include external libs in a subdir to make install easier

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diff --git a/extlib/Auth/OpenID/Consumer.php b/extlib/Auth/OpenID/Consumer.php
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+<?php
+
+/**
+ * This module documents the main interface with the OpenID consumer
+ * library.  The only part of the library which has to be used and
+ * isn't documented in full here is the store required to create an
+ * Auth_OpenID_Consumer instance.  More on the abstract store type and
+ * concrete implementations of it that are provided in the
+ * documentation for the Auth_OpenID_Consumer constructor.
+ *
+ * OVERVIEW
+ *
+ * The OpenID identity verification process most commonly uses the
+ * following steps, as visible to the user of this library:
+ *
+ *   1. The user enters their OpenID into a field on the consumer's
+ *      site, and hits a login button.
+ *   2. The consumer site discovers the user's OpenID server using the
+ *      YADIS protocol.
+ *   3. The consumer site sends the browser a redirect to the identity
+ *      server.  This is the authentication request as described in
+ *      the OpenID specification.
+ *   4. The identity server's site sends the browser a redirect back
+ *      to the consumer site.  This redirect contains the server's
+ *      response to the authentication request.
+ *
+ * The most important part of the flow to note is the consumer's site
+ * must handle two separate HTTP requests in order to perform the full
+ * identity check.
+ *
+ * LIBRARY DESIGN
+ * 
+ * This consumer library is designed with that flow in mind.  The goal
+ * is to make it as easy as possible to perform the above steps
+ * securely.
+ *
+ * At a high level, there are two important parts in the consumer
+ * library.  The first important part is this module, which contains
+ * the interface to actually use this library.  The second is the
+ * Auth_OpenID_Interface class, which describes the interface to use
+ * if you need to create a custom method for storing the state this
+ * library needs to maintain between requests.
+ *
+ * In general, the second part is less important for users of the
+ * library to know about, as several implementations are provided
+ * which cover a wide variety of situations in which consumers may use
+ * the library.
+ *
+ * This module contains a class, Auth_OpenID_Consumer, with methods
+ * corresponding to the actions necessary in each of steps 2, 3, and 4
+ * described in the overview.  Use of this library should be as easy
+ * as creating an Auth_OpenID_Consumer instance and calling the
+ * methods appropriate for the action the site wants to take.
+ *
+ * STORES AND DUMB MODE
+ *
+ * OpenID is a protocol that works best when the consumer site is able
+ * to store some state.  This is the normal mode of operation for the
+ * protocol, and is sometimes referred to as smart mode.  There is
+ * also a fallback mode, known as dumb mode, which is available when
+ * the consumer site is not able to store state.  This mode should be
+ * avoided when possible, as it leaves the implementation more
+ * vulnerable to replay attacks.
+ *
+ * The mode the library works in for normal operation is determined by
+ * the store that it is given.  The store is an abstraction that
+ * handles the data that the consumer needs to manage between http
+ * requests in order to operate efficiently and securely.
+ *
+ * Several store implementation are provided, and the interface is
+ * fully documented so that custom stores can be used as well.  See
+ * the documentation for the Auth_OpenID_Consumer class for more
+ * information on the interface for stores.  The implementations that
+ * are provided allow the consumer site to store the necessary data in
+ * several different ways, including several SQL databases and normal
+ * files on disk.
+ *
+ * There is an additional concrete store provided that puts the system
+ * in dumb mode.  This is not recommended, as it removes the library's
+ * ability to stop replay attacks reliably.  It still uses time-based
+ * checking to make replay attacks only possible within a small
+ * window, but they remain possible within that window.  This store
+ * should only be used if the consumer site has no way to retain data
+ * between requests at all.
+ *
+ * IMMEDIATE MODE
+ *
+ * In the flow described above, the user may need to confirm to the
+ * lidentity server that it's ok to authorize his or her identity.
+ * The server may draw pages asking for information from the user
+ * before it redirects the browser back to the consumer's site.  This
+ * is generally transparent to the consumer site, so it is typically
+ * ignored as an implementation detail.
+ *
+ * There can be times, however, where the consumer site wants to get a
+ * response immediately.  When this is the case, the consumer can put
+ * the library in immediate mode.  In immediate mode, there is an
+ * extra response possible from the server, which is essentially the
+ * server reporting that it doesn't have enough information to answer
+ * the question yet.
+ *
+ * USING THIS LIBRARY
+ *
+ * Integrating this library into an application is usually a
+ * relatively straightforward process.  The process should basically
+ * follow this plan:
+ *
+ * Add an OpenID login field somewhere on your site.  When an OpenID
+ * is entered in that field and the form is submitted, it should make
+ * a request to the your site which includes that OpenID URL.
+ *
+ * First, the application should instantiate the Auth_OpenID_Consumer
+ * class using the store of choice (Auth_OpenID_FileStore or one of
+ * the SQL-based stores).  If the application has a custom
+ * session-management implementation, an object implementing the
+ * {@link Auth_Yadis_PHPSession} interface should be passed as the
+ * second parameter.  Otherwise, the default uses $_SESSION.
+ *
+ * Next, the application should call the Auth_OpenID_Consumer object's
+ * 'begin' method.  This method takes the OpenID URL.  The 'begin'
+ * method returns an Auth_OpenID_AuthRequest object.
+ *
+ * Next, the application should call the 'redirectURL' method of the
+ * Auth_OpenID_AuthRequest object.  The 'return_to' URL parameter is
+ * the URL that the OpenID server will send the user back to after
+ * attempting to verify his or her identity.  The 'trust_root' is the
+ * URL (or URL pattern) that identifies your web site to the user when
+ * he or she is authorizing it.  Send a redirect to the resulting URL
+ * to the user's browser.
+ *
+ * That's the first half of the authentication process.  The second
+ * half of the process is done after the user's ID server sends the
+ * user's browser a redirect back to your site to complete their
+ * login.
+ *
+ * When that happens, the user will contact your site at the URL given
+ * as the 'return_to' URL to the Auth_OpenID_AuthRequest::redirectURL
+ * call made above.  The request will have several query parameters
+ * added to the URL by the identity server as the information
+ * necessary to finish the request.
+ *
+ * Lastly, instantiate an Auth_OpenID_Consumer instance as above and
+ * call its 'complete' method, passing in all the received query
+ * arguments.
+ *
+ * There are multiple possible return types possible from that
+ * method. These indicate the whether or not the login was successful,
+ * and include any additional information appropriate for their type.
+ *
+ * PHP versions 4 and 5
+ *
+ * LICENSE: See the COPYING file included in this distribution.
+ *
+ * @package OpenID
+ * @author JanRain, Inc. <openid@janrain.com>
+ * @copyright 2005-2008 Janrain, Inc.
+ * @license http://www.apache.org/licenses/LICENSE-2.0 Apache
+ */
+
+/**
+ * Require utility classes and functions for the consumer.
+ */
+require_once "Auth/OpenID.php";
+require_once "Auth/OpenID/Message.php";
+require_once "Auth/OpenID/HMAC.php";
+require_once "Auth/OpenID/Association.php";
+require_once "Auth/OpenID/CryptUtil.php";
+require_once "Auth/OpenID/DiffieHellman.php";
+require_once "Auth/OpenID/KVForm.php";
+require_once "Auth/OpenID/Nonce.php";
+require_once "Auth/OpenID/Discover.php";
+require_once "Auth/OpenID/URINorm.php";
+require_once "Auth/Yadis/Manager.php";
+require_once "Auth/Yadis/XRI.php";
+
+/**
+ * This is the status code returned when the complete method returns
+ * successfully.
+ */
+define('Auth_OpenID_SUCCESS', 'success');
+
+/**
+ * Status to indicate cancellation of OpenID authentication.
+ */
+define('Auth_OpenID_CANCEL', 'cancel');
+
+/**
+ * This is the status code completeAuth returns when the value it
+ * received indicated an invalid login.
+ */
+define('Auth_OpenID_FAILURE', 'failure');
+
+/**
+ * This is the status code completeAuth returns when the
+ * {@link Auth_OpenID_Consumer} instance is in immediate mode, and the
+ * identity server sends back a URL to send the user to to complete his
+ * or her login.
+ */
+define('Auth_OpenID_SETUP_NEEDED', 'setup needed');
+
+/**
+ * This is the status code beginAuth returns when the page fetched
+ * from the entered OpenID URL doesn't contain the necessary link tags
+ * to function as an identity page.
+ */
+define('Auth_OpenID_PARSE_ERROR', 'parse error');
+
+/**
+ * An OpenID consumer implementation that performs discovery and does
+ * session management.  See the Consumer.php file documentation for
+ * more information.
+ *
+ * @package OpenID
+ */
+class Auth_OpenID_Consumer {
+
+    /**
+     * @access private
+     */
+    var $discoverMethod = 'Auth_OpenID_discover';
+
+    /**
+     * @access private
+     */
+    var $session_key_prefix = "_openid_consumer_";
+
+    /**
+     * @access private
+     */
+    var $_token_suffix = "last_token";
+
+    /**
+     * Initialize a Consumer instance.
+     *
+     * You should create a new instance of the Consumer object with
+     * every HTTP request that handles OpenID transactions.
+     *
+     * @param Auth_OpenID_OpenIDStore $store This must be an object
+     * that implements the interface in {@link
+     * Auth_OpenID_OpenIDStore}.  Several concrete implementations are
+     * provided, to cover most common use cases.  For stores backed by
+     * MySQL, PostgreSQL, or SQLite, see the {@link
+     * Auth_OpenID_SQLStore} class and its sublcasses.  For a
+     * filesystem-backed store, see the {@link Auth_OpenID_FileStore}
+     * module.  As a last resort, if it isn't possible for the server
+     * to store state at all, an instance of {@link
+     * Auth_OpenID_DumbStore} can be used.
+     *
+     * @param mixed $session An object which implements the interface
+     * of the {@link Auth_Yadis_PHPSession} class.  Particularly, this
+     * object is expected to have these methods: get($key), set($key),
+     * $value), and del($key).  This defaults to a session object
+     * which wraps PHP's native session machinery.  You should only
+     * need to pass something here if you have your own sessioning
+     * implementation.
+     *
+     * @param str $consumer_cls The name of the class to instantiate
+     * when creating the internal consumer object.  This is used for
+     * testing.
+     */
+    function Auth_OpenID_Consumer(&$store, $session = null,
+                                  $consumer_cls = null)
+    {
+        if ($session === null) {
+            $session = new Auth_Yadis_PHPSession();
+        }
+
+        $this->session =& $session;
+
+        if ($consumer_cls !== null) {
+            $this->consumer =& new $consumer_cls($store);
+        } else {
+            $this->consumer =& new Auth_OpenID_GenericConsumer($store);
+        }
+
+        $this->_token_key = $this->session_key_prefix . $this->_token_suffix;
+    }
+
+    /**
+     * Used in testing to define the discovery mechanism.
+     *
+     * @access private
+     */
+    function getDiscoveryObject(&$session, $openid_url,
+                                $session_key_prefix)
+    {
+        return new Auth_Yadis_Discovery($session, $openid_url,
+                                        $session_key_prefix);
+    }
+
+    /**
+     * Start the OpenID authentication process. See steps 1-2 in the
+     * overview at the top of this file.
+     *
+     * @param string $user_url Identity URL given by the user. This
+     * method performs a textual transformation of the URL to try and
+     * make sure it is normalized. For example, a user_url of
+     * example.com will be normalized to http://example.com/
+     * normalizing and resolving any redirects the server might issue.
+     *
+     * @param bool $anonymous True if the OpenID request is to be sent
+     * to the server without any identifier information.  Use this
+     * when you want to transport data but don't want to do OpenID
+     * authentication with identifiers.
+     *
+     * @return Auth_OpenID_AuthRequest $auth_request An object
+     * containing the discovered information will be returned, with a
+     * method for building a redirect URL to the server, as described
+     * in step 3 of the overview. This object may also be used to add
+     * extension arguments to the request, using its 'addExtensionArg'
+     * method.
+     */
+    function begin($user_url, $anonymous=false)
+    {
+        $openid_url = $user_url;
+
+        $disco = $this->getDiscoveryObject($this->session,
+                                           $openid_url,
+                                           $this->session_key_prefix);
+
+        // Set the 'stale' attribute of the manager.  If discovery
+        // fails in a fatal way, the stale flag will cause the manager
+        // to be cleaned up next time discovery is attempted.
+
+        $m = $disco->getManager();
+        $loader = new Auth_Yadis_ManagerLoader();
+
+        if ($m) {
+            if ($m->stale) {
+                $disco->destroyManager();
+            } else {
+                $m->stale = true;
+                $disco->session->set($disco->session_key,
+                                     serialize($loader->toSession($m)));
+            }
+        }
+
+        $endpoint = $disco->getNextService($this->discoverMethod,
+                                           $this->consumer->fetcher);
+
+        // Reset the 'stale' attribute of the manager.
+        $m =& $disco->getManager();
+        if ($m) {
+            $m->stale = false;
+            $disco->session->set($disco->session_key,
+                                 serialize($loader->toSession($m)));
+        }
+
+        if ($endpoint === null) {
+            return null;
+        } else {
+            return $this->beginWithoutDiscovery($endpoint,
+                                                $anonymous);
+        }
+    }
+
+    /**
+     * Start OpenID verification without doing OpenID server
+     * discovery. This method is used internally by Consumer.begin
+     * after discovery is performed, and exists to provide an
+     * interface for library users needing to perform their own
+     * discovery.
+     *
+     * @param Auth_OpenID_ServiceEndpoint $endpoint an OpenID service
+     * endpoint descriptor.
+     *
+     * @param bool anonymous Set to true if you want to perform OpenID
+     * without identifiers.
+     *
+     * @return Auth_OpenID_AuthRequest $auth_request An OpenID
+     * authentication request object.
+     */
+    function &beginWithoutDiscovery($endpoint, $anonymous=false)
+    {
+        $loader = new Auth_OpenID_ServiceEndpointLoader();
+        $auth_req = $this->consumer->begin($endpoint);
+        $this->session->set($this->_token_key,
+              $loader->toSession($auth_req->endpoint));
+        if (!$auth_req->setAnonymous($anonymous)) {
+            return new Auth_OpenID_FailureResponse(null,
+              "OpenID 1 requests MUST include the identifier " .
+              "in the request.");
+        }
+        return $auth_req;
+    }
+
+    /**
+     * Called to interpret the server's response to an OpenID
+     * request. It is called in step 4 of the flow described in the
+     * consumer overview.
+     *
+     * @param string $current_url The URL used to invoke the application.
+     * Extract the URL from your application's web
+     * request framework and specify it here to have it checked
+     * against the openid.current_url value in the response.  If
+     * the current_url URL check fails, the status of the
+     * completion will be FAILURE.
+     *
+     * @param array $query An array of the query parameters (key =>
+     * value pairs) for this HTTP request.  Defaults to null.  If
+     * null, the GET or POST data are automatically gotten from the
+     * PHP environment.  It is only useful to override $query for
+     * testing.
+     *
+     * @return Auth_OpenID_ConsumerResponse $response A instance of an
+     * Auth_OpenID_ConsumerResponse subclass. The type of response is
+     * indicated by the status attribute, which will be one of
+     * SUCCESS, CANCEL, FAILURE, or SETUP_NEEDED.
+     */
+    function complete($current_url, $query=null)
+    {
+        if ($current_url && !is_string($current_url)) {
+            // This is ugly, but we need to complain loudly when
+            // someone uses the API incorrectly.
+            trigger_error("current_url must be a string; see NEWS file " .
+                          "for upgrading notes.",
+                          E_USER_ERROR);
+        }
+
+        if ($query === null) {
+            $query = Auth_OpenID::getQuery();
+        }
+
+        $loader = new Auth_OpenID_ServiceEndpointLoader();
+        $endpoint_data = $this->session->get($this->_token_key);
+        $endpoint =
+            $loader->fromSession($endpoint_data);
+
+        $message = Auth_OpenID_Message::fromPostArgs($query);
+        $response = $this->consumer->complete($message, $endpoint, 
+                                              $current_url);
+        $this->session->del($this->_token_key);
+
+        if (in_array($response->status, array(Auth_OpenID_SUCCESS,
+                                              Auth_OpenID_CANCEL))) {
+            if ($response->identity_url !== null) {
+                $disco = $this->getDiscoveryObject($this->session,
+                                                   $response->identity_url,
+                                                   $this->session_key_prefix);
+                $disco->cleanup(true);
+            }
+        }
+
+        return $response;
+    }
+}
+
+/**
+ * A class implementing HMAC/DH-SHA1 consumer sessions.
+ *
+ * @package OpenID
+ */
+class Auth_OpenID_DiffieHellmanSHA1ConsumerSession {
+    var $session_type = 'DH-SHA1';
+    var $hash_func = 'Auth_OpenID_SHA1';
+    var $secret_size = 20;
+    var $allowed_assoc_types = array('HMAC-SHA1');
+
+    function Auth_OpenID_DiffieHellmanSHA1ConsumerSession($dh = null)
+    {
+        if ($dh === null) {
+            $dh = new Auth_OpenID_DiffieHellman();
+        }
+
+        $this->dh = $dh;
+    }
+
+    function getRequest()
+    {
+        $math =& Auth_OpenID_getMathLib();
+
+        $cpub = $math->longToBase64($this->dh->public);
+
+        $args = array('dh_consumer_public' => $cpub);
+
+        if (!$this->dh->usingDefaultValues()) {
+            $args = array_merge($args, array(
+                'dh_modulus' =>
+                     $math->longToBase64($this->dh->mod),
+                'dh_gen' =>
+                     $math->longToBase64($this->dh->gen)));
+        }
+
+        return $args;
+    }
+
+    function extractSecret($response)
+    {
+        if (!$response->hasKey(Auth_OpenID_OPENID_NS,
+                               'dh_server_public')) {
+            return null;
+        }
+
+        if (!$response->hasKey(Auth_OpenID_OPENID_NS,
+                               'enc_mac_key')) {
+            return null;
+        }
+
+        $math =& Auth_OpenID_getMathLib();
+
+        $spub = $math->base64ToLong($response->getArg(Auth_OpenID_OPENID_NS,
+                                                      'dh_server_public'));
+        $enc_mac_key = base64_decode($response->getArg(Auth_OpenID_OPENID_NS,
+                                                       'enc_mac_key'));
+
+        return $this->dh->xorSecret($spub, $enc_mac_key, $this->hash_func);
+    }
+}
+
+/**
+ * A class implementing HMAC/DH-SHA256 consumer sessions.
+ *
+ * @package OpenID
+ */
+class Auth_OpenID_DiffieHellmanSHA256ConsumerSession extends
+      Auth_OpenID_DiffieHellmanSHA1ConsumerSession {
+    var $session_type = 'DH-SHA256';
+    var $hash_func = 'Auth_OpenID_SHA256';
+    var $secret_size = 32;
+    var $allowed_assoc_types = array('HMAC-SHA256');
+}
+
+/**
+ * A class implementing plaintext consumer sessions.
+ *
+ * @package OpenID
+ */
+class Auth_OpenID_PlainTextConsumerSession {
+    var $session_type = 'no-encryption';
+    var $allowed_assoc_types =  array('HMAC-SHA1', 'HMAC-SHA256');
+
+    function getRequest()
+    {
+        return array();
+    }
+
+    function extractSecret($response)
+    {
+        if (!$response->hasKey(Auth_OpenID_OPENID_NS, 'mac_key')) {
+            return null;
+        }
+
+        return base64_decode($response->getArg(Auth_OpenID_OPENID_NS,
+                                               'mac_key'));
+    }
+}
+
+/**
+ * Returns available session types.
+ */
+function Auth_OpenID_getAvailableSessionTypes()
+{
+    $types = array(
+      'no-encryption' => 'Auth_OpenID_PlainTextConsumerSession',
+      'DH-SHA1' => 'Auth_OpenID_DiffieHellmanSHA1ConsumerSession',
+      'DH-SHA256' => 'Auth_OpenID_DiffieHellmanSHA256ConsumerSession');
+
+    return $types;
+}
+
+/**
+ * This class is the interface to the OpenID consumer logic.
+ * Instances of it maintain no per-request state, so they can be
+ * reused (or even used by multiple threads concurrently) as needed.
+ *
+ * @package OpenID
+ */
+class Auth_OpenID_GenericConsumer {
+    /**
+     * @access private
+     */
+    var $discoverMethod = 'Auth_OpenID_discover';
+
+    /**
+     * This consumer's store object.
+     */
+    var $store;
+
+    /**
+     * @access private
+     */
+    var $_use_assocs;
+
+    /**
+     * @access private
+     */
+    var $openid1_nonce_query_arg_name = 'janrain_nonce';
+
+    /**
+     * Another query parameter that gets added to the return_to for
+     * OpenID 1; if the user's session state is lost, use this claimed
+     * identifier to do discovery when verifying the response.
+     */
+    var $openid1_return_to_identifier_name = 'openid1_claimed_id';
+
+    /**
+     * This method initializes a new {@link Auth_OpenID_Consumer}
+     * instance to access the library.
+     *
+     * @param Auth_OpenID_OpenIDStore $store This must be an object
+     * that implements the interface in {@link Auth_OpenID_OpenIDStore}.
+     * Several concrete implementations are provided, to cover most common use
+     * cases.  For stores backed by MySQL, PostgreSQL, or SQLite, see
+     * the {@link Auth_OpenID_SQLStore} class and its sublcasses.  For a
+     * filesystem-backed store, see the {@link Auth_OpenID_FileStore} module.
+     * As a last resort, if it isn't possible for the server to store
+     * state at all, an instance of {@link Auth_OpenID_DumbStore} can be used.
+     *
+     * @param bool $immediate This is an optional boolean value.  It
+     * controls whether the library uses immediate mode, as explained
+     * in the module description.  The default value is False, which
+     * disables immediate mode.
+     */
+    function Auth_OpenID_GenericConsumer(&$store)
+    {
+        $this->store =& $store;
+        $this->negotiator =& Auth_OpenID_getDefaultNegotiator();
+        $this->_use_assocs = ($this->store ? true : false);
+
+        $this->fetcher = Auth_Yadis_Yadis::getHTTPFetcher();
+
+        $this->session_types = Auth_OpenID_getAvailableSessionTypes();
+    }
+
+    /**
+     * Called to begin OpenID authentication using the specified
+     * {@link Auth_OpenID_ServiceEndpoint}.
+     *
+     * @access private
+     */
+    function begin($service_endpoint)
+    {
+        $assoc = $this->_getAssociation($service_endpoint);
+        $r = new Auth_OpenID_AuthRequest($service_endpoint, $assoc);
+        $r->return_to_args[$this->openid1_nonce_query_arg_name] =
+            Auth_OpenID_mkNonce();
+
+        if ($r->message->isOpenID1()) {
+            $r->return_to_args[$this->openid1_return_to_identifier_name] =
+                $r->endpoint->claimed_id;
+        }
+
+        return $r;
+    }
+
+    /**
+     * Given an {@link Auth_OpenID_Message}, {@link
+     * Auth_OpenID_ServiceEndpoint} and optional return_to URL,
+     * complete OpenID authentication.
+     *
+     * @access private
+     */
+    function complete($message, $endpoint, $return_to)
+    {
+        $mode = $message->getArg(Auth_OpenID_OPENID_NS, 'mode',
+                                 '<no mode set>');
+
+        $mode_methods = array(
+                              'cancel' => '_complete_cancel',
+                              'error' => '_complete_error',
+                              'setup_needed' => '_complete_setup_needed',
+                              'id_res' => '_complete_id_res',
+                              );
+
+        $method = Auth_OpenID::arrayGet($mode_methods, $mode,
+                                        '_completeInvalid');
+
+        return call_user_func_array(array(&$this, $method),
+                                    array($message, $endpoint, $return_to));
+    }
+
+    /**
+     * @access private
+     */
+    function _completeInvalid($message, &$endpoint, $unused)
+    {
+        $mode = $message->getArg(Auth_OpenID_OPENID_NS, 'mode',
+                                 '<No mode set>');
+
+        return new Auth_OpenID_FailureResponse($endpoint,
+                    sprintf("Invalid openid.mode '%s'", $mode));
+    }
+
+    /**
+     * @access private
+     */
+    function _complete_cancel($message, &$endpoint, $unused)
+    {
+        return new Auth_OpenID_CancelResponse($endpoint);
+    }
+
+    /**
+     * @access private
+     */
+    function _complete_error($message, &$endpoint, $unused)
+    {
+        $error = $message->getArg(Auth_OpenID_OPENID_NS, 'error');
+        $contact = $message->getArg(Auth_OpenID_OPENID_NS, 'contact');
+        $reference = $message->getArg(Auth_OpenID_OPENID_NS, 'reference');
+
+        return new Auth_OpenID_FailureResponse($endpoint, $error,
+                                               $contact, $reference);
+    }
+
+    /**
+     * @access private
+     */
+    function _complete_setup_needed($message, &$endpoint, $unused)
+    {
+        if (!$message->isOpenID2()) {
+            return $this->_completeInvalid($message, $endpoint);
+        }
+
+        return new Auth_OpenID_SetupNeededResponse($endpoint);
+    }
+
+    /**
+     * @access private
+     */
+    function _complete_id_res($message, &$endpoint, $return_to)
+    {
+        $user_setup_url = $message->getArg(Auth_OpenID_OPENID1_NS,
+                                           'user_setup_url');
+
+        if ($this->_checkSetupNeeded($message)) {
+            return new Auth_OpenID_SetupNeededResponse(
+                $endpoint, $user_setup_url);
+        } else {
+            return $this->_doIdRes($message, $endpoint, $return_to);
+        }
+    }
+
+    /**
+     * @access private
+     */
+    function _checkSetupNeeded($message)
+    {
+        // In OpenID 1, we check to see if this is a cancel from
+        // immediate mode by the presence of the user_setup_url
+        // parameter.
+        if ($message->isOpenID1()) {
+            $user_setup_url = $message->getArg(Auth_OpenID_OPENID1_NS,
+                                               'user_setup_url');
+            if ($user_setup_url !== null) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * @access private
+     */
+    function _doIdRes($message, $endpoint, $return_to)
+    {
+        // Checks for presence of appropriate fields (and checks
+        // signed list fields)
+        $result = $this->_idResCheckForFields($message);
+
+        if (Auth_OpenID::isFailure($result)) {
+            return $result;
+        }
+
+        if (!$this->_checkReturnTo($message, $return_to)) {
+            return new Auth_OpenID_FailureResponse(null,
+            sprintf("return_to does not match return URL. Expected %s, got %s",
+                    $return_to,
+                    $message->getArg(Auth_OpenID_OPENID_NS, 'return_to')));
+        }
+
+        // Verify discovery information:
+        $result = $this->_verifyDiscoveryResults($message, $endpoint);
+
+        if (Auth_OpenID::isFailure($result)) {
+            return $result;
+        }
+
+        $endpoint = $result;
+
+        $result = $this->_idResCheckSignature($message,
+                                              $endpoint->server_url);
+
+        if (Auth_OpenID::isFailure($result)) {
+            return $result;
+        }
+
+        $result = $this->_idResCheckNonce($message, $endpoint);
+
+        if (Auth_OpenID::isFailure($result)) {
+            return $result;
+        }
+
+        $signed_list_str = $message->getArg(Auth_OpenID_OPENID_NS, 'signed',
+                                            Auth_OpenID_NO_DEFAULT);
+        if (Auth_OpenID::isFailure($signed_list_str)) {
+            return $signed_list_str;
+        }
+        $signed_list = explode(',', $signed_list_str);
+
+        $signed_fields = Auth_OpenID::addPrefix($signed_list, "openid.");
+
+        return new Auth_OpenID_SuccessResponse($endpoint, $message,
+                                               $signed_fields);
+
+    }
+
+    /**
+     * @access private
+     */
+    function _checkReturnTo($message, $return_to)
+    {
+        // Check an OpenID message and its openid.return_to value
+        // against a return_to URL from an application.  Return True
+        // on success, False on failure.
+
+        // Check the openid.return_to args against args in the
+        // original message.
+        $result = Auth_OpenID_GenericConsumer::_verifyReturnToArgs(
+                                           $message->toPostArgs());
+        if (Auth_OpenID::isFailure($result)) {
+            return false;
+        }
+
+        // Check the return_to base URL against the one in the
+        // message.
+        $msg_return_to = $message->getArg(Auth_OpenID_OPENID_NS,
+                                          'return_to');
+        if (Auth_OpenID::isFailure($return_to)) {
+            // XXX log me
+            return false;
+        }
+
+        $return_to_parts = parse_url(Auth_OpenID_urinorm($return_to));
+        $msg_return_to_parts = parse_url(Auth_OpenID_urinorm($msg_return_to));
+
+        // If port is absent from both, add it so it's equal in the
+        // check below.
+        if ((!array_key_exists('port', $return_to_parts)) &&
+            (!array_key_exists('port', $msg_return_to_parts))) {
+            $return_to_parts['port'] = null;
+            $msg_return_to_parts['port'] = null;
+        }
+
+        // If path is absent from both, add it so it's equal in the
+        // check below.
+        if ((!array_key_exists('path', $return_to_parts)) &&
+            (!array_key_exists('path', $msg_return_to_parts))) {
+            $return_to_parts['path'] = null;
+            $msg_return_to_parts['path'] = null;
+        }
+
+        // The URL scheme, authority, and path MUST be the same
+        // between the two URLs.
+        foreach (array('scheme', 'host', 'port', 'path') as $component) {
+            // If the url component is absent in either URL, fail.
+            // There should always be a scheme, host, port, and path.
+            if (!array_key_exists($component, $return_to_parts)) {
+                return false;
+            }
+
+            if (!array_key_exists($component, $msg_return_to_parts)) {
+                return false;
+            }
+
+            if (Auth_OpenID::arrayGet($return_to_parts, $component) !==
+                Auth_OpenID::arrayGet($msg_return_to_parts, $component)) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    /**
+     * @access private
+     */
+    function _verifyReturnToArgs($query)
+    {
+        // Verify that the arguments in the return_to URL are present in this
+        // response.
+
+        $message = Auth_OpenID_Message::fromPostArgs($query);
+        $return_to = $message->getArg(Auth_OpenID_OPENID_NS, 'return_to');
+
+        if (Auth_OpenID::isFailure($return_to)) {
+            return $return_to;
+        }
+        // XXX: this should be checked by _idResCheckForFields
+        if (!$return_to) {
+            return new Auth_OpenID_FailureResponse(null,
+                           "Response has no return_to");
+        }
+
+        $parsed_url = parse_url($return_to);
+
+        $q = array();
+        if (array_key_exists('query', $parsed_url)) {
+            $rt_query = $parsed_url['query'];
+            $q = Auth_OpenID::parse_str($rt_query);
+        }
+
+        foreach ($q as $rt_key => $rt_value) {
+            if (!array_key_exists($rt_key, $query)) {
+                return new Auth_OpenID_FailureResponse(null,
+                  sprintf("return_to parameter %s absent from query", $rt_key));
+            } else {
+                $value = $query[$rt_key];
+                if ($rt_value != $value) {
+                    return new Auth_OpenID_FailureResponse(null,
+                      sprintf("parameter %s value %s does not match " .
+                              "return_to value %s", $rt_key,
+                              $value, $rt_value));
+                }
+            }
+        }
+
+        // Make sure all non-OpenID arguments in the response are also
+        // in the signed return_to.
+        $bare_args = $message->getArgs(Auth_OpenID_BARE_NS);
+        foreach ($bare_args as $key => $value) {
+            if (Auth_OpenID::arrayGet($q, $key) != $value) {
+                return new Auth_OpenID_FailureResponse(null,
+                  sprintf("Parameter %s = %s not in return_to URL",
+                          $key, $value));
+            }
+        }
+
+        return true;
+    }
+
+    /**
+     * @access private
+     */
+    function _idResCheckSignature($message, $server_url)
+    {
+        $assoc_handle = $message->getArg(Auth_OpenID_OPENID_NS,
+                                         'assoc_handle');
+        if (Auth_OpenID::isFailure($assoc_handle)) {
+            return $assoc_handle;
+        }
+
+        $assoc = $this->store->getAssociation($server_url, $assoc_handle);
+
+        if ($assoc) {
+            if ($assoc->getExpiresIn() <= 0) {
+                // XXX: It might be a good idea sometimes to re-start
+                // the authentication with a new association. Doing it
+                // automatically opens the possibility for
+                // denial-of-service by a server that just returns
+                // expired associations (or really short-lived
+                // associations)
+                return new Auth_OpenID_FailureResponse(null,
+                             'Association with ' . $server_url . ' expired');
+            }
+
+            if (!$assoc->checkMessageSignature($message)) {
+                return new Auth_OpenID_FailureResponse(null,
+                                                       "Bad signature");
+            }
+        } else {
+            // It's not an association we know about.  Stateless mode
+            // is our only possible path for recovery.  XXX - async
+            // framework will not want to block on this call to
+            // _checkAuth.
+            if (!$this->_checkAuth($message, $server_url)) {
+                return new Auth_OpenID_FailureResponse(null,
+                             "Server denied check_authentication");
+            }
+        }
+
+        return null;
+    }
+
+    /**
+     * @access private
+     */
+    function _verifyDiscoveryResults($message, $endpoint=null)
+    {
+        if ($message->getOpenIDNamespace() == Auth_OpenID_OPENID2_NS) {
+            return $this->_verifyDiscoveryResultsOpenID2($message,
+                                                         $endpoint);
+        } else {
+            return $this->_verifyDiscoveryResultsOpenID1($message,
+                                                         $endpoint);
+        }
+    }
+
+    /**
+     * @access private
+     */
+    function _verifyDiscoveryResultsOpenID1($message, $endpoint)
+    {
+        $claimed_id = $message->getArg(Auth_OpenID_BARE_NS,
+                                $this->openid1_return_to_identifier_name);
+
+        if (($endpoint === null) && ($claimed_id === null)) {
+            return new Auth_OpenID_FailureResponse($endpoint,
+              'When using OpenID 1, the claimed ID must be supplied, ' .
+              'either by passing it through as a return_to parameter ' .
+              'or by using a session, and supplied to the GenericConsumer ' .
+              'as the argument to complete()');
+        } else if (($endpoint !== null) && ($claimed_id === null)) {
+            $claimed_id = $endpoint->claimed_id;
+        }
+
+        $to_match = new Auth_OpenID_ServiceEndpoint();
+        $to_match->type_uris = array(Auth_OpenID_TYPE_1_1);
+        $to_match->local_id = $message->getArg(Auth_OpenID_OPENID1_NS,
+                                               'identity');
+
+        // Restore delegate information from the initiation phase
+        $to_match->claimed_id = $claimed_id;
+
+        if ($to_match->local_id === null) {
+            return new Auth_OpenID_FailureResponse($endpoint,
+                         "Missing required field openid.identity");
+        }
+
+        $to_match_1_0 = $to_match->copy();
+        $to_match_1_0->type_uris = array(Auth_OpenID_TYPE_1_0);
+
+        if ($endpoint !== null) {
+            $result = $this->_verifyDiscoverySingle($endpoint, $to_match);
+
+            if (is_a($result, 'Auth_OpenID_TypeURIMismatch')) {
+                $result = $this->_verifyDiscoverySingle($endpoint,
+                                                        $to_match_1_0);
+            }
+
+            if (Auth_OpenID::isFailure($result)) {
+                // oidutil.log("Error attempting to use stored
+                //             discovery information: " + str(e))
+                //             oidutil.log("Attempting discovery to
+                //             verify endpoint")
+            } else {
+                return $endpoint;
+            }
+        }
+
+        // Endpoint is either bad (failed verification) or None
+        return $this->_discoverAndVerify($to_match->claimed_id,
+                                         array($to_match, $to_match_1_0));
+    }
+
+    /**
+     * @access private
+     */
+    function _verifyDiscoverySingle($endpoint, $to_match)
+    {
+        // Every type URI that's in the to_match endpoint has to be
+        // present in the discovered endpoint.
+        foreach ($to_match->type_uris as $type_uri) {
+            if (!$endpoint->usesExtension($type_uri)) {
+                return new Auth_OpenID_TypeURIMismatch($endpoint,
+                             "Required type ".$type_uri." not present");
+            }
+        }
+
+        // Fragments do not influence discovery, so we can't compare a
+        // claimed identifier with a fragment to discovered
+        // information.
+        list($defragged_claimed_id, $_) =
+            Auth_OpenID::urldefrag($to_match->claimed_id);
+
+        if ($defragged_claimed_id != $endpoint->claimed_id) {
+            return new Auth_OpenID_FailureResponse($endpoint,
+              sprintf('Claimed ID does not match (different subjects!), ' .
+                      'Expected %s, got %s', $defragged_claimed_id,
+                      $endpoint->claimed_id));
+        }
+
+        if ($to_match->getLocalID() != $endpoint->getLocalID()) {
+            return new Auth_OpenID_FailureResponse($endpoint,
+              sprintf('local_id mismatch. Expected %s, got %s',
+                      $to_match->getLocalID(), $endpoint->getLocalID()));
+        }
+
+        // If the server URL is None, this must be an OpenID 1
+        // response, because op_endpoint is a required parameter in
+        // OpenID 2. In that case, we don't actually care what the
+        // discovered server_url is, because signature checking or
+        // check_auth should take care of that check for us.
+        if ($to_match->server_url === null) {
+            if ($to_match->preferredNamespace() != Auth_OpenID_OPENID1_NS) {
+                return new Auth_OpenID_FailureResponse($endpoint,
+                             "Preferred namespace mismatch (bug)");
+            }
+        } else if ($to_match->server_url != $endpoint->server_url) {
+            return new Auth_OpenID_FailureResponse($endpoint,
+              sprintf('OP Endpoint mismatch. Expected %s, got %s',
+                      $to_match->server_url, $endpoint->server_url));
+        }
+
+        return null;
+    }
+
+    /**
+     * @access private
+     */
+    function _verifyDiscoveryResultsOpenID2($message, $endpoint)
+    {
+        $to_match = new Auth_OpenID_ServiceEndpoint();
+        $to_match->type_uris = array(Auth_OpenID_TYPE_2_0);
+        $to_match->claimed_id = $message->getArg(Auth_OpenID_OPENID2_NS,
+                                                 'claimed_id');
+
+        $to_match->local_id = $message->getArg(Auth_OpenID_OPENID2_NS,
+                                                'identity');
+
+        $to_match->server_url = $message->getArg(Auth_OpenID_OPENID2_NS,
+                                                 'op_endpoint');
+
+        if ($to_match->server_url === null) {
+            return new Auth_OpenID_FailureResponse($endpoint,
+                         "OP Endpoint URL missing");
+        }
+
+        // claimed_id and identifier must both be present or both be
+        // absent
+        if (($to_match->claimed_id === null) &&
+            ($to_match->local_id !== null)) {
+            return new Auth_OpenID_FailureResponse($endpoint,
+              'openid.identity is present without openid.claimed_id');
+        }
+
+        if (($to_match->claimed_id !== null) &&
+            ($to_match->local_id === null)) {
+            return new Auth_OpenID_FailureResponse($endpoint,
+              'openid.claimed_id is present without openid.identity');
+        }
+
+        if ($to_match->claimed_id === null) {
+            // This is a response without identifiers, so there's
+            // really no checking that we can do, so return an
+            // endpoint that's for the specified `openid.op_endpoint'
+            return Auth_OpenID_ServiceEndpoint::fromOPEndpointURL(
+                                                $to_match->server_url);
+        }
+
+        if (!$endpoint) {
+            // The claimed ID doesn't match, so we have to do
+            // discovery again. This covers not using sessions, OP
+            // identifier endpoints and responses that didn't match
+            // the original request.
+            // oidutil.log('No pre-discovered information supplied.')
+            return $this->_discoverAndVerify($to_match->claimed_id,
+                                             array($to_match));
+        } else {
+
+            // The claimed ID matches, so we use the endpoint that we
+            // discovered in initiation. This should be the most
+            // common case.
+            $result = $this->_verifyDiscoverySingle($endpoint, $to_match);
+
+            if (Auth_OpenID::isFailure($result)) {
+                $endpoint = $this->_discoverAndVerify($to_match->claimed_id,
+                                                      array($to_match));
+                if (Auth_OpenID::isFailure($endpoint)) {
+                    return $endpoint;
+                }
+            }
+        }
+
+        // The endpoint we return should have the claimed ID from the
+        // message we just verified, fragment and all.
+        if ($endpoint->claimed_id != $to_match->claimed_id) {
+            $endpoint->claimed_id = $to_match->claimed_id;
+        }
+
+        return $endpoint;
+    }
+
+    /**
+     * @access private
+     */
+    function _discoverAndVerify($claimed_id, $to_match_endpoints)
+    {
+        // oidutil.log('Performing discovery on %s' % (claimed_id,))
+        list($unused, $services) = call_user_func($this->discoverMethod,
+                                                  $claimed_id,
+                                                  $this->fetcher);
+
+        if (!$services) {
+            return new Auth_OpenID_FailureResponse(null,
+              sprintf("No OpenID information found at %s",
+                      $claimed_id));
+        }
+
+        return $this->_verifyDiscoveryServices($claimed_id, $services,
+                                               $to_match_endpoints);
+    }
+
+    /**
+     * @access private
+     */
+    function _verifyDiscoveryServices($claimed_id, 
+                                      &$services, &$to_match_endpoints)
+    {
+        // Search the services resulting from discovery to find one
+        // that matches the information from the assertion
+
+        foreach ($services as $endpoint) {
+            foreach ($to_match_endpoints as $to_match_endpoint) {
+                $result = $this->_verifyDiscoverySingle($endpoint, 
+                                                        $to_match_endpoint);
+
+                if (!Auth_OpenID::isFailure($result)) {
+                    // It matches, so discover verification has
+                    // succeeded. Return this endpoint.
+                    return $endpoint;
+                }
+            }
+        }
+
+        return new Auth_OpenID_FailureResponse(null,
+          sprintf('No matching endpoint found after discovering %s',
+                  $claimed_id));
+    }
+
+    /**
+     * Extract the nonce from an OpenID 1 response.  Return the nonce
+     * from the BARE_NS since we independently check the return_to
+     * arguments are the same as those in the response message.
+     *
+     * See the openid1_nonce_query_arg_name class variable
+     *
+     * @returns $nonce The nonce as a string or null
+     *
+     * @access private
+     */
+    function _idResGetNonceOpenID1($message, $endpoint)
+    {
+        return $message->getArg(Auth_OpenID_BARE_NS,
+                                $this->openid1_nonce_query_arg_name);
+    }
+
+    /**
+     * @access private
+     */
+    function _idResCheckNonce($message, $endpoint)
+    {
+        if ($message->isOpenID1()) {
+            // This indicates that the nonce was generated by the consumer
+            $nonce = $this->_idResGetNonceOpenID1($message, $endpoint);
+            $server_url = '';
+        } else {
+            $nonce = $message->getArg(Auth_OpenID_OPENID2_NS,
+                                      'response_nonce');
+
+            $server_url = $endpoint->server_url;
+        }
+
+        if ($nonce === null) {
+            return new Auth_OpenID_FailureResponse($endpoint,
+                                     "Nonce missing from response");
+        }
+
+        $parts = Auth_OpenID_splitNonce($nonce);
+
+        if ($parts === null) {
+            return new Auth_OpenID_FailureResponse($endpoint,
+                                     "Malformed nonce in response");
+        }
+
+        list($timestamp, $salt) = $parts;
+
+        if (!$this->store->useNonce($server_url, $timestamp, $salt)) {
+            return new Auth_OpenID_FailureResponse($endpoint,
+                         "Nonce already used or out of range");
+        }
+
+        return null;
+    }
+
+    /**
+     * @access private
+     */
+    function _idResCheckForFields($message)
+    {
+        $basic_fields = array('return_to', 'assoc_handle', 'sig', 'signed');
+        $basic_sig_fields = array('return_to', 'identity');
+
+        $require_fields = array(
+            Auth_OpenID_OPENID2_NS => array_merge($basic_fields,
+                                                  array('op_endpoint')),
+
+            Auth_OpenID_OPENID1_NS => array_merge($basic_fields,
+                                                  array('identity'))
+            );
+
+        $require_sigs = array(
+            Auth_OpenID_OPENID2_NS => array_merge($basic_sig_fields,
+                                                  array('response_nonce',
+                                                        'claimed_id',
+                                                        'assoc_handle')),
+            Auth_OpenID_OPENID1_NS => array_merge($basic_sig_fields,
+                                                  array('nonce'))
+            );
+
+        foreach ($require_fields[$message->getOpenIDNamespace()] as $field) {
+            if (!$message->hasKey(Auth_OpenID_OPENID_NS, $field)) {
+                return new Auth_OpenID_FailureResponse(null,
+                             "Missing required field '".$field."'");
+            }
+        }
+
+        $signed_list_str = $message->getArg(Auth_OpenID_OPENID_NS,
+                                            'signed',
+                                            Auth_OpenID_NO_DEFAULT);
+        if (Auth_OpenID::isFailure($signed_list_str)) {
+            return $signed_list_str;
+        }
+        $signed_list = explode(',', $signed_list_str);
+
+        foreach ($require_sigs[$message->getOpenIDNamespace()] as $field) {
+            // Field is present and not in signed list
+            if ($message->hasKey(Auth_OpenID_OPENID_NS, $field) &&
+                (!in_array($field, $signed_list))) {
+                return new Auth_OpenID_FailureResponse(null,
+                             "'".$field."' not signed");
+            }
+        }
+
+        return null;
+    }
+
+    /**
+     * @access private
+     */
+    function _checkAuth($message, $server_url)
+    {
+        $request = $this->_createCheckAuthRequest($message);
+        if ($request === null) {
+            return false;
+        }
+
+        $resp_message = $this->_makeKVPost($request, $server_url);
+        if (($resp_message === null) ||
+            (is_a($resp_message, 'Auth_OpenID_ServerErrorContainer'))) {
+            return false;
+        }
+
+        return $this->_processCheckAuthResponse($resp_message, $server_url);
+    }
+
+    /**
+     * @access private
+     */
+    function _createCheckAuthRequest($message)
+    {
+        $signed = $message->getArg(Auth_OpenID_OPENID_NS, 'signed');
+        if ($signed) {
+            foreach (explode(',', $signed) as $k) {
+                $value = $message->getAliasedArg($k);
+                if ($value === null) {
+                    return null;
+                }
+            }
+        }
+        $ca_message = $message->copy();
+        $ca_message->setArg(Auth_OpenID_OPENID_NS, 'mode', 
+                            'check_authentication');
+        return $ca_message;
+    }
+
+    /**
+     * @access private
+     */
+    function _processCheckAuthResponse($response, $server_url)
+    {
+        $is_valid = $response->getArg(Auth_OpenID_OPENID_NS, 'is_valid',
+                                      'false');
+
+        $invalidate_handle = $response->getArg(Auth_OpenID_OPENID_NS,
+                                               'invalidate_handle');
+
+        if ($invalidate_handle !== null) {
+            $this->store->removeAssociation($server_url,
+                                            $invalidate_handle);
+        }
+
+        if ($is_valid == 'true') {
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * Adapt a POST response to a Message.
+     *
+     * @param $response Result of a POST to an OpenID endpoint.
+     *
+     * @access private
+     */
+    function _httpResponseToMessage($response, $server_url)
+    {
+        // Should this function be named Message.fromHTTPResponse instead?
+        $response_message = Auth_OpenID_Message::fromKVForm($response->body);
+
+        if ($response->status == 400) {
+            return Auth_OpenID_ServerErrorContainer::fromMessage(
+                        $response_message);
+        } else if ($response->status != 200 and $response->status != 206) {
+            return null;
+        }
+
+        return $response_message;
+    }
+
+    /**
+     * @access private
+     */
+    function _makeKVPost($message, $server_url)
+    {
+        $body = $message->toURLEncoded();
+        $resp = $this->fetcher->post($server_url, $body);
+
+        if ($resp === null) {
+            return null;
+        }
+
+        return $this->_httpResponseToMessage($resp, $server_url);
+    }
+
+    /**
+     * @access private
+     */
+    function _getAssociation($endpoint)
+    {
+        if (!$this->_use_assocs) {
+            return null;
+        }
+
+        $assoc = $this->store->getAssociation($endpoint->server_url);
+
+        if (($assoc === null) ||
+            ($assoc->getExpiresIn() <= 0)) {
+
+            $assoc = $this->_negotiateAssociation($endpoint);
+
+            if ($assoc !== null) {
+                $this->store->storeAssociation($endpoint->server_url,
+                                               $assoc);
+            }
+        }
+
+        return $assoc;
+    }
+
+    /**
+     * Handle ServerErrors resulting from association requests.
+     *
+     * @return $result If server replied with an C{unsupported-type}
+     * error, return a tuple of supported C{association_type},
+     * C{session_type}.  Otherwise logs the error and returns null.
+     *
+     * @access private
+     */
+    function _extractSupportedAssociationType(&$server_error, &$endpoint,
+                                              $assoc_type)
+    {
+        // Any error message whose code is not 'unsupported-type'
+        // should be considered a total failure.
+        if (($server_error->error_code != 'unsupported-type') ||
+            ($server_error->message->isOpenID1())) {
+            return null;
+        }
+
+        // The server didn't like the association/session type that we
+        // sent, and it sent us back a message that might tell us how
+        // to handle it.
+
+        // Extract the session_type and assoc_type from the error
+        // message
+        $assoc_type = $server_error->message->getArg(Auth_OpenID_OPENID_NS,
+                                                     'assoc_type');
+
+        $session_type = $server_error->message->getArg(Auth_OpenID_OPENID_NS,
+                                                       'session_type');
+
+        if (($assoc_type === null) || ($session_type === null)) {
+            return null;
+        } else if (!$this->negotiator->isAllowed($assoc_type,
+                                                 $session_type)) {
+            return null;
+        } else {
+          return array($assoc_type, $session_type);
+        }
+    }
+
+    /**
+     * @access private
+     */
+    function _negotiateAssociation($endpoint)
+    {
+        // Get our preferred session/association type from the negotiatior.
+        list($assoc_type, $session_type) = $this->negotiator->getAllowedType();
+
+        $assoc = $this->_requestAssociation(
+                           $endpoint, $assoc_type, $session_type);
+
+        if (Auth_OpenID::isFailure($assoc)) {
+            return null;
+        }
+
+        if (is_a($assoc, 'Auth_OpenID_ServerErrorContainer')) {
+            $why = $assoc;
+
+            $supportedTypes = $this->_extractSupportedAssociationType(
+                                     $why, $endpoint, $assoc_type);
+
+            if ($supportedTypes !== null) {
+                list($assoc_type, $session_type) = $supportedTypes;
+
+                // Attempt to create an association from the assoc_type
+                // and session_type that the server told us it
+                // supported.
+                $assoc = $this->_requestAssociation(
+                                   $endpoint, $assoc_type, $session_type);
+
+                if (is_a($assoc, 'Auth_OpenID_ServerErrorContainer')) {
+                    // Do not keep trying, since it rejected the
+                    // association type that it told us to use.
+                    // oidutil.log('Server %s refused its suggested association
+                    //             'type: session_type=%s, assoc_type=%s'
+                    //             % (endpoint.server_url, session_type,
+                    //                assoc_type))
+                    return null;
+                } else {
+                    return $assoc;
+                }
+            } else {
+                return null;
+            }
+        } else {
+            return $assoc;
+        }
+    }
+
+    /**
+     * @access private
+     */
+    function _requestAssociation($endpoint, $assoc_type, $session_type)
+    {
+        list($assoc_session, $args) = $this->_createAssociateRequest(
+                                      $endpoint, $assoc_type, $session_type);
+
+        $response_message = $this->_makeKVPost($args, $endpoint->server_url);
+
+        if ($response_message === null) {
+            // oidutil.log('openid.associate request failed: %s' % (why[0],))
+            return null;
+        } else if (is_a($response_message,
+                        'Auth_OpenID_ServerErrorContainer')) {
+            return $response_message;
+        }
+
+        return $this->_extractAssociation($response_message, $assoc_session);
+    }
+
+    /**
+     * @access private
+     */
+    function _extractAssociation(&$assoc_response, &$assoc_session)
+    {
+        // Extract the common fields from the response, raising an
+        // exception if they are not found
+        $assoc_type = $assoc_response->getArg(
+                         Auth_OpenID_OPENID_NS, 'assoc_type',
+                         Auth_OpenID_NO_DEFAULT);
+
+        if (Auth_OpenID::isFailure($assoc_type)) {
+            return $assoc_type;
+        }
+
+        $assoc_handle = $assoc_response->getArg(
+                           Auth_OpenID_OPENID_NS, 'assoc_handle',
+                           Auth_OpenID_NO_DEFAULT);
+
+        if (Auth_OpenID::isFailure($assoc_handle)) {
+            return $assoc_handle;
+        }
+
+        // expires_in is a base-10 string. The Python parsing will
+        // accept literals that have whitespace around them and will
+        // accept negative values. Neither of these are really in-spec,
+        // but we think it's OK to accept them.
+        $expires_in_str = $assoc_response->getArg(
+                             Auth_OpenID_OPENID_NS, 'expires_in',
+                             Auth_OpenID_NO_DEFAULT);
+
+        if (Auth_OpenID::isFailure($expires_in_str)) {
+            return $expires_in_str;
+        }
+
+        $expires_in = Auth_OpenID::intval($expires_in_str);
+        if ($expires_in === false) {
+            
+            $err = sprintf("Could not parse expires_in from association ".
+                           "response %s", print_r($assoc_response, true));
+            return new Auth_OpenID_FailureResponse(null, $err);
+        }
+
+        // OpenID 1 has funny association session behaviour.
+        if ($assoc_response->isOpenID1()) {
+            $session_type = $this->_getOpenID1SessionType($assoc_response);
+        } else {
+            $session_type = $assoc_response->getArg(
+                               Auth_OpenID_OPENID2_NS, 'session_type',
+                               Auth_OpenID_NO_DEFAULT);
+
+            if (Auth_OpenID::isFailure($session_type)) {
+                return $session_type;
+            }
+        }
+
+        // Session type mismatch
+        if ($assoc_session->session_type != $session_type) {
+            if ($assoc_response->isOpenID1() &&
+                ($session_type == 'no-encryption')) {
+                // In OpenID 1, any association request can result in
+                // a 'no-encryption' association response. Setting
+                // assoc_session to a new no-encryption session should
+                // make the rest of this function work properly for
+                // that case.
+                $assoc_session = new Auth_OpenID_PlainTextConsumerSession();
+            } else {
+                // Any other mismatch, regardless of protocol version
+                // results in the failure of the association session
+                // altogether.
+                return null;
+            }
+        }
+
+        // Make sure assoc_type is valid for session_type
+        if (!in_array($assoc_type, $assoc_session->allowed_assoc_types)) {
+            return null;
+        }
+
+        // Delegate to the association session to extract the secret
+        // from the response, however is appropriate for that session
+        // type.
+        $secret = $assoc_session->extractSecret($assoc_response);
+
+        if ($secret === null) {
+            return null;
+        }
+
+        return Auth_OpenID_Association::fromExpiresIn(
+                 $expires_in, $assoc_handle, $secret, $assoc_type);
+    }
+
+    /**
+     * @access private
+     */
+    function _createAssociateRequest($endpoint, $assoc_type, $session_type)
+    {
+        if (array_key_exists($session_type, $this->session_types)) {
+            $session_type_class = $this->session_types[$session_type];
+
+            if (is_callable($session_type_class)) {
+                $assoc_session = $session_type_class();
+            } else {
+                $assoc_session = new $session_type_class();
+            }
+        } else {
+            return null;
+        }
+
+        $args = array(
+            'mode' => 'associate',
+            'assoc_type' => $assoc_type);
+
+        if (!$endpoint->compatibilityMode()) {
+            $args['ns'] = Auth_OpenID_OPENID2_NS;
+        }
+
+        // Leave out the session type if we're in compatibility mode
+        // *and* it's no-encryption.
+        if ((!$endpoint->compatibilityMode()) ||
+            ($assoc_session->session_type != 'no-encryption')) {
+            $args['session_type'] = $assoc_session->session_type;
+        }
+
+        $args = array_merge($args, $assoc_session->getRequest());
+        $message = Auth_OpenID_Message::fromOpenIDArgs($args);
+        return array($assoc_session, $message);
+    }
+
+    /**
+     * Given an association response message, extract the OpenID 1.X
+     * session type.
+     *
+     * This function mostly takes care of the 'no-encryption' default
+     * behavior in OpenID 1.
+     *
+     * If the association type is plain-text, this function will
+     * return 'no-encryption'
+     *
+     * @access private
+     * @return $typ The association type for this message
+     */
+    function _getOpenID1SessionType($assoc_response)
+    {
+        // If it's an OpenID 1 message, allow session_type to default
+        // to None (which signifies "no-encryption")
+        $session_type = $assoc_response->getArg(Auth_OpenID_OPENID1_NS,
+                                                'session_type');
+
+        // Handle the differences between no-encryption association
+        // respones in OpenID 1 and 2:
+
+        // no-encryption is not really a valid session type for OpenID
+        // 1, but we'll accept it anyway, while issuing a warning.
+        if ($session_type == 'no-encryption') {
+            // oidutil.log('WARNING: OpenID server sent "no-encryption"'
+            //             'for OpenID 1.X')
+        } else if (($session_type == '') || ($session_type === null)) {
+            // Missing or empty session type is the way to flag a
+            // 'no-encryption' response. Change the session type to
+            // 'no-encryption' so that it can be handled in the same
+            // way as OpenID 2 'no-encryption' respones.
+            $session_type = 'no-encryption';
+        }
+
+        return $session_type;
+    }
+}
+
+/**
+ * This class represents an authentication request from a consumer to
+ * an OpenID server.
+ *
+ * @package OpenID
+ */
+class Auth_OpenID_AuthRequest {
+
+    /**
+     * Initialize an authentication request with the specified token,
+     * association, and endpoint.
+     *
+     * Users of this library should not create instances of this
+     * class.  Instances of this class are created by the library when
+     * needed.
+     */
+    function Auth_OpenID_AuthRequest(&$endpoint, $assoc)
+    {
+        $this->assoc = $assoc;
+        $this->endpoint =& $endpoint;
+        $this->return_to_args = array();
+        $this->message = new Auth_OpenID_Message(
+            $endpoint->preferredNamespace());
+        $this->_anonymous = false;
+    }
+
+    /**
+     * Add an extension to this checkid request.
+     *
+     * $extension_request: An object that implements the extension
+     * request interface for adding arguments to an OpenID message.
+     */
+    function addExtension(&$extension_request)
+    {
+        $extension_request->toMessage($this->message);
+    }
+
+    /**
+     * Add an extension argument to this OpenID authentication
+     * request.
+     *
+     * Use caution when adding arguments, because they will be
+     * URL-escaped and appended to the redirect URL, which can easily
+     * get quite long.
+     *
+     * @param string $namespace The namespace for the extension. For
+     * example, the simple registration extension uses the namespace
+     * 'sreg'.
+     *
+     * @param string $key The key within the extension namespace. For
+     * example, the nickname field in the simple registration
+     * extension's key is 'nickname'.
+     *
+     * @param string $value The value to provide to the server for
+     * this argument.
+     */
+    function addExtensionArg($namespace, $key, $value)
+    {
+        return $this->message->setArg($namespace, $key, $value);
+    }
+
+    /**
+     * Set whether this request should be made anonymously. If a
+     * request is anonymous, the identifier will not be sent in the
+     * request. This is only useful if you are making another kind of
+     * request with an extension in this request.
+     *
+     * Anonymous requests are not allowed when the request is made
+     * with OpenID 1.
+     */
+    function setAnonymous($is_anonymous)
+    {
+        if ($is_anonymous && $this->message->isOpenID1()) {
+            return false;
+        } else {
+            $this->_anonymous = $is_anonymous;
+            return true;
+        }
+    }
+
+    /**
+     * Produce a {@link Auth_OpenID_Message} representing this
+     * request.
+     *
+     * @param string $realm The URL (or URL pattern) that identifies
+     * your web site to the user when she is authorizing it.
+     *
+     * @param string $return_to The URL that the OpenID provider will
+     * send the user back to after attempting to verify her identity.
+     *
+     * Not specifying a return_to URL means that the user will not be
+     * returned to the site issuing the request upon its completion.
+     *
+     * @param bool $immediate If true, the OpenID provider is to send
+     * back a response immediately, useful for behind-the-scenes
+     * authentication attempts.  Otherwise the OpenID provider may
+     * engage the user before providing a response.  This is the
+     * default case, as the user may need to provide credentials or
+     * approve the request before a positive response can be sent.
+     */
+    function getMessage($realm, $return_to=null, $immediate=false)
+    {
+        if ($return_to) {
+            $return_to = Auth_OpenID::appendArgs($return_to,
+                                                 $this->return_to_args);
+        } else if ($immediate) {
+            // raise ValueError(
+            //     '"return_to" is mandatory when
+            //using "checkid_immediate"')
+            return new Auth_OpenID_FailureResponse(null,
+              "'return_to' is mandatory when using checkid_immediate");
+        } else if ($this->message->isOpenID1()) {
+            // raise ValueError('"return_to" is
+            // mandatory for OpenID 1 requests')
+            return new Auth_OpenID_FailureResponse(null,
+              "'return_to' is mandatory for OpenID 1 requests");
+        } else if ($this->return_to_args) {
+            // raise ValueError('extra "return_to" arguments
+            // were specified, but no return_to was specified')
+            return new Auth_OpenID_FailureResponse(null,
+              "extra 'return_to' arguments where specified, " .
+              "but no return_to was specified");
+        }
+
+        if ($immediate) {
+            $mode = 'checkid_immediate';
+        } else {
+            $mode = 'checkid_setup';
+        }
+
+        $message = $this->message->copy();
+        if ($message->isOpenID1()) {
+            $realm_key = 'trust_root';
+        } else {
+            $realm_key = 'realm';
+        }
+
+        $message->updateArgs(Auth_OpenID_OPENID_NS,
+                             array(
+                                   $realm_key => $realm,
+                                   'mode' => $mode,
+                                   'return_to' => $return_to));
+
+        if (!$this->_anonymous) {
+            if ($this->endpoint->isOPIdentifier()) {
+                // This will never happen when we're in compatibility
+                // mode, as long as isOPIdentifier() returns False
+                // whenever preferredNamespace() returns OPENID1_NS.
+                $claimed_id = $request_identity =
+                    Auth_OpenID_IDENTIFIER_SELECT;
+            } else {
+                $request_identity = $this->endpoint->getLocalID();
+                $claimed_id = $this->endpoint->claimed_id;
+            }
+
+            // This is true for both OpenID 1 and 2
+            $message->setArg(Auth_OpenID_OPENID_NS, 'identity',
+                             $request_identity);
+
+            if ($message->isOpenID2()) {
+                $message->setArg(Auth_OpenID_OPENID2_NS, 'claimed_id',
+                                 $claimed_id);
+            }
+        }
+
+        if ($this->assoc) {
+            $message->setArg(Auth_OpenID_OPENID_NS, 'assoc_handle',
+                             $this->assoc->handle);
+        }
+
+        return $message;
+    }
+
+    function redirectURL($realm, $return_to = null,
+                         $immediate = false)
+    {
+        $message = $this->getMessage($realm, $return_to, $immediate);
+
+        if (Auth_OpenID::isFailure($message)) {
+            return $message;
+        }
+
+        return $message->toURL($this->endpoint->server_url);
+    }
+
+    /**
+     * Get html for a form to submit this request to the IDP.
+     *
+     * form_tag_attrs: An array of attributes to be added to the form
+     * tag. 'accept-charset' and 'enctype' have defaults that can be
+     * overridden. If a value is supplied for 'action' or 'method', it
+     * will be replaced.
+     */
+    function formMarkup($realm, $return_to=null, $immediate=false,
+                        $form_tag_attrs=null)
+    {
+        $message = $this->getMessage($realm, $return_to, $immediate);
+
+        if (Auth_OpenID::isFailure($message)) {
+            return $message;
+        }
+
+        return $message->toFormMarkup($this->endpoint->server_url,
+                                      $form_tag_attrs);
+    }
+
+    /**
+     * Get a complete html document that will autosubmit the request
+     * to the IDP.
+     *
+     * Wraps formMarkup.  See the documentation for that function.
+     */
+    function htmlMarkup($realm, $return_to=null, $immediate=false,
+                        $form_tag_attrs=null)
+    {
+        $form = $this->formMarkup($realm, $return_to, $immediate, 
+                                  $form_tag_attrs);
+
+        if (Auth_OpenID::isFailure($form)) {
+            return $form;
+        }
+        return Auth_OpenID::autoSubmitHTML($form);
+    }
+
+    function shouldSendRedirect()
+    {
+        return $this->endpoint->compatibilityMode();
+    }
+}
+
+/**
+ * The base class for responses from the Auth_OpenID_Consumer.
+ *
+ * @package OpenID
+ */
+class Auth_OpenID_ConsumerResponse {
+    var $status = null;
+
+    function setEndpoint($endpoint)
+    {
+        $this->endpoint = $endpoint;
+        if ($endpoint === null) {
+            $this->identity_url = null;
+        } else {
+            $this->identity_url = $endpoint->claimed_id;
+        }
+    }
+
+    /**
+     * Return the display identifier for this response.
+     *
+     * The display identifier is related to the Claimed Identifier, but the
+     * two are not always identical.  The display identifier is something the
+     * user should recognize as what they entered, whereas the response's
+     * claimed identifier (in the identity_url attribute) may have extra
+     * information for better persistence.
+     *
+     * URLs will be stripped of their fragments for display.  XRIs will
+     * display the human-readable identifier (i-name) instead of the
+     * persistent identifier (i-number).
+     *
+     * Use the display identifier in your user interface.  Use
+     * identity_url for querying your database or authorization server.
+     *
+     */
+    function getDisplayIdentifier()
+    {
+        if ($this->endpoint !== null) {
+            return $this->endpoint->getDisplayIdentifier();
+        }
+        return null;
+    }
+}
+
+/**
+ * A response with a status of Auth_OpenID_SUCCESS. Indicates that
+ * this request is a successful acknowledgement from the OpenID server
+ * that the supplied URL is, indeed controlled by the requesting
+ * agent.  This has three relevant attributes:
+ *
+ * claimed_id - The identity URL that has been authenticated
+ *
+ * signed_args - The arguments in the server's response that were
+ * signed and verified.
+ *
+ * status - Auth_OpenID_SUCCESS.
+ *
+ * @package OpenID
+ */
+class Auth_OpenID_SuccessResponse extends Auth_OpenID_ConsumerResponse {
+    var $status = Auth_OpenID_SUCCESS;
+
+    /**
+     * @access private
+     */
+    function Auth_OpenID_SuccessResponse($endpoint, $message, $signed_args=null)
+    {
+        $this->endpoint = $endpoint;
+        $this->identity_url = $endpoint->claimed_id;
+        $this->signed_args = $signed_args;
+        $this->message = $message;
+
+        if ($this->signed_args === null) {
+            $this->signed_args = array();
+        }
+    }
+
+    /**
+     * Extract signed extension data from the server's response.
+     *
+     * @param string $prefix The extension namespace from which to
+     * extract the extension data.
+     */
+    function extensionResponse($namespace_uri, $require_signed)
+    {
+        if ($require_signed) {
+            return $this->getSignedNS($namespace_uri);
+        } else {
+            return $this->message->getArgs($namespace_uri);
+        }
+    }
+
+    function isOpenID1()
+    {
+        return $this->message->isOpenID1();
+    }
+
+    function isSigned($ns_uri, $ns_key)
+    {
+        // Return whether a particular key is signed, regardless of
+        // its namespace alias
+        return in_array($this->message->getKey($ns_uri, $ns_key),
+                        $this->signed_args);
+    }
+
+    function getSigned($ns_uri, $ns_key, $default = null)
+    {
+        // Return the specified signed field if available, otherwise
+        // return default
+        if ($this->isSigned($ns_uri, $ns_key)) {
+            return $this->message->getArg($ns_uri, $ns_key, $default);
+        } else {
+            return $default;
+        }
+    }
+
+    function getSignedNS($ns_uri)
+    {
+        $args = array();
+
+        $msg_args = $this->message->getArgs($ns_uri);
+        if (Auth_OpenID::isFailure($msg_args)) {
+            return null;
+        }
+
+        foreach ($msg_args as $key => $value) {
+            if (!$this->isSigned($ns_uri, $key)) {
+                return null;
+            }
+        }
+
+        return $msg_args;
+    }
+
+    /**
+     * Get the openid.return_to argument from this response.
+     *
+     * This is useful for verifying that this request was initiated by
+     * this consumer.
+     *
+     * @return string $return_to The return_to URL supplied to the
+     * server on the initial request, or null if the response did not
+     * contain an 'openid.return_to' argument.
+    */
+    function getReturnTo()
+    {
+        return $this->getSigned(Auth_OpenID_OPENID_NS, 'return_to');
+    }
+}
+
+/**
+ * A response with a status of Auth_OpenID_FAILURE. Indicates that the
+ * OpenID protocol has failed. This could be locally or remotely
+ * triggered.  This has three relevant attributes:
+ *
+ * claimed_id - The identity URL for which authentication was
+ * attempted, if it can be determined.  Otherwise, null.
+ *
+ * message - A message indicating why the request failed, if one is
+ * supplied.  Otherwise, null.
+ *
+ * status - Auth_OpenID_FAILURE.
+ *
+ * @package OpenID
+ */
+class Auth_OpenID_FailureResponse extends Auth_OpenID_ConsumerResponse {
+    var $status = Auth_OpenID_FAILURE;
+
+    function Auth_OpenID_FailureResponse($endpoint, $message = null,
+                                         $contact = null, $reference = null)
+    {
+        $this->setEndpoint($endpoint);
+        $this->message = $message;
+        $this->contact = $contact;
+        $this->reference = $reference;
+    }
+}
+
+/**
+ * A specific, internal failure used to detect type URI mismatch.
+ *
+ * @package OpenID
+ */
+class Auth_OpenID_TypeURIMismatch extends Auth_OpenID_FailureResponse {
+}
+
+/**
+ * Exception that is raised when the server returns a 400 response
+ * code to a direct request.
+ *
+ * @package OpenID
+ */
+class Auth_OpenID_ServerErrorContainer {
+    function Auth_OpenID_ServerErrorContainer($error_text,
+                                              $error_code,
+                                              $message)
+    {
+        $this->error_text = $error_text;
+        $this->error_code = $error_code;
+        $this->message = $message;
+    }
+
+    /**
+     * @access private
+     */
+    function fromMessage($message)
+    {
+        $error_text = $message->getArg(
+           Auth_OpenID_OPENID_NS, 'error', '<no error message supplied>');
+        $error_code = $message->getArg(Auth_OpenID_OPENID_NS, 'error_code');
+        return new Auth_OpenID_ServerErrorContainer($error_text,
+                                                    $error_code,
+                                                    $message);
+    }
+}
+
+/**
+ * A response with a status of Auth_OpenID_CANCEL. Indicates that the
+ * user cancelled the OpenID authentication request.  This has two
+ * relevant attributes:
+ *
+ * claimed_id - The identity URL for which authentication was
+ * attempted, if it can be determined.  Otherwise, null.
+ *
+ * status - Auth_OpenID_SUCCESS.
+ *
+ * @package OpenID
+ */
+class Auth_OpenID_CancelResponse extends Auth_OpenID_ConsumerResponse {
+    var $status = Auth_OpenID_CANCEL;
+
+    function Auth_OpenID_CancelResponse($endpoint)
+    {
+        $this->setEndpoint($endpoint);
+    }
+}
+
+/**
+ * A response with a status of Auth_OpenID_SETUP_NEEDED. Indicates
+ * that the request was in immediate mode, and the server is unable to
+ * authenticate the user without further interaction.
+ *
+ * claimed_id - The identity URL for which authentication was
+ * attempted.
+ *
+ * setup_url - A URL that can be used to send the user to the server
+ * to set up for authentication. The user should be redirected in to
+ * the setup_url, either in the current window or in a new browser
+ * window.  Null in OpenID 2.
+ *
+ * status - Auth_OpenID_SETUP_NEEDED.
+ *
+ * @package OpenID
+ */
+class Auth_OpenID_SetupNeededResponse extends Auth_OpenID_ConsumerResponse {
+    var $status = Auth_OpenID_SETUP_NEEDED;
+
+    function Auth_OpenID_SetupNeededResponse($endpoint,
+                                             $setup_url = null)
+    {
+        $this->setEndpoint($endpoint);
+        $this->setup_url = $setup_url;
+    }
+}
+
+?>