codeigniter源代码分析之URI处理类 URI.php

对http请求的uri进行解析处理

Router中uri请求为get的时候是不会调用到这里

这里处理的是默认请求跟path_info形式的请求

代码注释如下

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
class CI_URI {

var	$keyval			= array();
var $uri_string;
var $segments		= array();
var $rsegments		= array();
function __construct()
{
$this->config =& load_class('Config', 'core');
log_message('debug', "URI Class Initialized");
}
function _fetch_uri_string()
{
if (strtoupper($this->config->item('uri_protocol')) == 'AUTO')//自动识别
{
if (php_sapi_name() == 'cli' or defined('STDIN'))//命令行
{
$this->_set_uri_string($this->_parse_cli_args());
return;
}
if ($uri = $this->_detect_uri())//detect_uri 获取
{
$this->_set_uri_string($uri);// 设置uri_string
return;
}
// PATH_INFO
$path = (isset($_SERVER['PATH_INFO'])) ? $_SERVER['PATH_INFO'] : @getenv('PATH_INFO');
if (trim($path, '/') != '' && $path != "/".SELF)
{
$this->_set_uri_string($path);
return;
}
// QUERY_STRING
$path =  (isset($_SERVER['QUERY_STRING'])) ? $_SERVER['QUERY_STRING'] : @getenv('QUERY_STRING');
if (trim($path, '/') != '')
{
$this->_set_uri_string($path);
return;
}
// url?arg1
if (is_array($_GET) && count($_GET) == 1 && trim(key($_GET), '/') != '')
{
$this->_set_uri_string(key($_GET));
return;
}
// 设置为空
$this->uri_string = '';
return;
}
$uri = strtoupper($this->config->item('uri_protocol'));
if ($uri == 'REQUEST_URI')
{
$this->_set_uri_string($this->_detect_uri());
return;
}
elseif ($uri == 'CLI')
{
$this->_set_uri_string($this->_parse_cli_args());
return;
}

$path = (isset($_SERVER[$uri])) ? $_SERVER[$uri] : @getenv($uri);
$this->_set_uri_string($path);
}
function _set_uri_string($str)
{
// 这里意味着 如果uri参数部分为空 或者为GET请求 不过一般情况GET请求是过不来的
// Router先处理GET 成功就return了
// it means 参数部分为空就会返回 空的 uri_string 这样在Router中会调用set_default_controller
$str = remove_invisible_characters($str, FALSE);//过滤看不见的字符 不过滤URL
$this->uri_string = ($str == '/') ? '' : $str; //if (uri_string == '/') uri_string = '';
}
private function _detect_uri()
{
if ( ! isset($_SERVER['REQUEST_URI']) OR ! isset($_SERVER['SCRIPT_NAME']))
{//REQUEST_URI SCRIPT_NAME 不存在很可能是命令行 ？
return '';
}

// 获取URL的参数部分 赋值给 uri 变量
$uri = $_SERVER['REQUEST_URI'];
if (strpos($uri, $_SERVER['SCRIPT_NAME']) === 0)
{
$uri = substr($uri, strlen($_SERVER['SCRIPT_NAME']));
}
elseif (strpos($uri, dirname($_SERVER['SCRIPT_NAME'])) === 0)
{
$uri = substr($uri, strlen(dirname($_SERVER['SCRIPT_NAME'])));
}

if (strncmp($uri, '?/', 2) === 0)
{//如果uri是以 ?/ 开始的 说明这个请求可能是 Nginx 去除url中的'?/'
$uri = substr($uri, 2);
}
$parts = preg_split('#\?#i', $uri, 2);//用?将uri切割成两部分
$uri = $parts[0];
// GET请求的 parts[0] 为空 参数列在 parts[1]
// PATH_INFO 请求 parts[0] 就是参数列 /var1/var2...
if (isset($parts[1]))
{
$_SERVER['QUERY_STRING'] = $parts[1];
parse_str($_SERVER['QUERY_STRING'], $_GET);
}
else
{
$_SERVER['QUERY_STRING'] = '';
$_GET = array();
}
if ($uri == '/' || empty($uri))
{
// GET请求 和默认请求都将执行这里
return '/';
}
$uri = parse_url($uri, PHP_URL_PATH);
return str_replace(array('//', '../'), '/', trim($uri, '/'));
}
// 解析CLI模式的参数
private function _parse_cli_args()
{
$args = array_slice($_SERVER['argv'], 1);
return $args ? '/' . implode('/', $args) : '';
}
function _filter_uri($str)
{
// permitted_uri_chars 可以指定uri中允许出现的字符
if ($str != '' && $this->config->item('permitted_uri_chars') != '' && $this->config->item('enable_query_strings') == FALSE)
{
if ( ! preg_match("|^[".str_replace(array('\\-', '\-'), '-', preg_quote($this->config->item('permitted_uri_chars'), '-'))."]+$|i", $str))
{
show_error('The URI you submitted has disallowed characters.', 400);
}
}
$bad	= array('$',		'(',		')',		'%28',		'%29');
$good	= array('$',	'(',	')',	'(',	')');
// 用good（对应字符的HTML形式的十进制编码）替换uri中出现的bad 字符
return str_replace($bad, $good, $str);
}
function _remove_url_suffix()
{
// 去除uri后缀
if  ($this->config->item('url_suffix') != "")
{
$this->uri_string = preg_replace("|".preg_quote($this->config->item('url_suffix'))."$|", "", $this->uri_string);
}
}
function _explode_segments()
{
foreach (explode("/", preg_replace("|/*(.+?)/*$|", "\\1", $this->uri_string)) as $val)
{//PATH_INFO模式生成segments
$val = trim($this->_filter_uri($val));
if ($val != '')
{
// 为URI的segments赋值
$this->segments[] = $val;
}
}
}
// 将数组的0index unset 数组从1开始索引
function _reindex_segments()
{
array_unshift($this->segments, NULL);
array_unshift($this->rsegments, NULL);
unset($this->segments[0]);
unset($this->rsegments[0]);
}
// 返回指定的uri段
function segment($n, $no_result = FALSE)
{
return ( ! isset($this->segments[$n])) ? $no_result : $this->segments[$n];
}
function rsegment($n, $no_result = FALSE)
{
return ( ! isset($this->rsegments[$n])) ? $no_result : $this->rsegments[$n];
}

function uri_to_assoc($n = 3, $default = array())
{
return $this->_uri_to_assoc($n, $default, 'segment');
}
function ruri_to_assoc($n = 3, $default = array())
{
return $this->_uri_to_assoc($n, $default, 'rsegment');
}
function _uri_to_assoc($n = 3, $default = array(), $which = 'segment')
{
if ($which == 'segment')
{
$total_segments = 'total_segments';
$segment_array = 'segment_array';
}
else
{
$total_segments = 'total_rsegments';
$segment_array = 'rsegment_array';
}

if ( ! is_numeric($n))
{
return $default;
}

if (isset($this->keyval[$n]))
{
return $this->keyval[$n];//keyval中存在就返回索取的值
}

if ($this->$total_segments() < $n)//总segments数小于请求的索引
{
if (count($default) == 0)
{
return array();
}

$retval = array();
foreach ($default as $val)
{
$retval[$val] = FALSE;//用default array 设置
}
return $retval;
}

$segments = array_slice($this->$segment_array(), ($n - 1));//取出n后面的数据

$i = 0;
$lastval = '';
$retval  = array();
/*

*/
foreach ($segments as $seg)
{
if ($i % 2)
{
$retval[$lastval] = $seg;
}
else
{
$retval[$seg] = FALSE;
$lastval = $seg;
}

$i++;
}

if (count($default) > 0)
{
foreach ($default as $val)
{
if ( ! array_key_exists($val, $retval))
{
$retval[$val] = FALSE;
}
}
}

// Cache the array for reuse
$this->keyval[$n] = $retval;
return $retval;
}
// 将segments数组拼接成 uri字符串
function assoc_to_uri($array)
{
$temp = array();
foreach ((array)$array as $key => $val)
{
$temp[] = $key;
$temp[] = $val;
}

return implode('/', $temp);
}
function slash_segment($n, $where = 'trailing')
{
return $this->_slash_segment($n, $where, 'segment');
}
function slash_rsegment($n, $where = 'trailing')
{
return $this->_slash_segment($n, $where, 'rsegment');
}
function _slash_segment($n, $where = 'trailing', $which = 'segment')
{
$leading	= '/';
$trailing	= '/';

if ($where == 'trailing')
{
$leading	= '';
}
elseif ($where == 'leading')
{
$trailing	= '';
}

return $leading.$this->$which($n).$trailing;
}
function segment_array()
{
return $this->segments;
}
function rsegment_array()
{
return $this->rsegments;
}
function total_segments()
{
return count($this->segments);
}
function total_rsegments()
{
return count($this->rsegments);
}

function uri_string()
{
return $this->uri_string;
}
function ruri_string()
{
return '/'.implode('/', $this->rsegment_array());
}

}

总结：

_fetch_uri_string 获取uri string

_detect_uri 通过REQUEST_URI处理 uri的参数部分

_explode_segments 切割uri中（path_info）参数部分

下面很多对segments的操作

Code Tips：

1、方法 _uri_to_assoc 还有点没弄懂