dir/addon/twitter/twitter.php

<?php
/**
 * Name: Twitter Connector
 * Version: 1.0
 * Author: Tobias Diekershoff <https://diekershoff.homeunix.net/friendika/profile/tobias>
 */


/*   Twitter Plugin for Friendika
 *
 *   Author: Tobias Diekershoff
 *           tobias.diekershoff@gmx.net
 *
 *   License:3-clause BSD license (same as Friendika)
 *
 *   Configuration:
 *     To use this plugin you need a OAuth Consumer key pair (key & secret)
 *     you can get it from Twitter at https://twitter.com/apps
 *
 *     Register your Friendika site as "Client" application with "Read & Write" access
 *     we do not need "Twitter as login". When you've registered the app you get the
 *     OAuth Consumer key and secret pair for your application/site.
 *
 *     Add this key pair to your global .htconfig.php
 *
 *     $a->config['twitter']['consumerkey'] = 'your consumer_key here';
 *     $a->config['twitter']['consumersecret'] = 'your consumer_secret here';
 *
 *     To activate the plugin itself add it to the $a->config['system']['addon']
 *     setting. After this, your user can configure their Twitter account settings
 *     from "Settings -> Plugin Settings".
 *
 *     Requirements: PHP5, curl [Slinky library]
 *
 *     Documentation: http://diekershoff.homeunix.net/redmine/wiki/friendikaplugin/Twitter_Plugin
 */

/*   __TODO__
 *
 *   - what about multimedia content?
 *     so far we just strip HTML tags from the message
 */

function twitter_install() {
	//  we need some hooks, for the configuration and for sending tweets
	register_hook('plugin_settings', 'addon/twitter/twitter.php', 'twitter_settings'); 
	register_hook('plugin_settings_post', 'addon/twitter/twitter.php', 'twitter_settings_post');
	register_hook('post_local_end', 'addon/twitter/twitter.php', 'twitter_post_hook');
	register_hook('jot_networks', 'addon/twitter/twitter.php', 'twitter_jot_nets');
	logger("installed twitter");
}


function twitter_uninstall() {
	unregister_hook('plugin_settings', 'addon/twitter/twitter.php', 'twitter_settings'); 
	unregister_hook('plugin_settings_post', 'addon/twitter/twitter.php', 'twitter_settings_post');
	unregister_hook('post_local_end', 'addon/twitter/twitter.php', 'twitter_post_hook');
	unregister_hook('jot_networks', 'addon/twitter/twitter.php', 'twitter_jot_nets');
}

function twitter_jot_nets(&$a,&$b) {
	if(! local_user())
		return;

	$tw_post = get_pconfig(local_user(),'twitter','post');
	if(intval($tw_post) == 1) {
		$tw_defpost = get_pconfig(local_user(),'twitter','post_by_default');
		$selected = ((intval($tw_defpost) == 1) ? ' checked="checked" ' : '');
		$b .= '<div class="profile-jot-net"><input type="checkbox" name="twitter_enable"' . $selected . 'value="1" /> ' 
			. t('Post to Twitter') . '</div>';	
	}


}

function twitter_settings_post ($a,$post) {
	if(! local_user())
		return;
	if (isset($_POST['twitter-disconnect'])) {
		/***
		 * if the twitter-disconnect checkbox is set, clear the OAuth key/secret pair
		 * from the user configuration
		 * TODO can we revoke the access tokens at Twitter and do we need to do so?
		 */
		del_pconfig( local_user(), 'twitter', 'consumerkey'  );
		del_pconfig( local_user(), 'twitter', 'consumersecret' );
		del_pconfig( local_user(), 'twitter', 'post' );
	} else {
	if (isset($_POST['twitter-pin'])) {
		//  if the user supplied us with a PIN from Twitter, let the magic of OAuth happen
		logger('got a Twitter PIN');
		require_once('library/twitteroauth.php');
		$ckey    = get_config('twitter', 'consumerkey'  );
		$csecret = get_config('twitter', 'consumersecret' );
		//  the token and secret for which the PIN was generated were hidden in the settings
		//  form as token and token2, we need a new connection to Twitter using these token
		//  and secret to request a Access Token with the PIN
		$connection = new TwitterOAuth($ckey, $csecret, $_POST['twitter-token'], $_POST['twitter-token2']);
		$token   = $connection->getAccessToken( $_POST['twitter-pin'] );
		//  ok, now that we have the Access Token, save them in the user config
 		set_pconfig(local_user(),'twitter', 'oauthtoken',  $token['oauth_token']);
		set_pconfig(local_user(),'twitter', 'oauthsecret', $token['oauth_token_secret']);
                set_pconfig(local_user(),'twitter', 'post', 1);
                //  reload the Addon Settings page, if we don't do it see Bug #42
                header('Location: '.$a->get_baseurl().'/settings/addon');
	} else {
		//  if no PIN is supplied in the POST variables, the user has changed the setting
		//  to post a tweet for every new __public__ posting to the wall
		set_pconfig(local_user(),'twitter','post',intval($_POST['twitter-enable']));
	}}
}
function twitter_settings(&$a,&$s) {
        if(! local_user())
                return;
        $a->page['htmlhead'] .= '<link rel="stylesheet"  type="text/css" href="' . $a->get_baseurl() . '/addon/twitter/twitter.css' . '" media="all" />' . "\r\n";
	/***
	 * 1) Check that we have global consumer key & secret
	 * 2) If no OAuthtoken & stuff is present, generate button to get some
	 * 3) Checkbox for "Send public notices (140 chars only)
	 */
	$ckey    = get_config('twitter', 'consumerkey' );
	$csecret = get_config('twitter', 'consumersecret' );
	$otoken  = get_pconfig(local_user(), 'twitter', 'oauthtoken'  );
	$osecret = get_pconfig(local_user(), 'twitter', 'oauthsecret' );
        $enabled = get_pconfig(local_user(), 'twitter', 'post');
	$checked = (($enabled) ? ' checked="checked" ' : '');
	$s .= '<div class="settings-block">';
	$s .= '<h3>'. t('Twitter Posting Settings') .'</h3>';

	if ( (!$ckey) && (!$csecret) ) {
		/***
		 * no global consumer keys
		 * display warning and skip personal config
		 */
		$s .= '<p>'. t('No consumer key pair for Twitter found. Please contact your site administrator.') .'</p>';
	} else {
		/***
		 * ok we have a consumer key pair now look into the OAuth stuff
		 */
		if ( (!$otoken) && (!$osecret) ) {
			/***
			 * the user has not yet connected the account to twitter...
			 * get a temporary OAuth key/secret pair and display a button with
			 * which the user can request a PIN to connect the account to a
			 * account at Twitter.
			 */
		        require_once('library/twitteroauth.php');
			$connection = new TwitterOAuth($ckey, $csecret);
			$request_token = $connection->getRequestToken();
			$token = $request_token['oauth_token'];
			/***
			 *  make some nice form
			 */
			$s .= '<p>'. t('At this Friendika instance the Twitter plugin was enabled but you have not yet connected your account to your Twitter account. To do so click the button below to get a PIN from Twitter which you have to copy into the input box below and submit the form. Only your <strong>public</strong> posts will be posted to Twitter.') .'</p>';
			$s .= '<a href="'.$connection->getAuthorizeURL($token).'" target="_twitter"><img src="addon/twitter/lighter.png" alt="'.t('Log in with Twitter').'"></a>';
			$s .= '<div id="twitter-pin-wrapper">';
			$s .= '<label id="twitter-pin-label" for="twitter-pin">'. t('Copy the PIN from Twitter here') .'</label>';
			$s .= '<input id="twitter-pin" type="text" name="twitter-pin" />';
			$s .= '<input id="twitter-token" type="hidden" name="twitter-token" value="'.$token.'" />';
			$s .= '<input id="twitter-token2" type="hidden" name="twitter-token2" value="'.$request_token['oauth_token_secret'].'" />';
            $s .= '</div><div class="clear"></div>';
            $s .= '<div class="settings-submit-wrapper" ><input type="submit" name="submit" class="settings-submit" value="' . t('Submit') . '" /></div>';
		} else {
			/***
			 *  we have an OAuth key / secret pair for the user
			 *  so let's give a chance to disable the postings to Twitter
			 */
                        require_once('library/twitteroauth.php');
			$connection = new TwitterOAuth($ckey,$csecret,$otoken,$osecret);
			$details = $connection->get('account/verify_credentials');
			$s .= '<div id="twitter-info" ><img id="twitter-avatar" src="'.$details->profile_image_url.'" /><p id="twitter-info-block">'. t('Currently connected to: ') .'<a href="https://twitter.com/'.$details->screen_name.'" target="_twitter">'.$details->screen_name.'</a><br /><em>'.$details->description.'</em></p></div>';
			$s .= '<p>'. t('If enabled all your <strong>public</strong> postings will be posted to the associated Twitter account as well.') .'</p>';
			$s .= '<div id="twitter-enable-wrapper">';
			$s .= '<label id="twitter-enable-label" for="twitter-checkbox">'. t('Send public postings to Twitter'). '</label>';
			$s .= '<input id="twitter-checkbox" type="checkbox" name="twitter-enable" value="1" ' . $checked . '/>';
			$s .= '</div><div class="clear"></div>';
			$s .= '<div id="twitter-disconnect-wrapper">';
                        $s .= '<label id="twitter-disconnect-label" for="twitter-disconnect">'. t('Clear OAuth configuration') .'</label>';
                        $s .= '<input id="twitter-disconnect" type="checkbox" name="twitter-disconnect" value="1" />';
			$s .= '</div><div class="clear"></div>';
			$s .= '<div class="settings-submit-wrapper" ><input type="submit" name="submit" class="settings-submit" value="' . t('Submit') . '" /></div>'; 
		}
	}
        $s .= '</div><div class="clear"></div></div>';
}


function twitter_post_hook(&$a,&$b) {

	/**
	 * Post to Twitter
	 */

        logger('twitter post invoked');

	if((local_user()) && (local_user() == $b['uid']) && (! $b['private']) && (! $b['parent']) ) {

		load_pconfig(local_user(), 'twitter');

		$ckey    = get_config('twitter', 'consumerkey'  );
		$csecret = get_config('twitter', 'consumersecret' );
		$otoken  = get_pconfig(local_user(), 'twitter', 'oauthtoken'  );
		$osecret = get_pconfig(local_user(), 'twitter', 'oauthsecret' );

		if($ckey && $csecret && $otoken && $osecret) {

			$twitter_post = intval(get_pconfig(local_user(),'twitter','post'));
			$twitter_enable = (($twitter_post && x($_POST,'twitter_enable')) ? intval($_POST['twitter_enable']) : 0);

			if($twitter_post && $twitter_enable) {
				require_once('library/twitteroauth.php');
				require_once('include/bbcode.php');	
				$tweet = new TwitterOAuth($ckey,$csecret,$otoken,$osecret);
				$max_char = 140; // max. length for a tweet
				$msg = strip_tags(bbcode($b['body']));
				if ( strlen($msg) > $max_char) {
					$shortlink = "";
					require_once('library/slinky.php');
					// post url = base url + /display/ + owner + post id
					// we construct this from the Owner link and replace
					// profile by display - this will cause an error when
					// /profile/ is in the owner url twice but I don't
					// think this will be very common...
					$posturl = str_replace('/profile/','/display/',$b['owner-link']).'/'.$b['id'];
					$slinky = new Slinky( $posturl );
					// setup a cascade of shortening services
					// try to get a short link from these services
					// in the order ur1.ca, trim, id.gd, tinyurl
					$slinky->set_cascade( array( new Slinky_UR1ca(), new Slinky_Trim(), new Slinky_IsGd(), new Slinky_TinyURL() ) );
					$shortlink = $slinky->short();
					// the new message will be shortened such that "... $shortlink"
					// will fit into the character limit
					$msg = substr($msg, 0, $max_char-strlen($shortlink)-4);
					$msg .= '... ' . $shortlink;
				}
                // and now tweet it :-)
				if(strlen($msg))
					$tweet->post('statuses/update', array('status' => $msg));
			}
		}
	}
}

function twitter_plugin_admin_post(&$a){
	$consumerkey	=	((x($_POST,'consumerkey'))		? notags(trim($_POST['consumerkey']))	: '');
	$consumersecret	=	((x($_POST,'consumersecret'))	? notags(trim($_POST['consumersecret'])): '');
	set_config('twitter','consumerkey',$consumerkey);
	set_config('twitter','consumersecret',$consumersecret);
	info( t('Settings updated.'). EOL );
}
function twitter_plugin_admin(&$a, &$o){
	$t = file_get_contents( dirname(__file__). "/admin.tpl" );
	$o = replace_macros($t, array(
		'$submit' => t('Submit'),
								// name, label, value, help, [extra values]
		'$consumerkey' => array('consumerkey', t('Consumer key'),  get_config('twitter', 'consumerkey' ), ''),
		'$consumersecret' => array('consumersecret', t('Consumer secret'),  get_config('twitter', 'consumersecret' ), '')
	));
}