Query_string and Request_uri differences in $_server functions

http://blog.sina.com.cn/s/blog_686999de0100jgda.html  Example:

1,http://localhost/aaa/ (open index.php in AAA)
Results:
$_server[' query_string '] = "";
$_server[' request_uri '] = "/aaa/";
$_server[' script_name '] = "/aaa/index.php";
$_server[' php_self '] = "/aaa/index.php";

2,http://localhost/aaa/?p=222 (with inquiry)
Results:
$_server[' query_string '] = "p=222";
$_server[' request_uri '] = "/aaa/?p=222";
$_server[' script_name '] = "/aaa/index.php";
$_server[' php_self '] = "/aaa/index.php";

3,http://localhost/aaa/index.php?p=222&q=333
Results:
$_server[' query_string '] = "p=222&q=333";
$_server[' request_uri '] = "/aaa/index.php?p=222&q=333";
$_server[' script_name '] = "/aaa/index.php";
$_server[' php_self '] = "/aaa/index.php";

by Example:
$_server["Query_string"] gets the query statement, in the instance, gets the following value
$_server["Request_uri"] gets the value after http://localhost, including/
$_server["Script_name"] gets the path to the current script, such as: index.php
$_server["Php_self"] The file name of the script that is currently executing   difference between $_server[' Request_uri ' and $_server[' Http_x_rewrite_url '] http://www.hujuntao.com/web/php/difference-between-server-request-uri-and-server-http_x_rewrite_url.html
 

wordpress implementation of non-first-domain (non-WWW) jump by 301 redirects it would have been a simple thing, Because the difference between $_server[' Http_x_rewrite_url ' and $_server[' Request_uri ' was not clarified, the problem of cyclic redirection was caused.
Now to specifically study $_server[' Http_x_rewrite_url The difference between '] and $_server[' Request_uri ']
The first thing to correct is that iis+php does not support $_server[' Request_uri ']
No, the issue of PHP version is not supported, php4.4.0 does not support $_server[' Request_uri '],php5.2.5 adds support;

$_server[' Request_uri ') commonly used to obtain the current URL
Span style= "font-family: ' Microsoft Yahei '; font-size:18px; " > example: http://www.hujuntao.com/index.php?p=3
$_server[' Request_uri '] got/index.php?p=3 this part.

$_server["Http_x_rewrite_url"] The current URL is obtained under IIS, and the value under Apache is null

example:
current url:http://www.hujuntao.com/
IIS environment:
$_server[' request_uri '] =/ index.php

$_server[' request_uri ' =/
$_server[" Http_x_rewrite_url "] ="

Current url:http://www.hujuntao.com/index.php
In the IIS environment:
$_server[' Request_uri '] =/index.php
$_server["Http_x_rewrite_url"] =/index.php
Apache Environment:
$_server[' Request_uri '] =/index.php
$_server["Http_x_rewrite_url"] = "

Query_string and Request_uri differences in $_server functions