处理 URL 字符串:编码、解码与解析。




本函数库作为 PHP 内核的一部分,不用安装就能使用。


本扩展模块在 php.ini 中未定义任何配置选项。





base64_decode -- 对使用 MIME base64 编码的数据进行解码
base64_encode -- 使用 MIME base64 对数据进行编码
get_headers --  Fetches all the headers sent by the server in response to a HTTP request
get_meta_tags --  从一个文件中提取所有的 meta 标签 content 属性,返回一个数组
http_build_query -- 生成 url-encoded 之后的请求字符串
parse_url -- 解析 URL,返回其组成部分
rawurldecode -- 对已编码的 URL 字符串进行解码
rawurlencode -- 按照 RFC 1738 对 URL 进行编码
urldecode -- 解码已编码的 URL 字符串
urlencode -- 编码 URL 字符串

add a note add a note User Contributed Notes
Pawel dot Lesniak at ifmpan dot poznan dot pl
17-Aug-2006 06:04
How do I go and encode an URL, but EVERYTHING is encoded. As such:

This one does what you want

= '';
$output = '';
$tab_text = str_split($text);

foreach (
$tab_text as $id=>$char){
$hex = dechex(ord($char));
$output .= '%' . $hex;


martin at limitless dot co dot uk
24-Jul-2006 11:31
Each %xx represents a letter. You would need to remove %68%74%74%70%3a%2f%2f (http://) from the beginning.
regix11 [at] gmail [dot] com
05-Jun-2006 09:14
How do I go and encode an URL, but EVERYTHING is encoded. As such:



(note: I hand-url-encoded it)
Here is the URL-Encoded url, clickable (the http:// part shows up twice)
dbz at soli dot cl
21-Aug-2005 05:21
You should have named your form field "organization[]" (notice the square brackets), instead of just organization. When using square brackets, the get/post request is interpreted by PHP as an array.

If you follow this example you'll understand why it works the way it does:


= 92;
$organization = 93;

// The second asignment overwrites the value of the first
// asignment. $organization === 93.

$organization[] = 92;
$organization[] = 93;

// The above is interpreted as appending data to an array
// named "$organization". $organization is an array
// consisting of the values 92 AND 93.


When submitting form fields with appended square brackets to their name, PHP interprets the submission using the same logic exposed above. Thus PHP automatically creates an array with all selected options if "$organization[]" is used as the field name.

   Daniel Berstein.
dday at cnscorp dot com
25-Jun-2005 01:22
When using a multiple select on a form, I ran into a little issue of only receiving the last value form the select box.
I had a select box named organization_id with two values (92 and 93).
To get the values of both, I had to use the following:

   $temp_array = split("&", $_SERVER['QUERY_STRING']);
   foreach($temp_array as $key=>$value){
       if(substr($value, 0, 15) == "organization_id"){
           $_GET['organizations'][] = substr($value, 15, strlen($value));

this results in a $_GET array like this :

   [page] => idea_submission
   [organization_id] => 93
   [organizations] => Array
           [0] => =92
           [1] => =93

job oberio
15-Dec-2004 05:33
just want to share some tip:

my visitors usually type
in their browser (note: no www)
and i want them to automatically change the url
to use www.
(from to

The solution is:

you can add the ff code to your existing index.php script

if  ($HTTP_HOST=="")
header("Location:"); die();

your existing codes here ~~~


hope that helps
php at malaker dot com
17-Dec-2003 07:25
Following method do not show the URL in user browser (as the author claimed) if the code resides in the source page of  FRAME or IFRAME (say SRC="sourcepage.php") . In that case the URL of the SOURCE page is displayed.

$url = sprintf("%s%s%s","http://",$HTTP_HOST,$REQUEST_URI);
echo "$url";

Expected result: http://localhost/urltest/framedpage.php

Actual result: http://localhost/urltest/sourcepage.php
tappertzhofen at fdos dot de
24-Nov-2003 03:35
If you got a server which got only one subdomain and you can't add a subdomain you can easily create your own "subdomain script". You may create a file "index.php" or what ever your defaul filename is in the webpage root directory and add the following PHP Code:


// Get possible subdomain

$full_url = sprintf($HTTP_HOST);
$subdomain = "";

$i = 0;$i<=strlen($full_url);$i++)

$dummy = substr($full_url,$i,1);

$dummy == ".")

$subdomain = $subdomain.$dummy;


// Get Subdomain List

if ($subdomain <> "www")

$real_url = "";
$real_url = "";


header( "location: $real_url\r\n" );

chemanfit at hotmail
07-Jun-2003 08:24
just a side note to the above you will need to add the ?


ignacio paz posse
13-Mar-2003 09:31
Note on the above: the point is that is that using $_SERVER['QUERY_STRING'] along with $PHP_SELF we will have passed whatever variables are already appended (as they might be needed for database queries)

example, given the following url: http://www.your_domain/somepage.php?variable=1;

using $PHP_SELF" we are passing
[scheme]:(http://), [host]: www.your_domain/  and [path]: somepage.php

adding $_SERVER['QUERY_STRING'], we pass that, plus [query]: variable=1
13-Mar-2003 02:16
May be this is obvious but helps me since I found it:
If I want to append a variable to the url and pass it to the same page. ( in this example I'm using action=email to include an email form on the user click) i do:

// ...

<a href="<? echo $PHP_SELF,'?',$_SERVER['QUERY_STRING'],'&action=email' ?>">email to us</a>

// ...

/* somewhere in the the page (in my case at the bottom) I have: */

<? if ($action=='email') include('emailForm.htm'); ?>
jrg45 at pantheon dot yale dot edu
11-Jul-2002 05:14
Note that $_SERVER["HTTP_REFERER"] may not include GET data that was included in the referring address, depending on the browser.  So if you rely on GET variables to generate a page, it's not a good idea to use HTTP_REFERER to smoothly "bounce" someone back to the page he/she came from.
postmaster at asmatic dot ch
30-Apr-2002 12:15
If you want to get the filename requested on a global error page like a 404, just use this code...

// get the full var...

// part[1] is the url...
// part[0] is the http code (404, etc).
if(strpos($page,";")>0) {
   $pageParts = explode(";",$page);
   $page = $pageParts[1];

// get only the filename...
$page = basename($page);
stephane-wantiez at tiscalinet dot be
07-Feb-2002 10:29
if you do this, it will be easier :
echo "http://{$HTTP_HOST}{$REQUEST_URI}";
verdy_p at wanadoo dot fr
27-May-2001 01:47
Note also that the URL shown in $HTTP_REFERER is not always the URL of the web page where the user clicked to invoke the PHP script.
This may instead be a document of your own web site, which contains an HTML element whose one attribute references the script. Note also that the current page fragment (#anchor) may be transmitted or not with the URL, depending on the browser.
<FRAME src="your-page-script.php"8>
<IMAGE src="your-image-script.php">

In such case, browsers should transmit the URL of the container document, but some still persist in using the previous document in the browser history, and this could cause a different $HTTP_REFERER value be sent when the user comes back to the document referencing your script. If you wanna be sure that the actual current document or previous document in the history is sent, use client-side JavaScript to send it to your script:

<SCRIPT language="JavaScript"><!--
document.writeln('<FRAME src="your-page-script.php?js=1&amp;ref=' +
document.location + '">');
<FRAME src="your-page-script.php?js=0">

And then check the value of $js in your page script to generate appropriate content when the remote user agent does not support client-side scripts (such as most index/scan robots, some old or special simplified browsers, or browsers with JavaScript disabled by their users).
verdy_p at wanadoo dot fr
27-May-2001 12:55
Warning: when the PHP engine runs for your hosted web site, it may execute on a domain name which is completely different than the one the user requested in its browser. Many free web hosting site use proxies and/or multiple DNS entries for your hosted web site. This means that:
- the IP of the web server can change if multiple DNS entries are present (there may be several web servers running concurrently)
- reverse DNS name from the IP may give different domain name over time, or if the domain name is a CNAME only for a virtual web server hosting many domains
- the server running PHP may be different than the web server
- the web server may be hidden behind a proxy which balances the load between a farm of servers
- the queried host name in the HTTP headers may be different than the queried host name in the browser, if behind a redirecting proxy
- the actual path name of the ressource may be also different, with additional path elements: this is very common on free hosting servers, where you get a virtual CNAME domain, which gets translated by a proxy into an actual web server, and a domain-specific document root directory

So when thinking about using absolute path names you can retreive from PHP, beware that this may not be accurate to insert as absolute URL's in the HTML code built with PHP.

The best solution is then to ALWAYS USE relative URLs to reference documents and form scripts on your local server !

This applies to $PHP_SELF too, because it's an absolute pathname: don't use it directly but you can safely use basename($PHP_SELF) to reference your script within HTML forms:

<FORM method="GET" action="$self">
tumor at kkt dot bme dot hu
02-Apr-2000 02:18
To check if a URL is valid, try to fopen() it. If fopen() results an error (returns false), then PHP cannot open the URL you asked. This is usually because it is not valid...