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CI框架源码完全分析之核心文件Codeigniter.php

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$assign_to_config['subclass_prefix']));
}

/*
*php 程序运行默认是30s,这里用set_time_limt延长了,关于set_time_Limit() http://www.phpddt.com/php/set_time_limit.html
* 扩展阅读,关于safe_mode:http://www.phpddt.com/php/643.html ,你会完全明白的
*/
if (function_exists("set_time_limit") == TRUE AND @ini_get("safe_mode") == 0)
{
@set_time_limit(300);
}

/*
* 加载Benchmark,它很简单,就是计算任意两点之间程序的运行时间
*/
$BM =& load_class('Benchmark', 'core');
$BM->mark('total_execution_time_start');
$BM->mark('loading_time:_base_classes_start');

//加载钩子,后期会分析到,这玩意特好,扩展它能改变CI的运行流程
$EXT =& load_class('Hooks', 'core');

//这里就是一个钩子啦,其实就是该钩子程序在这里执行
$EXT->_call_hook('pre_system');

//加载配置文件,这里面都是一些加载或获取配置信息的函数
$CFG =& load_class('Config', 'core');

// 如果在index.php中也有配置$assign_to_config,则也把它加入到$CFG
if (isset($assign_to_config))
{
$CFG->_assign_to_config($assign_to_config);
}

//加载utf8组件、URI组件、Router组件
$UNI =& load_class('Utf8', 'core');
$URI =& load_class('URI', 'core');
$RTR =& load_class('Router', 'core');
$RTR->_set_routing();

//如果在index.php中定义了$routing,那么就会覆盖上面路由
if (isset($routing))
{
$RTR->_set_overrides($routing);
}

//加载output输出组件,不然你怎么用$this->Load->view()啊
$OUT =& load_class('Output', 'core');

//又见钩子,这里你可以自己写钩子程序替代Output类的缓存输出
if ($EXT->_call_hook('cache_override') === FALSE)
{
if ($OUT->_display_cache($CFG, $URI) == TRUE)
{
exit;
}
}

//安全组件啦,防xss攻击啊,csrf攻击啊
//关于xss攻击:http://www.phpddt.com/php/php-prevent-xss.html
//关于csrf:攻击:http://www.phpddt.com/reprint/csrf.html
$SEC =& load_class('Security', 'core');

//加载输入组件,就是你常用的$this->input->post();等
$IN =& load_class('Input', 'core');

//加载语言组件啦
$LANG =& load_class('Lang', 'core');

//引入CI的控制器父类
require BASEPATH.'core/Controller.php';

function &get_instance()
{
return CI_Controller::get_instance();
}

//当然你扩展了CI_Controller控制器的话,也要引入啦
if (file_exists(APPPATH.'core/'.$CFG->config['subclass_prefix'].'Controller.php'))
{
require APPPATH.'core/'.$CFG->config['subclass_prefix'].'Controller.php';
}

//加载你自己应用中的控制器Controller,如果没有当然error啦
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');

// 好的基础的类都加载完毕了,咱可以mark一下
$BM->mark('loading_time:_base_classes_end');

//路由获取了控制器名和方法名,比如说默认welcome/index
$class = $RTR->fetch_class();
$method = $RTR->fetch_method();
//这里CI规定一般非公共的方法以_开头,下面是判断,如果URI不可访问就show_404()
if ( ! class_exists($class)
OR strncmp($method, '_', 1) == 0
OR in_array(strtolower($method), array_map('strtolower', get_class_methods('CI_Controller')))
)
{
if ( ! empty($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}");
}
}

//又是钩子,该钩子发生在控制器实例化之前的
$EXT->_call_hook('pre_controller');

//又mark一个点
$BM->mark('controller_execution_time_( '.$class.' / '.$method.' )_start');
//终于实例化控制器了
$CI = new $class();

//钩子,不想多说了
$EXT->_call_hook('post_controller_constructor');

/*
* ------------------------------------------------------
* Call the requested method
* ------------------------------------------------------
*/
// Is there a "remap" function? If so, we call it instead
if (method_exists($CI, '_remap'))
{
$CI->_remap($method, array_slice($URI->rsegments, 2));
}
else
{
// is_callable() returns TRUE on some versions of PHP 5 for private and protected
// methods, so we'll use this workaround for consistent behavior
if ( ! in_array(strtolower($method), array_map('strtolower', get_class_methods($CI))))
{
// Check and see if we are using a 404 override and use it.
if ( ! empty($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}");
}
}

// 终于调用方法了,$this->load->view()把内容放到缓存区
call_user_func_array(array(&$CI, $method), array_slice($URI->rsegments, 2));
}
$BM->mark('controller_execution_time_( '.$class.' / '.$method.' )_end');
$EXT->_call_hook('post_controller');

//这里就是把缓存区的内容输出了
if ($EXT->_call_hook('display_override') === FALSE)
{

$OUT->_display();
}

$EXT->_call_hook('post_system');
//关闭数据库的链接
if (class_exists('CI_DB') AND isset($CI->db))
{
$CI->db->close();
}