function shift_days($date, $days) {

        return mktime(0, 0, 0, date("m", $date), date("d", $date) + $days, date("Y", $date));

 

function date2img($date) {

        return 'http://images.ucomics.com/comics/ga/' . date("Y", $date) . '/ga' . date("ymd", $date) . '.gif';

 

function date2url($date) {

        return 'http://www.gocomics.com/garfield/' . date("Y", $date) . '/' . date("m", $date) . '/' . date("d", $date);

 

function find_next_available_date($date, $cachedate) {

        $day = $date;

        $fp = fopen("/dev/null", "w");

        $i = 0;

        while(1) {

                if($day <= $cachedate)

                        break;

                $i++;

                if($i > 3) {

                        $i--;

                        break;

                }

                $ch = curl_init(date2img($day));

                curl_setopt($ch, CURLOPT_FAILONERROR, TRUE);

                curl_setopt($ch, CURLOPT_FOLLOWLOCATION, TRUE);

                curl_setopt($ch, CURLOPT_FILE, $fp);

                curl_exec($ch);

                $code = curl_getinfo($ch, CURLINFO_HTTP_CODE);

                curl_close($ch);

                if($code == 200)

                        break;

                $day = shift_days($day, -1);

        }

        fclose($fp);

        print("<!-- fetched $i url(s) -->\n");

        return $day;

 

 

$cache_file = ".rss-cache";

$count = intval($_REQUEST['n']);

if($count == 0)

        $count = 10;

$lastcheck = 0;

$cacheday = 0;

if(file_exists($cache_file)) {

        $handle = fopen($cache_file, "r");

        list($lastcheck, $cacheday) = fscanf($handle, "%u\t%u\n");

        fclose($handle);

$lastday = $cacheday;

if($cacheday == 0 || $lastcheck == 0 || (time() - $lastcheck) > 60*30) {

        $lastday = mktime(0, 0, 0, date("m"), date("d") + 1, date("Y"));

        $lastday = find_next_available_date($lastday, $cacheday);

        $handle = fopen($cache_file, "w");

        fwrite($handle, sprintf("%u\t%u\n", time(), $lastday));

        fclose($handle);

} else

        print("<!-- cache hit -->\n");

<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">

<channel>

<title>Garfield daily comic</title>

<link>http://www.garfield.com/comics/comics_todays.html</link>

<description>The daily comic of Garfield, from ucomics.com</description>

<docs>http://blogs.law.harvard.edu/tech/rss</docs>

<atom:link href="https://selif.yhsif.com/ga-rss.php" rel="self" type="application/rss+xml" />

for($i = 0; $i < $count; $i++) {

        $img = date2img($lastday);

        $url = date2url($lastday);

        $title = "Garfield comic " . date("Y-m-d", $lastday);

        $date = date("r", $lastday);

        $desc = "<![CDATA[<img src=\"$img\" />]]>";

        print <<<EOLAST

 

        $lastday = shift_days($lastday, -1);

</channel>

</rss>