Declaring dependencies

As explained on the main page of this section, composer manages dependencies. It does this by keeping track of the dependencies (and the dependencies of dependencies, etc...) in a file named composer.json . In most cases you will be able to find this file in the root of the project.

You can add new dependencies using the composer command "require". For example adding a dependency on PHP_Codesniffer can be done in the following way (assuming you installed composer globally and you are in the root of the project):

$ composer require squizlabs/php_codesniffer

This will add the dependency to the "require" section of the composer.json file. Since this dependency is only needed during development it might be better to add it to the "require-dev" section:

$ composer require squizlabs/php_codesniffer --dev

This way you can instruct composer not to install this dependency in production environments.