How to parse the jwt token from controller $jwtManager->decode($jwt) using pure token ( token as a string )

Question

So I'm using Lexik JWT Authentication Bundle (Symfony 2.6) and successful created user and token using this code:

$userRegistration = new UserRegistration();
$userRegistration->setPassword($request->request->get('password'));
$userRegistration->setEmail($request->request->filter('email'));
$userRegistration->setName($request->request->filter('name'));

$token = $this->jwtManager->create($RegisteredUser);
return $this->responseProvider->ok((object) [
    'userId' => $RegisteredUser->getId(),
    'token' => $token
]);

Response :

"data": {
    "userId": 24,
    "token": "eyJhbGciOiJSUzI1NiJ9.eyJyb2xlcyI6WyJST0xFX1VTRVIiXSwidXNlcm5hbWUiOiJqYWdhZHVAaHViaWktbmV0d29yay5jb20iLCJleHAiOjE1MzYxNTI0MDAsImlhdCI6MTUzNTU0NzYwMH0.B7gnfGdW1ijAIlo9xUI0DwkGaajQAQPBkRx4ChILXRNtpLdwgEl_9gvWdiidFbSXJseS8jslOfuAFUIWATmbNBoWVa3nc8SxkIrKI29xZuN6hB7R-63RH2BKsAVPsEjgTIJoqkkCrfrSum-_d3LEf36jcXqZb8M-GRKI477IwSDDwG_7YK5v0mu8N4TATXhN0tZGNYxp8Y27EI-g0Gmj9BIiobxnqVVoBWHN5J8d-UCrXRq94ifhEiQBxkG9r_eacMscB80n1VsiN2ouKH2kX-HRxRJmcgmydxvR7RcEW-P6koTxkaZJGO6mv7auSudTFlDENpwD4OD7gtn_wMUDS_OuN8WT7rZp8lwKY9f8J9fiGyq5J-8C_HmyjW-h8WhuJmTUaKhCZ-eLgDm4Vs2IQGYkHJEDFumnIZ607MAa1CW1ChAvurqvUqJ3G4TTN4wYqAHpSKz4y8SAMLjO91cedBPH6K5i9lh5htF-mW_htem7e5ornicU_djSccgHbxfXHQYTHCnqLp7-ONfl_p4nmhIEK0wcF0gkBXbIitzeTjy7C_uf_FV1sLPE5cY3PUP42DmHrG4PuXHLv_L1EjErkrpna7pChKA_TPeiZjqMcQoE70sZw8rr8KnRF2hpABdU_M2ZXOt_vF5-T8mLmKqs0LHxE089vVC3xsAh0mUr4FE"
}

The problem started when I try to decode current token in other controller using jwtManager->decode method :

$jwt = "eyJhbGciOiJSUzI1NiJ9.eyJyb2xlcyI6WyJST0xFX1VTRVIiXSwidXNlcm5hbWUiOiJqYWdhZHVAaHViaWktbmV0d29yay5jb20iLCJleHAiOjE1MzYxNTI0MDAsImlhdCI6MTUzNTU0NzYwMH0.B7gnfGdW1ijAIlo9xUI0DwkGaajQAQPBkRx4ChILXRNtpLdwgEl_9gvWdiidFbSXJseS8jslOfuAFUIWATmbNBoWVa3nc8SxkIrKI29xZuN6hB7R-63RH2BKsAVPsEjgTIJoqkkCrfrSum-_d3LEf36jcXqZb8M-GRKI477IwSDDwG_7YK5v0mu8N4TATXhN0tZGNYxp8Y27EI-g0Gmj9BIiobxnqVVoBWHN5J8d-UCrXRq94ifhEiQBxkG9r_eacMscB80n1VsiN2ouKH2kX-HRxRJmcgmydxvR7RcEW-P6koTxkaZJGO6mv7auSudTFlDENpwD4OD7gtn_wMUDS_OuN8WT7rZp8lwKY9f8J9fiGyq5J-8C_HmyjW-h8WhuJmTUaKhCZ-eLgDm4Vs2IQGYkHJEDFumnIZ607MAa1CW1ChAvurqvUqJ3G4TTN4wYqAHpSKz4y8SAMLjO91cedBPH6K5i9lh5htF-mW_htem7e5ornicU_djSccgHbxfXHQYTHCnqLp7-ONfl_p4nmhIEK0wcF0gkBXbIitzeTjy7C_uf_FV1sLPE5cY3PUP42DmHrG4PuXHLv_L1EjErkrpna7pChKA_TPeiZjqMcQoE70sZw8rr8KnRF2hpABdU_M2ZXOt_vF5-T8mLmKqs0LHxE089vVC3xsAh0mUr4FE";
$test = $this->jwtManager->decode($jwt);

But the JWTManager::decode() must implement interface Symfony\Component\Security\Core\Authentication\Token\TokenInterface and not expect string given.

My goal is just to get userId form this token but can't find any information how to decode the token. Does anyone have any idea how to simply decode the token?

jps · Accepted Answer · 2023-05-24T09:40:28.023

Manually getting the information out of a token without using a JWT lib is quite simple.

A JWT string consists of 3 parts: The base64url encoded header and payload, both are JSON 'objects', and the signature. All 3 parts are separated by a ..

So you just need to split the token into its 3 parts, done here with explode, then decode the base64url encoded strings (base64_decode) and finally decode the JSON (json_decode):

$token = "eyJhbGciOiJSUzI1NiJ9.eyJyb2xlcyI6WyJST0xFX1VTRVIiXSwidXNlcm5hbWUiOiJqYWdhZHVAaHViaWktbmV0d29yay5jb20iLCJleHAiOjE1MzYxNTI0MDAsImlhdCI6MTUzNTU0NzYwMH0.B7gnfGdW1ijAIlo9xUI0DwkGaajQAQPBkRx4ChILXRNtpLdwgEl_9gvWdiidFbSXJseS8jslOfuAFUIWATmbNBoWVa3nc8SxkIrKI29xZuN6hB7R-63RH2BKsAVPsEjgTIJoqkkCrfrSum-_d3LEf36jcXqZb8M-GRKI477IwSDDwG_7YK5v0mu8N4TATXhN0tZGNYxp8Y27EI-g0Gmj9BIiobxnqVVoBWHN5J8d-UCrXRq94ifhEiQBxkG9r_eacMscB80n1VsiN2ouKH2kX-HRxRJmcgmydxvR7RcEW-P6koTxkaZJGO6mv7auSudTFlDENpwD4OD7gtn_wMUDS_OuN8WT7rZp8lwKY9f8J9fiGyq5J-8C_HmyjW-h8WhuJmTUaKhCZ-eLgDm4Vs2IQGYkHJEDFumnIZ607MAa1CW1ChAvurqvUqJ3G4TTN4wYqAHpSKz4y8SAMLjO91cedBPH6K5i9lh5htF-mW_htem7e5ornicU_djSccgHbxfXHQYTHCnqLp7-ONfl_p4nmhIEK0wcF0gkBXbIitzeTjy7C_uf_FV1sLPE5cY3PUP42DmHrG4PuXHLv_L1EjErkrpna7pChKA_TPeiZjqMcQoE70sZw8rr8KnRF2hpABdU_M2ZXOt_vF5-T8mLmKqs0LHxE089vVC3xsAh0mUr4FE";

$tokenParts = explode(".", $token);  
$tokenHeader = base64_decode($tokenParts[0]);
$tokenPayload = base64_decode($tokenParts[1]);
$jwtHeader = json_decode($tokenHeader);
$jwtPayload = json_decode($tokenPayload);
print $jwtPayload->username;

In the last line you have the desired information. But to be clear, $jwtPayload->username will of course only work if the token contains such a field. This is the case for the token provided in the question, but the fields in other tokens might be different.

You can also inspect your token on https://jwt.io to see which fields are in the payload. There's also a good introduction about JWT on that site.

There should be a check before decoding if the token is valid or not otherwise it will give some offset errors. — Muhammad, Apr 09 '21 at 14:56

score 11 · Answer 2 · answered Aug 31 '18 at 08:00

11

You can use the JWTEncoder service for this. The service name is lexik_jwt_authentication.jws_provider.lcobucci

Or if you want class named services use Lexik\Bundle\JWTAuthenticationBundle\Encoder\JWTEncoderInterface

The method you are looking for is decode()

$jwtEncoder->decode($yourToken);

answered Aug 31 '18 at 08:00

Iwan Wijaya

2,077
1
16
14

But if the JWT is expired, decode() will throw an Exception : ( – Med Karim Garali Jan 02 '20 at 00:25
1

Then catch the exception.. :) You won't use invalid, expired token. – Vural Feb 19 '20 at 09:53

score 1 · Answer 3 · answered Jul 06 '21 at 14:58

Please find my code for doing this without any libraries.

function decodeJWTPayloadOnly($token){
        $tks = explode('.', $token);
        if (count($tks) != 3) {
            return null;
        }
        list($headb64, $bodyb64, $cryptob64) = $tks;
        $input=$bodyb64;
        $remainder = strlen($input) % 4;
        if ($remainder) {
            $padlen = 4 - $remainder;
            $input .= str_repeat('=', $padlen);
        }
        $input = (base64_decode(strtr($input, '-_', '+/')));

        if (version_compare(PHP_VERSION, '5.4.0', '>=') && !(defined('JSON_C_VERSION') && PHP_INT_SIZE > 4)) {
            $obj = json_decode($input, false, 512, JSON_BIGINT_AS_STRING);
        } else {
            $max_int_length = strlen((string) PHP_INT_MAX) - 1;
            $json_without_bigints = preg_replace('/:\s*(-?\d{'.$max_int_length.',})/', ': "$1"', $input);
            $obj = json_decode($json_without_bigints);
        }
        return $obj;
}

finally a jwt decoder that doesn't need library, thank you! – radren Sep 19 '22 at 04:24 — radren, Sep 19 '22 at 04:24

How to parse the jwt token from controller $jwtManager->decode($jwt) using pure token ( token as a string )

3 Answers3