PHP: WORDPRESS - Auto convert URL into clickable hyperlink

In wordpress, if you want to auto convert all URLs in your string into clickable hyperlinks, you can actually do it using the built-in function make_clickable(). If you need to do that outside of wordpress, you can refer to the function’s source code at wp-includes/formatting.php:

<?php

function _make_url_clickable_cb($matches) {

$ret = '';

$url = $matches[2];



if ( empty($url) )

return $matches[0];

// removed trailing [.,;:] from URL

if ( in_array(substr($url, -1), array('.', ',', ';', ':')) === true ) {

$ret = substr($url, -1);

$url = substr($url, 0, strlen($url)-1);

}

return $matches[1] . "<a href=\"$url\" rel=\"nofollow\">$url</a>" . $ret;

}



function _make_web_ftp_clickable_cb($matches) {

$ret = '';

$dest = $matches[2];

$dest = 'http://' . $dest;



if ( empty($dest) )

return $matches[0];

// removed trailing [,;:] from URL

if ( in_array(substr($dest, -1), array('.', ',', ';', ':')) === true ) {

$ret = substr($dest, -1);

$dest = substr($dest, 0, strlen($dest)-1);

}

return $matches[1] . "<a href=\"$dest\" rel=\"nofollow\">$dest</a>" . $ret;

}



function _make_email_clickable_cb($matches) {

$email = $matches[2] . '@' . $matches[3];

return $matches[1] . "<a href=\"mailto:$email\">$email</a>";

}



function make_clickable($ret) {

$ret = ' ' . $ret;

// in testing, using arrays here was found to be faster

$ret = preg_replace_callback('#([\s>])([\w]+?://[\w\\x80-\\xff\#$%&~/.\-;:=,?@\[\]+]*)#is', '_make_url_clickable_cb', $ret);

$ret = preg_replace_callback('#([\s>])((www|ftp)\.[\w\\x80-\\xff\#$%&~/.\-;:=,?@\[\]+]*)#is', '_make_web_ftp_clickable_cb', $ret);

$ret = preg_replace_callback('#([\s>])([.0-9a-z_+-]+)@(([0-9a-z-]+\.)+[0-9a-z]{2,})#i', '_make_email_clickable_cb', $ret);



// this one is not in an array because we need it to run last, for cleanup of accidental links within links

$ret = preg_replace("#(<a( [^>]+?>|>))<a [^>]+?>([^>]+?)</a></a>#i", "$1$3</a>", $ret);

$ret = trim($ret);

return $ret;

}

?>