However, as my script relies on screen scraping, problems do occur when TFL decide to change their HTML or site structure which has happened recently. Previously, every tube line had it’s own page with it’s messages listed on it but now there is one single page with all of them shown and hidden with javascript. This meant that for a short period, my API was posting out the messages for every single line with each line returned (so if you wanted to look at circle line messages, you would in fact get every line).

This has now been fixed and actually makes the service slightly better for me as it now means I can crawl just 3 pages rather than the 14 I was crawling before (thus better for both bandwidth and CPU cycles). I have a number of functions set up to report when TFL change their site structure as the usual problem is that a site redesign changes class names or markup in such a way that the API just breaks. However, in this case none of these warnings kicked in as it was getting the data correctly and all seemed to be ok.

So, a big thank you to those of you that emailed in to report the bug! If you have any questions about the Tube Updates API, then please check out the site or drop me an email.

So, I’m pleased to say that I’m working on some major updates which will provide not only the current RSS feed but also a full REST API and dedicated site so you can get more data and more flexibility into your applications.

I should have everything ready in the next few days so sign up to my RSS feed to be notified when the new service goes live! If you have any suggestions, please contact me.

Previously I have used the script at conor.net to power any projects requiring a tube RSS feed but this went down a few weeks ago when I was in the middle of some crucial testing. So, like any other crazy developer would, I decided to write my own PHP scraping script that would generate me a nice RSS feed to basically tell me TFL had messed up my journey home!

For those of you just looking for an RSS feed of the London Underground tube delays, you can find it at http://tube.bendodson.com/rss.xml – This is automatically updated every 5 minutes and will email me if anything goes wrong so I can fix it! If you are going to use it for any projects, please let me know so that I can monitor bandwidth, etc. If you are interested in how it works, then the code that powers this is below – feel free to use and modify it for your own projects:

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<?php
 
// This file should be run on a CRON job every 5 minutes.
// The server will need to be able to write to this folder in order to create the XML file.
 
$array = array(
        'bakerloo',
        'central',
        'circle',
        'district',
        'east london',
        'hammersmith & city',
        'jubilee',
        'metropolitan',
        'northern',
        'piccadilly',
        'victoria',
        'waterloo & city'
        );
 
$i = 0;
foreach ($array as $ref) {
    $id = str_replace(' ','',$ref);
    $id = str_replace('&','and',$id);
 
    $lines[$i]['id'] = $id;
    $lines[$i]['name'] = ucwords($ref);
    $lines[$i]['url'] = 
        'http://www.tfl.gov.uk/tfl/livetravelnews/realtime/tube/tube-' . $id . '-now.html';
 
    $i++;
}
 
$i = 0;
foreach ($lines as $line) {
    $file = file_get_contents($line['url']);
    $needle = strtoupper($line['ref']) . ' LINE:';
    $pos = strpos($file,$needle);
    if ($pos !== false) {
        $pos += strlen($needle);
        $end = strpos($file,'</div>',$pos);
         $status = strip_tags(substr($file,$pos,($end-$pos)));
    } else {
        $status = 'A good service is currently running.';
    }
 
    $lines[$i]['status'] = $status;
    $i++;
}
 
$now = date('r');
 
$xml = <<<XML
 
<rss version="2.0">
    <channel>
        <title>London Tube Updates</title>
        <link>http://www.tfl.gov.uk/tfl/livetravelnews/realtime/tube/default.html</link>
        <description>The latest London Underground tube update information</description>
        <language>en</language>
        <pubDate>$now</pubDate>
        <lastBuildDate>$now</lastBuildDate>
        <docs>http://tube.bendodson.com/</docs>
        <webMaster>ben@bendodson.com (Ben Dodson)</webMaster>
        <generator>PHP script by Ben Dodson</generator>
        <ttl>5</ttl>
        <image>
            <title>Transport for London</title>
            <url>http://www.tfl.gov.uk/tfl-global/images/roundel.gif</url>
            <link>http://www.tfl.gov.uk/</link>
            <width>52</width>
            <height>44</height>
            <description>Transport for London Logo</description>
        </image>
XML;
 
foreach ($lines as $line) {
    $xml .= '<item>' . "\r\n";
    $xml .= '<title>' . htmlentities(ucwords($line['name'])) . '</title>' . "\r\n";
    $xml .= '<link>' . $line['url'] . '</link>' . "\r\n";
    $xml .= '<description>' . htmlentities($line['status']) . '</description>' . "\r\n";
    $xml .= '</item>' . "\r\n";
}
 
$xml .= '</channel>' . "\r\n";
$xml .= '</rss>';
 
file_put_contents('rss.xml',$xml);
 
?>

As I mentioned earlier, I am working on a few projects that utilise this script and I shall be making those available shortly. However, for a sneak peek, you can check out iTube, my Web App for iPhone that keeps you up-to-date on all of the London Underground lines. There are still a few improvements to be made but you get the general idea!