CodeIgniter框架源码学习之路由类－－Router.php

文件位置：./system/core/Router.php
<?php
/**
* CodeIgniter
*
* An open source application development framework for PHP
*
* This content is released under the MIT License (MIT)
*
* Copyright (c) 2014 - 2017, British Columbia Institute of Technology
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*
* @package CodeIgniter
* @author EllisLab Dev Team
* @copyright Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
* @copyright Copyright (c) 2014 - 2017, British Columbia Institute of Technology (http://bcit.ca/)
* @license http://opensource.org/licenses/MIT MIT License
* @link https://codeigniter.com * @since Version 1.0.0
* @filesource
*/
defined('BASEPATH') OR exit('No direct script access allowed');

/**
* Router Class
*
* Parses URIs and determines routing
*
* @package CodeIgniter
* @subpackage Libraries
* @category Libraries
* @author EllisLab Dev Team
* @link https://codeigniter.com/user_guide/general/routing.html */
class CI_Router {

/**
* CI_Config class object
*配置类对象
* @var object
*/
public $config;

/**
* List of routes
*路由列表来自APPPATH/config/route.php
* @var array
*/
public $routes = array();

/**
* Current class name
*当前类名
* @var string
*/
public $class = '';

/**
* Current method name
*当前方法名
* @var string
*/
public $method = 'index';

/**
* Sub-directory that contains the requested controller class
*包含请求中controller类的目录信息
* @var string
*/
public $directory;

/**
* Default controller (and method if specific)
*默认控制器（以及定义过的方法）
* @var string
*/
public $default_controller;

/**
1510d

* Translate URI dashes
*
* Determines whether dashes in controller & method segments
* should be automatically replaced by underscores.
*确定控制器和方法中是否存在'-'(破折号)，如果存在则自动被替换成(下划线)'_'
* @var bool
*/
public $translate_uri_dashes = FALSE;

/**
* Enable query strings flag
*
* Determines whether to use GET parameters or segment URIs
*确定是否使用GET的参数或者uri的段
* @var bool
*/
public $enable_query_strings = FALSE;

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

/**
* Class constructor
*
* Runs the route mapping function.
*加载并实例化config类和URI类 
* @param array $routing
* @return void
*/
public function __construct($routing = NULL)
{
$this->config =& load_class('Config', 'core');
$this->uri =& load_class('URI', 'core');

$this->enable_query_strings = ( ! is_cli() && $this->config->item('enable_query_strings') === TRUE);

// If a directory override is configured, it has to be set before any dynamic routing logic
is_array($routing) && isset($routing['directory']) && $this->set_directory($routing['directory']);
$this->_set_routing();

// Set any routing overrides that may exist in the main index file
if (is_array($routing))
{
empty($routing['controller']) OR $this->set_class($routing['controller']);
empty($routing['function']) OR $this->set_method($routing['function']);
}

log_message('info', 'Router Class Initialized');
}

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

/**
* Set route mapping
*
* Determines what should be served based on the URI request,
* as well as any "routes" that have been set in the routing config file.
*确定基于uri请求以及在路由配置文件的routes数组中的什么应该被保存
* @return void
*/
protected function _set_routing()
{
// Load the routes.php file. It would be great if we could
// skip this for enable_query_strings = TRUE, but then
// default_controller would be empty ...
if (file_exists(APPPATH.'config/routes.php'))
{
include(APPPATH.'config/routes.php');
}

if (file_exists(APPPATH.'config/'.ENVIRONMENT.'/routes.php'))
{
include(APPPATH.'config/'.ENVIRONMENT.'/routes.php');
}

// Validate & get reserved routes
if (isset($route) && is_array($route))
{
isset($route['default_controller']) && $this->default_controller = $route['default_controller'];
isset($route['translate_uri_dashes']) && $this->translate_uri_dashes = $route['translate_uri_dashes'];
unset($route['default_controller'], $route['translate_uri_dashes']);
$this->routes = $route;
}

// Are query strings enabled in the config file? Normally CI doesn't utilize（利用） query strings
// since URI segments are more search-engine friendly, but they can optionally be used.
// If this feature （特征）is enabled, we will gather the directory/class/method a little differently
if ($this->enable_query_strings)
{
// If the directory is set at this time, it means an override exists, so skip the checks
if ( ! isset($this->directory))
{
$_d = $this->config->item('directory_trigger');
$_d = isset($_GET[$_d]) ? trim($_GET[$_d], " \t\n\r\0\x0B/") : '';

if ($_d !== '')
{
$this->uri->filter_uri($_d);
$this->set_directory($_d);
}
}

$_c = trim($this->config->item('controller_trigger'));
if ( ! empty($_GET[$_c]))
{
$this->uri->filter_uri($_GET[$_c]);
$this->set_class($_GET[$_c]);

$_f = trim($this->config->item('function_trigger'));
if ( ! empty($_GET[$_f]))
{
$this->uri->filter_uri($_GET[$_f]);
$this->set_method($_GET[$_f]);
}

$this->uri->rsegments = array(
1 => $this->class,
2 => $this->method
);
}
else
{
$this->_set_default_controller();
}

// Routing rules don't apply to query strings and we don't need to detect
// directories, so we're done here
return;
}

// Is there anything to parse?
if ($this->uri->uri_string !== '')
{
$this->_parse_routes();
}
else
{
$this->_set_default_controller();
}
}

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

/**
* Set request route
*
* Takes an array of URI segments as input and sets the class/method
* to be called.
*获取一个uri段的数组作为输入参数，设置博哦调用的类和方法
* @used-by CI_Router::_parse_routes()
* @param array $segments URI segments
* @return void
*/
protected function _set_request($segments = array())
{
$segments = $this->_validate_request($segments);
// If we don't have any segments left - try the default controller;
// WARNING: Directories get shifted out of the segments array!
if (empty($segments))
{
$this->_set_default_controller();
return;
}

if ($this->translate_uri_dashes === TRUE)
{
$segments[0] = str_replace('-', '_', $segments[0]);
if (isset($segments[1]))
{
$segments[1] = str_replace('-', '_', $segments[1]);
}
}

$this->set_class($segments[0]);
if (isset($segments[1]))
{
$this->set_method($segments[1]);
}
else
{
$segments[1] = 'index';
}

array_unshift($segments, NULL);
array_unshift() 函数用于向数组插入新元素。新数组的值将被插入到数组的开头。
被加上的元素作为一个整体添加，这些元素在数组中的顺序和在参数中的顺序一样。
该函数会返回数组中元素的个数。$a = array('a','b');array_unshift($a,'c');print_r($a) ---array('0'=>'c','1'=>'a','2'=>'b')

unset($segments[0]);
$this->uri->rsegments = $segments;
}

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

/**
* Set default controller
*设置默认控制器
* @return void
*/
protected function _set_default_controller()
{
if (empty($this->default_controller))
{
show_error('Unable to determine what should be displayed. A default route has not been specified in the routing file.');
}

// Is the method being specified?
sscanf() 函数根据指定的格式解析来自字符串的输入。 sscanf() 函数基于格式字符串向变量中解析字符串。
如果只向该函数传递两个参数，数据将以数组的形式返回。否则，如果传递了额外的参数，则被解析的数据会存储在这些参数中。如果区分符的数目大于包含它们的变量的数目，则会发生错误。不过，如果区分符的数目小于包含它们的变量的数目，则额外的变量包含 NULL。
<?php$str = "age:30 weight:60kg";sscanf($str,"age:%d weight:%dkg",$age,$weight);// 显示类型和值var_dump($age,$weight);?>
int(30) int(60)
if (sscanf($this->default_controller, '%[^/]/%s', $class, $method) !== 2)
{
$method = 'index';
}

if ( ! file_exists(APPPATH.'controllers/'.$this->directory.ucfirst($class).'.php'))
{

ucfirst()将字符串首字母大写，此时表明加载的控制器名首字母药大写否则无法加载
// This will trigger 404 later
return;
}

$this->set_class($class);
$this->set_method($method);

// Assign routed segments, index starting from 1

设置URI.php文件中重新排序的uri段数组
$this->uri->rsegments = array(
1 => $class,
2 => $method
);

log_message('debug', 'No URI present. Default controller set.');
}

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

/**
* Validate request
*
* Attempts validate the URI request and determine the controller path.
*企图验证uri请求确定控制器路径
* @used-by CI_Router::_set_request()
* @param array $segments URI segments
* @return mixed URI segments
*/
protected function _validate_request($segments)
{
$c = count($segments);
$directory_override = isset($this->directory);

// Loop through our segments and return as soon as a controller
// is found or when such a directory doesn't exist
while ($c-- > 0)
{
$test = $this->directory
.ucfirst($this->translate_uri_dashes === TRUE ? str_replace('-', '_', $segments[0]) : $segments[0]);

if ( ! file_exists(APPPATH.'controllers/'.$test.'.php')
&& $directory_override === FALSE
&& is_dir(APPPATH.'controllers/'.$this->directory.$segments[0])
)
{
$this->set_directory(array_shift($segments), TRUE);
continue;
}

return $segments;
}

// This means that all segments were actually directories
return $segments;
}

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

/**
* Parse Routes
*
* Matches any routes that may exist in the config/routes.php file
* against the URI to determine if the class/method need to be remapped.
*将可能已经存在的路由配置和URI进行匹配，以确定类或者方法需要被重新定位
* @return void
*/
protected function _parse_routes()
{
// Turn the segment array into a URI string
$uri = implode('/', $this->uri->segments);

// Get HTTP verb
$http_verb = isset($_SERVER['REQUEST_METHOD']) ? strtolower($_SERVER['REQUEST_METHOD']) : 'cli';

// Loop through the route array looking for wildcards
foreach ($this->routes as $key => $val)
{
// Check if route format is using HTTP verbs
if (is_array($val))
{
$val = array_change_key_case($val, CASE_LOWER);
array_change_key_case() 函数将数组的所有的键都转换为大写字母或小写字母。
数组的数字索引不发生变化。如果未提供可选参数（即第二个参数），则默认转换为小写字母。
if (isset($val[$http_verb]))
{
$val = $val[$http_verb];
}
else
{
continue;
}
}

// Convert wildcards to RegEx
$key = str_replace(array(':any', ':num'), array('[^/]+', '[0-9]+'), $key);

// Does the RegEx match?
if (preg_match('#^'.$key.'$#', $uri, $matches))
{
// Are we using callbacks to process back-references?
if ( ! is_string($val) && is_callable($val))
{
// Remove the original string from the matches array.
array_shift($matches);

// Execute the callback using the values in matches as its parameters.
$val = call_user_func_array($val, $matches);
}
// Are we using the default routing method for back-references?
elseif (strpos($val, '$') !== FALSE && strpos($key, '(') !== FALSE)
{
$val = preg_replace('#^'.$key.'$#', $val, $uri);
}

$this->_set_request(explode('/', $val));
return;
}
}

// If we got this far it means we didn't encounter a
// matching route so we'll set the site default route
$this->_set_request(array_values($this->uri->segments));
}

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

/**
* Set class name
*设置类名
* @param string $class Class name
* @return void
*/
public function set_class($class)
{
$this->class = str_replace(array('/', '.'), '', $class);
}

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

/**
* Fetch the current class
*获取当前类
* @deprecated 3.0.0 Read the 'class' property instead
* @return string
*/
public function fetch_class()
{
return $this->class;
}

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

/**
* Set method name
*设置方法名
* @param string $method Method name
* @return void
*/
public function set_method($method)
{
$this->method = $method;
}

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

/**
* Fetch the current method
*获取当前方法名
* @deprecated 3.0.0 Read the 'method' property instead
* @return string
*/
public function fetch_method()
{
return $this->method;
}

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

/**
* Set directory name
*设置目录名
* @param string $dir Directory name
* @param bool $append Whether we're appending rather than setting the full value
* @return void
*/
public function set_directory($dir, $append = FALSE)
{
if ($append !== TRUE OR empty($this->directory))
{
$this->directory = str_replace('.', '', trim($dir, '/')).'/';
}
else
{
$this->directory .= str_replace('.', '', trim($dir, '/')).'/';
}
}

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

/**
* Fetch directory
*获取当前目录
* Feches the sub-directory (if any) that contains the requested
* controller class.
*
* @deprecated 3.0.0 Read the 'directory' property instead
* @return string
*/
public function fetch_directory()
{
return $this->directory;
}

}