Composer: WTF

Stef Horner

History

PHP

PECL

PEAR

Background: Autoloading

include / require hell

lazy / eager loading

Background: Namespaces

PHP 5.3

http://daylerees.com/php-namespaces-explained

(game of thrones knowledge required)

composer.json

Every project that uses composer is technically a package.

name
description
...
autoload
require
require-dev
scripts
repositories

composer.json: autoload

What classes and files to autoload from this package

composer.json: require

a map of classes that this project requires

{ "vendor/package": "version" }// eg.
{ "carbon/carbon": "1.8.*" }

versions correspond to git tags

http://semver.org/

versions can also be branch names (prefix with 'dev-')

{ "mockery/mockery": "dev-master" }

composer.json: require-dev

Requirements specifically for development - ie. not the production environment

testing, seeding, debugging, utilities etc.

composer.json: scripts

commands that will be run at given points in the composer process:

{
  "pre-update-cmd": [ "git pull" ],
  "post-update-cmd": [ "grunt", "grunt clear-cache" ]
}

list of hooks:

http://getcomposer.org/doc/articles/scripts.md

composer.json: scripts II

the commands can either be a terminal command or a PHP class/method combo:

"post-update-cmd": [ "grunt", "Namespace\\Class::migrate" ]

This method gets passed a Composer\Script\Event object

http://getcomposer.org/doc/articles/scripts.md

composer.json: repositories

The default composer repository is packagist.org

You can add your own repository, or just individual packages, if you don't want to publish them on packagist (private packages, or packages in development)

"repositories": [
  {
    "type": "git",
    "url": "git@bitbucket.org:architectagency/utilities.git"
  }
]

composer install

Composer will download all the required packages (and their dependancies)

It will generate an autoloader

All you have to do is:

require __DIR__ . 'vendor/autoload.php'

at the top of your code.

composer update

composer.lock

generated by install and update

will lock future installs to the exact versions and packages

only composer install should be run on server

Frameworks & CMSs

Laravel

Silex

Slim

Symfony

Zend

Joomla

Silverstripe

Wordpress (not officially)

Autoloading

Files

Classmap

PSR-0

PSR-4

Lazy Loading

Files

An array of files to require_once

Globals
Functions
Constants

"autoload": {
  "files": [
    "some/functions.php", "morefunctions.php"
  ]
}

Classmap

An array of files and folders to map for loading

Scans folders for .php files

Tries to resolve namespaces and classes

Maps those FQNs to those files

"autoload": {
  "classmap": [
    "src/controllers", "src/utilities", "src/phpclass.php"
  ]
}

PSR-0

A project structure standard

Namespaces = Directories

Classes = Files

"autoload": {
  "psr-0": {
    "Project\\": "src/"
  }
}

src /  IrrelaventFile.php, AnotherIrrelaventFile.json
  Project /    ClassOne.php    ClassTwo.php    AnotherNamespace /      ClassOne.php

PSR-4

Cleaner than PSR-0

More Implicit

"autoload": {
  "psr-4": {
    "Project\\": "src"
  }
}

src /
  ClassOne.php    # these files must all be in the Project namespace
  ClassTwo.php
  SubNamespace /
    ClassOne.php

composer dump-autoload

PSR-0 && classmap && files

Will re-map all classes

Adds new classes

Removes old classes

PSR-4

Only maps namespaces

Laravel's Lazy Loading

Outside of Composer

" Sort of " PSR-0

It maps at runtime

(no composer dump-autoload required)

composer init

Will interactively create a composer.json file

composer create-project

Dry-Clones the project

Installs

Runs separate hook

composer create-project laravel/laravel new-project