Installation of Composer and third-party packages

Introduction to Composer

Composer is a dependency manager for PHP that makes it possible to define third-party code packages used by a project that can then be easily installed and updated. It leverages the built-in class autoloading features of PHP, repositories of PHP packages such as Packagist, and common project layout and coding conventions.

For example, if a PHP application or website needs to work with UUID values, Ben Ramsey's ramsey/uuid package that implements the widely known and used types of UUIDs that are defined by RFC 4122 could be used.

Briefly, this is done by creating a composer.json in the project, using Composer to install the latest version of the package, and including Composer's autoload script to make it available to the code. The Composer "Basic Usage" documentation goes into this in more depth.

composer.json that requires a single package

{
    "require": {
        "ramsey/uuid": "^4.7"
    }
}