Laravel Passport - oauth/token gives Client authentication failed - php

Question

I've installed Laravel Passport.
Here is how I generate auth code:
public function auth(Request $request)
{
$request->session()->put('state', $state = Str::random(40));
$request->session()->put(
'code_verifier', $code_verifier = Str::random(128)
);
$codeChallenge = strtr(rtrim(
base64_encode(hash('sha256', $code_verifier, true))
, '='), '+/', '-_');
$query = http_build_query([
'client_id' => '1',
'redirect_uri' => 'http://127.0.0.1:8000/authorize/response',
'response_type' => 'code',
'scope' => '',
'state' => $state,
'code_challenge' => $codeChallenge,
'code_challenge_method' => 'S256',
]);
return redirect('http://127.0.0.1:9000/oauth/authorize?'.$query);
}
Above request all passes well.
Here is how I try to generate access token:
public function authResponse(Request $request)
{
$state = $request->session()->pull('state');
throw_unless(
strlen($state) > 0 && $state === $request->state,
InvalidArgumentException::class
);
$response = Http::asForm()->post('http://127.0.0.1:9000/oauth/token', [
'grant_type' => 'authorization_code',
'client_id' => '1',
'client_secret' => 'hYMELQ1VKAWrG0TwrkM3JxUuoICSCWCzCztClZZi',
'redirect_uri' => 'http://127.0.0.1:8000/authorize/response',
'code' => $request->code,
]);
return $response->json();
}
When I execute the code for generating the access token I get the following error:
{"error":"invalid_client","error_description":"Client authentication
failed","message":"Client authentication failed"}
Any idea what can be the cause of this error? I've taken the client_secret from the DB.
Any idea what can be the problem and how can I fix it?

Answer 1

You are missing to pull from session the code_verifier on your authResponse() method.
$codeVerifier = $request->session()->pull('code_verifier');
Then add the $codeVerifier to the 'code_verifier' in post method when your are converting authorization codes to access tokens.
$response = Http::asForm()->post('http://127.0.0.1:9000/oauth/token', [
'grant_type' => 'authorization_code',
'client_id' => '1',
'client_secret' => 'hYMELQ1VKAWrG0TwrkM3JxUuoICSCWCzCztClZZi',
'redirect_uri' => 'http://127.0.0.1:8000/authorize/response',
'code' => $request->code,
]);
Check out the docs about this.