问题
I'm aware you can force update a page's cache by entering the URL on Facebook's debugger tool while been logged in as admin for that app/page: https://developers.facebook.com/tools/debug
But what I need is a way to automatically call an API endpoint or something from our internal app whenever somebody from our Sales department updates the main image of one of our pages. It is not an option to ask thousands of sales people to login as an admin and manually update a page's cache whenever they update one of our item's description or image.
We can't afford to wait 24 hours for Facebook to update its cache because we're getting daily complaints from our clients whenever they don't see a change showing up as soon as we change it on our side.
回答1:
Page metadata isn't the sort of thing that should change very often, but you can manually clear the cache by going to Facebook's Debug Tool and entering the URL you want to scrape
There's also an API for doing this, which works for any OG object:
curl -X POST \
-F "id={object-url OR object-id}" \
-F "scrape=true" \
-F "access_token={your access token}" \
"https://graph.facebook.com"
An access_token is now required. This can be an app or page access_token; no user authentication is required.
回答2:
If you'd like to do this in PHP in a with-out waiting for a reply, the following function will do this:
//Provide a URL in $url to empty the OG cache
function clear_open_graph_cache($url, $token) {
$vars = array('id' => $url, 'scrape' => 'true', 'access_token' => $token);
$body = http_build_query($vars);
$fp = fsockopen('ssl://graph.facebook.com', 443);
fwrite($fp, "POST / HTTP/1.1\r\n");
fwrite($fp, "Host: graph.facebook.com\r\n");
fwrite($fp, "Content-Type: application/x-www-form-urlencoded\r\n");
fwrite($fp, "Content-Length: ".strlen($body)."\r\n");
fwrite($fp, "Connection: close\r\n");
fwrite($fp, "\r\n");
fwrite($fp, $body);
fclose($fp);
}
回答3:
If you're using the javascript sdk, the version of this you'd want to use is
FB.api('https://graph.facebook.com/', 'post', {
id: [your-updated-or-new-link],
scrape: true
}, function(response) {
//console.log('rescrape!',response);
});
I happen to like promises, so an alternate version using jQuery Deferreds might be
function scrapeLink(url){
var masterdfd = $.Deferred();
FB.api('https://graph.facebook.com/', 'post', {
id: [your-updated-or-new-link],
scrape: true
}, function(response) {
if(!response || response.error){
masterdfd.reject(response);
}else{
masterdfd.resolve(response);
}
});
return masterdfd;
}
then:
scrapeLink([SOME-URL]).done(function(){
//now the link should be scraped/rescraped and ready to use
});
Note that the scraper can take varying amounts of time to complete, so no guarantees that it will be quick. Nor do I know what Facebook thinks about repeated or automated usages of this method, so it probably pays to be judicious and conservative about using it.
回答4:
This is a simple ajax implementation. Put this on any page you want facebook to scrape immediately;
var url= "your url here";
$.ajax({
type: 'POST',
url: 'https://graph.facebook.com?id='+url+'&scrape=true',
success: function(data){
console.log(data);
}
});
回答5:
An alternative solution from within a Drupal node update using curl could be something like this :
<?php
function your_module_node_postsave($node) {
if($node->type == 'your_type') {
$url = url('node/'.$node->nid,array('absolute' => TRUE));
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'https://graph.facebook.com/v1.0/?id='. urlencode($url). '&scrape=true');
$auth_header = 'Oauth yOUR-ACCESS-TOKEn';
curl_setopt($ch, CURLOPT_HTTPHEADER, array($auth_header));
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
$r = curl_exec($ch);
curl_close ($ch);
}
}
Notice the hook_node_postsave() implementation which is not standard Drupal core supported. I had to use www.drupal.org/project/hook_post_action in order to get this facebook scrape pickup last made changes to the node, since hook_node_update() is not triggered after databases have been updated.
Facebook requires now the access token in order to get this done. Guidelines to acquire a token can be found here : https://smashballoon.com/custom-facebook-feed/access-token/
回答6:
I'm the author of Facebook Object Debugger CLI, a command-line interface written in PHP, aim to refresh the Facebook cache for a single URL or a bunch of URLS using as input a text file. The package is also available on Packagist and can be installed using Composer.
回答7:
There are changes in Graph API v2.10:
When making a GET request against a URL we haven't scraped before, we will also omit the og_object field. To trigger a scrape and populate the og_object, issue a POST /{url}?scrape=true. Once scraped, the og_object will remain cached and returned on all future read requests.
We will require an access token for these requests in all versions of the Graph API beginning October 16, 2017.
Source: Introducing Graph API v2.10
So now we should use POST-method for scraping:
POST /{url}?scrape=true
Not
回答8:
A solution with the PHP Facebook SDK:
<?php
try {
$params = [
'id' => 'https://www.mysitetoscrape.com/page',
'scrape' => 'true',
];
$response = $fb->post('/', $params);
print_r($response);
} catch(\Facebook\Exceptions\FacebookResponseException $e) {
// When Graph returns an error
echo 'Graph returned an error: ' . $e->getMessage();
} catch(\Facebook\Exceptions\FacebookSDKException $e) {
// When validation fails or other local issues
echo 'Facebook SDK returned an error: ' . $e->getMessage();
}
?>
回答9:
Here's my Ruby solution using Koala gem and Facebook API v2.9
api = Koala::Facebook::API.new(access_token)
response = api.put_object(nil, nil, {scrape: true, id: "url-of-page-to-scrape"})
response should be a hash of attributes retrieved from the og: meta tags on the page which was scraped.
回答10:
I was facing this same problem. There is a simple way to clear cache.
- http://developers.facebook.com/tools/debug
- Enter the URL following by fbrefresh=CAN_BE_ANYTHING
Examples: http://www.example.com?fbrefresh=CAN_BE_ANYTHING
来源：https://stackoverflow.com/questions/12100574/is-there-an-api-to-force-facebook-to-scrape-a-page-again