Composer (software)

Composer is an application-level package manager for the PHP programming language that provides a standard format for managing dependencies of PHP software and required libraries. It was developed by Nils Adermann and Jordi Boggiano, who continue to manage the project. They began development in April 2011 and first released it on March 1, 2012.[1] Composer is strongly inspired by Node.js's "npm" and Ruby's "bundler".[3] The project's dependency solving algorithm started out as a PHP-based port of openSUSE's libzypp satsolver.[4]

Composer

Developer(s)	Nils Adermann, Jordi Boggiano
Initial release	March 1, 2012[1]
Stable release	2.0.8 / December 3, 2020[2]
Repository	github.com/composer/composer
Written in	PHP
Operating system	Cross-platform
Type	Package manager
License	MIT License
Website	getcomposer.org

Composer runs from the command line and installs dependencies (e.g. libraries) for an application. It also allows users to install PHP applications that are available on "Packagist"[5] which is its main repository containing available packages. It also provides autoload capabilities for libraries that specify autoload information to ease usage of third-party code.

Syntax

Commands

Composer offers several parameters including :[6]

• require: add the library in parameter to the file composer.json, and install it.
• install: install all libraries from composer.json. It's the command to use to download all PHP repository dependencies.
• update: update all libraries from composer.json, according to the allowed versions mentioned into it.
• remove: uninstall a library and remove it from composer.json.

Libraries definition

Example of composer.json generated by the following command:

composer require monolog/monolog

{
    "require": {
        "monolog/monolog": "1.2.*"
    }
}

Versions

The different authorized versions of the libraries are defined by:[7]

Symbol	Role (placed before a version number)	Example
>=	allows to extend the number. Moreover, we can use: >, <, <=.	"php": ">=5.5.9" includes PHP 7.
!=	excludes a version.
-	defines a range of versions.
¦¦	add possibles versions.	"symfony/symfony": "2.8 ¦¦ 3.0" regroups only these two versions.
*	extends to all subversions.	"symfony/symfony": "3.1.*" includes the 3.1.1.
~	extends to the next versions of the same level.	"doctrine/orm": "~2.5" also concerns the 2.6, but neither the 2.4 nor the 3.0.
^	same as tilde, only if there is a backward compatibility.

Supported frameworks

• Symfony version 2 and later
• Laravel version 4 and later
• CodeIgniter version 3.0 and later
• CakePHP version 3.0 and later
• FuelPHP version 2.0 and later
• Drupal version 8 and later
• TYPO3 version 6.2 and later
• SilverStripe version 3.0 later
• Magento version 2.0 later
• Yii version 1.1 and later
• Zend Framework version 1 and later
• Silex (web framework)
• Lumen (web framework)

See also

• PEAR

References

1. Software release, github.com, Retrieved April 24, 2016.
2. "Composer". getcomposer.org. Retrieved Nov 6, 2020.
3. Getting Started/Dependency management, getcomposer.org, Retrieved November 28, 2013.
4. "composer/composer". Jun 23, 2020. Retrieved Jun 24, 2020 – via GitHub.
5. See packagist.org
6. "Command-line interface / Commands". getcomposer.org.
7. "Versions and constraints - Composer". getcomposer.org.

External links

• Official website
• Composer on GitHub
• Composer documentation
• Composer Tutorial
• Packagist - the main Composer repository
• Composer at Open Hub