程序入口文件-php CI 框架源码阅读笔记

最近在学习CI框架，自己在按照代码执行顺序阅读源码。做了一些笔记。与其自己珍藏不如拿出来和大家分享

本人并非大牛，是一名处于成长初期的phper，难免有错误的地方。还希望大家能给予指正。

我的CI版本是2.1.3

csdn好像不能上传文件，我就讲代码放在笔记下面了。

如果觉得能对您有一些可以经常来看，我会不定期更新。知道读完CI源码

程序入口：

1、应用程序环境设置development testing production 可以设置这三种环境

2、对不同的环境应用不同的错误级别

3、设置系统文件夹名

4、设置应用程序文件夹名

5、设置默认控制器（这里被注释掉了，如果想设置直接开启）

6、设置自定义配置

7、增强system path的可靠性

a) 设置当前目录保证正确的请求

b) 保证目录后面有/

c) 判断当前系统路径是否存在

8、开始设置主路径常量

SELF 当前文件的路径

EXT 文件扩展名

BASEPATH 系统路径

FCPATH 前端控制器路径

SYSDIR 系统文件夹路径

APPPATH 应用程序文件夹路径

9、调用BASEPATH."core/CodeIgniter.php"文件进入系统引导程序

<?php

/*
 *---------------------------------------------------------------
 * APPLICATION ENVIRONMENT
 *---------------------------------------------------------------
 *
 * You can load different configurations depending on your
 * current environment. Setting the environment also influences
 * things like logging and error reporting.
 *
 * This can be set to anything, but default usage is:
 *
 *     development
 *     testing
 *     production
 *
 * NOTE: If you change these, also change the error_reporting() code below
 *
 */
	define("ENVIRONMENT", "development");
/*
 *---------------------------------------------------------------
 * ERROR REPORTING
 *---------------------------------------------------------------
 *
 * Different environments will require different levels of error reporting.
 * By default development will show errors but testing and live will hide them.
 */

if (defined("ENVIRONMENT"))
{
	switch (ENVIRONMENT)
	{
		case "development":
			error_reporting(E_ALL);
		break;
	
		case "testing":
		case "production":
			error_reporting(0);
		break;

		default:
			exit("The application environment is not set correctly.");
	}
}

/*
 *---------------------------------------------------------------
 * SYSTEM FOLDER NAME
 *---------------------------------------------------------------
 *
 * This variable must contain the name of your "system" folder.
 * Include the path if the folder is not in the same  directory 
 * as this file.
 *
 */
	$system_path = "system";

/*
 *---------------------------------------------------------------
 * APPLICATION FOLDER NAME
 *---------------------------------------------------------------
 *
 * If you want this front controller to use a different "application"
 * folder then the default one you can set its name here. The folder
 * can also be renamed or relocated anywhere on your server.  If
 * you do, use a full server path. For more info please see the user guide:
 * http://codeigniter.com/user_guide/general/managing_apps.html
 *
 * NO TRAILING SLASH!
 *
 */
	$application_folder = "application";

/*
 * --------------------------------------------------------------------
 * DEFAULT CONTROLLER
 * --------------------------------------------------------------------
 *
 * Normally you will set your default controller in the routes.php file.
 * You can, however, force a custom routing by hard-coding a specific 
 * controller class/function here.  For most applications, you
 * WILL NOT set your routing here, but it"s an option for those 那些
 * special 特殊 instances where you might 可能 want to override the standard 标准
 * routing in a specific 明确的 front 前面 controller that shares a common CI installation.
 *
 * IMPORTANT: 重要的 If you set the routing here, NO OTHER controller will be
 * callable. 可赎回的 In essence,本质 this preference 偏好、倾向、优先权 limits 范围、限制
 * your application to ONE specific controller.  
 * Leave 许可、离开、留下 the function name blank空白，消失 if you need
 * to call functions dynamically 动态的 via 通过 the URI.
 *
 * Un-comment the $routing array below 在下面 to use this feature 特色，特写，起重要作用
 *
 */
	// The directory name, relative 相关的 to the "controllers" folder.  Leave blank
	// if your controller is not in a sub-folder 代替-文件夹 within 在。。。之内 
    // the "controllers" folder
	// $routing["directory"] = "";

	// The controller class file name.  Example:  Mycontroller
	// $routing["controller"] = "";

	// The controller function you wish 希望 to be called.
	// $routing["function"]	= "";

/*
 * -------------------------------------------------------------------
 *  CUSTOM 习惯、定制的、自定义的 CONFIG VALUES
 * -------------------------------------------------------------------
 *
 * The $assign_to_config array below will be passed 通过 dynamically to the
 * config class when initialized.初始化 This allows you to set custom config
 * items or override any default config values found in the config.php file.
 * This can be handy 方便的 as it permits 许可 you to share one application between
 * multiple front controller files, with each 每各 file containing 包含 different
 * config values.
 *
 * Un-comment the $assign_to_config array below to use this feature
 *
 */
	// $assign_to_config["name_of_config_item"] = "value of config item";

// --------------------------------------------------------------------
// END OF USER CONFIGURABLE 可配置的 SETTINGS.  DO NOT EDIT BELOW THIS LINE
// end of 最终 user configurable settings . do not edit below this line
// --------------------------------------------------------------------

/*
 * ---------------------------------------------------------------
 *  Resolve 决定 the system path for increased 增强的、增加 reliability 可靠性
 * ---------------------------------------------------------------
 */

	// Set the current directory correctly 正确的 for CLI requests 请求
	if (defined("STDIN"))
	{
		chdir(dirname(__FILE__));
	}

	if (realpath($system_path) !== FALSE)
	{
		$system_path = realpath($system_path)."/";
	}

	// ensure 保证 there"s a trailing 后面的 slash 斜杠
	$system_path = rtrim($system_path, "/")."/";

	// Is the system path correct?
	if ( ! is_dir($system_path))
	{
		exit("Your system folder path does not appear to be set correctly. Please open the following file and correct this: ".pathinfo(__FILE__, PATHINFO_BASENAME));
	}

/*
 * -------------------------------------------------------------------
 *  Now that we know the path, set the main path constants 常量
 * -------------------------------------------------------------------
 */
	// The name of THIS file
	define("SELF", pathinfo(__FILE__, PATHINFO_BASENAME));

	// The PHP file extension 扩展
	// this global constant is deprecated.不赞成 弃用
	define("EXT", ".php");

	// Path to the system folder
	define("BASEPATH", str_replace("", "/", $system_path));

	// Path to the front controller （front controller）前端控制器 (this file)
	define("FCPATH", str_replace(SELF, "", __FILE__));

	// Name of the "system folder"
	define("SYSDIR", trim(strrchr(trim(BASEPATH, "/"), "/"), "/"));

	// The path to the "application" folder
	if (is_dir($application_folder))
	{
		define("APPPATH", $application_folder."/");
	}
	else
	{
		if ( ! is_dir(BASEPATH.$application_folder."/"))
		{
			exit("Your application folder path does not appear to be set correctly. Please open the following file and correct this: ".SELF);
		}

		define("APPPATH", BASEPATH.$application_folder."/");
	}

/*
 * --------------------------------------------------------------------
 * LOAD THE BOOTSTRAP 引导程序 FILE
 * --------------------------------------------------------------------
 *
 * And away we go... 和我们走	
 *
 */
require_once BASEPATH."core/CodeIgniter.php";

/* End of file index.php */
/* Location: ./index.php */