How To Encode URI Data In Popular Languages

Contributed by pradeep () On 27th July, 2012

This is an article on How To Encode URI Data In Popular Languages in Web Development.

URL Encoding also known as Percent-encoding is the way to encode data passed in an URI (Uniform Resource Identifier), this system is used to convert special characters to hex form prefixed with a % sign, and prevents broken URLs. An encoded URL will look like the following:

Code:

http://www.google.com/search?q=%26pradeep+]%3D

In this article we'll see how URL encoding can be done in different languages:

PHP

PHP comes with a built-in function urlencode which Percent-encodes the string passed to it.

Code: PHP

<?php
print '<a href="/script/home.php?user_input=', urlencode($user_input), '">User Input</a>';
?>

Perl

In Perl there are multiple modules available which can do the work for you, or you can write such a subroutine yourself, let's take a look at booth examples below:

Code: Perl

use URI::Escape;

$url = sprintf('http://pradeep.net.in/cgi-bin/hello.pl?user_input=%s',uri_escape($user_input));

sub urlencode {
    my $s = shift;
    $s =~ s/ /+/g;
    $s =~ s/([^A-Za-z0-9\+-])/sprintf("%%%02X", ord($1))/seg;
    return $s;
}

$url = sprintf('http://pradeep.net.in/cgi-bin/hello.pl?user_input=%s',urlencode($user_input));

Python

In Python the urllib module is used:

Code: Python

import urllib

print "Url : http://pradeep.net.in/cgi-bin/hello.py?user_input=%s" % (urllib.quote_plus(user_input))

JavaScript

The built-in functions encodeURIComponent(str) and encodeURI(str)

Code: JavaScript

var url = "http://pradeep.net.in/cgi-bin/hello.py?user_input=" + encodeURIComponent(user_input);

ASP.Net

ASP.Net also has a built-in function to encode URL components with special characters.

Code: C#

String sUrl;
sUrl = "http://pradeep.net.in/cgi-bin/hello.py?user_input=" + Server.UrlEncode(sUserInput);

Response.Write("<a href=" + sUrl + ">User Input</a>");