Test Twitter Friendships with PHP

Another awesome functionality provided by Twitter is the ability to test friendships between two people. I mean testing if two people follow each other, not if one spams the world with crap tweets. Just as with every other Twitter API call, executing this test is easy with PHP.

The PHP

/* persons to test */
$person1 = 'davidwalshblog';
$person2 = 'mootools';

/* send request to twitter */
$url = 'http://twitter.com/friendships/exists';
$format = 'xml';

/* check */
$persons12 = make_request($url.'.'.$format.'?user_a='.$person1.'&user_b='.$person2);
$result = get_match('/<friends>(.*)<\/friends>/isU',$persons12);
echo '<pre>Am I friends with @mootools?'.$result.'</pre>'; // returns "true" or "false"

/* makes the request */
function make_request($url) {
	$ch = curl_init();
	curl_setopt($ch,CURLOPT_URL,$url);
	curl_setopt($ch,CURLOPT_RETURNTRANSFER,1);
	$result = curl_exec($ch);
	curl_close($ch);
	return $result;
}

/* gets the match */
function get_match($regex,$content)
{
	preg_match($regex,$content,$matches);
	return $matches[1];
}

That's it. I didn't use SimpleXML in my example because of the small size of the return XML. Too much extra overhead. Here's the XML sample response:

<friends>true</friends>

The Twitter API is fun, isn't it?