yii2-bootstrap/docs/guide/extensions.md

Extending Yii

Code style

• Extension code style SHOULD be similar to core framework code style.
• All classes, methods and properties SHOULD be documented using phpdoc. Note that you can use markdown and link to properties and methods using the following syntax: e.g. [[name()]], [[name\space\MyClass::name()]].
• If you're displaying errors to developers do not translate these (i.e. do not use \Yii::t()). Errors should be translated only if they're displayed to end users.
• Extension SHOULD NOT use class prefixes (i.e. TbNavBar, EMyWidget, etc.)

Namespace

• Extension MUST NOT use yiisoft in the namespaces used in the package.
• Extension MUST NOT have a root-namespace named \yii, \yii2 or \yiisoft.
• Extension SHOULD use namespaces in this format vendor-name\type (all lowercase).

Distribution

• There should be a readme.md file clearly describing what extension does in English, its requirements, how to install and use it. It should be written using markdown. If you want to provide translated readme, name it as readme_ru.md where ru is your language code. If extension provides a widget it is a good idea to include some screenshots.
• It is recommended to host your extensions at Github.
• Extension MUST be registered at Packagist. Choose package name wisely since changing it leads to losing stats and inability to install package by the old name.
• Extension MUST provide a valid autoloading configuration in composer.json.

Composer package name

If your extension was made specifically for Yii2 (i.e. cannot be used as a standalone PHP library) it is recommended to name it like the following:

yii2-my-extension-name-type

In the above:

• yii2- prefix.
• Extension name lowecase, words separated by -.
• -type postfix where type may be widget, behavior, module etc.

Dependencies

• Additional code, eg. libraries, SHOULD be required in your composer.json file.
• When extension is released in a stable version, its requirements SHOULD NOT include dev packages that do not have a stable release.
• Use appropriate version constraints, eg. 1.*, @stable for requirements.

Versioning

• Extension SHOULD follow the rules of semantic versioning.
• Use a consistent format for your repository tags, as they are treated as version strings by composer, eg. 0.2.4,0.2.5,0.3.0,1.0.0.

composer.json

• Extension MUST use the type yii2-extension in composer.json file.
• Extension MUST NOT use yii or yii2 in their composer vendor name.
• Extension MUST NOT use yiisoft in the composer package name or the composer vendor name.

If your extension classes reside directly in repository root use PSR-4 the following way in your composer.json:

{
        "name": "samdark/yii2-iconized-menu-widget",
        "description": "IconizedMenu automatically adds favicons in front of menu links",
        "keywords": ["yii", "extension", "favicon", "menu", "icon"],
        "homepage": "https://github.com/samdark/yii2-iconized-menu-widget",
        "type": "yii2-extension",
        "license": "BSD-3-Clause",
        "authors": [
                {
                        "name": "Alexander Makarov",
                        "email": "sam@rmcreative.ru"
                }
        ],
        "require": {
                "yiisoft/yii2": "*"
        },
        "autoload": {
                "psr-4": {
                        "samdark\\widgets\\": ""
                }
        }
}

In the above samdark/yii2-iconized-menu-widget is the package name that will be registered at Packagist. It is common for it to match your github repository.

We're using psr-4 autoloader and mapping samdark\widgets namespace to the root directory where our classes reside.

More details can be found in the composer documentation.

Working with database

• If extension creates or modifies database schema always use Yii migrations instead of SQL files or custom scripts.
• Migrations SHOULD be DBMS agnostic.
• You MUST NOT make use of active-record model classes in your migrations.

Assets

• Asset files MUST be registered through Bundles.

Events

TBD

i18n

• Extension SHOULD provide at least one message catalogue with either source or target language in English.
• Extension MAY provide a configuration for creating message catalogues.

Authorization

• Auth-items for controllers SHOULD be named after the following format vendor\ext\controller\action.
• Auth-items names may be shortened using an asterisk, eg. vendor\ext\*

Testing your extension

• Extension SHOULD be testable with PHPUnit.