README

PHP RFC 7636 - Proof Key for Code Exchange by OAuth Public Clients (PKCE) implementation independent of OAuth servers.

Why this package?

Already known OAuth2 server implementations (eg league/oauth2-server) implement PKCE, but not servers based on the latest implementation. This library provides functionality for adding PKCE verification to an independent OAuth server.

Usage

See Figure 3: Authorization Code Flow in OAuth 2.0: 4.1. Authorization Code Grant.

For Authorization Server

1. Store code_challenge in step (A) and (B)

In this flow, write as follows:

// This (pseudo) code is written in vanilla PHP.
// Actually follow your framework / project conventions.

use Bag2\OAuth\PKCE\Challenge;

// Request by Web Browser
$code_challenge = \filter_input(INPUT_POST, 'code_challenge');
$code_challenge_method = \filter_input(INPUT_GET, 'code_challenge_method') ?: 'plain';

if ($code_verifier !== null) {
    if (!Verifier::isValidCodeVerifier($code_challenge)) {
        throw new Exception('invalid code_challenge');
    }
    if (!Verifier::isValidCodeChallengeMethod($code_challenge_method)) {
        throw new Exception('invalid code_challenge_method');
    }
}

store_value([
    'code' => getnerate_oauth_code(),
    'code_challenge' => $code_challenge,
    'code_challenge_method' => $code_challenge_method,
]);

// Redirect

2. Verify code_verifier in step (D)

// This (pseudo) code is written in vanilla PHP.
// Actually follow your framework / project conventions.

use Bag2\OAuth\PKCE\Challenge;

// Request by Client
$code = \filter_input(INPUT_POST, 'code');
$code_verifier = \filter_input(INPUT_POST, 'code_verifier');
$saved = get_stored_value($code);

if (isset($saved['code_challenge'])) {
    if ($code_verifier === null) {
        throw new Exception('$code_verifier required');
    }

    $verifier = Challenge::fromArray($saved);
    if (!$verifier->verify($code_verifier)) {
        throw new Exception('code_challenge required');
    }
}

// Return generated Access Token

Copyright

This package is licenced under Apache License 2.0.

Copyright 2019 Baguette HQ

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.