facebook php sdk - Error #200 when trying to use setExtendedAccessToken - php

Question

I have been trying for several days now to successfully post to a client's Facebook Page wall from their website. I need to be able to do this without having a user logged in, which I was able to achieve with an extended access token generated by going to the URL provided in the docs.
What I am trying to do is to fetch an extended token using the PHP SDK as in this question - Facebook PHP SDK: getting "long-lived" access token now that "offline_access" is deprecated, however I receive the following error:
(#200) The user hasn't authorized the application to perform this action
The debug of the auth token generated by the Graph API Explorer shows myself as the User and includes the needed manage_pages and status_update scopes. However, if I run me/accounts, the perms array does not list these under the data for the page in question - not sure if this is relevant.
Here is the code that I have attempted to use:
$facebook = new Facebook(array('appId' => 'xxxxxxx', 'secret' => 'xxxxxx'));
$pageID = 'xxxxxxxx';
$facebook->setExtendedAccessToken();
$accessToken = $facebook->getAccessToken();
try {
$page_info = $facebook->api("/$pageID?fields=access_token");
print_r ($page_info);
} catch (FacebookApiException $e) {
echo $e->getMessage();
}
if( !empty($accessToken) ) {
$args = array(
'access_token' => $accessToken,
'message' => "Catch phrase!"
);
$facebook->api("/$pageID/feed","post",$args);
} else {
// Handle error
}
UPDATE
I found that if I echoed the output of getAccessToken() the result was the app ID and the secret separated by an | - is this what I should be receiving? Seems odd to me since all of the other tokens I have seen are random and much longer.
ANY help at all would be appreciated, I have wasted so much time on this so far. It just seems to work for everyone else.
UPDATE 2
Hi Warren! Looks like you're new around these parts, welcome! Thanks for your research into this, do I need to save these tokens into a DB table and check to see if they are expired every time I try to post? I am ONLY posting to a Page as the Page, apparently this requires the Page access_token rather than what I am assuming is the USER access_token. I believe I also read somewhere that the Page access token never expires, although it changes if I refresh the Graph API Explorer page or request a new user token. Very puzzling.. do not know if I even need to deal with getting new tokens in this app or just use a Page access_token that appears to work?

Answer 1

Also just looking at the base_facebook.php file and the following function:
/**
* Returns the access token that should be used for logged out
* users when no authorization code is available.
*
* #return string The application access token, useful for gathering
* public information about users and applications.
*/
protected function getApplicationAccessToken() {
return $this->appId.'|'.$this->appSecret;
}
Shows what you are experiencing the function setExtendedAccessToken() calls getAccessToken() which calls the function above to do the following inside setExtendedAccessToken:
$access_token_response = $this->_oauthRequest(
$this->getUrl('graph', '/oauth/access_token'),
$params = array(
'client_id' => $this->getAppId(),
'client_secret' => $this->getAppSecret(),
'grant_type' => 'fb_exchange_token',
'fb_exchange_token' => $this->getAccessToken(),
)
);
the return of this function is then {"error":{"message":"No user access token specified","type":"OAuthException","code":1}} but because there is no access_token the function just returns false
the fb_exchange_token can not be the app id and app secret combined.

Answer 2

I have done some testing and what I have found out is if you get the user to login, you can get there access token. If you pass this token into setAccessToken then run setExtendedToken. If you then save the toke by running getAccessToken you can use this token later when the user is logged out.
$facebook->setAccessToken($facebook->getAccessToken());
$facebook->setExtendedAccessToken();
$access_token = $facebook->getAccessToken(); // save this for later use
You need to get the user to login to ask them for permission to get access to there account. If you need to get access to a facebook page make sure they are an admin and ask for the manage_page permission.
Hope this helps

Answer 3

From what I have found so far the extended token that is returned when the user is logged in does not expire as you do not get back a unix timestamp so you would have no way of knowing when it expires.
This is what I have done in my application.
Request the user to login to facebook and except the access permissions. Use getAccessToken to get the current access token. With this I pass into getExtendedAccessToken then run getAccessToken again to finally get the extended access token which I store in a database for later use.

Answer 4

$facebook = new Facebook(array(
'appId' => 'YOURAPPID',
'secret' => 'YOURSECRET',
));
$params = array(
'scope'=>'publish_stream,manage_pages'
);
$loginUrl = $facebook->getLoginUrl($params); // Use this to request them to login in then when they are do the following you will need them to return to your app
$facebook = new Facebook(array(
'appId' => 'YOURAPPID',
'secret' => 'YOURSECRET',
));
$facebook->setAccessToken($facebook->getAccessToken());
$facebook->setExtendedAccessToken();
$access_token = $facebook->getAccessToken(); // store $access_token for later use