/apps/user/handlers/login/twitter.php

<?php

/**
 * Twitter social login handler.
 */

if (! in_array ('twitter', $appconf['User']['login_methods'])) {
	echo $this->error (404, __ ('Not found'), __ ('The page you requested could not be found.'));
	return;
}

$twauth = new tmhOAuth (array (
	'consumer_key' => $appconf['Twitter']['consumer_key'],
	'consumer_secret' => $appconf['Twitter']['consumer_secret']
));

$here = tmhUtilities::php_self ();
if (strpos ($here, '?redirect=') === false) {
	$here .= '?redirect=' . urlencode ($_GET['redirect']);
}
@session_start ();

if (isset ($_SESSION['access_token'])) {
	// already have some credentials stored
	$twauth->config['user_token'] = $_SESSION['access_token']['oauth_token'];
	$twauth->config['user_secret'] = $_SESSION['access_token']['oauth_token_secret'];

	$code = $twauth->request ('GET', $twauth->url ('1/account/verify_credentials'));

	if ($code == 200) {
		// we have a user
		$resp = json_decode ($twauth->response['response']);
		$uid = User_OpenID::get_user_id ('tw:' . $resp->screen_name);
		if ($uid) {
			$u = new User ($uid);
		}

		if ($u) {
			// already have an account, log them in
			$u->session_id = md5 (uniqid (mt_rand (), 1));
			$u->expires = gmdate ('Y-m-d H:i:s', time () + 2592000);
			$try = 0;
			while (! $u->put ()) {
				$u->session_id = md5 (uniqid (mt_rand (), 1));
				$try++;
				if ($try == 5) {
					$this->redirect ($_GET['redirect']);
				}
			}
			$_SESSION['session_id'] = $u->session_id;

			// save token
			$oid = new User_OpenID (array (
				'token' => 'tw:' . $resp->screen_name,
				'user_id' => $u->id
			));
			$oid->put ();
			
			$this->redirect ($_GET['redirect']);
		} else {
			// signup form to create a linked account, prefill name
			$_POST['name'] = $resp->name;
			$_POST['redirect'] = $_GET['redirect'];
			$_POST['token'] = 'tw:' . $resp->screen_name;
			echo $this->run ('user/login/newuser');
			return;
		}
	} else {
		// error
		@error_log ('3. ' . $twauth->response['response']);
		$this->redirect ($_GET['redirect']);
	}
} elseif (isset ($_REQUEST['oauth_verifier'])) {
	// we're being called back by Twitter
	$twauth->config['user_token'] = $_SESSION['oauth']['oauth_token'];
	$twauth->config['user_secret'] = $_SESSION['oauth']['oauth_token_secret'];

	$params = array ('oauth_verifier' => $_REQUEST['oauth_verifier']);

	$code = $twauth->request ('POST', $twauth->url ('oauth/access_token', ''), $params);

	if ($code == 200) {
		$_SESSION['access_token'] = $twauth->extract_params ($twauth->response['response']);
		unset ($_SESSION['oauth']);
		$this->redirect ($here);
	} else {
		// error
		@error_log ('2. ' . $twauth->response['response']);
		$this->redirect ($_GET['redirect']);
	}
} else {
	// start oauth dance
	$params = array (
		'oauth_callback' => $here,
		'x_auth_access_type' => 'read'
	);

	$code = $twauth->request ('POST', $twauth->url ('oauth/request_token', ''), $params);

	if ($code == 200) {
		$_SESSION['oauth'] = $twauth->extract_params ($twauth->response['response']);
		$authurl = $twauth->url ('oauth/authenticate', '') . '?oauth_token=' . $_SESSION['oauth']['oauth_token'] . '&force_login=1';
		$this->redirect ($authurl);
	} else {
		// error
		@error_log ('1. ' . $twauth->response['response']);
		$this->redirect ($_GET['redirect']);
	}
}

?>