PHP Composer 安裝
系統需求：
Composer 需要PHP5.3.2+ 以上的環境來運行。有幾個敏感的PHP設置和編譯標志也是必需的，但安裝程序會發出警告當存在任何不兼容的情況。
比如PHP的擴展的要求是，安裝或重新編譯php without –disable-phar
為了從源地址安裝軟件包，而不是簡單的壓縮文件包，您將需要安裝軟件包的版本控制工具，比如git、svn或hg等。
Composer 是兼容多平台的，其運行適用於Windows，Linux和OSX。
安裝失敗的錯誤消息：
curl -sS https://getcomposer.org/installer | PHP #!/usr/bin/env php some settings on your machine make Composer unable to work properly. Make sure that you fix the issues listed below and run this script again: The phar extension is missing. Install it or recompile php without –disable-phar Your PHP (5.2.9) is too old, you must upgrade to PHP 5.3.2 or higher.
我的本地默認開發環境是PHP 5.2.9，當我嘗試在PHP 5.2.9上安裝時，提示版本過低，需要升級到PHP 5.3.2 或者更高的版本。
於是我下載XAMPP 1.7.7 usb lite 版本。
E:\USB\Dropbox\phpstorm\php53>E:\USB\xampp_177\php\php.exe -v PHP 5.3.8 (cli) (built: Aug 23 2011 11:50:20) Copyright (c) 1997-2011 The PHP Group Zend Engine v2.3.0, Copyright (c) 1998-2011 Zend Technologies
XAMPP 1.7.7 下的PHP環境是5.3.8。確認我的PHP環境大於等於PHP5.3.2後。
PHP 5.3 安裝 Composer
E:\USB\Dropbox\phpstorm\php53>curl -sS https://getcomposer.org/installer | E:\USB\xampp_177\php\php.exe #!/usr/bin/env php Some settings on your machine may cause stability issues with Composer. If you encounter issues, try to change the following: The openssl extension is missing, which will reduce the security and stability o f Composer. If possible you should enable it or recompile php with –with-openssl Downloading… Composer successfully installed to: E:\USB\Dropbox\phpstorm\php53\composer.phar Use it: php composer.phar
注意：
我關閉了XAMPP 1.7.7 Apache的SSL模塊，所以Composer提示我警告，為了安全因素建議我開啟SSL模塊。不開啟也不影響使用。
安裝時的參數 | PHP，一定要更改為真實的PHP環境路徑，比如 | E:\USB\xampp_177\php\php.exe
使用Composer為PHP路徑 + 命令，在我們安裝的環境中，使用方法為：E:\USB\xampp_177\php/php.exe composer.phar 命令。
我安裝的環境是在Windows下，如果在Linux下，而PHP 5.3 環境也不在默認PHP命令下時，應該采用 | /usr/php/53/usr/bin/php，例如：
curl -sS https://getcomposer.org/installer | /usr/php/53/usr/bin/php
安裝完成後，檢查安裝版本。
E:\USB\Dropbox\phpstorm\php53>E:\USB\xampp_177\php/php.exe composer.phar -V Composer version 0209bd31a0ac3aeb2a68fc81e2d03c71072bef33
檢查PHP Composer命令：
E:\USB\Dropbox\phpstorm\php53>E:\USB\xampp_177\php/php.exe composer.phar
______
/ ____/___ ____ ___ ____ ____ ________ _____
/ / / __ \/ __ `__ \/ __ \/ __ \/ ___/ _ \/ ___/
/ /___/ /_/ / / / / / / /_/ / /_/ (__ ) __/ /
\____/\____/_/ /_/ /_/ .___/\____/____/\___/_/
/_/
Composer version 0209bd31a0ac3aeb2a68fc81e2d03c71072bef33
Usage:
[options] command [arguments]
Options:
–help -h Display this help message.
–quiet -q Do not output any message.
–verbose -v Increase verbosity of messages.
–version -V Display this application version.
–ansi Force ANSI output.
–no-ansi Disable ANSI output.
–no-interaction -n Do not ask any interactive question.
–profile Display timing and memory usage information
–working-dir -d If specified, use the given directory as working directory
.
Available commands:
about Short information about Composer
archive Create an archive of this composer package
config Set config options
create-project Create new project from a package into given directory.
depends Shows which packages depend on the given package
diagnose Diagnoses the system to identify common errors.
dump-autoload Dumps the autoloader
dumpautoload Dumps the autoloader
help Displays help for a command
init Creates a basic composer.json file in current directory.
install Installs the project dependencies from the composer.lock file
if present, or falls back on the composer.json.
list Lists commands
require Adds required packages to your composer.json and installs the
m
run-script Run the scripts defined in composer.json.
search Search for packages
self-update Updates composer.phar to the latest version.
selfupdate Updates composer.phar to the latest version.
show Show information about packages
status Show a list of locally modified packages
update Updates your dependencies to the latest version according to
composer.json, and updates the composer.lock file.
validate Validates a composer.json
這樣我們在PHP5.3環境下的Composer已經安裝完成。
類似的方法我們也可以安裝PHP 5.4的環境上。
PHP 5.4 安裝 Composer
下載XAMPP 1.8.1 usb lite 版本，將得到PHP5.4.7環境。
E:\USB\Dropbox\phpstorm\php53>E:\USB\xampp_181\php\php.exe -v PHP 5.4.7 (cli) (built: Sep 12 2012 23:48:31) Copyright (c) 1997-2012 The PHP Group Zend Engine v2.4.0, Copyright (c) 1998-2012 Zend Technologies
確定版本高於PHP 5.3.2 後，開始安裝：
E:\USB\Dropbox\phpstorm\php54>curl -sS https://getcomposer.org/installer | E:\USB\xampp_181\php\php.exe #!/usr/bin/env php Some settings on your machine may cause stability issues with Composer. If you encounter issues, try to change the following: The openssl extension is missing, which will reduce the security and stability o f Composer. If possible you should enable it or recompile php with –with-openssl Downloading… Composer successfully installed to: E:\USB\Dropbox\phpstorm\php54\composer.phar Use it: php composer.phar
安裝完成後，檢查安裝版本。
E:\USB\Dropbox\phpstorm\php54>E:\USB\xampp_181\php/php.exe composer.phar -V Composer version 0209bd31a0ac3aeb2a68fc81e2d03c71072bef33
這樣，PHP 5.4 環境下的Composer也安裝成功了。
PHP Composer 使用
這裡我只簡單演示使用PHP Composer安裝Symfony框架。
首先大概講解一下命令的標准格式：
php composer.phar create-project symfony/framework-standard-edition path/ 2.2.1
第一個參數PHP為本地PHP開發環境，指向PHP運行命令。
第二個參數，為composer.phar方式下載。
第三個參數，為動作命令，例如create-project，目的是為了創建一個新的項目從一個軟件包到指定目錄。
第四個參數，為本地安裝的目錄。
第五個參數，為安裝軟件包的版本。
根據上述我們在PHP5.4環境下安裝的Composer，我們的安裝命令為：
E:\USB\Dropbox\phpstorm\php54>E:\USB\xampp_181\php/php.exe composer.phar create-project symfony/framework-standard-edition E:\USB\xampp_181\htdocs\Symfony 2.2.1
安裝結果：
Installing symfony/framework-standard-edition (v2.2.1) – Installing symfony/framework-standard-edition (v2.2.1) Downloading: 100% Created project in E:\USB\xampp_181\htdocs\Symfony Loading composer repositories with package information Installing dependencies from lock file – Installing doctrine/lexer (v1.0) Downloading: 100% – Installing doctrine/annotations (v1.1) Downloading: 100% – Installing doctrine/cache (v1.0) Downloading: 100% – Installing doctrine/collections (v1.1) Downloading: 100% – Installing twig/twig (v1.12.2) Downloading: 100% – Installing psr/log (1.0.0) Downloading: 100% – Installing doctrine/inflector (v1.0) Downloading: 100% – Installing doctrine/common (2.4.0-RC1) Downloading: 100% – Installing symfony/symfony (v2.2.1) Downloading: 100% – Installing jdorn/sql-formatter (v1.2.0) Downloading: 100% – Installing doctrine/dbal (2.3.3) Downloading: 100% – Installing doctrine/doctrine-bundle (v1.2.0-beta1) Downloading: 100% – Installing doctrine/orm (2.3.3) Downloading: 100% – Installing jms/cg (1.0.0) Downloading: 100% – Installing phpoption/phpoption (1.2.0) Downloading: 100% – Installing jms/parser-lib (1.0.0) Downloading: 100% – Installing jms/metadata (1.3.0) Downloading: 100% – Installing jms/aop-bundle (1.0.0) Downloading: 100% – Installing jms/di-extra-bundle (1.3.0) Downloading: 100% – Installing jms/security-extra-bundle (1.4.0) Downloading: 100% – Installing sensio/distribution-bundle (v2.2.1) Downloading: 100% – Installing sensio/framework-extra-bundle (v2.2.1) Downloading: 100% – Installing sensio/generator-bundle (v2.2.1) Downloading: 100% – Installing kriswallsmith/assetic (v1.1.0-alpha4) Downloading: 100% – Installing symfony/assetic-bundle (v2.1.2) Downloading: 100% – Installing monolog/monolog (1.4.1) Downloading: 100% – Installing symfony/monolog-bundle (v2.2.0) Downloading: 100% – Installing swiftmailer/swiftmailer (v4.3.0) Downloading: 100% – Installing symfony/swiftmailer-bundle (v2.2.0) Downloading: 100% – Installing twig/extensions (v1.0.0) Downloading: 100% kriswallsmith/assetic suggests installing leafo/lessphp (Assetic provides the integration with the lessphp LESS compiler) kriswallsmith/assetic suggests installing leafo/scssphp (Assetic provides the integration with the scssphp SCSS compiler) kriswallsmith/assetic suggests installing leafo/scssphp-compass (Assetic provides the integration with the SCSS compass plugin) kriswallsmith/assetic suggests installing ptachoire/cssembed (Assetic provides the integration with phpcssembed to embed data uris) monolog/monolog suggests installing doctrine/couchdb (Allow sending log messages to a CouchDB server) monolog/monolog suggests installing ext-amqp (Allow sending log messages to an AMQP server (1.0+ required)) monolog/monolog suggests installing ext-mongo (Allow sending log messages to a MongoDB server) monolog/monolog suggests installing mlehner/gelf-php (Allow sending log messages to a GrayLog2 server) monolog/monolog suggests installing raven/raven (Allow sending log messages to a Sentry server) Generating autoload files Clearing the cache for the dev environment with debug true Installing assets using the hard copy option Installing assets for Symfony\Bundle\FrameworkBundle into web/bundles/framework Installing assets for Acme\DemoBundle into web/bundles/acmedemo Installing assets for Sensio\Bundle\DistributionBundle into web/bundles/sensiodistribution
從命令行結果，我們看到了整個Symfony框架的安裝過程與結果。
PHP Composer 定義依賴關系
Composer在使用時會自動尋找composer.json這個文件。 composer.json將用來定義整個項目的依賴包。例如：
{
"require": {
"monolog/monolog": "1.2.*"
}
}
依賴包簡單的說明，我們的項目需要一些從1.2開始的任何版本的monolog/monolog包。
Composer是PHP中的一個依賴關系管理工具。通過Composer我們可以在發布軟件時節省大量的文件數目和控制依賴包的版本。
PHP Composer 項目
Composer 項目官方：http://getcomposer.org
Composer Github項目：https://github.com/composer/composer
PHP Composer軟件包列表：https://packagist.org/
