CI框架源码阅读---------系统初始化文件-php手册-php.cn

CodeIgniter.php 执行流程分析

这是系统初始化文件

1.定义CI版本

2.定义CI分支这里我认为CI有两个分支一个是Core ，另一个是Reactor。但是这里具体的作用我还没弄白。

3.加载全局函数system/core/common.php

4.加载框架常量如果定义了ENVIRONMENT常量并且在APPPATH/cofig/下面有以ENVIRONMENT常量为名字的文件夹并且里面存在constants.php则加载这个constants.php

如果没有则直接加载APPPATH/cofig/下面的constants.php

5.定义一个自定义的错误处理函数，让我们用来记录php错误日志

6.如果当前php版本>5.3 则关闭魔术转义

7.设置类前缀（在index.php中可以通过$assign_to_config[]来自定义配置项）

一般的类前缀会在config文件中被设置，这个类前缀可以让CI知道application下的libraries文件夹下哪些的类继承了CI核心类的类，因为CI容许入口文件index.php中覆盖配置文件的配置项，所以程序开始执行之前我们需要知道类前缀是否被覆盖，如果被覆盖了，我们将在所有类加载之前设置它的值。

8.设置脚本执行时间

9.脚本开始执行

加载并实例化基准测试类（类文件：core/Benchmark.php）

记下total_execution_time_start 、loading_time:_base_classes_start这两个时间点

10、如果可以加载并实例化钩子类（类文件core/Hooks.php）我们就加载并实例化

这需要在钩子是在 application/config/config.php 中开启并在 application/config/hooks.php文件中定义当前的钩子

详情：http://codeigniter.org.cn/user_guide/general/hooks.html

11.加载并实例化配置类

如果我们在index.php中手动的通过$assign_to_config[]来进行配置

12、加载并实例化UTF-8类，这里的顺序是非常重要的UTF-8类必须跟在配置类的后面加载

13、加载并实例化URI类

14、加载并实例化router类，设置router

15、加载并实例化输出类

16、判断有没有缓存文件如果有输出

17、为了防止xss和csrf攻击加载并实例化security类

18、加载并实例化输入类

19、加载并实例化语言包

20、加载并实例化控制器类

get_instance() 这个函数用于实例化控制器类

21、判断是否存在子控制器类如果存在加载

22、通过控制器去加载本地应用程序下请求的控制器

23、记录loading_time:_base_classes_end时间点

24、进行安全监测此处有说明：所有的功能不管是应用程序控制器还是加载类可以通过URI调用,控制器function不能用下划线开始

先通过控制器获得加载的类和方法

当加载的类或者方法又或者方法不在CI_Controller这个类中的时候，显示404页面

25、如果设置了pre_controller这个钩子则调用

26、记录请求控制器的时间并且实例化请求的类

27、如果设置了post_controller_constructor这个钩子则调用

28、调用请求的方法

首先监测请求的类中是否有_remap方法，如果有调用

如果没有再判断请求的类中是否有请求的方法如果没有显示404页面

最后调用请求的方法

29、记录控制器执行结束的时间

30、如果设置了post_controller这个钩子则调用

31、将最终的输出发送到浏览器

32、如果设置了post_system钩子则调用

33、判断CI_DB类是否存在还有$CI->db是否设置了值如果为真则关闭数据库连接。

下面是文件源码：

[php]

/**

* CodeIgniter

* An open source application development framework for PHP 5.1.6 or newer

* @package CodeIgniter

* @author ExpressionEngine Dev Team

* @license http://codeigniter.com/user_guide/license.html

* @link http://codeigniter.com

* @since Version 1.0

* @filesource

// ------------------------------------------------------------------------

/**

* System Initialization File

* Loads the base classes and executes 执行 the request.

* @package CodeIgniter

* @subpackage codeigniter

* @category Front-controller

* @author ExpressionEngine Dev Team

* @link http://codeigniter.com/user_guide/

/**

* CodeIgniter Version

* @var string

define('CI_VERSION', '2.1.3');

/**

* CodeIgniter Branch 分支 (Core = TRUE, Reactor 反应器 = FALSE)

* @var boolean

define('CI_CORE', FALSE);

* ------------------------------------------------------

* Load the global functions

* ------------------------------------------------------

require(BASEPATH.'core/Common.php');

* ------------------------------------------------------

* Load the framework constants

* ------------------------------------------------------

if (defined('ENVIRONMENT') AND file_exists(APPPATH.'config/'.ENVIRONMENT.'/constants.php'))

{

require(APPPATH.'config/'.ENVIRONMENT.'/constants.php');

}

else

{

require(APPPATH.'config/constants.php');

}

* ------------------------------------------------------

* Define a custom 自定义 error handler 处理器 so we can log PHP errors

* ------------------------------------------------------

set_error_handler('_exception_handler');

if ( ! is_php('5.3'))

{

@set_magic_quotes_runtime(0); // Kill magic quotes 关闭魔术转义

}

* ------------------------------------------------------

* Set the subclass_prefix 类前缀

* ------------------------------------------------------

* Normally the "subclass_prefix" is set in the config file.

* The subclass prefix allows CI to know if a core class is

* being extended via 通过 a library in the local application

* "libraries" folder. Since 因为 CI allows config items to be

* overriden via data set in the main index. php file,

* before proceeding 开始、程序 we need to know if a subclass_prefix

* override exists. 存在 If so, we will set this value now,

* before any 任何 classes are loaded

* Note: Since the config file data is cached it doesn't

* hurt 伤害，使受伤 to load it here.

* 注意：因为配置文件的数据已经被缓存，所以它加载到这里也不会有伤害。

if (isset($assign_to_config['subclass_prefix']) AND $assign_to_config['subclass_prefix'] != '')

{

get_config(array('subclass_prefix' => $assign_to_config['subclass_prefix']));

}

* ------------------------------------------------------

* Set a liberal 自由主义者 script execution 执行 time limit

* ------------------------------------------------------

if (function_exists("set_time_limit") == TRUE AND @ini_get("safe_mode") == 0)

{

@set_time_limit(300);

}

* ------------------------------------------------------

* Start the timer... tick tock tick tock...

* ------------------------------------------------------

$BM =& load_class('Benchmark', 'core');

$BM->mark('total_execution_time_start');

$BM->mark('loading_time:_base_classes_start');

* ------------------------------------------------------

* Instantiate the hooks class

* ------------------------------------------------------

$EXT =& load_class('Hooks', 'core');

* ------------------------------------------------------

* Is there a "pre_system" hook?

* ------------------------------------------------------

$EXT->_call_hook('pre_system');

* ------------------------------------------------------

* Instantiate the config class

* ------------------------------------------------------

$CFG =& load_class('Config', 'core');

// Do we have any manually 手动的 set config items in the index.php file?

if (isset($assign_to_config))

{

$CFG->_assign_to_config($assign_to_config);

}

* ------------------------------------------------------

* Instantiate the UTF-8 class

* ------------------------------------------------------

* Note: Order 命令顺序 here is rather 宁可，当然 important as the UTF-8

* class needs to be used very early 早期的，提早 on, but it cannot

* properly 适当的、正确的 determine 决定 if UTf-8 can be supported until 在。。。以前

* after the Config class is instantiated.

$UNI =& load_class('Utf8', 'core');

* ------------------------------------------------------

* Instantiate the URI class

* ------------------------------------------------------

$URI =& load_class('URI', 'core');

* ------------------------------------------------------

* Instantiate the routing class and set the routing

* ------------------------------------------------------

$RTR =& load_class('Router', 'core');

$RTR->_set_routing();

// Set any routing overrides that may exist in the main index file

if (isset($routing))

{

$RTR->_set_overrides($routing);

}

* ------------------------------------------------------

* Instantiate the output class

* ------------------------------------------------------

$OUT =& load_class('Output', 'core');

* ------------------------------------------------------

* Is there a valid 有效的 cache file? If so, we're done...

* ------------------------------------------------------

if ($EXT->_call_hook('cache_override') === FALSE)

{

if ($OUT->_display_cache($CFG, $URI) == TRUE)

{

exit;

}

* -----------------------------------------------------

* Load the security 安全 class for xss and csrf support

* -----------------------------------------------------

$SEC =& load_class('Security', 'core');

* ------------------------------------------------------

* Load the Input class and sanitize 使。。。无害 globals

* ------------------------------------------------------

$IN =& load_class('Input', 'core');

* ------------------------------------------------------

* Load the Language class

* ------------------------------------------------------

$LANG =& load_class('Lang', 'core');

* ------------------------------------------------------

* Load the app controller and local controller

* ------------------------------------------------------

// Load the base controller class

require BASEPATH.'core/Controller.php';

function &get_instance()

{

return CI_Controller::get_instance();

}

if (file_exists(APPPATH.'core/'.$CFG->config['subclass_prefix'].'Controller.php'))

{

require APPPATH.'core/'.$CFG->config['subclass_prefix'].'Controller.php';

}

// Load the local application controller

// Note: The Router class automatically 不经思索的、自动的 validates 确认 the controller

// path using the router->_validate_request().

// If this include fails it means 手段、意思是 that 因为、那么 the default controller in

// the Routes.php fi.le is not resolving 解析 to something 非常 valid 有效地

if ( ! file_exists(APPPATH.'controllers/'.$RTR->fetch_directory().$RTR->fetch_class().'.php'))

{

show_error('Unable to load your default controller. Please make sure the controller specified in your Routes.php file is valid.');

}

include(APPPATH.'controllers/'.$RTR->fetch_directory().$RTR->fetch_class().'.php');

// Set a mark point for benchmarking 管理标记

$BM->mark('loading_time:_base_classes_end');

* ------------------------------------------------------

* Security check

* ------------------------------------------------------

* None of the functions in the app controller or the

* loader class can be called via the URI, nor 也不是、也没有 can

* controller functions that begin with an underscore 下划线、强调、底线

* 所有的功能不管是应用程序控制器还是加载类可以通过URI调用,控制器function不能用下划线开始

$class = $RTR->fetch_class();

$method = $RTR->fetch_method();

if ( ! class_exists($class)

OR strncmp($method, '_', 1) == 0

OR in_array(strtolower($method), array_map('strtolower', get_class_methods('CI_Controller')))

)

{

if ( ! emptyempty($RTR->routes['404_override']))

{

$x = explode('/', $RTR->routes['404_override']);

$class = $x[0];

$method = (isset($x[1]) ? $x[1] : 'index');

if ( ! class_exists($class))

{

if ( ! file_exists(APPPATH.'controllers/'.$class.'.php'))

{

show_404("{$class}/{$method}");

}

include_once(APPPATH.'controllers/'.$class.'.php');

}

else

{

show_404("{$class}/{$method}");

}

* ------------------------------------------------------

* Is there a "pre_controller" hook?

* ------------------------------------------------------

$EXT->_call_hook('pre_controller');

* ------------------------------------------------------

* Instantiate the requested controller

* ------------------------------------------------------

// Mark a start point so we can benchmark the controller

$BM->mark('controller_execution_time_( '.$class.' / '.$method.' )_start');

$CI = new $class();

* ------------------------------------------------------

* Is there a "post_controller_constructor" hook?

* ------------------------------------------------------

$EXT->_call_hook('post_controller_constructor');

* ------------------------------------------------------

* Call the requested method

* ------------------------------------------------------

// Is there a "remap" 重测图、再交换 function? If so, we call it instead 更换、代替

if (method_exists($CI, '_remap'))

{

$CI->_remap($method, array_slice($URI->rsegments, 2));

}

else

{

// is_callable() returns TRUE on some versions of PHP 5 for private and protected

// methods, so we'll use this workaround 变通方案 for consistent behavior 一致的行为

if ( ! in_array(strtolower($method), array_map('strtolower', get_class_methods($CI))))

{

// Check and see if we are using a 404 override and use it.

if ( ! emptyempty($RTR->routes['404_override']))

{

$x = explode('/', $RTR->routes['404_override']);

$class = $x[0];

$method = (isset($x[1]) ? $x[1] : 'index');

if ( ! class_exists($class))

{

if ( ! file_exists(APPPATH.'controllers/'.$class.'.php'))

{

show_404("{$class}/{$method}");

}

include_once(APPPATH.'controllers/'.$class.'.php');

unset($CI);

$CI = new $class();

}

else

{

show_404("{$class}/{$method}");

}

// Call the requested method.

// Any URI segments 片段 present 礼物、现在、目前 (besides 除了。。。之外 the class/function)

// will be passed to the method for convenience 便利、方便

call_user_func_array(array(&$CI, $method), array_slice($URI->rsegments, 2));

}

// Mark a benchmark end point

$BM->mark('controller_execution_time_( '.$class.' / '.$method.' )_end');

* ------------------------------------------------------

* Is there a "post_controller" hook?

* ------------------------------------------------------

$EXT->_call_hook('post_controller');

* ------------------------------------------------------

* Send the final rendered 提出、已渲染的 output to the browser

* ------------------------------------------------------

if ($EXT->_call_hook('display_override') === FALSE)

{

$OUT->_display();

}

* ------------------------------------------------------

* Is there a "post_system" hook?

* ------------------------------------------------------

*/ www.2cto.com

$EXT->_call_hook('post_system');

* ------------------------------------------------------

* Close the DB connection if one exists

* ------------------------------------------------------

if (class_exists('CI_DB') AND isset($CI->db))

{

$CI->db->close();

}

/* End of file CodeIgniter.php */

/* Location: ./system/core/CodeIgniter.php */