/../vendor/yiisoft/extensions.php',
    'components' => [
        'cache' => [
            'class' => 'yii\caching\FileCache',
        ],
        'mailer' => [
            'class' => 'yii\symfonymailer\Mailer',
        ],
        'log' => [
            'class' => 'yii\log\Dispatcher',
            'traceLevel' => YII_DEBUG ? 3 : 0,
            'targets' => [
                [
                    'class' => 'yii\log\FileTarget',
                ],
            ],
        ],
        'db' => [
            'class' => 'yii\db\Connection',
            'dsn' => 'mysql:host=localhost;dbname=stay2',
            'username' => 'root',
            'password' => '',
            'charset' => 'utf8',
        ],
    ],
];
```

--------------------------------

### Subscribing to ActiveForm beforeSubmit event

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/input-form-javascript.md

This JavaScript example shows how to attach a handler to the 'beforeSubmit' event of an ActiveForm. If the handler returns false, the form submission is stopped. This example is for the #contact-form form.

```javascript
$('#contact-form').on('beforeSubmit', function (e) {
	if (!confirm("Everything is correct. Submit?")) {
		return false;
	}
	return true;
});
```

--------------------------------

### Recommended Apache Configuration

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/start-installation.md

Use this configuration in httpd.conf or a virtual host file. Replace path/to/basic/web with your actual directory path.

```apache
# Set document root to be "basic/web"
DocumentRoot "path/to/basic/web"

<Directory "path/to/basic/web">
    # use mod_rewrite for pretty URL support
    RewriteEngine on
    
    # if $showScriptName is false in UrlManager, do not allow accessing URLs with script name
    RewriteRule ^index.php/ - [L,R=404]
    
    # If a directory or a file exists, use the request directly
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_FILENAME} !-d
    
    # Otherwise forward the request to index.php
    RewriteRule . index.php

    # ...other settings...
</Directory>
```

--------------------------------

### Example JSON response with expanded profile

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/rest-resources.md

Example JSON response returned when requesting http://localhost/users?fields=id,email&expand=profile. Shows the structure with id, email, and a nested profile object.

```php
[
    {
        "id": 100,
        "email": "100@example.com",
        "profile": {
            "id": 100,
            "age": 30,
        }
    },
    ...
]
```

--------------------------------

### where() string format - dangerous example

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/db-query-builder.md

Warns against embedding variables directly in the condition due to SQL injection risk. This example is explicitly marked as dangerous and should not be used unless the variable is guaranteed to be an integer.

```php
// Dangerous! Do NOT do this unless you are very certain $status must be an integer.
$query->where("status=$status");
```

--------------------------------

### Loading configuration file to run application

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/concept-configurations.md

Loads a configuration file using require and creates a new Yii web application instance with it, then runs the application.

```php
$config = require 'path/to/web.php';
(new yii\web\Application($config))->run();
```

--------------------------------

### Get module instance using getInstance()

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/structure-modules.md

Use MyModuleClass::getInstance() to get the currently requested instance of the module class. Returns null if the module is not requested. Do not manually create a new instance.

```php
$module = MyModuleClass::getInstance();
```

--------------------------------

### Configure extraPatterns to add a search action

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/rest-routing.md

Adds a custom `search` action accessible via `GET /users/search` by configuring the `extraPatterns` option. The pattern 'GET search' maps to the 'search' action.

```php
[
    'class' => 'yii\rest\UrlRule',
    'controller' => 'user',
    'extraPatterns' => [
        'GET search' => 'search',
    ],
]
```

--------------------------------

### where() hash format - vulnerable example

Source: https://github.com/yiisoft/yii2/blob/master/docs/guide/db-query-builder.md

Warns against using user input as column names without validation. The example shows a vulnerable code pattern where the column name is not encoded, leading to SQL injection risk.

```php
// Vulnerable code:
$column = $request->get('column');
$value = $request->get('value');
$query->where([$column => $value]);
// $value is safe, but $column name won't be encoded!
```

--------------------------------

### Stage files

Source: https://github.com/yiisoft/yii2/blob/master/docs/internals/git-workflow.md

Add files to the staging area. Use -p to select changes.

```bash
git add path/to/my/file.php
```
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