parse_url

(PHP 4, PHP 5, PHP 7)

parse_url — 解析 URL，返回其组成部分

说明

parse_url ( string $url [, int $component = -1 ] ) : mixed

本函数解析一个 URL 并返回一个关联数组，包含在 URL 中出现的各种组成部分。

本函数不是用来验证给定 URL 的合法性的，只是将其分解为下面列出的部分。不完整的 URL 也被接受，parse_url() 会尝试尽量正确地将其解析。

参数

url

要解析的 URL。无效字符将使用 _ 来替换。

component

指定 PHP_URL_SCHEME、 PHP_URL_HOST、 PHP_URL_PORT、 PHP_URL_USER、 PHP_URL_PASS、 PHP_URL_PATH、 PHP_URL_QUERY 或 PHP_URL_FRAGMENT 的其中一个来获取 URL 中指定的部分的 string。 （除了指定为 PHP_URL_PORT 后，将返回一个 integer 的值）。

返回值

对严重不合格的 URL，parse_url() 可能会返回 FALSE。

如果省略了 component 参数，将返回一个关联数组 array，在目前至少会有一个元素在该数组中。数组中可能的键有以下几种：

  • scheme - 如 http
  • host
  • port
  • user
  • pass
  • path
  • query - 在问号 ? 之后
  • fragment - 在散列符号 # 之后

如果指定了 component 参数， parse_url() 返回一个 string （或在指定为 PHP_URL_PORT 时返回一个 integer）而不是 array。如果 URL 中指定的组成部分不存在，将会返回 NULL。

更新日志

版本 说明
5.4.7 修复了 host 在 协议 省略时的识别。
5.3.3 在 URL 解析失败时将不会产生 E_WARNING 级别的错误。
5.1.2 增加了参数 component。

范例

Example #1 parse_url() 例子

<?php
$url = 'http://username:password@hostname/path?arg=value#anchor';

print_r(parse_url($url));

echo parse_url($url, PHP_URL_PATH);
?>

以上例程会输出：

Array
(
    [scheme] => http
    [host] => hostname
    [user] => username
    [pass] => password
    [path] => /path
    [query] => arg=value
    [fragment] => anchor
)
/path

Example #2 parse_url() 解析丢失协议的例子

<?php
$url = '//www.example.com/path?googleguy=googley';

// 在 5.4.7 之前这会输出路径 "//www.example.com/path"
var_dump(parse_url($url));
?>

以上例程会输出：

array(3) {
  ["host"]=>
  string(15) "www.example.com"
  ["path"]=>
  string(5) "/path"
  ["query"]=>
  string(17) "googleguy=googley"
}

注释

Note:

本函数不能用于相对 URL。

Note:

parse_url() 是专门用来解析 URL 而不是 URI 的。不过为遵从 PHP 向后兼容的需要有个例外，对 file:// 协议允许三个斜线（file:///...）。其它任何协议都不能这样。

参见

User Contributed Notes

boctulus @ gmail co!m 27-Oct-2019 01:39
parse_url() does not parse some obvious errors so I made a complementary function

function url_check(string $url){
        $sym = null;
   
        $len = strlen($url);
        for ($i=0; $i<$len; $i++){
            if ($url[$i] == '?'){
                if ($sym == '?' || $sym == '&')
                    return false;
   
                $sym = '?';
            }elseif ($url[$i] == '&'){
                if ($sym === null)
                    return false;
   
                $sym = '&';
            }
        }
        return true;
    }
}
Michael 30-Jun-2019 06:52
There's a quirk where this function will return the host as the "path" if there is a leading space.

<?php

$url = ' https://foobar.com:80/mypath/myfile.php';

print_r(parse_url($url));
/*
Array
(
    [path] =>  https://foobar.com:80/mypath/myfile.php
)
*/

print_r(trim(parse_url($url)));
/*
Array
(
    [scheme] => https
    [host] => foobar.com
    [port] => 80
    [path] => /mypath/myfile.php
)
*/

?>
bramg dot net1 at gmail dot com 21-Sep-2018 10:07
this is my 404 error page is this ok  or it need improvements

<?php
/**
 * 404.php
 *
 * The template for displaying 404 pages (not found)
 *
 * @author    BetterStudio
 * @package   Publisher
 * @version   2.0.2
 */

get_header();

// Shows breadcrumb
if ( publisher_show_breadcrumb() ) {
    Better_Framework()->breadcrumb()->generate( array(
        'before'       => '<div class="container bf-breadcrumb-container">',
        'after'        => '</div>',
        'custom_class' => 'bc-top-style'
    ) );
}

?>
    <div class="content-wrap">
        <main <?php publisher_attr( 'content', '' ); ?>>

            <div class="container layout-1-col layout-no-sidebar">
                <div class="row main-section">

                    <div class="content-column content-404">

                        <div class="row first-row">

                            <div class="col-lg-12 text-404-section">
                                <p class="text-404 heading-typo">404</p>
                            </div>

                            <div class="col-lg-12 desc-section">
                                <h1 class="title-404"><?php publisher_translation_echo( '404_not_found' ); ?></h1>
                                <p><?php publisher_translation_echo( '404_not_found_message' ); ?></p>
                                <div class="action-links clearfix">

                                    <script type="text/javascript">
                                        if (document.referrer) {
                                            document.write('<div class="search-action-container"><a href="' + document.referrer + '"><i class="fa fa-angle-double-right"></i> <?php publisher_translation_echo( '404_go_previous_page' ); ?></a></div>');
                                        }
                                    </script>

                                    <div class="search-action-container">
                                        <a href="<?php echo esc_url( home_url( '/' ) ); ?>"><i
                                                    class="fa fa-angle-double-right"></i> <?php publisher_translation_echo( '404_go_homepage' ); ?>
                                        </a>
                                    </div>
                                </div>
                            </div>

                        </div><!-- .first-row -->

                        <div class="row second-row">
                            <div class="col-lg-12">
                                <div class="top-line">
                                    <?php get_search_form(); ?>
                                </div>
                            </div>
                        </div><!-- .second-row -->

                    </div><!-- .content-column -->

                </div><!-- .main-section -->
            </div> <!-- .layout-1-col -->

        </main><!-- main -->
    </div><!-- .content-wrap -->

<?php get_footer(); ?>

https://bramg.net
Anonymous 26-Feb-2018 12:33
Hello, for some odd reason, parse_url returns the host (ex. example.com) as the path when no scheme is provided in the input url. So I've written a quick function to get the real host:

<?php
function getHost($Address) {
   $parseUrl = parse_url(trim($Address));
   return trim($parseUrl[host] ? $parseUrl[host] : array_shift(explode('/', $parseUrl[path], 2)));
}

getHost("example.com"); // Gives example.com
getHost("http://example.com"); // Gives example.com
getHost("www.example.com"); // Gives www.example.com
getHost("http://example.com/xyz"); // Gives example.com
?>

You could try anything! It gives the host (including the subdomain if exists).

Hope it helped you.
https://vb.3dlat.com/
Anonymous 30-Dec-2017 07:47
This function will attempt to parse relative URLs but relaying on it can produce unexpected behavior that can cause some hard to track bugs. (The following results are obtained from PHP 5.5.19)

Attempting to parse a url like this
http://example.com/entities/GOA:98/?search=8989157d1f22
Correctly produces
<?php
array (
  'scheme' => 'http',
  'host' => 'example.com',
  'path' => '/entities/GOA:98/',
  'query' => 'search=8989157d1f22',
);
?>

However, Attempting to parse the relative URL
entities/GOA:98/?search=8989157d1f22
<?php
array (
  'host' => 'entities',
  'port' => 98,
  'path' => '/GOA:98/',
  'query' => 'search=8989157d1f22',
)
?>
If I change :98 to :A98 parse_url parses the URL correctly as
<?php
array (
  'path' => 'entities/GOA:A98/',
  'query' => 'search=8989157d1f22',
)
?>
Bottom line, Avoid using parse_url for relative urls unless you have tested the expected input and you know parse_url will handle them well.

https://forums.hawacastle.com/
Anonymous 03-Oct-2017 07:29
To get the params (url query) as Associative array, use this function:

<?php
/**
* Returns the url query as associative array
*
* @param    string    query
* @return    array    params
*/
function convertUrlQuery($query) {
    $queryParts = explode('&', $query);
   
    $params = array();
    foreach ($queryParts as $param) {
        $item = explode('=', $param);
        $params[$item[0]] = $item[1];
    }
   
    return $params;
}
?>
demerit 09-Aug-2017 12:06
There is a change in PHP 7 (I noticed it in 7.1 upgrading from 5.3) where if the password portion has an octothorpe (#) in it, parsing fails in 7.1, whereas it succeeds in 5.3.
zappascripts at gmail com 17-Jul-2017 01:30
Here's a simple class I made that makes use of this parse_url.
I needed a way for a page to retain get parameters but also edit or add onto them.
I also had some pages that needed the same GET paramaters so I also added a way to change the path.

<?php
class Paths{

    private $url;
    public function __construct($url){
        $this->url = parse_url($url);
    }
   
    public function returnUrl(){
        $return = $this->url['path'].'?'.$this->url['query'];
        $return = (substr($return,-1) == "&")? substr($return,0,-1) : $return;
        $this->resetQuery();
        return $return;
    }
   
    public function changePath($path){
        $this->url['path'] = $path;
    }
   
    public function editQuery($get,$value){
        $parts = explode("&",$this->url['query']);
        $return = "";
        foreach($parts as $p){
            $paramData = explode("=",$p);
            if($paramData[0] == $get){
                $paramData[1] = $value;
            }
            $return .= implode("=",$paramData).'&';
           
        }
       
        $this->url['query'] = $return;
    }
   
    public function addQuery($get,$value){
        $part = $get."=".$value;
        $and = ($this->url['query'] == "?") ? "" : "&";
        $this->url['query'] .= $and.$part;
    }
   
    public function checkQuery($get){
        $parts = explode("&",$this->url['query']);
       
            foreach($parts as $p){
                $paramData = explode("=",$p);
                if($paramData[0] == $get)
                    return true;
            }
            return false;
       
    }
   
    public function buildQuery($get,$value){
        if($this->checkQuery($get))
            $this->editQuery($get,$value);
        else
            $this->addQuery($get,$value);
       
    }
   
    public function resetQuery(){
        $this->url = parse_url($_SERVER['REQUEST_URI']);
    }
   
   
   

}
?>

Useage:

Test.php?foo=1:

<?php
$path = new Paths($_SERVER['REQUEST_URI']);
$path->changePath("/baz.php");
$path->buildQuery("foo",2);
$path->buildQuery("bar",3);
echo $path->returnUrl();
?>

returns: /baz.php?foo=2&bar=3   

Hope this is of some use to someone!
mys5droid at gmail dot com 20-Mar-2016 12:30
I have coded a function which converts relative URL to absolute URL for a project of mine. Considering I could not find it elsewhere, I figured I would post it here.

The following function takes in 2 parameters, the first parameter is the URL you want to convert from relative to absolute, and the second parameter is a sample of the absolute URL.

Currently it does not resolve '../' in the URL, only because I do not need it. Most webservers will resolve this for you. If you want it to resolve the '../' in the path, it just takes minor modifications.

<?php

function relativeToAbsolute($inurl, $absolute) {
    // Get all parts so not getting them multiple times :)
    $absolute_parts = parse_url($absolute);   
    // Test if URL is already absolute (contains host, or begins with '/')
    if ( (strpos($inurl, $absolute_parts['host']) == false) ) {
        // Define $tmpurlprefix to prevent errors below
        $tmpurlprefix = "";
        // Formulate URL prefix    (SCHEME)                   
        if (!(empty($absolute_parts['scheme']))) {
            // Add scheme to tmpurlprefix
            $tmpurlprefix .= $absolute_parts['scheme'] . "://";
        }
        // Formulate URL prefix (USER, PASS)   
        if ((!(empty($absolute_parts['user']))) and (!(empty($absolute_parts['pass'])))) {
            // Add user:port to tmpurlprefix
            $tmpurlprefix .= $absolute_parts['user'] . ":" . $absolute_parts['pass'] . "@";   
        }
        // Formulate URL prefix    (HOST, PORT)   
        if (!(empty($absolute_parts['host']))) {
            // Add host to tmpurlprefix
            $tmpurlprefix .= $absolute_parts['host'];
            // Check for a port, add if exists
            if (!(empty($absolute_parts['port']))) {
                // Add port to tmpurlprefix
                $tmpurlprefix .= ":" . $absolute_parts['port'];
            }
        }
        // Formulate URL prefix    (PATH) and only add it if the path to image does not include ./   
        if ( (!(empty($absolute_parts['path']))) and (substr($inurl, 0, 1) != '/') ) {
            // Get path parts
            $path_parts = pathinfo($absolute_parts['path']);
            // Add path to tmpurlprefix
            $tmpurlprefix .= $path_parts['dirname'];
            $tmpurlprefix .= "/";
        }
        else {   
            $tmpurlprefix .= "/";   
        }   
        // Lets remove the '/'
        if (substr($inurl, 0, 1) == '/') { $inurl = substr($inurl, 1); }   
        // Lets remove the './'
        if (substr($inurl, 0, 2) == './') { $inurl = substr($inurl, 2); }   
        return $tmpurlprefix . $inurl;
    }   
    else {
        // Path is already absolute. Return it :)
        return $inurl;
    }
}

// Define a sample absolute  URL
$absolute = "http://" . "user:pass@example.com:8080/path/to/index.html"; // Just evading php.net spam filter, not sure how example.com is spam...

/* EXAMPLE 1 */
echo relativeToAbsolute($absolute, $absolute) . "\n";
/* EXAMPLE 2 */
echo relativeToAbsolute("img.gif", $absolute) . "\n";
/* EXAMPLE 3 */
echo relativeToAbsolute("/img.gif", $absolute) . "\n";
/* EXAMPLE 4 */
echo relativeToAbsolute("./img.gif", $absolute) . "\n";
/* EXAMPLE 5 */
echo relativeToAbsolute("../img.gif", $absolute) . "\n";
/* EXAMPLE 6 */
echo relativeToAbsolute("images/img.gif", $absolute) . "\n";
/* EXAMPLE 7 */
echo relativeToAbsolute("/images/img.gif", $absolute) . "\n";
/* EXAMPLE 8 */
echo relativeToAbsolute("./images/img.gif", $absolute) . "\n";
/* EXAMPLE 9 */
echo relativeToAbsolute("../images/img.gif", $absolute) . "\n";

?>

OUTPUTS:
http :// user:pass@example.com:8080/path/to/index.html
http :// user:pass@example.com:8080/path/to/img.gif
http :// user:pass@example.com:8080/img.gif
http :// user:pass@example.com:8080/path/to/img.gif
http :// user:pass@example.com:8080/path/to/../img.gif
http :// user:pass@example.com:8080/path/to/images/img.gif
http :// user:pass@example.com:8080/images/img.gif
http :// user:pass@example.com:8080/path/to/images/img.gif
http :// user:pass@example.com:8080/path/to/../images/img.gif

Sorry if the above code is not your style, or if you see it as "messy" or you think there is a better way to do it. I removed as much of the white space as possible.

Improvements are welcome :)
Rob 21-Apr-2015 12:27
I've been working on a generic class that would make URI parsing / building a little easier.

The composer package is here: https://packagist.org/packages/enrise/urihelper

And the repository is here: https://github.com/Enrise/UriHelper

An example of the usage:

<?php
$uri = new \Enrise\Uri('http://usr:pss@example.com:81/mypath/myfile.html?a=b&b[]=2&b[]=3#myfragment');
echo $uri->getScheme(); // http
echo $uri->getUser(); // usr
echo $uri->getPass(); // pss
echo $uri->getHost(); // example.com
echo $uri->getPort(); // 81
echo $uri->getPath(); // /mypath/myfile.html
echo $uri->getQuery(); // a=b&b[]=2&b[]=3
echo $uri->getFragment(); // myfragment
echo $uri->isSchemeless(); // false
echo $uri->isRelative(); // false

$uri->setScheme('scheme:child:scheme.VALIDscheme123:');
$uri->setPort(null);

echo $uri->getUri(); //scheme:child:scheme.VALIDscheme123:usr:pss@example.com/mypath/myfile.html?a=b&b[]=2&b[]=3#myfragment
?>
jerome at chaman dot ca 16-Jan-2015 10:53
It may be worth reminding that the value of the #fragment never gets sent to the server.  Anchors processing is exclusively client-side.
admin at griefer1999 dot uhostfull dot com 06-Jan-2015 06:46
<?php
function url_parse($url){
$sflfdfldf=$url;
if(strpos($url,"?")>-1){
$a=explode("?",$url,2);
$url=$a[0];
$query=$a[1];
}
if(strpos($url,"://")>-1){
$scheme=substr($url,0,strpos($url,"//")-1);
$url=substr($url,strpos($url,"//")+2,strlen($url));
}
if(strpos($url,"/")>-1){
$a=explode("/",$url,2);
$url=$a[0];
$path="/".$a[1];
}
if(strpos($url,":")>-1){
$a=explode(":",$url,2);
$url=$a[0];
$port=$a[1];
}
$host=$url;
$url=null;
foreach(array("url","scheme","host","port","path","query") as $var){
if(!empty($$var)){
$return[$var]=$$var;
}
}
//return array("url"=>$sflfdfldf,"scheme"=>$scheme,"host"=>$host,"port"=>$port,"path"=>$path,"query"=>$query,"a"=>$url);
return $return;
}
?>

<?php
/* Compare two outputs */
//mine
print_r(url_parse("http://login.yahoo.com?.src=ym&.intl=gb&.lang=zh-Hans-HK&.done=https://mail.yahoo.com"));
//internal
print_r(parse_url("http://login.yahoo.com?.src=ym&.intl=gb&.lang=zh-Hans-HK&.done=https://mail.yahoo.com"));
?>
lauris () lauris ! lv 09-Apr-2014 08:49
Here is utf-8 compatible parse_url() replacement function based on "laszlo dot janszky at gmail dot com" work. Original incorrectly handled URLs with user:pass. Also made PHP 5.5 compatible (got rid of now deprecated regex /e modifier).

<?php

    /**
     * UTF-8 aware parse_url() replacement.
     *
     * @return array
     */
    function mb_parse_url($url)
    {
        $enc_url = preg_replace_callback(
            '%[^:/@?&=#]+%usD',
            function ($matches)
            {
                return urlencode($matches[0]);
            },
            $url
        );
       
        $parts = parse_url($enc_url);
       
        if($parts === false)
        {
            throw new \InvalidArgumentException('Malformed URL: ' . $url);
        }
       
        foreach($parts as $name => $value)
        {
            $parts[$name] = urldecode($value);
        }
       
        return $parts;
    }

?>
ivijan dot stefan at gmail dot com 26-Mar-2014 04:49
Here's a good way to using parse_url () gets the youtube link.
This function I used in many works:

<?php
function youtube($url, $width=560, $height=315, $fullscreen=true)
{
    parse_str( parse_url( $url, PHP_URL_QUERY ), $my_array_of_vars );
    $youtube= '<iframe allowtransparency="true" scrolling="no" width="'.$width.'" height="'.$height.'" src="//www.youtube.com/embed/'.$my_array_of_vars['v'].'" frameborder="0"'.($fullscreen?' allowfullscreen':NULL).'></iframe>';
    return $youtube;
}

// show youtube on my page
$url='http://www.youtube.com/watch?v=yvTd6XxgCBE';
 youtube($url, 560, 315, true);
?>

parse_url () allocates a unique youtube code and  put into iframe link and displayed on your page. The size of the videos choose yourself.

Enjoy.
utilmind 01-Jul-2013 12:06
parse_url doesn't works if the protocol doesn't specified. This seems like sandard, even the youtube doesn't gives the protocol name when generates code for embedding which have a look like "//youtube.com/etc".

So, to avoid bug, you must always check, whether the provided url has the protocol, and if not (starts with 2 slashes) -- add the "http:" prefix.
laszlo dot janszky at gmail dot com 24-May-2012 08:20
Created another parse_url utf-8 compatible function.
<?php
function mb_parse_url($url) {
    $encodedUrl = preg_replace('%[^:/?#&=\.]+%usDe', 'urlencode(\'$0\')', $url);
    $components = parse_url($encodedUrl);
    foreach ($components as &$component)
        $component = urldecode($component);
    return $components;
}
?>
therselman at gmail 28-Jan-2012 01:03
UTF-8 aware parse_url() replacement.

I've realized that even though UTF-8 characters are not allowed in URL's, I have to work with a lot of them and parse_url() will break.

Based largely on the work of "mallluhuct at gmail dot com", I added parse_url() compatible "named values" which makes the array values a lot easier to work with (instead of just numbers). I also implemented detection of port, username/password and a back-reference to better detect URL's like this: //en.wikipedia.com
... which, although is technically an invalid URL, it's used extensively on sites like wikipedia in the href of anchor tags where it's valid in browsers (one of the types of URL's you have to support when crawling pages). This will be accurately detected as the host name instead of "path" as in all other examples.

I will submit my complete function (instead of just the RegExp) which is an almost "drop-in" replacement for parse_url(). It returns a cleaned up array (or false) with values compatible with parse_url(). I could have told the preg_match() not to store the unused extra values, but it would complicate the RegExp and make it more difficult to read, understand and extend. The key to detecting UTF-8 characters is the use of the "u" parameter in preg_match().

<?php
function parse_utf8_url($url)
{
    static $keys = array('scheme'=>0,'user'=>0,'pass'=>0,'host'=>0,'port'=>0,'path'=>0,'query'=>0,'fragment'=>0);
    if (is_string($url) && preg_match(
            '~^((?P<scheme>[^:/?#]+):(//))?((\\3|//)?(?:(?P<user>[^:]+):(?P<pass>[^@]+)@)?(?P<host>[^/?:#]*))(:(?P<port>\\d+))?' .
            '(?P<path>[^?#]*)(\\?(?P<query>[^#]*))?(#(?P<fragment>.*))?~u', $url, $matches))
    {
        foreach ($matches as $key => $value)
            if (!isset($keys[$key]) || empty($value))
                unset($matches[$key]);
        return $matches;
    }
    return false;
}
?>

UTF-8 URL's can/should be "normalized" after extraction with this function.
thomas at gielfeldt dot com 02-Dec-2011 02:50
[If you haven't yet] been able to find a simple conversion back to string from a parsed url, here's an example:

<?php

$url = 'http://usr:pss@example.com:81/mypath/myfile.html?a=b&b[]=2&b[]=3#myfragment';
if ($url === unparse_url(parse_url($url))) {
  print "YES, they match!\n";
}

function unparse_url($parsed_url) {
  $scheme   = isset($parsed_url['scheme']) ? $parsed_url['scheme'] . '://' : '';
  $host     = isset($parsed_url['host']) ? $parsed_url['host'] : '';
  $port     = isset($parsed_url['port']) ? ':' . $parsed_url['port'] : '';
  $user     = isset($parsed_url['user']) ? $parsed_url['user'] : '';
  $pass     = isset($parsed_url['pass']) ? ':' . $parsed_url['pass']  : '';
  $pass     = ($user || $pass) ? "$pass@" : '';
  $path     = isset($parsed_url['path']) ? $parsed_url['path'] : '';
  $query    = isset($parsed_url['query']) ? '?' . $parsed_url['query'] : '';
  $fragment = isset($parsed_url['fragment']) ? '#' . $parsed_url['fragment'] : '';
  return "$scheme$user$pass$host$port$path$query$fragment";
}

?>
jesse at example dot com 25-Sep-2010 07:48
@ solenoid: Your code was very helpful, but it fails when the current URL has no query string (it appends '&' instead of '?' before the query).  Below is a fixed version that catches this edge case and corrects it.

<?php
function modify_url($mod)
{
    $url = "http://".$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];
    $query = explode("&", $_SERVER['QUERY_STRING']);
    if (!$_SERVER['QUERY_STRING']) {$queryStart = "?";} else {$queryStart = "&";}
    // modify/delete data
    foreach($query as $q)
    {
        list($key, $value) = explode("=", $q);
        if(array_key_exists($key, $mod))
        {
            if($mod[$key])
            {
                $url = preg_replace('/'.$key.'='.$value.'/', $key.'='.$mod[$key], $url);
            }
            else
            {
                $url = preg_replace('/&?'.$key.'='.$value.'/', '', $url);
            }
        }
    }
    // add new data
    foreach($mod as $key => $value)
    {
        if($value && !preg_match('/'.$key.'=/', $url))
        {
            $url .= $queryStart.$key.'='.$value;
        }
    }
    return $url;
}
?>
solenoid at example dot com 22-Apr-2010 04:05
Here's a piece of code that modifies, replaces or removes the url query. This can typically used in paging situations where there are more parameters than the page.

<?php
function modify_url($mod)
{
    $url = "http://".$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];
    $query = explode("&", $_SERVER['QUERY_STRING']);
    // modify/delete data
    foreach($query as $q)
    {
        list($key, $value) = explode("=", $q);
        if(array_key_exists($key, $mod))
        {
            if($mod[$key])
            {
                $url = preg_replace('/'.$key.'='.$value.'/', $key.'='.$mod[$key], $url);
            }
            else
            {
                $url = preg_replace('/&?'.$key.'='.$value.'/', '', $url);
            }
        }
    }
    // add new data
    foreach($mod as $key => $value)
    {
        if($value && !preg_match('/'.$key.'=/', $url))
        {
            $url .= '&'.$key.'='.$value;
        }
    }
    return $url;
}

// page url: "http://www.example.com/page.php?p=5&show=list&style=23"

$url = modify_url(array('p' => 4, 'show' => 'column'));

// $url = "http://www.example.com/page.php?p=4&show=column&style=23"
?>
james at roundeights dot com 26-Feb-2010 11:24
I was writing unit tests and needed to cause this function to kick out an error and return FALSE in order to test a specific execution path. If anyone else needs to force a failure, the following inputs will work:

<?php
parse_url("http:///example.com");
parse_url("http://:80");
parse_url("http://user@:80");
?>
need_sunny at yahoo dot com 25-Dec-2009 05:57
Thanks to xellisx for his parse_query function. I used it in one of my projects and it works well. But it has an error. I fixed the error and improved it a little bit. Here is my version of it:

<?php
// Originally written by xellisx
function parse_query($var)
 {
  /**
   *  Use this function to parse out the query array element from
   *  the output of parse_url().
   */
  $var  = parse_url($var, PHP_URL_QUERY);
  $var  = html_entity_decode($var);
  $var  = explode('&', $var);
  $arr  = array();

  foreach($var as $val)
   {
    $x          = explode('=', $val);
    $arr[$x[0]] = $x[1];
   }
  unset($val, $x, $var);
  return $arr;
 }
?>

At the first line there was parse_query($val), I made it $var. It used to return a null array before this fix.

I have added the parse_url line. So now the function will only focus in the query part, not the whole URL. This is useful if something like below is done:
<?php
$my_GET = parse_query($_SERVER['REQUEST_URI']);
?>
nirazuelos at gmail dot com 09-Oct-2009 02:45
Hello, for some odd reason, parse_url returns the host (ex. example.com) as the path when no scheme is provided in the input url. So I've written a quick function to get the real host:

<?php
function getHost($Address) {
   $parseUrl = parse_url(trim($Address));
   return trim($parseUrl[host] ? $parseUrl[host] : array_shift(explode('/', $parseUrl[path], 2)));
}

getHost("example.com"); // Gives example.com
getHost("http://example.com"); // Gives example.com
getHost("www.example.com"); // Gives www.example.com
getHost("http://example.com/xyz"); // Gives example.com
?>

You could try anything! It gives the host (including the subdomain if exists).

Hope it helped you.
ap dot public1 at gmail dot com 14-Jul-2009 08:36
Simple static library that allows easy manipulation of url parameters:

<?php
    /**
     * File provides easy way to manipulate url parameters
     * @author Alexander Podgorny
     */

    class Url {
        /**
         * Splits url into array of it's pieces as follows:
         * [scheme]://[user]:[pass]@[host]/[path]?[query]#[fragment]
         * In addition it adds 'query_params' key which contains array of
         * url-decoded key-value pairs
         *
         * @param String $sUrl Url
         * @return Array Parsed url pieces
         */
        public static function explode($sUrl) {
            $aUrl = parse_url($sUrl);
            $aUrl['query_params'] = array();
            $aPairs = explode('&', $aUrl['query']);
            DU::show($aPairs);
            foreach($aPairs as $sPair) {
                if (trim($sPair) == '') { continue; }
                list($sKey, $sValue) = explode('=', $sPair);
                $aUrl['query_params'][$sKey] = urldecode($sValue);
            }
            return $aUrl;
        }
        /**
         * Compiles url out of array of it's pieces (returned by explodeUrl)
         * 'query' is ignored if 'query_params' is present
         *
         * @param Array $aUrl Array of url pieces
         */
        public static function implode($aUrl) {
            //[scheme]://[user]:[pass]@[host]/[path]?[query]#[fragment]
           
            $sQuery = '';
           
            // Compile query
            if (isset($aUrl['query_params']) && is_array($aUrl['query_params'])) {
                $aPairs = array();
                foreach ($aUrl['query_params'] as $sKey=>$sValue) {
                    $aPairs[] = $sKey.'='.urlencode($sValue);              
                }
                $sQuery = implode('&', $aPairs);   
            } else {
                $sQuery = $aUrl['query'];
            }
           
            // Compile url
            $sUrl =
                $aUrl['scheme'] . '://' . (
                    isset($aUrl['user']) && $aUrl['user'] != '' && isset($aUrl['pass'])
                       ? $aUrl['user'] . ':' . $aUrl['pass'] . '@'
                       : ''
                ) .
                $aUrl['host'] . (
                    isset($aUrl['path']) && $aUrl['path'] != ''
                       ? $aUrl['path']
                       : ''
                ) . (
                   $sQuery != ''
                       ? '?' . $sQuery
                       : ''
                ) . (
                   isset($aUrl['fragment']) && $aUrl['fragment'] != ''
                       ? '#' . $aUrl['fragment']
                       : ''
                );
            return $sUrl;
        }
        /**
         * Parses url and returns array of key-value pairs of url params
         *
         * @param String $sUrl
         * @return Array
         */
        public static function getParams($sUrl) {
            $aUrl = self::explode($sUrl);
            return $aUrl['query_params'];
        }
        /**
         * Removes existing url params and sets them to those specified in $aParams
         *
         * @param String $sUrl Url
         * @param Array $aParams Array of Key-Value pairs to set url params to
         * @return  String Newly compiled url
         */
        public static function setParams($sUrl, $aParams) {
            $aUrl = self::explode($sUrl);
            $aUrl['query'] = '';
            $aUrl['query_params'] = $aParams;
            return self::implode($aUrl);
        }
        /**
         * Updates values of existing url params and/or adds (if not set) those specified in $aParams
         *
         * @param String $sUrl Url
         * @param Array $aParams Array of Key-Value pairs to set url params to
         * @return  String Newly compiled url
         */
        public static function updateParams($sUrl, $aParams) {
            $aUrl = self::explode($sUrl);
            $aUrl['query'] = '';
            $aUrl['query_params'] = array_merge($aUrl['query_params'], $aParams);
            return self::implode($aUrl);
        }
    }

?>
vdklah at hotmail dot com 17-Oct-2008 02:53
Some example that determines the URL port.
When port not specified, it derives it from the scheme.

<?php
function getUrlPort( $urlInfo )
{
    if( isset($urlInfo['port']) ) {
        $port = $urlInfo['port'];
    } else { // no port specified; get default port
        if (isset($urlInfo['scheme']) ) {
            switch( $urlInfo['scheme'] ) {
                case 'http':
                    $port = 80; // default for http
                    break;
                case 'https':
                    $port = 443; // default for https
                    break;
                case 'ftp':
                    $port = 21; // default for ftp
                    break;
                case 'ftps':
                    $port = 990; // default for ftps
                    break;
                default:
                    $port = 0; // error; unsupported scheme
                    break;
            }
        } else {
            $port = 0; // error; unknown scheme
        }
    }
    return $port;
}

$url = "http://nl3.php.net/manual/en/function.parse-url.php";
$urlInfo = parse_url( $url );
$urlPort = getUrlPort( $urlInfo );
if( $urlPort !== 0 ) {
    print 'Found URL port: '.$urlPort;
} else {
    print 'ERROR: Could not find port at URL: '.$url;
}
?>
xellisx 01-Oct-2008 08:37
I need to parse out the query string from the referrer, so I created this function.

<?php
function parse_query($val)
 {
  /**
   *  Use this function to parse out the query array element from
   *  the output of parse_url().
   */
  $var  = html_entity_decode($var);
  $var  = explode('&', $var);
  $arr  = array();

  foreach($var as $val)
   {
    $x          = explode('=', $val);
    $arr[$x[0]] = $x[1];
   }
  unset($val, $x, $var);
  return $arr;
 }
?>
nospam at spellingcow dot com 08-Sep-2008 02:03
URL's in the query string of a relative URL will cause a problem

fails:
/page.php?foo=bar&url=http://www.example.com

parses:
http://www.foo.com/page.php?foo=bar&url=http://www.example.com
to1ne at hotmail dot com 13-Jun-2008 11:01
Based on the idea of "jbr at ya-right dot com" have I been working on a new function to parse the url:

<?php
function parseUrl($url) {
    $r  = "^(?:(?P<scheme>\w+)://)?";
    $r .= "(?:(?P<login>\w+):(?P<pass>\w+)@)?";
    $r .= "(?P<host>(?:(?P<subdomain>[\w\.]+)\.)?" . "(?P<domain>\w+\.(?P<extension>\w+)))";
    $r .= "(?::(?P<port>\d+))?";
    $r .= "(?P<path>[\w/]*/(?P<file>\w+(?:\.\w+)?)?)?";
    $r .= "(?:\?(?P<arg>[\w=&]+))?";
    $r .= "(?:#(?P<anchor>\w+))?";
    $r = "!$r!";                                                // Delimiters
   
    preg_match ( $r, $url, $out );
   
    return $out;
}
print_r ( parseUrl ( 'me:you@sub.site.org:29000/pear/validate.html?happy=me&sad=you#url' ) );
?>

This returns:
Array
(
    [0] => me:you@sub.site.org:29000/pear/validate.html?happy=me&sad=you#url
    [scheme] =>
    [1] =>
    [login] => me
    [2] => me
    [pass] => you
    [3] => you
    [host] => sub.site.org
    [4] => sub.site.org
    [subdomain] => sub
    [5] => sub
    [domain] => site.org
    [6] => site.org
    [extension] => org
    [7] => org
    [port] => 29000
    [8] => 29000
    [path] => /pear/validate.html
    [9] => /pear/validate.html
    [file] => validate.html
    [10] => validate.html
    [arg] => happy=me&sad=you
    [11] => happy=me&sad=you
    [anchor] => url
    [12] => url
)

So both named and numbered array keys are possible.

It's quite advanced, but I think it works in any case... Let me know if it doesn't...
spam at paulisageek dot com 08-Aug-2007 12:05
In reply to adrian,

Thank you very much for your function. There is a small issue with your relative protocol function. You need to remove the // when making the url the path. Here is the new function.

function resolve_url($base, $url) {
        if (!strlen($base)) return $url;
        // Step 2
        if (!strlen($url)) return $base;
        // Step 3
        if (preg_match('!^[a-z]+:!i', $url)) return $url;
        $base = parse_url($base);
        if ($url{0} == "#") {
                // Step 2 (fragment)
                $base['fragment'] = substr($url, 1);
                return unparse_url($base);
        }
        unset($base['fragment']);
        unset($base['query']);
        if (substr($url, 0, 2) == "//") {
                // Step 4
                return unparse_url(array(
                        'scheme'=>$base['scheme'],
                        'path'=>substr($url,2),
                ));
        } else if ($url{0} == "/") {
                // Step 5
                $base['path'] = $url;
        } else {
                // Step 6
                $path = explode('/', $base['path']);
                $url_path = explode('/', $url);
                // Step 6a: drop file from base
                array_pop($path);
                // Step 6b, 6c, 6e: append url while removing "." and ".." from
                // the directory portion
                $end = array_pop($url_path);
                foreach ($url_path as $segment) {
                        if ($segment == '.') {
                                // skip
                        } else if ($segment == '..' && $path && $path[sizeof($path)-1] != '..') {
                                array_pop($path);
                        } else {
                                $path[] = $segment;
                        }
                }
                // Step 6d, 6f: remove "." and ".." from file portion
                if ($end == '.') {
                        $path[] = '';
                } else if ($end == '..' && $path && $path[sizeof($path)-1] != '..') {
                        $path[sizeof($path)-1] = '';
                } else {
                        $path[] = $end;
                }
                // Step 6h
                $base['path'] = join('/', $path);

        }
        // Step 7
        return unparse_url($base);
}
adrian-php at sixfingeredman dot net 25-Jul-2007 02:58
Here's a function which implements resolving a relative URL according to RFC 2396 section 5.2. No doubt there are more efficient implementations, but this one tries to remain close to the standard for clarity. It relies on a function called "unparse_url" to implement section 7, left as an exercise for the reader (or you can substitute the "glue_url" function posted earlier).

<?php
/**
 * Resolve a URL relative to a base path. This happens to work with POSIX
 * filenames as well. This is based on RFC 2396 section 5.2.
 */
function resolve_url($base, $url) {
        if (!strlen($base)) return $url;
        // Step 2
        if (!strlen($url)) return $base;
        // Step 3
        if (preg_match('!^[a-z]+:!i', $url)) return $url;
        $base = parse_url($base);
        if ($url{0} == "#") {
                // Step 2 (fragment)
                $base['fragment'] = substr($url, 1);
                return unparse_url($base);
        }
        unset($base['fragment']);
        unset($base['query']);
        if (substr($url, 0, 2) == "//") {
                // Step 4
                return unparse_url(array(
                        'scheme'=>$base['scheme'],
                        'path'=>$url,
                ));
        } else if ($url{0} == "/") {
                // Step 5
                $base['path'] = $url;
        } else {
                // Step 6
                $path = explode('/', $base['path']);
                $url_path = explode('/', $url);
                // Step 6a: drop file from base
                array_pop($path);
                // Step 6b, 6c, 6e: append url while removing "." and ".." from
                // the directory portion
                $end = array_pop($url_path);
                foreach ($url_path as $segment) {
                        if ($segment == '.') {
                                // skip
                        } else if ($segment == '..' && $path && $path[sizeof($path)-1] != '..') {
                                array_pop($path);
                        } else {
                                $path[] = $segment;
                        }
                }
                // Step 6d, 6f: remove "." and ".." from file portion
                if ($end == '.') {
                        $path[] = '';
                } else if ($end == '..' && $path && $path[sizeof($path)-1] != '..') {
                        $path[sizeof($path)-1] = '';
                } else {
                        $path[] = $end;
                }
                // Step 6h
                $base['path'] = join('/', $path);

        }
        // Step 7
        return unparse_url($base);
}
?>