facebook access token expired

Question

Based on facebook instructions (Scenario 4) i am using the following URL

https://graph.facebook.com/oauth/access_token?client_id=APP_ID&client_secret=CLIENT_SECRET& grant_type=fb_exchange_token&fb_exchange_token=OLD_ACCESS_TOKEN

to get the new access token but i get the following:

{ "error": { "message": "Error validating access token: Session has expired at unix time 1365257820. The current unix time is 1365759029.", "type": "OAuthException", "code": 190, "error_subcode": 463 } }

does not work. Any help appreciated.

EDIT: Got it! Works like this

if access token expires run the below php script first on the browser after you store it on your server

<?php
  $app_id = "your app id";
  $app_secret = "your app secret"; 
  $my_url = "http://apps.facebook.com/your_app_name";

  // known valid access token stored in a database 
  $access_token = "your old access token";

  $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" . $decoded_response->name);
    echo($access_token);
  }

  // note this wrapper function exists in order to circumvent PHP’s 
  //strict obeying of HTTP error codes.  In this case, Facebook 
  //returns error code 400 which PHP obeys and wipes out 
  //the response.
  function curl_get_file_contents($URL) {
    $c = curl_init();
    curl_setopt($c, CURLOPT_RETURNTRANSFER, 1);
    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;
  }
?>

the above script will give you a URL like the one below on the browser

https://graph.facebook.com/oauth/access_token?code=…

then get the string (should be something like this: AQCn41Svv5DbWrnFY0Wf.....YbNm_yz2rE#_ ) after code= and paste it on the code= URL below and RUN the URL below on the browser

https://graph.facebook.com/oauth/access_token?client_id=App_Id&redirect_uri=http://apps.facebook.com/poemsoflove&client_secret=App_Secret&code=AQCn41Svv5DbWrnFY0Wf.....YbNm_yz2rE#_&display=popup

you will get the following respond which is a new access token for 60 days

access_token=<Extended_Access_Token>&expires=5180130

copy and paste the string after the access_token= to the script on your server that publishes the new posts on your page

Answer 1

1. Create application Facebook Developer Page

After with php can get live access toke

$app_id = '{Application Id}';
$app_secret = '{Application Secret}';
$access_token = "https://graph.facebook.com/oauth/access_token?client_id=$app_id&client_secret=$app_secret&grant_type=client_credentials";
$access_token = file_get_contents($access_token); // returns 'accesstoken=APP_TOKEN|APP_SECRET'
$access_token = str_replace('access_token=', '', $access_token);