CI框架源码完全分析之核心文件URI.php

<?php
/**
* 解析uri，确定路由
*/
class CI_URI {

//缓存uri片段
var $keyval = array();
//当前的uri片段
var $uri_string;
//URI片段数组 数组键值从0开始
var $segments = array();
//重建索引的片段数组 数组键值从1开始
var $rsegments = array();

//构造函数，需要获取config文件中的配置
function __construct()
{
$this->config =& load_class('Config', 'core');
log_message('debug', "URI Class Initialized");
}

//获取uri_string
function _fetch_uri_string()
{
//$this->config->item('uri_protocol')是获取config.php中uri_protocol的配置，AUTO为默认
if (strtoupper($this->config->item('uri_protocol')) == 'AUTO')
{
// 命令行方式执行
if (php_sapi_name() == 'cli' or defined('STDIN'))
{
$this->_set_uri_string($this->_parse_cli_args());
return;
}
// REQUEST_URI方式，绝大部分情况都能获取
if ($uri = $this->_detect_uri())
{
$this->_set_uri_string($uri);
return;
}

// PATH_INFO方式
$path = (isset($_SERVER['PATH_INFO'])) ? $_SERVER['PATH_INFO'] : @getenv('PATH_INFO');
if (trim($path, '/') != '' && $path != "/".SELF)
{
$this->_set_uri_string($path);
return;
}

// QUERY_STRING方式
$path = (isset($_SERVER['QUERY_STRING'])) ? $_SERVER['QUERY_STRING'] : @getenv('QUERY_STRING');
if (trim($path, '/') != '')
{
$this->_set_uri_string($path);
return;
}

// 尝试最后一种方式，通过$_GET获取键名
if (is_array($_GET) && count($_GET) == 1 && trim(key($_GET), '/') != '')
{
$this->_set_uri_string(key($_GET));
return;
}

// 如果还没获取到uri_string ,只能返回空了
$this->uri_string = '';
return;
}
//其实下面很多都是把上面的东西重写了，这是根据用户在config.php中配置的
$uri = strtoupper($this->config->item('uri_protocol'));
//若为REQUEST_URI方式
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);
}

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

//就是给uri_string赋值
function _set_uri_string($str)
{
// 防止在ASCII字符之间插入空字符，如Java\0script.
$str = remove_invisible_characters($str, FALSE);

// If the URI contains only a slash we'll kill it
$this->uri_string = ($str == '/') ? '' : $str;
}

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

//检测URI
private function _detect_uri()
{
//$_SERVER['REQUEST_URI']和$_SERVER['SCRIPT_NAME']两者都存在才可使用
if ( ! isset($_SERVER['REQUEST_URI']) OR ! isset($_SERVER['SCRIPT_NAME']))
{
return '';
}

$uri = $_SERVER['REQUEST_URI'];
//去掉相同的部分，剩下有用的uri部分
if (strpos($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'])));
}

//允许?/welcome/index这种格式
if (strncmp($uri, '?/', 2) === 0)
{
$uri = substr($uri, 2);
}
$parts = preg_split('#\?#i', $uri, 2);
$uri = $parts[0];
if (isset($parts[1]))
{
$_SERVER['QUERY_STRING'] = $parts[1];
parse_str($_SERVER['QUERY_STRING'], $_GET);
}
else
{
$_SERVER['QUERY_STRING'] = '';
$_GET = array();
}

if ($uri == '/' || empty($uri))
{
return '/';
}

$uri = parse_url($uri, PHP_URL_PATH);

//做最后的处理返回uri
return str_replace(array('//', '../'), '/', trim($uri, '/'));
}

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

//解析命令行方式参数
private function _parse_cli_args()
{
$args = array_slice($_SERVER['argv'], 1);

return $args ? '/' . implode('/', $args) : '';
}

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

//过滤不合法的url字符，允许的uri是你的配置$config['permitted_uri_chars'] = 'a-z 0-9~%.:_\-';
function _filter_uri($str)
{
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);
}
}

// Convert programatic characters to entities
$bad = array('$', '(', ')', '%28', '%29');
$good = array('$', '(', ')', '(', ')');

return str_replace($bad, $good, $str);
}

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

//如果你配置了url_suffix，则去掉
function _remove_url_suffix()
{
if ($this->config->item('url_suffix') != "")
{
$this->uri_string = preg_replace("|".preg_quote($this->config->item('url_suffix'))."$|", "", $this->uri_string);
}
}

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

//用/分隔uri_string,将结果保存到segments中
function _explode_segments()
{
foreach (explode("/", preg_replace("|/*(.+?)/*$|", "\\1", $this->uri_string)) as $val)
{
// Filter segments for security
$val = trim($this->_filter_uri($val));

if ($val != '')
{
$this->segments[] = $val;
}
}
}

//这个是重建索引，将数组从下标1开始，这是为了你的使用习惯，如$this->uri->segment(1)就是获取第一段
function _reindex_segments()
{
array_unshift($this->segments, NULL);
array_unshift($this->rsegments, NULL);
unset($this->segments[0]);
unset($this->rsegments[0]);
}

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

//获取uri中的一个片段
function segment($n, $no_result = FALSE)
{
return ( ! isset($this->segments[$n])) ? $no_result : $this->segments[$n];
}

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

//返回确定路由后的一个uri片段
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];
}

if ($this->$total_segments() < $n)
{
if (count($default) == 0)
{
return array();
}

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

$segments = array_slice($this->$segment_array(), ($n - 1));

$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;
}

//很明显，它是将数组中的信息翻转成uri_string
function assoc_to_uri($array)
{
$temp = array();
foreach ((array)$array as $key => $val)
{
$temp[] = $key;
$temp[] = $val;
}

return implode('/', $temp);
}

//通过第二个参数看是否给uri前后加上“/”线
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;
}

// --------------------------------------------------------------------
//返回uri片段数组
function segment_array()
{
return $this->segments;
}
function rsegment_array()
{
return $this->rsegments;
}

//计算uri片段的个数
function total_segments()
{
return count($this->segments);
}

function total_rsegments()
{
return count($this->rsegments);
}

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

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

}