如何在Symfony 4控制器中获取composer.json的版本号？

Absolutely! There are a few straightforward ways to pull the version number from your composer.json file in a Symfony 4 controller. Let me walk you through the most common approaches:

1. Directly Read and Parse composer.json #

You can read the composer.json file directly from your project root, then decode its JSON content to access the version. To get the correct path, use Symfony's KernelInterface to retrieve the project root directory.

Here's how to do it in your controller:

use Symfony\Component\HttpKernel\KernelInterface;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;

class YourController extends AbstractController
{
    public function getVersion(KernelInterface $kernel): Response
    {
        // Get the full path to composer.json
        $composerPath = $kernel->getProjectDir() . '/composer.json';
        
        // Read and decode the JSON file
        $composerData = json_decode(file_get_contents($composerPath), true);
        
        // Safely access the version key with a fallback
        $version = $composerData['version'] ?? 'Unknown';
        
        return new Response("Current project version: {$version}");
    }
}

Note: Ensure your web server has read permissions for composer.json, and use the null coalescing operator (??) to handle cases where the version key might be missing.

2. Use Composer's InstalledVersions Class (Recommended) #

If you're running Composer 2.0 or later, the Composer\InstalledVersions class provides a reliable, maintained way to fetch your project's version without manual file parsing. This leverages Composer's internal metadata, so it avoids path-related issues.

Here's the code for your controller:

use Composer\InstalledVersions;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;

class YourController extends AbstractController
{
    public function getVersion(): Response
    {
        // Replace 'myProject' with the "name" value from your composer.json
        $version = InstalledVersions::getVersion('myProject');
        
        // Fallback if the version can't be retrieved
        $version = $version ?? 'Unknown';
        
        return new Response("Current project version: {$version}");
    }
}

This method is more robust than manual parsing because it uses Composer's own tracked data about installed packages and your project.

3. Add the Version to Symfony's Parameters (Best for Reusability) #

For a more Symfony-native workflow, you can define the version as a parameter in your configuration, then inject it wherever you need it. This is ideal if you'll use the version across multiple controllers or services.

1. Open config/services.yaml and add a new parameter:

parameters:
    app.version: '%env(APP_VERSION)%'

2. Update your .env file to set the version (you can hardcode it or sync it with your composer.json value):

# .env
APP_VERSION=0.0.0

3. Inject the parameter into your controller:

use Symfony\Component\HttpFoundation\Response;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;

class YourController extends AbstractController
{
    public function getVersion(): Response
    {
        // Retrieve the version from Symfony's parameter bag
        $version = $this->getParameter('app.version');
        
        return new Response("Current project version: {$version}");
    }
}

This follows Symfony's dependency injection best practices and makes the version easily accessible throughout your app.

内容的提问来源于stack exchange，提问作者Manolo