Simple Twitter Feed display with caching.

SimpleTwitterFeed.php

<?php

$twitter_name = '';
$number_of_tweets = 2;

$url = "https://api.twitter.com/1/statuses/user_timeline/$twitter_name.xml?count=$number_of_tweets&include_rts=1callback=?";

$cache_expire = 3600; // in seconds

$ts = time();
$info_file = 'tmp-info.txt';
$cache_file = 'tmp-'.$ts.'.xml';

// current info
$info = unserialize(@file_get_contents($info_file));

if (empty($info) OR $ts > ($info['cache_ts'] - $cache_expire))
{
    $ch = curl_init();
    curl_setopt ($ch, CURLOPT_URL, $url);
    curl_setopt ($ch, CURLOPT_RETURNTRANSFER, 1);
    $content = curl_exec($ch);
    curl_close($ch);

    // if a description tag is present we're OK
    if (preg_match('/<description>/iS',$content))
    {
        file_put_contents($cache_file,$content);
        @unlink($info['cache_file']);
    }

    // known error strings: "over capacity", "rate limit exceeded"
    // else if a description tag is not present something is wrong
    else
    {
        // use current cache until errors resolve itself
        $cache_file = $info['cache_file'];

        $content = file_get_contents($info['cache_file']);
    }

    // update next cache time and cache file name
    file_put_contents($info_file,serialize(array('cache_ts'=>$ts,'cache_file'=>$cache_file)));
    }
    else
    {
        $content = file_get_contents($info['cache_file']);
    }

    $feed = array();

    $doc = new DOMDocument();
    $doc->loadXML($content);

    foreach ($doc->getElementsByTagName('status') as $node)
    {
        array_push($feed, array
        (
            'title' => $node->getElementsByTagName('title')->item(0)->nodeValue,
            'desc' => preg_replace('/^w :/i','',$node->getElementsByTagName('text')->item(0)->nodeValue),
            'link' => 'http://www.twitter.com/' . $twitter_name . '/status/' . $node->getElementsByTagName('id')->item(0)->nodeValue,
            'date' => $node->getElementsByTagName('created_at')->item(0)->nodeValue
        ));
    }

    function relativedate($secs) {
            $second = 1;
            $minute = 60;
            $hour = 60*60;
            $day = 60*60*24;
            $week = 60*60*24*7;
            $month = 60*60*24*7*30;
            $year = 60*60*24*7*30*365;

            if ($secs <= 0)
            {
                $output = "now";
            }
            elseif ($secs > $second && $secs < $minute)
            {
                $output = round($secs/$second)." second";
            }
            elseif ($secs >= $minute && $secs < $hour)
            {
                $output = round($secs/$minute)." minute";
            }
            elseif ($secs >= $hour && $secs < $day)
            {
                $output = round($secs/$hour)." hour";
            }
            elseif ($secs >= $day && $secs < $week)
            {
                $output = round($secs/$day)." day";
            }
            elseif ($secs >= $week && $secs < $month)
            {
                $output = round($secs/$week)." week";
            }
            elseif ($secs >= $month && $secs < $year)
            {
                $output = round($secs/$month)." month";
            }
            elseif ($secs >= $year && $secs < $year*10)
            {
                $output = round($secs/$year)." year";
            }
            else
            {
                $output = " more than a decade ago";
            }

            if ($output <> "now"){
                $output = (substr($output,0,2)<>"1 ") ? $output."s" : $output;
            }
            return $output;
        }

    foreach($feed as $row)
    {
        echo('<div>'.$row['desc'].'<span><a href="'.$row['link'].'">'.relativedate(time()-strtotime($row['date'])).' ago</a></span></div>');
    }

?>

Just fyi line 17 should be:

if (empty($info) OR $ts > ($info['cache_ts'] + $cache_expire)) // Note the plus instead of the minus.

Otherwise the Cache always expires and you will always be polling for the new version.

Credit to Kevin Relland for noticing this.