1 files changed, 383 insertions, 0 deletions
diff --git a/mod/twitter_api/lib/twitter_api.php b/mod/twitter_api/lib/twitter_api.php
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+++ b/mod/twitter_api/lib/twitter_api.php
@@ -0,0 +1,383 @@
+<?php
+/**
+ * Common library of functions used by Twitter Services.
+ *
+ * @package twitter_api
+ */
+
+/**
+ * Get the API wrapper object
+ * 
+ * @param string $oauth_token        User's OAuth token
+ * @param string $oauth_token_secret User's OAuth secret
+ * @return TwitterOAuth|null
+ */
+function twitter_api_get_api_object($oauth_token = null, $oauth_token_secret = null) {
+	$consumer_key = elgg_get_plugin_setting('consumer_key', 'twitter_api');
+	$consumer_secret = elgg_get_plugin_setting('consumer_secret', 'twitter_api');
+	if (!($consumer_key && $consumer_secret)) {
+		return null;
+	}
+
+	$api = new TwitterOAuth($consumer_key, $consumer_secret, $oauth_token, $oauth_token_secret);
+	if ($api) {
+		$api->host = "https://api.twitter.com/1.1/";
+	}
+	return $api;
+}
+
+/**
+ * Tests if the system admin has enabled Sign-On-With-Twitter
+ *
+ * @param void
+ * @return bool
+ */
+function twitter_api_allow_sign_on_with_twitter() {
+	if (!$consumer_key = elgg_get_plugin_setting('consumer_key', 'twitter_api')) {
+		return FALSE;
+	}
+
+	if (!$consumer_secret = elgg_get_plugin_setting('consumer_secret', 'twitter_api')) {
+		return FALSE;
+	}
+
+	return elgg_get_plugin_setting('sign_on', 'twitter_api') == 'yes';
+}
+
+/**
+ * Forwards the user to twitter to authenticate
+ *
+ * This includes the login URL as the callback
+ */
+function twitter_api_forward() {
+	global $SESSION;
+
+	// sanity check
+	if (!twitter_api_allow_sign_on_with_twitter()) {
+		forward();
+	}
+
+	$callback = elgg_normalize_url("twitter_api/login");
+	$request_link = twitter_api_get_authorize_url($callback);
+
+	// capture metadata about login to persist through redirects
+	$login_metadata = array(
+		'persistent' => (bool) get_input("persistent"),
+	);
+	// capture referrer if in site, but not the twitter_api
+	if (!empty($SESSION['last_forward_from'])) {
+		$login_metadata['forward'] = $SESSION['last_forward_from'];
+	} elseif (!empty($_SERVER['HTTP_REFERER'])
+			&& 0 === strpos($_SERVER['HTTP_REFERER'], elgg_get_site_url())
+			&& 0 !== strpos($_SERVER['HTTP_REFERER'], elgg_get_site_url() . 'twitter_api/')) {
+		$login_metadata['forward'] = $_SERVER['HTTP_REFERER'];
+	}
+	$SESSION['twitter_api_login_metadata'] = $login_metadata;
+
+	forward($request_link, 'twitter_api');
+}
+
+/**
+ * Log in a user referred from Twitter's OAuth API
+ *
+ * If the user has already linked their account with Twitter, it is a seamless
+ * login. If this is a first time login (or a user from deprecated twitter login
+ * plugin), we create a new account (update the account).
+ *
+ * If a plugin wants to be notified when someone logs in with twitter or a new
+ * twitter user signs up, register for the standard login or create user events
+ * and check for 'twitter_api' context.
+ *
+ * The user has to be redirected from Twitter for this to work. It depends on
+ * the Twitter OAuth data.
+ */
+function twitter_api_login() {
+	/* @var ElggSession $SESSION */
+	global $SESSION;
+
+	// sanity check
+	if (!twitter_api_allow_sign_on_with_twitter()) {
+		forward();
+	}
+
+	$token = twitter_api_get_access_token(get_input('oauth_verifier'));
+
+	$persistent = false;
+	$forward = '';
+
+	// fetch login metadata from session
+	$login_metadata = $SESSION['twitter_api_login_metadata'];
+	unset($SESSION['twitter_api_login_metadata']);
+	if (!empty($login_metadata['persistent'])) {
+		$persistent = true;
+	}
+	if (!empty($login_metadata['forward'])) {
+		$forward = $login_metadata['forward'];
+	}
+
+	if (!isset($token['oauth_token']) || !isset($token['oauth_token_secret'])) {
+		register_error(elgg_echo('twitter_api:login:error'));
+		forward();
+	}
+
+	// attempt to find user and log them in.
+	// else, create a new user.
+	$options = array(
+		'type' => 'user',
+		'plugin_user_setting_name_value_pairs' => array(
+			'access_key' => $token['oauth_token'],
+			'access_secret' => $token['oauth_token_secret'],
+		),
+		'limit' => 0,
+	);
+
+	$users = elgg_get_entities_from_plugin_user_settings($options);
+
+	if ($users) {
+		if (count($users) == 1 && login($users[0], $persistent)) {
+			system_message(elgg_echo('twitter_api:login:success'));
+			forward($forward);
+		} else {
+			register_error(elgg_echo('twitter_api:login:error'));
+			forward();
+		}
+	} else {
+		$api = twitter_api_get_api_object($token['oauth_token'], $token['oauth_token_secret']);
+		$twitter = $api->get('account/verify_credentials');
+
+		// backward compatibility for deprecated Twitter Login plugin
+		$user = FALSE;
+		if ($twitter_user = get_user_by_username($token['screen_name'])) {
+			if (($screen_name = $twitter_user->twitter_screen_name) && ($screen_name == $token['screen_name'])) {
+				// convert existing account
+				$user = $twitter_user;
+				$forward = '';
+			}
+		}
+
+		// create new user
+		if (!$user) {
+			$user = twitter_api_create_user($twitter);
+			$site_name = elgg_get_site_entity()->name;
+			system_message(elgg_echo('twitter_api:login:email', array($site_name)));
+			$forward = "twitter_api/interstitial";
+		}
+
+		// set twitter services tokens
+		elgg_set_plugin_user_setting('twitter_name', $token['screen_name'], $user->guid);
+		elgg_set_plugin_user_setting('access_key', $token['oauth_token'], $user->guid);
+		elgg_set_plugin_user_setting('access_secret', $token['oauth_token_secret'], $user->guid);
+
+		// pull in Twitter icon
+		twitter_api_update_user_avatar($user, $twitter->profile_image_url);
+
+		// login new user
+		if (login($user)) {
+			system_message(elgg_echo('twitter_api:login:success'));
+		} else {
+			system_message(elgg_echo('twitter_api:login:error'));
+		}
+
+		forward($forward, 'twitter_api');
+	}
+
+	// register login error
+	register_error(elgg_echo('twitter_api:login:error'));
+	forward();
+}
+
+/**
+ * Create a new user from Twitter information
+ * 
+ * @param object $twitter Twitter OAuth response
+ * @return ElggUser
+ */
+function twitter_api_create_user($twitter) {
+	// check new registration allowed
+	if (!twitter_api_allow_new_users_with_twitter()) {
+		register_error(elgg_echo('registerdisabled'));
+		forward();
+	}
+
+	// Elgg-ify Twitter credentials
+	$username = $twitter->screen_name;
+	while (get_user_by_username($username)) {
+		// @todo I guess we just hope this is good enough
+		$username = $twitter->screen_name . '_' . rand(1000, 9999);
+	}
+
+	$password = generate_random_cleartext_password();
+	$name = $twitter->name;
+
+	$user = new ElggUser();
+	$user->username = $username;
+	$user->name = $name;
+	$user->access_id = ACCESS_PUBLIC;
+	$user->salt = generate_random_cleartext_password();
+	$user->password = generate_user_password($user, $password);
+	$user->owner_guid = 0;
+	$user->container_guid = 0;
+
+	if (!$user->save()) {
+		register_error(elgg_echo('registerbad'));
+		forward();
+	}
+
+	return $user;
+}
+
+/**
+ * Pull in the latest avatar from twitter.
+ *
+ * @param ElggUser $user
+ * @param string   $file_location
+ */
+function twitter_api_update_user_avatar($user, $file_location) {
+	// twitter's images have a few suffixes:
+	// _normal
+	// _reasonably_small
+	// _mini
+	// the twitter app here returns _normal.  We want standard, so remove the suffix.
+	// @todo Should probably check that it's an image file.
+	$file_location = str_replace('_normal.jpg', '.jpg', $file_location);
+
+	$icon_sizes = elgg_get_config('icon_sizes');
+
+	$filehandler = new ElggFile();
+	$filehandler->owner_guid = $user->getGUID();
+	foreach ($icon_sizes as $size => $dimensions) {
+		$image = get_resized_image_from_existing_file(
+			$file_location,
+			$dimensions['w'],
+			$dimensions['h'],
+			$dimensions['square']
+		);
+
+		$filehandler->setFilename("profile/$user->guid$size.jpg");
+		$filehandler->open('write');
+		$filehandler->write($image);
+		$filehandler->close();
+	}
+	
+	// update user's icontime
+	$user->icontime = time();
+}
+
+/**
+ * User-initiated Twitter authorization
+ *
+ * Callback action from Twitter registration. Registers a single Elgg user with
+ * the authorization tokens. Will revoke access from previous users when a
+ * conflict exists.
+ *
+ * Depends upon {@link twitter_api_get_authorize_url} being called previously
+ * to establish session request tokens.
+ */
+function twitter_api_authorize() {
+	$token = twitter_api_get_access_token(get_input('oauth_verifier'));
+	if (!isset($token['oauth_token']) || !isset($token['oauth_token_secret'])) {
+		register_error(elgg_echo('twitter_api:authorize:error'));
+		forward('settings/plugins', 'twitter_api');
+	}
+
+	// make sure no other users are registered to this twitter account.
+	$options = array(
+		'type' => 'user',
+		'plugin_user_setting_name_value_pairs' => array(
+			'access_key' => $token['oauth_token'],
+			'access_secret' => $token['oauth_token_secret'],
+		),
+		'limit' => 0
+	);
+	$users = elgg_get_entities_from_plugin_user_settings($options);
+
+	if ($users) {
+		foreach ($users as $user) {
+			// revoke access
+			elgg_unset_plugin_user_setting('twitter_name', $user->getGUID());
+			elgg_unset_plugin_user_setting('access_key', $user->getGUID());
+			elgg_unset_plugin_user_setting('access_secret', $user->getGUID());
+		}
+	}
+
+	// register user's access tokens
+	elgg_set_plugin_user_setting('twitter_name', $token['screen_name']);
+	elgg_set_plugin_user_setting('access_key', $token['oauth_token']);
+	elgg_set_plugin_user_setting('access_secret', $token['oauth_token_secret']);
+	
+	// trigger authorization hook
+	elgg_trigger_plugin_hook('authorize', 'twitter_api', array('token' => $token));
+
+	system_message(elgg_echo('twitter_api:authorize:success'));
+	forward('settings/plugins', 'twitter_api');
+}
+
+/**
+ * Remove twitter access for the currently logged in user.
+ */
+function twitter_api_revoke() {
+	// unregister user's access tokens
+	elgg_unset_plugin_user_setting('twitter_name');
+	elgg_unset_plugin_user_setting('access_key');
+	elgg_unset_plugin_user_setting('access_secret');
+
+	system_message(elgg_echo('twitter_api:revoke:success'));
+	forward('settings/plugins', 'twitter_api');
+}
+
+/**
+ * Gets the url to authorize a user.
+ *
+ * @param string $callback The callback URL
+ */
+function twitter_api_get_authorize_url($callback = NULL, $login = true) {
+	global $SESSION;
+
+	// request tokens from Twitter
+	$twitter = twitter_api_get_api_object();
+	$token = $twitter->getRequestToken($callback);
+
+	// save token in session for use after authorization
+	$SESSION['twitter_api'] = array(
+		'oauth_token' => $token['oauth_token'],
+		'oauth_token_secret' => $token['oauth_token_secret'],
+	);
+
+	return $twitter->getAuthorizeURL($token['oauth_token'], $login);
+}
+
+/**
+ * Returns the access token to use in twitter calls.
+ *
+ * @param bool $oauth_verifier
+ * @return array
+ */
+function twitter_api_get_access_token($oauth_verifier = FALSE) {
+	/* @var ElggSession $SESSION */
+	global $SESSION;
+
+	// retrieve stored tokens
+	$oauth_token = $SESSION['twitter_api']['oauth_token'];
+	$oauth_token_secret = $SESSION['twitter_api']['oauth_token_secret'];
+	unset($SESSION['twitter_api']);
+
+	// fetch an access token
+	$api = twitter_api_get_api_object($oauth_token, $oauth_token_secret);
+	return $api->getAccessToken($oauth_verifier);
+}
+
+/**
+ * Checks if this site is accepting new users.
+ * Admins can disable manual registration, but some might want to allow
+ * twitter-only logins.
+ */
+function twitter_api_allow_new_users_with_twitter() {
+	$site_reg = elgg_get_config('allow_registration');
+	$twitter_reg = elgg_get_plugin_setting('new_users');
+
+	if ($site_reg || (!$site_reg && $twitter_reg == 'yes')) {
+		return true;
+	}
+
+	return false;
+}