Regular expression pattern to match URL with or without http://www

Question

I'm not very good at regular expressions at all.

I've been using a lot of framework code to date, but I'm unable to find one that is able to match a URL like http://www.example.com/etcetc, but it is also is able to catch something like www.example.com/etcetc and example.com/etcetc.

Answer 1

For matching all kinds of URLs, the following code should work:

<?php     $regex = "((https?|ftp)://)?"; // SCHEME     $regex .= "([a-z0-9+!*(),;?&=$_.-]+(:[a-z0-9+!*(),;?&=$_.-]+)?@)?"; // User and Pass     $regex .= "([a-z0-9\-\.]*)\.(([a-z]{2,4})|([0-9]{1,3}\.([0-9]{1,3})\.([0-9]{1,3})))"; // Host or IP     $regex .= "(:[0-9]{2,5})?"; // Port     $regex .= "(/([a-z0-9+$_%-]\.?)+)*/?"; // Path     $regex .= "(\?[a-z+&\$_.-][a-z0-9;:@&%=+/$_.-]*)?"; // GET Query     $regex .= "(#[a-z_.-][a-z0-9+$%_.-]*)?"; // Anchor ?> 

Then, the correct way to check against the regex is as follows:

<?php    if(preg_match("~^$regex$~i", 'www.example.com/etcetc', $m))       var_dump($m);     if(preg_match("~^$regex$~i", 'http://www.example.com/etcetc', $m))       var_dump($m); ?> 

Courtesy: Comments made by splattermania in the PHP manual: http://php.net/manual/en/function.preg-match.php

RegEx Demo in regex101

Answer 2

This worked for me in all cases I had tested:

$url_pattern = '/((http|https)\:\/\/)?[a-zA-Z0-9\.\/\?\:@\-_=#]+\.([a-zA-Z0-9\&\.\/\?\:@\-_=#])*/'; 

Tests:

http://test.test-75.1474.stackoverflow.com/ https://www.stackoverflow.com https://www.stackoverflow.com/ http://wwww.stackoverflow.com/ http://wwww.stackoverflow.com   http://test.test-75.1474.stackoverflow.com/ http://www.stackoverflow.com http://www.stackoverflow.com/ stackoverflow.com/ stackoverflow.com  http://www.example.com/etcetc www.example.com/etcetc example.com/etcetc user:[email protected]/etcetc  example.com/etcetc?query=aasd example.com/etcetc?query=aasd&dest=asds  http://stackoverflow.com/questions/6427530/regular-expression-pattern-to-match-url-with-or-without-http-www http://stackoverflow.com/questions/6427530/regular-expression-pattern-to-match-url-with-or-without-http-www/ 

Every valid Internet URL has at least one dot, so the above pattern will simply try to find any at least two strings chained by a dot and has valid characters that URL may have.