Application practice of PSR2 and PSR4 specifications in Symfony framework

The application practice of PSR2 and PSR4 specifications in the Symfony framework

Introduction:

Symfony is a popular and widely used PHP framework. Many convenient features and tools are provided to speed up the development process. In order to maintain code readability and consistency, the Symfony framework encourages developers to follow specifications. This article will focus on the application practice of PSR2 and PSR4 specifications in the Symfony framework and provide specific code examples.

1. Application practice of PSR2 specification in Symfony framework

1. Indentation and line breaks

According to the PSR2 specification, four are required to be used in the Symfony framework spaces for indentation. Here is an example:

class ExampleClass
{
    public function exampleMethod()
    {
        if (true) {
            // do something
        } else {
            // do something else
        }
    }

    public function anotherExampleMethod()
    {
        for ($i = 0; $i < 10; $i++) {
            // do something in the loop
        }
    }
}

2. Use of braces

In the Symfony framework, it is recommended to use braces in the declaration of a function or class, and on a new line start. Here is an example:

class ExampleClass
{
    public function exampleMethod()
    {
        // do something
    }

    public function anotherExampleMethod()
    {
        // do something else
    }
}

3. Use of spaces

According to the PSR2 specification, the use of spaces around operators is required in the Symfony framework. The following is an example:

class ExampleClass
{
    public function exampleMethod()
    {
        $result = $this->addNumbers(4, 5);
        $this->doSomething($result);
    }

    public function addNumbers($a, $b)
    {
        return $a + $b;
    }

    public function doSomething($result)
    {
        // do something with the result
    }
}

2. Application practice of PSR4 specification in Symfony framework

1. Namespace

PSR4 specification requires the use of namespace Organize code and map them to directory structures. In the Symfony framework, we can use Composer to automatically load class files. Here's an example:

// 文件路径：src/Example/Namespace/ExampleClass.php
namespace ExampleNamespace;

class ExampleClass
{
    // class code here
}

Similarly, Composer's autoload configuration items can be used to map namespaces to directories:

// composer.json
{
    "autoload": {
        "psr-4": {
            "Example\Namespace\": "src/Example/Namespace"
        }
    }
}

2. Canonical directory structure

According to the PSR4 specification, the directory structure in the Symfony framework should be consistent with the namespace hierarchy. Here is an example:

src/
    Example/
        Namespace/
            ExampleClass.php

3. Using Composer for automatic loading

In order for Composer to automatically load class files, we need to run composer in the root directory of the project update command to update the autoload file. The following is an example:

$ composer update

Then use the automatic loading function provided by Composer to load the file:

require_once __DIR__ . '/vendor/autoload.php';

Using the PSR4 specification, the class files in the Symfony framework will be automatically loaded without manual introduction. .

Summary:

This article introduces the application practice of PSR2 and PSR4 specifications in the Symfony framework, and provides specific code examples. Following specifications can improve code readability and consistency, helping developers better maintain and expand projects. In order to facilitate automatic loading, we use Composer in the Symfony framework to manage the dependencies of class files and the automatic loading mechanism.

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