gistfile1.txt

<?php
/*
Plugin Name: GModules Rewrite Links
Description: This will filter links in posts, pages, and comments to use "http://gmodules.com/ig/proxy?url=" instead.
Version: 1.0
*/

add_filter( 'the_content' , 'mh_gmodule' , 50 );
add_filter( 'the_content_rss' , 'mh_gmodule' , 50 );
add_filter( 'comment_text' , 'mh_gmodule' , 50 );
add_filter( 'comment_text_rss' , 'mh_gmodule' , 50 );

function mh_gmodule( $content ) {

// Regex to put all <a href="http://some-url-here/path/etc" into an array
$mh_url_regex = "/\<a\ href\=\"http\:\/\/[a-zA-Z0-9\-\.]+[a-zA-Z]{2,3}.*\"/";

preg_match_all( $mh_url_regex , $content, $mh_matches );

// Go through that array and add gmodules hack
for ( $mh_count = 0; $mh_count < count( $mh_matches[0] ); $mh_count++ )
	{
	$mh_old_url = $mh_matches[0][$mh_count];
	$mh_new_url = str_replace( '<a href="http://' , '<a href="http://gmodules.com/ig/proxy?url=http://' , $mh_matches[0][$mh_count] );

	// Array of destinations we don't want to apply the hack to.
	// Some sites such as core.trac.wordpress.org don't work with the gmodules hack
	// Partial matches work here, the more specific the better.

	$mh_ignore = array(
		home_url( '/' ),
		'trac.wordpress.org/'
		);

	// Make the substitution on all links except the ignore list
	if( !mh_array_find( $mh_old_url , $mh_ignore ) )
		$content = str_replace( $mh_old_url  , $mh_new_url , $content );
	}

return $content;
}


// Only see if the array element is contained in the string
function mh_array_find( $needle , $haystack ) {
	if(!is_array($haystack)) return false;
	foreach ($haystack as $key=>$item) {
		// See if the item is in the needle
		if (strpos($needle, $item ) !== false) return true;
	}
	return false;
}