Using packages

Reusable code is distributed as Composer packages. A package can be an infrastructure library, a Yii integration, a reusable feature, or a module representing an application context.

This page explains how to use packages in an application. To create a Yii-aware package, see Designing packages for Yii applications.

Installing packages

By default, Composer installs packages registered on Packagist, the main repository for open source PHP packages.

Install a package with:

composer require vendor-name/package-name

Composer updates two files:

• composer.json stores the package name and version constraint.
• composer.lock stores the exact versions installed.

Commit both files so other environments install the same dependency versions.

Installed packages are stored in the application vendor/ directory.

WARNING

Never edit files in vendor/ directly. Change application configuration, extend classes, decorate services, or contribute fixes to the package instead.

Package classes are available through Composer autoloading after installation. See Autoloading for details.

Updating packages

Update a package within the version constraint recorded in composer.json:

composer update vendor-name/package-name

Change the accepted version constraint with composer require:

composer require vendor-name/package-name:^2.0

After updating a Yii-aware package, Composer rebuilds Yii's configuration merge plan. If you changed configuration group mappings manually, rebuild it explicitly:

composer yii-config-rebuild

Removing packages

Remove a package with:

composer remove vendor-name/package-name

Then remove application code and configuration that referenced classes, services, routes, commands, assets, migrations, or translations from that package.

Private packages

For private code, configure Composer repositories in the application composer.json. Common options are:

• vcs for a Git repository.
• path for a local package during development.
• composer for a private Composer repository.

For example, to work with a package located next to the application:

{
    "repositories": [
        {
            "type": "path",
            "url": "../packages/blog"
        }
    ]
}

Then install it normally:

composer require vendor/blog

Read more in the Composer repository documentation.

Package configuration

Some Yii packages provide default configuration through yiisoft/config. After installation, the package configuration becomes part of the vendor layer and the application can override it in the root package configuration.

Prefer partial overrides in application config files over copying whole package config files. For example, override only the parameter or service definition you need.

For more details, see Configuration and Designing packages for Yii applications.