CMS Made Simple user-defined tag to show latest tweets. Includes caching. Original source listed in comments.

gistfile1.aw

/**
* TWITTER FEED PARSER
* 
* @version    1.1.2
* @author    Jonathan Nicol
* @link    http://f6design.com/journal/2010/10/07/display-recent-twitter-tweets-using-php/
* 
* Notes:
* We employ caching because Twitter only allows their RSS feeds to be accesssed 150
* times an hour per user client.
* --
* Dates can be displayed in Twitter style (e.g. "1 hour ago") by setting the 
* $twitter_style_dates param to true.
* 
* Credits:
*
* Hashtag/username parsing based on: http://snipplr.com/view/16221/get-twitter-tweets/
* Feed caching: http://www.addedbytes.com/articles/caching-output-in-php/
* Feed parsing: http://boagworld.com/forum/comments.php?DiscussionID=4639
*
* CMS Made Simple usage:
*
* {tweets username="example" number="5"}
*/

$twitter_user_id = $params['username'];
$cache_file = './twitter.txt';
$tweets_to_display = (isset($params['number'])) ? $params['number'] : 5;
$ignore_replies = true;
$twitter_wrap_open = '<ul id="twitter">';
$twitter_wrap_close = '</ul>';
$tweet_wrap_open = '<li><span class="status">';
$meta_wrap_open = '</span><br><span class="meta"> ';
$meta_wrap_close = '</span>';
$tweet_wrap_close = '</li>';
$date_format = 'g:i A M jS';
$twitter_style_dates = true;

// Seconds to cache feed (1 hour).
$cachetime = 60*60;
// Time that the cache was last filled.
$cache_file_created = ((@file_exists($cache_file))) ? @filemtime($cache_file) : 0;

// A flag so we know if the feed was successfully parsed.
$tweet_found = false;

// Show file from cache if still valid.
if (time() - $cachetime < $cache_file_created) {

    $tweet_found = true;
    // Display tweets from the cache.
    @readfile($cache_file);    

} else {

    // Cache file not found, or old. Fetch the RSS feed from Twitter.
    $rss = @file_get_contents('http://twitter.com/statuses/user_timeline/'.$twitter_user_id.'.rss');

    if($rss) {

        // Parse the RSS feed to an XML object.
        $xml = @simplexml_load_string($rss);

        if($xml !== false) {

            // Error check: Make sure there is at least one item.
            if (count($xml->channel->item)) {

                $tweet_count = 0;

                // Start output buffering.
                ob_start();

                // Open the twitter wrapping element.
                $twitter_html = $twitter_wrap_open;

                // Iterate over tweets.
                foreach($xml->channel->item as $tweet) {

                    // Twitter feeds begin with the username, "e.g. User name: Blah"
                    // so we need to strip that from the front of our tweet.
                    $tweet_desc = substr($tweet->description,strpos($tweet->description,":")+2);
                    $tweet_desc = htmlspecialchars($tweet_desc);
                    $tweet_first_char = substr($tweet_desc,0,1);

                    // If we are not gnoring replies, or tweet is not a reply, process it.
                    if ($tweet_first_char!='@' || $ignore_replies==false){

                        $tweet_found = true;
                        $tweet_count++;

                        // Add hyperlink html tags to any urls, twitter ids or hashtags in the tweet.
                        $tweet_desc = preg_replace('/(https?:\/\/[^\s"<>]+)/','<a href="$1">$1</a>',$tweet_desc);
                        $tweet_desc = preg_replace('/(^|[\n\s])@([^\s"\t\n\r<:]*)/is', '$1<a href="http://twitter.com/$2">@$2</a>', $tweet_desc);
                        $tweet_desc = preg_replace('/(^|[\n\s])#([^\s"\t\n\r<:]*)/is', '$1<a href="http://twitter.com/search?q=%23$2">#$2</a>', $tweet_desc);

                         // Convert Tweet display time to a UNIX timestamp. Twitter timestamps are in UTC/GMT time.
                        $tweet_time = strtotime($tweet->pubDate);    
                         if ($twitter_style_dates == true){
                            // Current UNIX timestamp.
                            $current_time = time();
                            $time_diff = abs($current_time - $tweet_time);
                            switch ($time_diff) 
                            {
                                case ($time_diff < 60):
                                    $display_time = $time_diff.' seconds ago';                  
                                    break;      
                                case ($time_diff >= 60 && $time_diff < 3600):
                                    $min = floor($time_diff/60);
                                    $display_time = $min.' minutes ago';                  
                                    break;      
                                case ($time_diff >= 3600 && $time_diff < 86400):
                                    $hour = floor($time_diff/3600);
                                    $display_time = 'about '.$hour.' hour';
                                    if ($hour > 1){ $display_time .= 's'; }
                                    $display_time .= ' ago';
                                    break;          
                                default:
                                    $display_time = date($date_format,$tweet_time);
                                    break;
                            }
                         } else {
                             $display_time = date($date_format,$tweet_time);
                         }

                        // Render the tweet.
                        $twitter_html .= $tweet_wrap_open.$tweet_desc.$meta_wrap_open.'<a href="' . $tweet->link . '">'.$display_time.'</a>'.$meta_wrap_close.$tweet_wrap_close;

                    }

                    // If we have processed enough tweets, stop.
                    if ($tweet_count >= $tweets_to_display){
                        break;
                    }

                }

                // Close the twitter wrapping element.
                $twitter_html .= $twitter_wrap_close;
                echo $twitter_html;

                // Generate a new cache file.
                $file = @fopen($cache_file, 'w');

                // Save the contents of output buffer to the file, and flush the buffer. 
                @fwrite($file, ob_get_contents()); 
                @fclose($file); 
                ob_end_flush();

            }
        }
    }
} 
// In case the RSS feed did not parse or load correctly, show a link to the Twitter account.
if (!$tweet_found){
    echo $twitter_wrap_open.$tweet_wrap_open.'Oops, our twitter feed is unavailable right now. '.$meta_wrap_open.'<a href="http://twitter.com/'.$twitter_user_id.'">Follow us on Twitter</a>'.$meta_wrap_close.$tweet_wrap_close.$twitter_wrap_close;
}