Facebook SDK returned an error: Cross-site request forgery validation failed. The “state” param from the URL and session do not match

Question

i\'m trying to get Facebook user id using the php sdk like this

$fb = new Facebook\\Facebook([
    \'app_id\' => \'11111111111\',
    \'app_secret\' =>         


        

Answer 1

Finally, looking into FB code, I discovered that the problem

Cross-site request forgery validation failed. Required param “state” missing

and similars are caused by PHP variable $_SESSION['FBRLH_state'] that for some "strange" reason when FB call the login-callback file.

To solve it I store this variable "FBRLH_state" AFTER the call of function $helper->getLoginUrl(...). Is very important to do only after the call of this function due to is inside this function when the variable $_SESSION['FBRLH_state'] is populated.

Below an example of my code in the login.php:

$uri=$helper->getLoginUrl($uri, $permissions);
foreach ($_SESSION as $k=>$v) {                    
    if(strpos($k, "FBRLH_")!==FALSE) {
        if(!setcookie($k, $v)) {
            //what??
        } else {
            $_COOKIE[$k]=$v;
        }
    }
}
var_dump($_COOKIE);

And in the login-callback.php before calling all FB code:

foreach ($_COOKIE as $k=>$v) {
    if(strpos($k, "FBRLH_")!==FALSE) {
        $_SESSION[$k]=$v;
    }
}

Last, but not least, remember also to include code for PHP session so..

if(!session_id()) {
    session_start();
}
...
...
...
...

I hope this response can help you to save 8-10 hours of work :) Bye, Alex.