重用Bundle的最佳实践

Bundle Name¶

A bundle is also a PHP namespace. The namespace must follow the technical interoperability standards for PHP namespaces and class names: it starts with a vendor segment, followed by zero or more category segments, and it ends with the namespace short name, which must end with a Bundle suffix.

A namespace becomes a bundle as soon as you add a bundle class to it. The bundle class name must follow these simple rules:

• Use only alphanumeric characters and underscores;
• Use a CamelCased name;
• Use a descriptive and short name (no more than 2 words);
• Prefix the name with the concatenation of the vendor (and optionally the category namespaces);
• Suffix the name with Bundle.

Here are some valid bundle namespaces and class names:

By convention, the getName() method of the bundle class should return the class name.

Each bundle has an alias, which is the lower-cased short version of the bundle name using underscores (acme_hello for AcmeHelloBundle, or acme_social_blog for AcmeSocialBlogBundle for instance). This alias is used to enforce uniqueness within a bundle (see below for some usage examples).

Directory Structure¶

The basic directory structure of a HelloBundle must read as follows:

XXX/...
    HelloBundle/
        HelloBundle.php
        Controller/
        Resources/
            meta/
                LICENSE
            config/
            doc/
                index.rst
            translations/
            views/
            public/
        Tests/

The XXX directory(ies) reflects the namespace structure of the bundle.

The following files are mandatory:

• HelloBundle.php;
• Resources/meta/LICENSE: The full license for the code;
• Resources/doc/index.rst: The root file for the Bundle documentation.

The depth of sub-directories should be kept to the minimal for most used classes and files (2 levels at a maximum). More levels can be defined for non-strategic, less-used files.

The bundle directory is read-only. If you need to write temporary files, store them under the cache/ or log/ directory of the host application. Tools can generate files in the bundle directory structure, but only if the generated files are going to be part of the repository.

The following classes and files have specific emplacements:

Classes¶

The bundle directory structure is used as the namespace hierarchy. For instance, a HelloController controller is stored in Bundle/HelloBundle/Controller/HelloController.php and the fully qualified class name is BundleHelloBundleControllerHelloController.

All classes and files must follow the Symfony coding standards.

Some classes should be seen as facades and should be as short as possible, like Commands, Helpers, Listeners, and Controllers.

Classes that connect to the event dispatcher should be suffixed with Listener.

Exceptions classes should be stored in an Exception sub-namespace.

Vendors¶

A bundle must not embed third-party PHP libraries. It should rely on the standard Symfony autoloading instead.

A bundle should not embed third-party libraries written in JavaScript, CSS, or any other language.

Tests¶

A bundle should come with a test suite written with PHPUnit and stored under the Tests/ directory. Tests should follow the following principles:

• The test suite must be executable with a simple phpunit command run from a sample application;
• The functional tests should only be used to test the response output and some profiling information if you have some;
• The tests should cover at least 95% of the code base.

Documentation¶

All classes and functions must come with full PHPDoc.

Extensive documentation should also be provided in the reStructuredText format, under the Resources/doc/ directory; the Resources/doc/index.rst file is the only mandatory file and must be the entry point for the documentation.

Installation
============

Step 1: Download the Bundle
---------------------------

Open a command console, enter your project directory and execute the
following command to download the latest stable version of this bundle:

```bash
$ composer require <package-name> "~1"
```

This command requires you to have Composer installed globally, as explained
in the [installation chapter](https://getcomposer.org/doc/00-intro.md)
of the Composer documentation.

Step 2: Enable the Bundle
-------------------------

Then, enable the bundle by adding the following line in the `app/AppKernel.php`
file of your project:

```php
<?php
// app/AppKernel.php

// ...
class AppKernel extends Kernel
{
    public function registerBundles()
    {
        $bundles = array(
            // ...

            new <vendor><bundle-name><bundle-long-name>(),
        );

        // ...
    }

    // ...
}
```

Routing¶

If the bundle provides routes, they must be prefixed with the bundle alias. For an AcmeBlogBundle for instance, all routes must be prefixed with acme_blog_.

Templates¶

If a bundle provides templates, they must use Twig. A bundle must not provide a main layout, except if it provides a full working application.

Translation Files¶

If a bundle provides message translations, they must be defined in the XLIFF format; the domain should be named after the bundle name (bundle.hello).

A bundle must not override existing messages from another bundle.

Configuration¶

To provide more flexibility, a bundle can provide configurable settings by using the Symfony built-in mechanisms.

For simple configuration settings, rely on the default parameters entry of the Symfony configuration. Symfony parameters are simple key/value pairs; a value being any valid PHP value. Each parameter name should start with the bundle alias, though this is just a best-practice suggestion. The rest of the parameter name will use a period (.) to separate different parts (e.g. acme_hello.email.from).

The end user can provide values in any configuration file:

Retrieve the configuration parameters in your code from the container:

$container->getParameter('acme_hello.email.from');

Even if this mechanism is simple enough, you are highly encouraged to use the semantic configuration described in the cookbook.

Custom Validation Constraints¶

Starting with Symfony 2.5, a new Validation API was introduced. In fact, there are 3 modes, which the user can configure in their project:

• 2.4: the original 2.4 and earlier validation API;
• 2.5: the new 2.5 and later validation API;
• 2.5-BC: the new 2.5 API with a backwards-compatible layer so that the 2.4 API still works. This is only available in PHP 5.3.9+.

As a bundle author, you’ll want to support both API’s, since some users may still be using the 2.4 API. Specifically, if your bundle adds a violation directly to the ExecutionContext (e.g. like in a custom validation constraint), you’ll need to check for which API is being used. The following code, would work for all users:

use SymfonyComponentValidatorConstraintValidator;
use SymfonyComponentValidatorConstraint;
use SymfonyComponentValidatorContextExecutionContextInterface;
// ...

class ContainsAlphanumericValidator extends ConstraintValidator
{
    public function validate($value, Constraint $constraint)
    {
        if ($this->context instanceof ExecutionContextInterface) {
            // the 2.5 API
            $this->context->buildViolation($constraint->message)
                ->setParameter('%string%', $value)
                ->addViolation()
            ;
        } else {
            // the 2.4 API
            $this->context->addViolation(
                $constraint->message,
                array('%string%' => $value)
            );
        }
    }
}

Learn more from the Cookbook¶

• 如何在Bundle内部载入Service配置