Getting Started Tutorial with PHP Dependency Management Tool Composer

Composer is a dependency management tool for PHP. It allows you to declare code libraries that your project depends on and it will install them for you in your project.

Dependency Management

Composer is not a package manager. Yes, it involves "packages" and "libraries", but it's managed on a per-project basis, with installations in some directory within your project (e.g. vendor). By default it won't install anything globally. So this is just a dependency management.

This idea is not new, Composer is strongly inspired by node's npm and ruby's bundler. At that time, there was no similar tool for PHP.

Composer will solve the problem for you like this:

You have a project that depends on several libraries.

Some of these libraries depend on other libraries.

You declare what you rely on.

Composer will figure out which versions of packages need to be installed, and install them (download them into your project).

Declare Dependencies

Let’s say you are creating a project and you need a library for logging. You decide to use monolog. In order to add it to your project, all you need to do is create a composer.json file that describes the project's dependencies.

{
    "require": {
        "monolog/monolog": "1.2.*"
    }
}

Let’s just point out that our project requires some monolog/monolog package, any version starting from 1.2.

System Requirements

PHP 5.3.2+ or above is required to run Composer. Some sensitive PHP settings and compilation flags are also required, but the installer will throw a warning for any incompatibilities.

We will install directly from the source of the package, rather than simply downloading the zip file, you will need git , svn or hg , depending on the version management system you are loading the package into.

Composer is multi-platform, and we strive to make it run equally well on Windows, Linux and OSX platforms.

Installation under Linux/Unix

Partial installation

To really get Composer, we need to do two things. First install Composer (again, this means it will be downloaded into your project):

curl -sS https://getcomposer.org/installer | php

Note: If the above method fails for some reason, you can also download the installer via php >:

php -r "readfile('https://getcomposer.org/installer');" | php

This It will check some PHP settings and then download composer.phar to your working directory. This is the Composer binary. This is a PHAR package (PHP Archive), which is a PHP archive format that helps users perform some operations on the command line.

You can specify the Composer installation directory via the --install-dir option (it can be an absolute or relative path):

curl -sS https://getcomposer.org/installer | php -- --install-dir=bin

Global installation

You can place this file anywhere. If you put it in your system's PATH directory, you can access it globally. On Unix-like systems, you can even use it without the php prefix.

You can execute these commands to make composer call globally in your system:

curl -sS https://getcomposer.org/installer | php
mv composer.phar /usr/local/bin/composer

Note: If the appeal command fails due to permissions, please use sudo to try running the mv command again. Now you can use Composer by just running the composer command without typing php composer.phar.

Global installation (on OSX via homebrew)

Composer is part of the homebrew-php project.

brew update
brew tap josegonzalez/homebrew-php
brew tap homebrew/versions
brew install php55-intl
brew install josegonzalez/php/composer

Installation under Windows

Use the installer

This is the easiest way to install Composer on your machine.

Download and run Composer-Setup.exe, it will install the latest version of Composer and set the system environment variables, so you can use the composer command directly in any directory.

Manual installation

Set the system environment variable PATH and run the installation command to download the composer.phar file:

C:\Users\username>cd C:\bin
C:\bin>php -r "readfile('https://getcomposer.org/installer');" | php

Note: If you receive a readfile error message, please use an http link or enable php_openssl.dll in php.ini. Create a new file composer.bat in the same directory as composer.phar:

C:\bin>echo @php "%~dp0composer.phar" %*>composer.bat

Close the current command line window and open a new command line window for testing:

C:\Users\username>composer -V
Composer version 27d8904

Use Composer

Now we will use Composer to install the project's dependencies .

To resolve and download dependencies, please execute the install command:

php composer.phar install

If you installed it globally and there is no phar file in the current directory, please use the following command instead:

composer install

Continuing the above example, monolog will be downloaded here Go to the vendor/monolog/monolog directory.

Automatic loading

In addition to library downloads, Composer also prepares an automatic loading file, which can load all class files in the library downloaded by Composer. To use it, you just need to add the following line of code to your project's bootstrap file:

require 'vendor/autoload.php';

Now we can use monolog!