Caution!
In Symfony versions prior to 4.0, it was recommended to organize your own application code using bundles. This is :ref:`no longer recommended <best-practice-no-application-bundles>` and bundles should only be used to share code and features between multiple applications.
A bundle is similar to a plugin in other software, but even better. The core features of Symfony framework are implemented with bundles (FrameworkBundle, SecurityBundle, DebugBundle, etc.) They are also used to add new features in your application via third-party bundles.
Bundles used in your applications must be enabled per
:ref:`environment <configuration-environments>` in the config/bundles.php
file:
// config/bundles.php
return [
// 'all' means that the bundle is enabled for any Symfony environment
Symfony\Bundle\FrameworkBundle\FrameworkBundle::class => ['all' => true],
// ...
// this bundle is enabled only in 'dev'
Symfony\Bundle\DebugBundle\DebugBundle::class => ['dev' => true],
// ...
// this bundle is enabled only in 'dev' and 'test', so you can't use it in 'prod'
Symfony\Bundle\WebProfilerBundle\WebProfilerBundle::class => ['dev' => true, 'test' => true],
// ...
];
Tip
In a default Symfony application that uses :ref:`Symfony Flex <symfony-flex>`,
bundles are enabled/disabled automatically for you when installing/removing
them, so you don't need to look at or edit this bundles.php file.
This section creates and enables a new bundle to show there are only a few steps required.
The new bundle is called AcmeBlogBundle, where the Acme portion is an example
name that should be replaced by some "vendor" name that represents you or your
organization (e.g. AbcBlogBundle for some company named Abc).
Start by creating a new class called AcmeBlogBundle:
// src/AcmeBlogBundle.php
namespace Acme\BlogBundle;
use Symfony\Component\HttpKernel\Bundle\AbstractBundle;
class AcmeBlogBundle extends AbstractBundle
{
}
Caution!
If your bundle must be compatible with previous Symfony versions you have to extend from the :class:`Symfony\\Component\\HttpKernel\\Bundle\\Bundle` instead.
Tip
The name AcmeBlogBundle follows the standard
:ref:`Bundle naming conventions <bundles-naming-conventions>`. You could
also choose to shorten the name of the bundle to simply BlogBundle by naming
this class BlogBundle (and naming the file BlogBundle.php).
This empty class is the only piece you need to create the new bundle. Though commonly empty, this class is powerful and can be used to customize the behavior of the bundle. Now that you've created the bundle, enable it:
// config/bundles.php
return [
// ...
Acme\BlogBundle\AcmeBlogBundle::class => ['all' => true],
];
And while it doesn't do anything yet, AcmeBlogBundle is now ready to be used.
The directory structure of a bundle is meant to help to keep code consistent between all Symfony bundles. It follows a set of conventions, but is flexible to be adjusted if needed:
assets/- Contains the web asset sources like JavaScript and TypeScript files, CSS and
Sass files, but also images and other assets related to the bundle that are
not in
public/(e.g. Stimulus controllers). config/- Houses configuration, including routing configuration (e.g.
routes.php). public/- Contains web assets (images, compiled CSS and JavaScript files, etc.) and is
copied or symbolically linked into the project
public/directory via theassets:installconsole command. src/- Contains all PHP classes related to the bundle logic (e.g.
Controller/CategoryController.php). templates/- Holds templates organized by controller name (e.g.
category/show.html.twig). tests/- Holds all tests for the bundle.
translations/- Holds translations organized by domain and locale (e.g.
AcmeBlogBundle.en.xlf).
Caution!
The recommended bundle structure was changed in Symfony 5, read the Symfony 4.4 bundle documentation for information about the old structure.
When using the new AbstractBundle class, the bundle defaults to the
new structure. Override the Bundle::getPath() method to change to
the old structure:
class AcmeBlogBundle extends AbstractBundle
{
public function getPath(): string
{
return __DIR__;
}
}
Tip
It's recommended to use the PSR-4 autoload standard: use the namespace as key,
and the location of the bundle's main class (relative to composer.json)
as value. As the main class is located in the src/ directory of the bundle:
{
"autoload": {
"psr-4": {
"Acme\\BlogBundle\\": "src/"
}
},
"autoload-dev": {
"psr-4": {
"Acme\\BlogBundle\\Tests\\": "tests/"
}
}
}