Facebook的动态OG元数据

Question

I have a small web page that, every day, displays a one word answer - either Yes or No - depending on some other factor that changes daily.

Underneath this, I have a Facebook like button. I want this button to post, in the title/description, either "Yes" or "No", depending on the verdict that day.

I have set up the OG metadata dynamically using php to echo the correct string into the og:title etc. But Facebook caches the value, so someone sharing my page on Tuesday can easily end up posting the wrong content to Facebook.

I have confirmed this is the issue by using the Facebook object debugger. As soon as I force a refresh, all is well. I attempted to automate this using curl, but this doesn't seem to work.

$ch = curl_init();
$timeout = 30;
curl_setopt($ch, CURLOPT_URL, "http://developers.facebook.com/tools/lint/?url={http://ispizzahalfprice.com}");
curl_setopt($ch,CURLOPT_USERAGENT,'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.13) Gecko/20080311 Firefox/2.0.0.13');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
$data = curl_exec($ch);
curl_close($ch);
echo $data;

Am I missing some easy fix here? Or do I need to re-evaluate my website structure to acheive what I am looking for (e.g. use two separate pages)?

Here's the page in case it's useful: http://ispizzahalfprice.com

Answer 1

Using two separate URL's would be the safe bet. As you have observed, Facebook does quite heavy caching on URL scrapes. You've also seen that you, as the admin of the App, can flush and refresh Facebook's cache by pulling the page through the debugger again.

Using two URL's would solve this issue because Facebook could cache the results all they want! There will still be a separate URL for "yes" and one for "no".