auto-link-text.php

<?php

function auto_link_text($text) {
	$pattern  = '#\b(([\w-]+://?|www[.])[^\s()<>]+(?:\([\w\d]+\)|([^[:punct:]\s]|/)))#';
	return preg_replace_callback($pattern, 'auto_link_text_callback', $text);
}

function auto_link_text_callback($matches) {
	$max_url_length = 50;
	$max_depth_if_over_length = 2;
	$ellipsis = '&hellip;';
	
	$url_full = $matches[0];
	$url_short = '';
	
	if (strlen($url_full) > $max_url_length) {
		$parts = parse_url($url_full);
		$url_short = $parts['scheme'] . '://' . preg_replace('/^www\./', '', $parts['host']) . '/';
	
		$path_components = explode('/', trim($parts['path'], '/'));
		foreach ($path_components as $dir) {
			$url_string_components[] = $dir . '/';
		}
		
		if (!empty($parts['query'])) {
			$url_string_components[] = '?' . $parts['query'];
		}
		
		if (!empty($parts['fragment'])) {
			$url_string_components[] = '#' . $parts['fragment'];
		}

		for ($k = 0; $k < count($url_string_components); $k++) {
			$curr_component = $url_string_components[$k];
			if ($k >= $max_depth_if_over_length || strlen($url_short) + strlen($curr_component) > $max_url_length) {
				if ($k == 0 && strlen($url_short) < $max_url_length) {
					// Always show a portion of first directory
					$url_short .= substr($curr_component, 0, $max_url_length - strlen($url_short));
				}
				$url_short .= $ellipsis;
				break;
			}
			$url_short .= $curr_component;
		}
		
	} else {
		$url_short = $url_full;
	}
	
	return "<a rel=\"nofollow\" href=\"$url_full\">$url_short</a>";
}