Current Path : C:/xampp/htdocs/moodle/lib/ltiprovider/src/OAuth/ |
Current File : C:/xampp/htdocs/moodle/lib/ltiprovider/src/OAuth/OAuthServer.php |
<?php namespace IMSGlobal\LTI\OAuth; /** * Class to represent an %OAuth Server * * @copyright Andy Smith * @version 2008-08-04 * @license https://opensource.org/licenses/MIT The MIT License */ class OAuthServer { protected $timestamp_threshold = 300; // in seconds, five minutes protected $version = '1.0'; // hi blaine protected $signature_methods = array(); protected $data_store; function __construct($data_store) { $this->data_store = $data_store; } public function add_signature_method($signature_method) { $this->signature_methods[$signature_method->get_name()] = $signature_method; } // high level functions /** * process a request_token request * returns the request token on success */ public function fetch_request_token(&$request) { $this->get_version($request); $consumer = $this->get_consumer($request); // no token required for the initial token request $token = NULL; $this->check_signature($request, $consumer, $token); // Rev A change $callback = $request->get_parameter('oauth_callback'); $new_token = $this->data_store->new_request_token($consumer, $callback); return $new_token; } /** * process an access_token request * returns the access token on success */ public function fetch_access_token(&$request) { $this->get_version($request); $consumer = $this->get_consumer($request); // requires authorized request token $token = $this->get_token($request, $consumer, "request"); $this->check_signature($request, $consumer, $token); // Rev A change $verifier = $request->get_parameter('oauth_verifier'); $new_token = $this->data_store->new_access_token($token, $consumer, $verifier); return $new_token; } /** * verify an api call, checks all the parameters */ public function verify_request(&$request) { $this->get_version($request); $consumer = $this->get_consumer($request); $token = $this->get_token($request, $consumer, "access"); $this->check_signature($request, $consumer, $token); return array($consumer, $token); } // Internals from here /** * version 1 */ private function get_version(&$request) { $version = $request->get_parameter("oauth_version"); if (!$version) { // Service Providers MUST assume the protocol version to be 1.0 if this parameter is not present. // Chapter 7.0 ("Accessing Protected Ressources") $version = '1.0'; } if ($version !== $this->version) { throw new OAuthException("OAuth version '$version' not supported"); } return $version; } /** * figure out the signature with some defaults */ private function get_signature_method($request) { $signature_method = $request instanceof OAuthRequest ? $request->get_parameter('oauth_signature_method') : NULL; if (!$signature_method) { // According to chapter 7 ("Accessing Protected Ressources") the signature-method // parameter is required, and we can't just fallback to PLAINTEXT throw new OAuthException('No signature method parameter. This parameter is required'); } if (!in_array($signature_method, array_keys($this->signature_methods))) { throw new OAuthException( "Signature method '$signature_method' not supported " . 'try one of the following: ' . implode(', ', array_keys($this->signature_methods)) ); } return $this->signature_methods[$signature_method]; } /** * try to find the consumer for the provided request's consumer key */ private function get_consumer($request) { $consumer_key = $request instanceof OAuthRequest ? $request->get_parameter('oauth_consumer_key') : NULL; if (!$consumer_key) { throw new OAuthException('Invalid consumer key'); } $consumer = $this->data_store->lookup_consumer($consumer_key); if (!$consumer) { throw new OAuthException('Invalid consumer'); } return $consumer; } /** * try to find the token for the provided request's token key */ private function get_token($request, $consumer, $token_type="access") { $token_field = $request instanceof OAuthRequest ? $request->get_parameter('oauth_token') : NULL; $token = $this->data_store->lookup_token($consumer, $token_type, $token_field); if (!$token) { throw new OAuthException("Invalid $token_type token: $token_field"); } return $token; } /** * all-in-one function to check the signature on a request * should guess the signature method appropriately */ private function check_signature($request, $consumer, $token) { // this should probably be in a different method $timestamp = $request instanceof OAuthRequest ? $request->get_parameter('oauth_timestamp') : NULL; $nonce = $request instanceof OAuthRequest ? $request->get_parameter('oauth_nonce') : NULL; $this->check_timestamp($timestamp); $this->check_nonce($consumer, $token, $nonce, $timestamp); $signature_method = $this->get_signature_method($request); $signature = $request->get_parameter('oauth_signature'); $valid_sig = $signature_method->check_signature($request, $consumer, $token, $signature); if (!$valid_sig) { throw new OAuthException('Invalid signature'); } } /** * check that the timestamp is new enough */ private function check_timestamp($timestamp) { if(!$timestamp) throw new OAuthException('Missing timestamp parameter. The parameter is required'); // verify that timestamp is recentish $now = time(); if (abs($now - $timestamp) > $this->timestamp_threshold) { throw new OAuthException("Expired timestamp, yours $timestamp, ours $now"); } } /** * check that the nonce is not repeated */ private function check_nonce($consumer, $token, $nonce, $timestamp) { if(!$nonce) throw new OAuthException('Missing nonce parameter. The parameter is required'); // verify that the nonce is uniqueish $found = $this->data_store->lookup_nonce($consumer, $token, $nonce, $timestamp); if ($found) { throw new OAuthException("Nonce already used: $nonce"); } } }