urlencode

(PHP 4, PHP 5, PHP 7)

urlencode — URL-encodes string

Description

string urlencode ( string $str )

This function is convenient when encoding a string to be used in a query part of a URL, as a convenient way to pass variables to the next page.

Parameters

str: The string to be encoded.

Return Values

Returns a string in which all non-alphanumeric characters except -_. have been replaced with a percent (%) sign followed by two hex digits and spaces encoded as plus (+) signs. It is encoded the same way that the posted data from a WWW form is encoded, that is the same way as in application/x-www-form-urlencoded media type. This differs from the » RFC 3986 encoding (see rawurlencode()) in that for historical reasons, spaces are encoded as plus (+) signs.

Examples

Example #1 urlencode() example


<?php
echo '<a href="mycgi?foo=', urlencode($userinput), '">';
?>

Example #2 urlencode() and htmlentities() example


<?php
$query_string = 'foo=' . urlencode($foo) . '&bar=' . urlencode($bar);
echo '<a href="mycgi?' . htmlentities($query_string) . '">';
?>

Notes

Note:
Be careful about variables that may match HTML entities. Things like &amp, &copy and &pound are parsed by the browser and the actual entity is used instead of the desired variable name. This is an obvious hassle that the W3C has been telling people about for years. The reference is here: » http://www.w3.org/TR/html4/appendix/notes.html#h-B.2.2.

PHP supports changing the argument separator to the W3C-suggested semi-colon through the arg_separator .ini directive. Unfortunately most user agents do not send form data in this semi-colon separated format. A more portable way around this is to use & instead of & as the separator. You don't need to change PHP's arg_separator for this. Leave it as &, but simply encode your URLs using htmlentities() or htmlspecialchars().

User Contributed Notes

davis dot peixoto at gmail dot com

5 years ago


urlencode function and rawurlencode are mostly based on RFC 1738.

However, since 2005 the current RFC in use for URIs standard is RFC 3986.

Here is a function to encode URLs according to RFC 3986.

<?php
function myUrlEncode($string) {
    $entities = array('%21', '%2A', '%27', '%28', '%29', '%3B', '%3A', '%40', '%26', '%3D', '%2B', '%24', '%2C', '%2F', '%3F', '%25', '%23', '%5B', '%5D');
    $replacements = array('!', '*', "'", "(", ")", ";", ":", "@", "&", "=", "+", "$", ",", "/", "?", "%", "#", "[", "]");
    return str_replace($entities, $replacements, urlencode($string));
}
?>

leaksin [ at ] gmail [ dot ] com

3 years ago


"cleaning the URL",Totally and in a nut shell:
1.You must use rawurlencode() for parts that come before "?" 
2.Use urlencode for all GET parameters (values that come after each "=")(POST parameters are automatically encoded).
3.Use htmlspecialchars for HTML tag parameters and HTML text content

<?php
$url_page = 'example/page/url.php';
//page the link will request
$text = 'this is a simple string';    
$id = '4334%3434';        
$linktext = "<Clickit> & you will see it";
//text of the link, with HTML unfriendly characters
?>
<?php
// this gives you a clean link to use
$url = "http://localhost/";
$url .= rawurlencode($url_page);
$url .= "?text=" . urlencode($text);
$url .= "&id=" . urlencode($id);

// htmlspecialchars escapes any html that 
// might do bad things to your html page
?>
<a href="<?php echo htmlspecialchars($url); ?>">
<?php echo htmlspecialchars($linktext); ?>
</a>

omid at omidsakhi dot com

6 years ago


I needed a function in PHP to do the same job as the complete escape function in Javascript. It took me some time not to find it. But findaly I decided to write my own code. So just to save time:



<?php

function fullescape($in)

{

  $out = '';

  for ($i=0;$i<strlen($in);$i++)

  {

    $hex = dechex(ord($in[$i]));

    if ($hex=='') 

       $out = $out.urlencode($in[$i]);

    else 

       $out = $out .'%'.((strlen($hex)==1) ? ('0'.strtoupper($hex)):(strtoupper($hex)));

  }

  $out = str_replace('+','%20',$out);

  $out = str_replace('_','%5F',$out);

  $out = str_replace('.','%2E',$out);

  $out = str_replace('-','%2D',$out);

  return $out;

 }

?>



It can be fully decoded using the unscape function in Javascript.

david winiecki gmail

1 year ago


Since PHP 5.3.0, urlencode and rawurlencode also differ in that rawurlencode does not encode ~ (tilde), while urlencode does.

frx dot apps at gmail dot com

6 years ago


I wrote this simple function that creates a GET query (for URLS) from an array:

<?php
function encode_array($args)
{
  if(!is_array($args)) return false;
  $c = 0;
  $out = '';
  foreach($args as $name => $value)
  {
    if($c++ != 0) $out .= '&';
    $out .= urlencode("$name").'=';
    if(is_array($value))
    {
      $out .= urlencode(serialize($value));
    }else{
      $out .= urlencode("$value");
    }
  }
  return $out . "\n";
}
?>

If there are arrays within the $args array, they will be serialized before being urlencoded.

Some examples:
<?php
echo encode_array(array('foo' => 'bar'));                    // foo=bar
echo encode_array(array('foo&bar' => 'some=weird/value'));   // foo%26bar=some%3Dweird%2Fvalue
echo encode_array(array('foo' => 1, 'bar' =>  'two'));       // foo=1&bar=two
echo encode_array(array('args' => array('key' => 'value'))); // args=a%3A1%3A%7Bs%3A3%3A%22key%22%3Bs%3A5%3A%22value%22%3B%7D
?>

ahrensberg at gmail dot com

8 years ago


Like "Benjamin dot Bruno at web dot de" earlier has writen, you can have problems with encode strings with special characters to flash. Benjamin write that:

<?php
   function flash_encode ($input)
   {
      return rawurlencode(utf8_encode($input));
   }
?>

... could do the problem. Unfortunately flash still have problems with read some quotations, but with this one:

<?php
   function flash_encode($string)
   {
      $string = rawurlencode(utf8_encode($string));

      $string = str_replace("%C2%96", "-", $string);
      $string = str_replace("%C2%91", "%27", $string);
      $string = str_replace("%C2%92", "%27", $string);
      $string = str_replace("%C2%82", "%27", $string);
      $string = str_replace("%C2%93", "%22", $string);
      $string = str_replace("%C2%94", "%22", $string);
      $string = str_replace("%C2%84", "%22", $string);
      $string = str_replace("%C2%8B", "%C2%AB", $string);
      $string = str_replace("%C2%9B", "%C2%BB", $string);

      return $string;
   }
?>

... should solve this problem.

neugey at cox dot net

11 years ago


Be careful when encoding strings that came from simplexml in PHP 5.  If you try to urlencode a simplexml object, the script tanks.

I got around the problem by using a cast.

$newValue = urlencode( (string) $oldValue );

9 years ago


Apache's mod_rewrite and mod_proxy are unable to handle urlencoded URLs properly - http://issues.apache.org/bugzilla/show_bug.cgi?id=34602

If you need to use any of these modules and handle paths that contain %2F or %3A (and few other encoded special url characters), you'll have use a different encoding scheme.

My solution is to replace "%" with "'".
<?php
function urlencode($u)
{
    return str_replace(array("'",'%'),array('%27',"'"),urlencode($u));
}

function urldecode($u)
{
    return urldecode(strtr($u,"'",'%'));
}
?>

Thomas

8 years ago


Reply to 'peter at mailinator dot com'

If you are having problems using urldecode in PHP following the escape() function in Javascript, try to do a decodeURI() before the escape(). This fixed it for me at least.

Thomas

temu92 at gmail dot com

6 years ago


I needed encoding and decoding for UTF8 urls, I came up with these very simple fuctions. Hope this helps!

<?php
    function url_encode($string){
        return urlencode(utf8_encode($string));
    }
    
    function url_decode($string){
        return utf8_decode(urldecode($string));
    }
?>

daniel+php at danielnorton dot com

6 years ago


Don't use urlencode() or urldecode() if the text includes an email address, as it destroys the "+" character, a perfectly valid email address character.

Unless you're certain that you won't be encoding email addresses AND you need the readability provided by the non-standard "+" usage, instead always use use rawurlencode() or rawurldecode().

root at jusme dot org

7 years ago


I'm running PHP version 5.0.5 and urlencode() doesn't seem to encode the "#" character, although the function's description says it encodes "all non-alphanumeric" characters. This was a particular problem for me when trying to open local files with a "#" in the filename as Firefox will interpret this as an anchor target (for better or worse). It seems a manual str_replace is required unless this was fixed in a future PHP version.

Example:

$str = str_replace("#", "%23", $str);

kerdster at gmail dot com

8 years ago


> php dot net at samokhvalov dot com
 > 12-Dec-2006 09:49

Thanx for idea!
I have wrote more simple function based on your function to simulate JS function escape (); It uses mb_string functions unstead of iconv.

<?php
function utf16urlencode($str)
{
    $str = mb_convert_encoding($str, 'UTF-16', 'UTF-8');
    $out = '';
    for ($i = 0; $i < mb_strlen($str, 'UTF-16'); $i++) 
    {
        $out .= '%u'.bin2hex(mb_substr($str, $i, 1, 'UTF-16'));
    }
    return $out;
}
?>

izhankhalib at gmail dot com

2 years ago


Below is our jsonform source code in  mongo db which consists a lot of double quotes. we are able to pass this source code to the ajax form submit function by using php urlencode :

<script type="text/javascript">
$(function() {
      // Generate a form using jquery.dfrom
        $("#myform").dform({
                       
        "html":[
            {
                "type":"p",
                "html":"Patient Record"
            },
            {
                "name":"patient.name.first",
                "id":"txt-patient.name.first",
                "caption":"first name",
                "type":"text",
            },
            {
                
                "name":"patient.name.last",
                "id":"txt-patient.name.last",
                "caption":"last name",
                "type":"text",
            },
            {
               "type" : "submit",
              }
            
        ]
    });
    });
</script>
<form id="myform">

<?php
//get the json source code from the mongodb
$jsonform= urlencode($this->data['Post']['jsonform']);

?>
//AJAX SUBMIT FORM
<script type="text/javascript">
$('#myform').submit(function(){
  
                
    //    passing the variable fro PHP to javascript    
        var thejsonform="<?php echo $jsonform ?>";

  //var fname = $('input#fname').val();
  var dataString = "jsonform=" + thejsonform ; 

    $.ajax({
          type: "POST",
        //  url: "test1.php",
          data: dataString,
          success: function() {
           
          }
         }); 
  

return false;
});

sroolig at gmail dot com

4 years ago


I write this code, to full protect from XSS:



<?php

   $url = "";

   for($i = 0; $i < strlen($value); $i++)

    $url .= strpos("/:@&%=?.#", $value[$i]) === False ? urlencode($value[$i]) : $value[$i];

   $value = $url;

?>

php dot net at unixen dot dk

7 years ago


>> Hi muthuishere , i saw your excellent contribution, but couldnt make it work, so i corrected some bits and pieces and had the following done:

<?php
function SmartUrlEncode($url){
    if (strpos($url, '=') === false):
        return $url;
    else:
        $startpos = strpos($url, "?");
        $tmpurl=substr($url, 0 , $startpos+1) ;
        $qryStr=substr($url, $startpos+1 ) ;
         $qryvalues=explode("&", $qryStr);
          foreach($qryvalues as $value):
              $buffer=explode("=", $value);
            $buffer[1]=urlencode($buffer[1]);
           endforeach;
          $finalqrystr=implode("&amp;", &$qryvalues);
        $finalURL=$tmpurl . $finalqrystr;
        return $finalURL;
    endif;
}
?>

As you see its very much yours, modfied primarily using '&amp;' instead of '&', and ofcourse an if test to see if anything in input is to be cursed... Thanks for great function !

R Mortimer

10 years ago


Do not let the browser auto encode an invalid URL. Not all browsers perform the same encodeing. Keep it cross browser do it server side.

peter at runempire dot com

9 years ago


I think this was mentioned earlier but it was confusing.. But I had some problems with the urlencode eating my '/' so I did a simple str_replace like the following:

$url = urlencode($img);
$img2 = "$url";
$img2 = str_replace('%2F54', '/', $img2);
$img2 = str_replace('+' , '%20' , $img2);

You don't need to replace the '+' but I just feel comfortable with my %20, although it may present a problem if whatever you're using the str_replace for has a '+' in it where it shouldn't be.

But that fixed my problem.. all the other encodes like htmlentities and rawurlencode just ate my /'s

Roamy: info AT roamy DOT de

10 years ago


<?// urlencode + urldecode 4 Linux/Unix-Servers:=============
//==================================================
//=====This small script matches all encoded String for ========
//=====Linux/Unix-Servers For IIS it got to be  The Other Way  ==
//===== around...and remember in a propper Url =============
//===== there shoudn't be the 'dirty Letter': %C3==============
//==================================================
function int2hex($intega){
    $Ziffer = "0123456789ABCDEF";
return $Ziffer[($intega%256)/16].$Ziffer[$intega%16];
}
function url_decode($text){
    if(!strpos($text,"%C3"))
        for($i=129;$i<255;$i++){
            $in = "%".int2hex($i);
            $out = "%C3%".int2hex($i-64);
            $text = str_replace($in,$out,$text);
        }
return urldecode($text);
}
function url_encode($text){
    $text = urlencode($text);
    if(!strpos($text,"%C3"))
        for($i=129;$i<255;$i++){
            $in = "%".int2hex($i);
            $out = "%C3%".int2hex($i-64);
            $text = str_replace($in,$out,$text);
        }
return $text;
}//==================================================
?>

roberlamerma at gmail dot com

10 years ago


I rewrote inus at flowingcreativity dot net function to generate an encoded url string from the POST, or GET array. It handles properly POST/GET array vars.

function _HTTPRequestToString($arr_request, $var_name, $separator='&') {
    $ret = "";
    if (is_array($arr_request)) {
        foreach ($arr_request as $key => $value) {
            if (is_array($value)) {
                if ($var_name) {
                    $ret .= $this->_HTTPRequestToString($value, "{$var_name}[{$key}]", $separator);
                } else {
                    $ret .= $this->_HTTPRequestToString($value, "{$key}", $separator);
                }
            } else {
                if ($var_name) {
                    $ret .= "{$var_name}[{$key}]=".urlencode($value)."&";
                } else {
                    $ret .= "{$key}=".urlencode($value)."&";
                }
            }
        }
    }
    if (!$var_name) {
        $ret = substr($ret,0,-1);
    }
    return $ret;
}

edwardzyang at thewritingpot dot com

11 years ago


I was testing my input sanitation with some strange character entities. Ones like � and � were passed correctly and were in their raw form when I passed them through without any filtering.

However, some weird things happen when dealing with characters like (these are HTML entities): &#8252; &#9616; &#9488;and &#920; have weird things going on.

If you try to pass one in Internet Explorer, IE will *disable* the submit button. Firefox, however, does something weirder: it will convert it to it's HTML entity. It will display properly, but only when you don't convert entities.

The point? Be careful with decorative characters.

PS: If you try copy/pasting one of these characters to a TXT file, it will translate to a ?.

monty3 at hotmail dot com

11 years ago


If you want to pass a url with parameters as a value IN a url AND through a javascript function, such as...

   <a href="javascript:openWin('page.php?url=index.php?id=4&pg=2');">

...pass the url value through the PHP urlencode() function twice, like this...

<?php

   $url = "index.php?id=4&pg=2";
   $url = urlencode(urlencode($url));

   echo "<a href=\"javascript:openWin('page.php?url=$url');\">";
?>

On the page being opened by the javascript function (page.php), you only need to urldecode() once, because when javascript 'touches' the url that passes through it, it decodes the url once itself. So, just decode it once more in your PHP script to fully undo the double-encoding...

<?php

   $url = urldecode($_GET['url']);
?>

If you don't do this, you'll find that the result url value in the target script is missing all the var=values following the ? question mark...

   index.php?id=4

homebot at yandex dot ru

2 years ago


Simple static class for array URL encoding

[code]

<?php

/**
* 
*  URL Encoding class
*  Use : urlencode_array::go() as function
* 
*/
class urlencode_array
{

  /** Main encoding worker
  * @param string $perfix
  * @param array $array
  * @param string $ret byref Push record to return array
  * @param mixed $fe Is first call to function?
  */
  private static function encode_part($perfix, $array, &$ret, $fe = false)
  {
    foreach ( $array as $k => $v )
    {
      switch ( gettype($v))
      {
        case 'float'   : 
        case 'integer' :
        case 'string'  : $ret [ $fe ? $k : $perfix.'['.$k.']' ] = $v; break;
        case 'boolean' : $ret [ $fe ? $k : $perfix.'['.$k.']' ] = ( $v ? '1' : '0' ); break;
        case 'null'    : $ret [ $fe ? $k : $perfix.'['.$k.']' ] = 'NULL'; break;
        case 'object'  : $v = (array) $v;
        case 'array'   : self::encode_part( $fe?$perfix.$k:$perfix.'['.$k.']' , $v, $ret, false); break;
      }
    }
  }

  /** UrlEncode Array
  * @param mixed $array Array or stdClass to encode
  * @returns string Strings ready for send as 'application/x-www-form-urlencoded'
  */
  public static function go($array)
  {
    $buff = array();
    if ( gettype($array) == 'object') $array = (array) $array;
    self::encode_part('', $array, $buff, true);
    $retn = '';
    foreach ( $buff as $k => $v )
      $retn .= urlencode($k) . '=' . urlencode($v) . '&';
    return $retn;
  }
}

#-------------------------------- TEST AREA ------------------------------------

$buffer = array(
  'master'  =>'master.zenith.lv',
  'join'    =>array('slave'=>'slave1.zenith.lv','slave2'=>array('node1.slave2.zenith.lv','slave2.zenith.lv')),
  'config'  => new stdClass()
);
$buffer['config']->MaxServerLoad  = 200;
$buffer['config']->MaxSlaveLoad   = 100;
$buffer['config']->DropUserNoWait = true;

$buffer = urlencode_array::go($buffer);
parse_str( $buffer , $data_decoded);

header('Content-Type: text/plain; charset=utf-8');
echo 'Encoded String :' . str_repeat('-', 80) . "\n";
echo $buffer;
echo str_repeat("\n", 3) . 'Decoded String byPhp :' . str_repeat('-', 80) . "\n";
print_r($data_decoded);

[/code]

Anonymous

7 years ago


What about this one? A bit more complex but very practically,...



<?php

static function urlencode($url)

{

        // safely cast back already encoded "&" within the query

        $url = str_replace( "&amp;","&",$url );

        $phpsep = (strlen(ini_get('arg_separator.input')>0))

?ini_get('arg_separator.output')

:"&";

        // cut optionally anchor

        $ancpos = strrpos($url,"#");

        $lasteq = strrpos($url,"=");

        $lastsep = strrpos($url,"&");

        $lastqsep = strrpos($url,"?");

        $firstsep = strpos($url, "?");

        // recognize wrong positioned anchor example.php#anchor?asdasd

        if ($ancpos !== false

        || ($ancpos > 0

            && ($lasteq > 0 && $lasteq < $ancpos )

            && ($lastsep > 0 && $lastsep < $ancpos )

            && ($lastqsep > 0 && $lastqsep < $ancpos )

            )

        )

        {

               $anc = "#" . urlencode( substr( $url,$ancpos+1 ) );

               $url = substr( $url,0,$ancpos );

        }

        else

        {

            $anc = "";

        }

        // separate uri and query string

        if ($firstsep == false)

        {

            $qry = "";    // no query

            $urlenc = $url.$anc;  // anchor

        }

        else

        {

            $qry = substr( $url, $firstsep + 1 ) ;

            $vals = explode( "&", $qry );

            $valsenc = array();

            foreach( $vals as $v )

            {

                $buf = explode( "=", $v );

                $buf[0]=urlencode($buf[0]);

                $buf[1]=urlencode($buf[1]);

                $valsenc[] = implode("=",$buf);

            }

            $urlenc = substr( $url, 0 , $firstsep  );    // encoded origin uri

            $urlenc.= "?" . implode($phpsep, $valsenc )    // encoded query string

            . $anc; // anchor

        }

        $urlenc = htmlentities( $urlenc, ENT_QUOTES );

        return $urlenc;

}

?>

Mark Seecof

7 years ago


When using XMLHttpRequest or another AJAX technique to submit data to a PHP script using GET (or POST with content-type header set to 'x-www-form-urlencoded') you must urlencode your data before you upload it.  (In fact, if you don't urlencode POST data MS Internet Explorer may pop a "syntax error" dialog when you call XMLHttpRequest.send().)  But, you can't call PHP's urlencode() function in Javascript!  In fact, NO native Javascript function will urlencode data correctly for form submission.  So here is a function to do the job fairly efficiently:

<?php /******

<script type="text/javascript" language="javascript1.6">
 // PHP-compatible urlencode() for Javascript
 function urlencode(s) {
  s = encodeURIComponent(s);
  return s.replace(/~/g,'%7E').replace(/%20/g,'+');
 }

 // sample usage:  suppose form has text input fields for
 // country, postcode, and city with id='country' and so-on.
 // We'll use GET to send values of country and postcode
 // to "city_lookup.php" asynchronously, then update city
 // field in form with the reply (from database lookup)

 function lookup_city() {
  var elm_country = document.getElementById('country');
  var elm_zip = document.getElementById('postcode');
  var elm_city = document.getElementById('city');
  var qry = '?country=' + urlencode(elm_country.value) +
                '&postcode=' + urlencode(elm_zip.value);
  var xhr;
  try {
   xhr = new XMLHttpRequest(); // recent browsers
  } catch (e) {
   alert('No XMLHttpRequest!');
   return;
  }
  xhr.open('GET',('city_lookup.php'+qry),true);
  xhr.onreadystatechange = function(){
    if ((xhr.readyState != 4) || (xhr.status != 200)) return;
    elm_city.value = xhr.responseText;
  }
  xhr.send(null);
 }
</script>

******/ ?>

in reply to "kL"

9 years ago


kL's example is very bugged since it loops itself and the encode function is two-way.

Why do you replace all %27 through '  in the same string in that you replace all ' through %27?

Lets say I have a string: Hello %27World%27. It's a nice day.
I get: Hello Hello 'World'. It%27s a nice day.

With other words that solution is pretty useless.

Solution:
Just replace ' through %27 when encoding
Just replace %27 through ' when decoding. Or just use url_decode.

Bachsau

10 years ago


Diferrent from the above example you do not have to encode URLs in hrefs with this. The browser does it automaticaly, so you just have to encode it with htmlentities() ;)

tk at example dot com

5 years ago


To easily encode an array to an url :
<?php
$y= ("I"=>"like","she"=>"likes");
array_walk($y , create_function('&$v,$k', '$v = $k."=".$v ;'));
"index.php?".htmlentities(urlencode(implode("&",$y)), ENT_QUOTES);
?>
returns :
"index.php?I=like&amp;she=likes"
=)

nehuensd at gmail dot com

1 year ago


if you have a url like this: test-blablabla-4>3-y-3<6 or with any excluded US-ASCII Characters (see chapter 2.4.3 on http://www.ietf.org/rfc/rfc2396.txt) you can use urlencode two times for fix the 403 error.

Example:
.htaccess
Options +FollowSymLinks
RewriteEngine on 
RewriteRule ^test-(.*)$ index.php?token=$1

index.php
<?php
    var_dump($_GET);
    
    $foo = 'test-bla-bla-4>2-y-3<6';
    $foo_encoded = urlencode(urlencode($foo));
?>
<a href="<?=$foo_encoded;?>"><?=$foo_encoded;?></a>

look on index.php
array (size=0)
  empty
test-bla-bla-4%253E2-y-3%253C6

look on test-bla-bla-4%253E2-y-3%253C6
array (size=1)
  'token' => string 'bla-bla-4>2-y-3<6' (length=17)
test-bla-bla-4%253E2-y-3%253C6

the problem is that the characters are decoded 2 times, 1 single, the first time mod_rewrite, the second is to create the php $ _GET array.

also, you can use this technique to the same as the complex functions of other notes.

torecs at sfe dot uio dot no

10 years ago


This very simple function makes an valid parameters part of an URL, to me it looks like several of the other versions here are decoding wrongly as they do not convert & seperating the variables into &amp;. 

  $vars=array('name' => 'tore','action' => 'sell&buy');
  echo MakeRequestUrl($vars);
  
  /* Makes an valid html request url by parsing the params array
   * @param $params The parameters to be converted into URL with key as name.
   */
  function MakeRequestUrl($params)
  {
      $querystring=null;
    foreach ($params as $name => $value)
    {
      $querystring=$name.'='.urlencode($value).'&'.$querystring;
    }
      // Cut the last '&'
      $querystring=substr($querystring,0,strlen($querystring)-1);
      return htmlentities($querystring);
  }

  Will output: action=sell%26buy&amp;name=tore

bisqwit at iki dot fi

10 years ago


Constructing hyperlinks safely HOW-TO:

<?php
$path_component = 'machine/generated/part';
$url_parameter1 = 'this is a string';
$url_parameter2 = 'special/weird "$characters"';

$url = 'http://example.com/lab/cgi/test/'. rawurlencode($path_component) . '?param1=' . urlencode($url_parameter1) . '&param2=' . urlencode($url_parameter2);

$link_label = "Click here & you'll be <happy>";

echo '<a href="', htmlspecialchars($url), '">', htmlspecialchars($link_label), '</a>';
?>

This example covers all the encodings you need to apply in order to create URLs safely without problems with any special characters. It is stunning how many people make mistakes with this.

Shortly:
- Use urlencode for all GET parameters (things that come after each "=").
- Use rawurlencode for parts that come before "?".
- Use htmlspecialchars for HTML tag parameters and HTML text content.

linus at flowingcreativity dot net

10 years ago


I just came across the need for a function that exports an array into a query string. Being able to use urlencode($theArray) would be nice, but here's what I came up with:

<?php

function urlencode_array(
    $var,                // the array value
    $varName,            // variable name to be used in the query string
    $separator = '&'    // what separating character to use in the query string
) {
    $toImplode = array();
    foreach ($var as $key => $value) {
        if (is_array($value)) {
            $toImplode[] = urlencode_array($value, "{$varName}[{$key}]", $separator);
        } else {
            $toImplode[] = "{$varName}[{$key}]=".urlencode($value);
        }
    }
    return implode($separator, $toImplode);
}

?>

This function supports n-dimensional arrays (it encodes recursively).

urlencode

Description

Parameters

Return Values

Examples

Notes

See Also

User Contributed Notes