从零开始，OSX环境启用composer，并安装包HTTP_Request2

启用composer

bogon:work rudon$ curl -sS https://getcomposer.org/installer | php
All settings correct for using Composer
Downloading...

Composer (version 1.6.4) successfully installed to: /Users/rudon/work/composer.phar
Use it: php composer.phar

bogon:work rudon$ mv composer.phar /usr/local/bin/composer

精简命令为：

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

mv composer.phar /usr/local/bin/composer

参考自：http://docs.phpcomposer.com/00-intro.html

使用composer为项目下载并部署包HTTP_Request2

1.假定项目目录为/var/www/cms/

2.在项目根目录创建composer.json，内容如下：

{
    "name": "Rudon",
    "description": "",
    "require": {
        "php": ">= 5.3.0",
        "pear/http_request2": "*"
    }
}

其中包名“pear/http_request2”请确认正确，我们可以在 https://packagist.org/ 通过包名搜索得到。

3.启动composer进行全自动的匹配＋下载＋部署，结果如下：

Loading composer repositories with package information
Updating dependencies (including require-dev)
Package operations: 3 installs, 0 updates, 0 removals
  - Installing pear/pear_exception (v1.0.0): Downloading (100%)         
  - Installing pear/net_url2 (v2.2.2): Downloading (100%)         
  - Installing pear/http_request2 (v2.3.0): Downloading (100%)         
Writing lock file
Generating autoload files

4.现在包已经安装好，存放在 {项目根目录}/vendor/pear/http_request2 和  {项目根目录}/vendor/pear/net_url2，其中net_url2是依赖包，也被安装好了。

5.在项目index.php中引入composer的所有的包，方法如下：

<?php
     require 'vendor/autoload.php';
     $obj = new HTTP_Request2( ... );
     $obj->anyAction();