One way of significantly speeding up your website is by caching information you retrieve remotely from other websites or databases. Caching information is extremely simple and can save your users seconds of unnecessary waiting. Here’s how I cache my FeedBurner follower count on my site.

The PHP

/* settings */
$cache_path = '/cache/';
$rss_file_name = date('Y-m-d').'-rss.txt';

/* rss */
if(file_exists($cache_path.$rss_file_name)) {
	$rss_subcribers = file_get_contents($cache_path.$rss_file_name);
}
else {
	$rss_content = get_url('https://feedburner.google.com/api/awareness/1.0/GetFeedData?id=dfadajf324789fhSDFDf48');
	$subscribers = get_match('/circulation="(.*)"/isU',$rss_content);
	if($subscribers) {
		$subscribers = number_format($subscribers,0,'',',');
		file_put_contents($cache_path.$rss_file_name,$subscribers);
		$rss_subcribers = $subscribers;
	}
}

/* display */
echo 'My subscriber count is: ',$rss_subscribers;

/* connects to the URL, returns content */
function get_url($url) {
	$ch = curl_init();
	curl_setopt($ch,CURLOPT_URL,$url);
	curl_setopt($ch,CURLOPT_RETURNTRANSFER,1);
	curl_setopt($ch,CURLOPT_CONNECTTIMEOUT,1);
	$content = curl_exec($ch);
	curl_close($ch);
	return $content;
}

/* helper: does the regex */
function get_match($regex,$content) {
	preg_match($regex,$content,$matches);
	return $matches[1];
}

The first thing we do is check to see if our cached file exists. If it does, we simply return its contents. If the cache file doesn’t exist, we connect to our private FeedBurner URL, parse the content, and save the feed to a file named after the current day. Note the way we can check if we had gotten the count for the current day is by naming the file in “year-month-day” format.

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Retrieve, Cache, and Display Your FeedBurner Subscriber Count

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1. Get Your FeedBurner Reader Statistic Using PHP cURL and the FeedBurner API
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4. Retrieve Google Analytics Visits and PageViews with PHP
5. Add the Script & Style Feed to Your Website

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