Linux / Unix / Mac

curl -sS | sudo php -- --install-dir=/usr/local/bin --filename=composer

Confirm install with: composer -V

Composer is a dependency manager, like npm.

npm composer
npm init composer init
package.json composer.json
npm install –save-dev composer require
node_module vendors

What is the name of the folder that composer puts all of the packages in? Ans: vendors

Versioning: 1.2.3 = major.minor.patch

Getting started

In your project folder, create the composer.json file with the command

composer init

To add a package to the composer.json file

composer require

If you have an existing composer.json file, install dependencies with

composer install

Using the libraries composer installed in your project

To use the library you installed via composer in your project, all you need is a require statement, like so:

require 'vendor/autoload.php';

Everything you installed via composer is now available in your project with the require statement.


Since PHP 5.3 was released we now use a common practice of namespacing our libraries and code. Namespacing is a very powerful process to help us avoid conflicts within our project. In this video I will give you an simple metaphor for Namespacing as well as walk you through an example of how it is used in Monolog.

the idea is to avoid conflicts if same class names are present in different vendors. Use multiple vendors that may or may not have the same class names without conflicts. Another function is to shorten really long class names (or locations of classes) by using an alias with name spacing

Namespacing code looks like this:

namespace Monolog;

use Monolog\Handler\HandlerInterface;
use Monolog\Handler\StreamHandler;
use Psr\Log\LoggerInterface;
use Psr\Log\InvalidArgumentException;