php-regex-favicon.php

<?php
function parseFavicon($html) {
	$s = '[ \t\r\n]*?';
	
	// Get the 'href' attribute value in a <link rel="icon" ... />
	// Also works for IE style: <link rel="shortcut icon" href="http://www.example.com/myicon.ico" />
	// And for iOS style: <link rel="apple-touch-icon" href="somepath/image.ico">
	$matches = array();
	// Search for <link rel="icon" type="image/png" href="http://example.com/icon.png" />
	;
	if (preg_match("/<link{$s}rel{$s}={$s}[\"'](?:shortcut )?icon[\"']{$s}href{$s}={$s}[\"']([^\"']*)[\"']/i", $html, $matches)) {
		return trim($matches[1]);
	}
	// Order of attributes could be swapped around: <link type="image/png" href="http://example.com/icon.png" rel="icon" />
	
	if (preg_match("/<link{$s}href{$s}={$s}[\"']([^\"']*)[\"']{$s}rel{$s}={$s}[\"'](?:shortcut )?icon[\"']/i", $html, $matches)) {
		return trim($matches[1]);
	}
	
	if (preg_match("/<meta{$s}content{$s}={$s}[\"']([^\"']*)[\"']{$s}itemprop{$s}={$s}[\"']image[\"']/i", $html, $matches)) {
		return trim($matches[1]);
	}
	// No match
	return null;
}