Laravel Token Signature could not be verified - php

Question

I'm using Laravel/Lumen as an API for the backend of a webapp and run into a hiccup.
In an example I have a route that does not need the user to be authenticated. But I do want to check in the routes controller if the user visiting has a valid token.
So I wrote the following:
if ($tokenFetch = JWTAuth::parseToken()->authenticate()) {
$token = str_replace("Bearer ", "", $request->header('Authorization'));
} else {
$token = '';
}
I believe the above will check the Bearer token is valid else it will return a blank variable.
The following is my entire Controller.
public function show($url, Request $request)
{
if ($tokenFetch = JWTAuth::parseToken()->authenticate()) {
$token = str_replace("Bearer ", "", $request->header('Authorization'));
} else {
$token = 'book';
}
return response()->json(['token' => $token]);
}
The Problem
If I a pass in a valid Token Bearer, it returns the token but if I pass in an invalid one I get the following error:
TokenInvalidException in NamshiAdapter.php line 62:
Token Signature could not be verified.
If I don't pass a token at all:
JWTException in JWTAuth.php line 195:
The token could not be parsed from the request
Is there a way to check if a token is passed and if it has then check if its valid, but also if one has not been passed then return a blank return?

Answer 1

You can wrap it inside try/catch block
public function show($url, Request $request)
{
try {
$tokenFetch = JWTAuth::parseToken()->authenticate())
$token = str_replace("Bearer ", "", $request->header('Authorization'));
}catch(\Tymon\JWTAuth\Exceptions\JWTException $e){//general JWT exception
$token = 'book';
}
return response()->json(['token' => $token]);
}
There are few exceptions that you might want to handle separately (jwt-auth/Exceptions)
Also as you're using laravel 5 you can global handling for JWT exceptions ,not recommended in this case but you should know of this option and choose yourself. app/Exceptions/Handler.php and inside render method add [at the top]
if ($e instanceof \Tymon\JWTAuth\Exceptions\JWTException) {
//what happen when JWT exception occurs
}

Answer 2

Yes it's possible to achieve what you want.
Check if a token is passed:
If you check in the documentation of parseToken you'll see that the algorithm to check if we pass a token is:
if (! $token = $this->parseAuthHeader($header, $method)) {
if (! $token = $this->request->query($query, false)) {
}
}
// which it will be in your case:
$hasToken = true;
$header = $request->headers->get('authorization');
if (! starts_with(strtolower('authorization'), 'bearer')) {
if (! $request->query('token', false)) {
$hasToken = false;
}
}
Check if a token is valid:
Please note that the NamshiAdapter use the Namshi\JOSE package so read the documentation here.
In NamshiAdapter.php as you can see the line who rise your error are:
if (! $jws->verify($this->secret, $this->algo)) {
throw new TokenInvalidException('Token Signature could not be verified.');
}
// in your case:
// + try to var_dump $this->secret, $this->algo
// + use Namshi\JOSE\JWS
// if you var_dump
$jsw = new JWS(['typ' => 'JWT', 'alg' => $algo]);
$jws = $this->jws->load($token, false);
// if you want to follow the documentation of Namshi\JOSE
$jws = JWS::load($tokenString, false, $encoder, 'SecLib');
// again var_dump for $this->secret, $this->algo
$isValidToken = ($jws->verify($this->secret, $this->algo));