| Composer | |
| Logo Size: | 120px |
| Developer: | Nils Adermann, Jordi Boggiano |
| Programming Language: | PHP |
| Operating System: | Cross-platform |
| Genre: | Package manager |
| License: | MIT License |
Composer is an application-level dependency 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".[2] The project's dependency solving algorithm started out as a PHP-based port of openSUSE's libzypp SAT solver.[3]
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"[4] 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.
Composer offers several parameters including :[5]
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.Example of composer.json generated by the following command: composer require monolog/monolog
The different authorized versions of the libraries are defined by:[6]
| 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. | ||
| 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. |