PHP OpenID 库 介绍
该项目是一个使 PHP 开发的网站支持 OpenID 认证的框架 ，它包含了 OpenID Consumer、存储实现以及 OpenID Server
的实现，最新版本 2.x 的主要特性包括：
- Runs on a wide range of PHP versions: from 4.3.0 and up (tested on 5.2.4)
- Licensed under the Apache Software License.
- Includes extensive documentation, working example code, and a test suite
- Attempts to use PHP extensions such as Curl, but does not depend on them
- Includes extension modules for Attribute Exchange, Simple Registration, and PAPE
- Supports i-names
- Tested on Windows and Linux
- Versions 2.x.x support both major OpenID protocol versions transparently