Use PHP cURL to get your Google Feedburner subscriber count text, with result caching

The problem

Recently I was looking for a simple, clean way to pull my total feed subscriber count from Google's FeedBurner, so I could style it as I liked. Something like these (and no, I don't have 323 readers, that's just for styling purposes);

• 323 subscribers
• "323 subscribers"
• 323 RSS readers

As always, I searched for an existing solution first, and I arrived at Hongkiat's little code snippet, very useful, uses cURL, almost perfect, except that this code will run on every single page view, that's way too much overhead. Though I can't find any documentation anywhere, I doubt Google's Feedburner updates subscriber counts more than a few times a day, if that.

The solution

Simple, we'll just cache the result to a plain text file, and only use the cURL functions after a period of time.

The code

Simply edit the highlighted bits to get it the way you want;

<?php
//path to file that will store the subscriber count
$feed_file = '/home/yoursite/feedcounter.txt';

 // update after how many minutes, 15 minutes, 120 minutes, etc
$feed_timer = '240';

if (!file_exists($feed_file)) {
    $time = time() - ($feed_timer * 60) - 60; 
    touch($feed_file, $time); // create the file and set it past the timer so it will update
}

if (filemtime($feed_file) + ($feed_timer * 60) > time()) { //check if it's old
    $feedcount = file_get_contents($feed_file);
    echo $feedcount;
} else {
    //get cool feedburner count
    $whaturl="https://feedburner.google.com/api/awareness/1.0/GetFeedData?uri=feedburner-id";

    //Initialize the Curl session
    $ch = curl_init();

    //Set curl to return the data instead of printing it to the browser.
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

    //Set the URL
    curl_setopt($ch, CURLOPT_URL, $whaturl);

    //Execute the fetch
    $data = curl_exec($ch);

    //Close the connection
    curl_close($ch);
    $xml = new SimpleXMLElement($data);
    $fb = $xml->feed->entry['circulation'];
    //end get cool feedburner count
    
    //echo the subscriber count
    echo $fb;
    //save the subscriber count to cache
    fwrite(fopen($feed_file, "w"), $fb);
}
?>

You can paste that code directly inside existing code, or simply save it as a separate file, something like feedcount.php, then include it wherever you'd like the count to appear, i.e.;

include('feedcount.php');

Notes:

As DJ Nightlife noted in the comments, if you're getting "permission denied" errors, make sure you've activated "Awareness API" in your feedburner account.

That's it.