Facebook: Post on Page as Page issue (access token / php) - php

Question

I'm totally frustrated with my first facebook app project. I'm having major issues with what seems to be a simple task.
I want to setup a cron job on my server (easy) that will post something smart on a facebook page (not my profile), and it should be posted as page. I coded myself into a corner and am totally confused now... Can anyone help, please?
I've been thru pretty much every error message and am now stuck on
"OAuthException: Error validating application."
Here's what I have now:
First php -> Gets a new Access Token for my page access. This part seems to work fine, as I get the next page called and receive a new access token.
<?php
require_once 'facebook.php';
$app_id = "1234....";
$app_secret = "5678....";
$my_url = "http://.../next.php";
$facebook = new Facebook(array(
'appId' => $app_id,
'secret' => $app_secret,
'cookie' => true
));
// known valid access token stored in a database
$access_token = "abc....";
$code = $_REQUEST["code"];
// If we get a code, it means that we have re-authed the user
//and can get a valid access_token.
if (isset($code)) {
$token_url="https://graph.facebook.com/oauth/access_token?
client_id="
. $app_id . "&redirect_uri=" . urlencode($my_url)
. "&client_secret=" . $app_secret
. "&code=" . $code . "&display=popup";
$response = file_get_contents($token_url);
$params = null;
parse_str($response, $params);
$access_token = $params['access_token'];
}
// Attempt to query the graph:
$graph_url = "https://graph.facebook.com/me?"
. "access_token=" . $access_token;
$response = curl_get_file_contents($graph_url);
$decoded_response = json_decode($response);
//Check for errors
if ($decoded_response->error) {
// check to see if this is an oAuth error:
if ($decoded_response->error->type== "OAuthException") {
// Retrieving a valid access token.
$dialog_url= "https://www.facebook.com/dialog/oauth?"
. "client_id=" . $app_id
. "&redirect_uri=" . urlencode($my_url);
echo("<script> top.location.href='" . $dialog_url
. "'</script>");
} else {
echo "other error has happened";
}
} else {
// success
echo("success" . $decoded_response->name);
}
function curl_get_file_contents($URL) {
$c = curl_init();
curl_setopt($c, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($c, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($c, CURLOPT_URL, $URL);
$contents = curl_exec($c);
$err = curl_getinfo($c,CURLINFO_HTTP_CODE);
curl_close($c);
if ($contents) return $contents;
else return FALSE;
}
?>
Next php -> Read the access token and post on the wall. I get the access token from my query string, but then why do I receive the error message. My id, secret and page id are all in order...
<?php
require_once 'facebook.php';
$app_id = "1234....";
$app_secret = "5678....";
$page_id = "0909....";
$facebook = new Facebook(array(
'appId' => $app_id,
'secret' => $app_secret,
'cookie' => true
));
$access_token = $_GET['code'];
echo($access_token);
try {
$attachment = array(
'access_token' => $access_token,
'message'=> "Hello World"
);
$result = $facebook->api('/'.$page_id.'/feed','POST',
$attachment);
var_dump($result);
} catch(Exception $e) {
echo $e;
}
?>
I'm sure there is a simpler way to do so.... and a way to actually make it work!
Any help is appreciated!
I followed this script
Update facebook page status from that page itself
and this
https://developers.facebook.com/blog/post/500
Thank you.

Answer 1

// firstly include the fb sdk
$facebook = new Facebook(array(
'appId' => 'your app id',
'secret' => 'your app secret',`enter code here`
'cookie' => true,
));
$session = $facebook->getUser();
$loginUrl = $facebook->getLoginUrl(
array(
'scope' => 'user_status,publish_stream,email,user_location,user_birthday,friends_birthday,manage_pages',
'redirect_uri' => 'http://www.example.com/'
)
);
$logoutUrl = $facebook->getLogoutUrl(
array(
// any url u want to redirsct onto
'redirect_uri' => 'http://www.example.com/'
)
);
// when redirected from facebook get the code
$code = $_GET['code'];
//
$my_url = 'http://www.example.com/';
$app_id = 'your app id ';
$app_secret = 'your app secret ';
// here we have the access token so we will play with it
if (isset($code)) {
$token_url="https://graph.facebook.com/oauth/access_token?client_id="
. $app_id . "&redirect_uri=" . urlencode($my_url)
. "&client_secret=" . $app_secret
. "&code=" . $code ;
$response = file_get_contents($token_url);
$params = null;
parse_str($response, $params);
$user_access_token = $params['access_token'];
}
// here we got the access token of user over here in $user_access_token
// now we will get for our page
//------ get PAGE access token
$attachment_1 = array(
'access_token' => $user_access_token
);
$page_id = 'your page id ';
$result = $facebook->api("/me/accounts", $attachment_1);
foreach($result["data"] as $page) {
if($page["id"] == $page_id) {
$page_access_token = $page["access_token"];
break;
}
}
// write to page wall
try {
$attachment = array(
'access_token' => $page_access_token,
'message'=> 'hello world posting like admin!',
'page_id'=> $page_id
);
$result = $facebook->api('/'.$page_id.'/feed','POST',$attachment);
//$result = $facebook->api('/me/feed','POST', $attachment);
var_dump($result);
} catch(Exception $e) {
echo $e;
}

Answer 2

From your code, it appears you are not getting a PAGE access token which you need, but instead you're using a USER access token, hence why the API doesn't like it. For more information on how to get a PAGE access token from a USER one, please see the Page login section of https://developers.facebook.com/docs/authentication/

Answer 3

After many hours of trial and error, here's my solution that works so far.
<?php
require_once 'facebook.php';
//------ vars
$app_id = "123...";
$app_secret = "abc...";
$page_id = "999...";
$my_url = "http://exactly the same as defined /";
//------ fb object
$facebook = new Facebook(array(
'appId' => $app_id,
'secret' => $app_secret,
'cookie' => true
));
//------ verification CODE
// this is not pretty -> the code should be received with a another graph query...
// but I couldn't get this to work. Thus I'm using my last known Verification Code
$code = "ABC123...";
//------ get USER access token
if (isset($code)) {
$token_url="https://graph.facebook.com/oauth/access_token?client_id=" . $app_id
. "&client_secret=" . $app_secret
. "&code=" . $code
. "&redirect_uri=" . $my_url;
$response = file_get_contents($token_url);
$params = null;
parse_str($response, $params);
$user_access_token = $params['access_token'];
} else {
echo("No code");
}
//------ get PAGE access token
$attachment_1 = array(
'access_token' => $user_access_token
);
$result = $facebook->api("/me/accounts", $attachment_1);
foreach($result["data"] as $page) {
if($page["id"] == $page_id) {
$page_access_token = $page["access_token"];
break;
}
}
//------ write to page wall
try {
$attachment = array(
'access_token' => $page_access_token,
'message'=> 'hello world!'
);
$result = $facebook->api('/me/feed','POST', $attachment);
var_dump($result);
} catch(Exception $e) {
echo $e;
}
?>