Merge pull request #1 from friendica/master

Update this fork

1 files changed, 781 insertions, 0 deletions

diff --git a/library/openid/openid.php b/library/openid/openid.php
new file mode 100644
index 000000000..00250c59d
--- /dev/null
+++ b/library/openid/openid.php
@@ -0,0 +1,781 @@
+<?php
+/**
+ * This class provides a simple interface for OpenID (1.1 and 2.0) authentication.
+ * Supports Yadis discovery.
+ * The authentication process is stateless/dumb.
+ *
+ * Usage:
+ * Sign-on with OpenID is a two step process:
+ * Step one is authentication with the provider:
+ * <code>
+ * $openid = new LightOpenID('my-host.example.org');
+ * $openid->identity = 'ID supplied by user';
+ * header('Location: ' . $openid->authUrl());
+ * </code>
+ * The provider then sends various parameters via GET, one of them is openid_mode.
+ * Step two is verification:
+ * <code>
+ * if ($this->data['openid_mode']) {
+ *     $openid = new LightOpenID('my-host.example.org');
+ *     echo $openid->validate() ? 'Logged in.' : 'Failed';
+ * }
+ * </code>
+ *
+ * Change the 'my-host.example.org' to your domain name. Do NOT use $_SERVER['HTTP_HOST']
+ * for that, unless you know what you are doing.
+ *
+ * Optionally, you can set $returnUrl and $realm (or $trustRoot, which is an alias).
+ * The default values for those are:
+ * $openid->realm     = (!empty($_SERVER['HTTPS']) ? 'https' : 'http') . '://' . $_SERVER['HTTP_HOST'];
+ * $openid->returnUrl = $openid->realm . $_SERVER['REQUEST_URI'];
+ * If you don't know their meaning, refer to any openid tutorial, or specification. Or just guess.
+ *
+ * AX and SREG extensions are supported.
+ * To use them, specify $openid->required and/or $openid->optional before calling $openid->authUrl().
+ * These are arrays, with values being AX schema paths (the 'path' part of the URL).
+ * For example:
+ *   $openid->required = array('namePerson/friendly', 'contact/email');
+ *   $openid->optional = array('namePerson/first');
+ * If the server supports only SREG or OpenID 1.1, these are automaticaly
+ * mapped to SREG names, so that user doesn't have to know anything about the server.
+ *
+ * To get the values, use $openid->getAttributes().
+ *
+ *
+ * The library requires PHP >= 5.1.2 with curl or http/https stream wrappers enabled.
+ * @author Mewp
+ * @copyright Copyright (c) 2010, Mewp
+ * @license http://www.opensource.org/licenses/mit-license.php MIT
+ */
+class LightOpenID
+{
+    public $returnUrl
+         , $required = array()
+         , $optional = array()
+         , $verify_peer = null
+         , $capath = null
+         , $cainfo = null
+         , $data;
+    private $identity, $claimed_id;
+    protected $server, $version, $trustRoot, $aliases, $identifier_select = false
+            , $ax = false, $sreg = false, $setup_url = null;
+    static protected $ax_to_sreg = array(
+        'namePerson/friendly'     => 'nickname',
+        'contact/email'           => 'email',
+        'namePerson'              => 'fullname',
+        'birthDate'               => 'dob',
+        'person/gender'           => 'gender',
+        'contact/postalCode/home' => 'postcode',
+        'contact/country/home'    => 'country',
+        'pref/language'           => 'language',
+        'pref/timezone'           => 'timezone',
+        );
+
+    function __construct($host)
+    {
+        $this->trustRoot = (strpos($host, '://') ? $host : 'http://' . $host);
+        if ((!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] != 'off')
+            || (isset($_SERVER['HTTP_X_FORWARDED_PROTO'])
+            && $_SERVER['HTTP_X_FORWARDED_PROTO'] == 'https')
+        ) {
+            $this->trustRoot = (strpos($host, '://') ? $host : 'https://' . $host);
+        }
+
+        if(($host_end = strpos($this->trustRoot, '/', 8)) !== false) {
+            $this->trustRoot = substr($this->trustRoot, 0, $host_end);
+        }
+
+        $uri = rtrim(preg_replace('#((?<=\?)|&)openid\.[^&]+#', '', $_SERVER['REQUEST_URI']), '?');
+        $this->returnUrl = $this->trustRoot . $uri;
+
+        $this->data = ($_SERVER['REQUEST_METHOD'] === 'POST') ? $_POST : $_GET;
+
+        if(!function_exists('curl_init') && !in_array('https', stream_get_wrappers())) {
+            throw new ErrorException('You must have either https wrappers or curl enabled.');
+        }
+    }
+
+    function __set($name, $value)
+    {
+        switch ($name) {
+        case 'identity':
+            if (strlen($value = trim((String) $value))) {
+                if (preg_match('#^xri:/*#i', $value, $m)) {
+                    $value = substr($value, strlen($m[0]));
+                } elseif (!preg_match('/^(?:[=@+\$!\(]|https?:)/i', $value)) {
+                    $value = "http://$value";
+                }
+                if (preg_match('#^https?://[^/]+$#i', $value, $m)) {
+                    $value .= '/';
+                }
+            }
+            $this->$name = $this->claimed_id = $value;
+            break;
+        case 'trustRoot':
+        case 'realm':
+            $this->trustRoot = trim($value);
+        }
+    }
+
+    function __get($name)
+    {
+        switch ($name) {
+        case 'identity':
+            # We return claimed_id instead of identity,
+            # because the developer should see the claimed identifier,
+            # i.e. what he set as identity, not the op-local identifier (which is what we verify)
+            return $this->claimed_id;
+        case 'trustRoot':
+        case 'realm':
+            return $this->trustRoot;
+        case 'mode':
+            return empty($this->data['openid_mode']) ? null : $this->data['openid_mode'];
+        }
+    }
+
+    /**
+     * Checks if the server specified in the url exists.
+     *
+     * @param $url url to check
+     * @return true, if the server exists; false otherwise
+     */
+    function hostExists($url)
+    {
+        if (strpos($url, '/') === false) {
+            $server = $url;
+        } else {
+            $server = @parse_url($url, PHP_URL_HOST);
+        }
+
+        if (!$server) {
+            return false;
+        }
+
+        return !!gethostbynamel($server);
+    }
+
+    protected function request_curl($url, $method='GET', $params=array())
+    {
+        $params = http_build_query($params, '', '&');
+        $curl = curl_init($url . ($method == 'GET' && $params ? '?' . $params : ''));
+        curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true);
+        curl_setopt($curl, CURLOPT_HEADER, false);
+        curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
+        curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
+        curl_setopt($curl, CURLOPT_HTTPHEADER, array('Accept: application/xrds+xml, */*'));
+
+        if($this->verify_peer !== null) {
+            curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, $this->verify_peer);
+            if($this->capath) {
+                curl_setopt($curl, CURLOPT_CAPATH, $this->capath);
+            }
+
+            if($this->cainfo) {
+                curl_setopt($curl, CURLOPT_CAINFO, $this->cainfo);
+            }
+        }
+
+        if ($method == 'POST') {
+            curl_setopt($curl, CURLOPT_POST, true);
+            curl_setopt($curl, CURLOPT_POSTFIELDS, $params);
+        } elseif ($method == 'HEAD') {
+            curl_setopt($curl, CURLOPT_HEADER, true);
+            curl_setopt($curl, CURLOPT_NOBODY, true);
+        } else {
+            curl_setopt($curl, CURLOPT_HTTPGET, true);
+        }
+        $response = curl_exec($curl);
+
+        if($method == 'HEAD') {
+            $headers = array();
+            foreach(explode("\n", $response) as $header) {
+                $pos = strpos($header,':');
+                $name = strtolower(trim(substr($header, 0, $pos)));
+                $headers[$name] = trim(substr($header, $pos+1));
+            }
+
+            # Updating claimed_id in case of redirections.
+            $effective_url = curl_getinfo($curl, CURLINFO_EFFECTIVE_URL);
+            if($effective_url != $url) {
+                $this->identity = $this->claimed_id = $effective_url;
+            }
+
+            return $headers;
+        }
+
+        if (curl_errno($curl)) {
+            throw new ErrorException(curl_error($curl), curl_errno($curl));
+        }
+
+        return $response;
+    }
+
+    protected function request_streams($url, $method='GET', $params=array())
+    {
+        if(!$this->hostExists($url)) {
+            throw new ErrorException("Could not connect to $url.", 404);
+        }
+
+        $params = http_build_query($params, '', '&');
+        switch($method) {
+        case 'GET':
+            $opts = array(
+                'http' => array(
+                    'method' => 'GET',
+                    'header' => 'Accept: application/xrds+xml, */*',
+                    'ignore_errors' => true,
+                ), 'ssl' => array(
+                    'CN_match' => parse_url($url, PHP_URL_HOST),
+                ),
+            );
+            $url = $url . ($params ? '?' . $params : '');
+            break;
+        case 'POST':
+            $opts = array(
+                'http' => array(
+                    'method' => 'POST',
+                    'header'  => 'Content-type: application/x-www-form-urlencoded',
+                    'content' => $params,
+                    'ignore_errors' => true,
+                ), 'ssl' => array(
+                    'CN_match' => parse_url($url, PHP_URL_HOST),
+                ),
+            );
+            break;
+        case 'HEAD':
+            # We want to send a HEAD request,
+            # but since get_headers doesn't accept $context parameter,
+            # we have to change the defaults.
+            $default = stream_context_get_options(stream_context_get_default());
+            stream_context_get_default(
+                array(
+                    'http' => array(
+                        'method' => 'HEAD',
+                        'header' => 'Accept: application/xrds+xml, */*',
+                        'ignore_errors' => true,
+                    ), 'ssl' => array(
+                        'CN_match' => parse_url($url, PHP_URL_HOST),
+                    ),
+                )
+            );
+
+            $url = $url . ($params ? '?' . $params : '');
+            $headers_tmp = get_headers ($url);
+            if(!$headers_tmp) {
+                return array();
+            }
+
+            # Parsing headers.
+            $headers = array();
+            foreach($headers_tmp as $header) {
+                $pos = strpos($header,':');
+                $name = strtolower(trim(substr($header, 0, $pos)));
+                $headers[$name] = trim(substr($header, $pos+1));
+
+                # Following possible redirections. The point is just to have
+                # claimed_id change with them, because get_headers() will
+                # follow redirections automatically.
+                # We ignore redirections with relative paths.
+                # If any known provider uses them, file a bug report.
+                if($name == 'location') {
+                    if(strpos($headers[$name], 'http') === 0) {
+                        $this->identity = $this->claimed_id = $headers[$name];
+                    } elseif($headers[$name][0] == '/') {
+                        $parsed_url = parse_url($this->claimed_id);
+                        $this->identity =
+                        $this->claimed_id = $parsed_url['scheme'] . '://'
+                                          . $parsed_url['host']
+                                          . $headers[$name];
+                    }
+                }
+            }
+
+            # And restore them.
+            stream_context_get_default($default);
+            return $headers;
+        }
+
+        if($this->verify_peer) {
+            $opts['ssl'] += array(
+                'verify_peer' => true,
+                'capath'      => $this->capath,
+                'cafile'      => $this->cainfo,
+            );
+        }
+
+        $context = stream_context_create ($opts);
+
+        return file_get_contents($url, false, $context);
+    }
+
+    protected function request($url, $method='GET', $params=array())
+    {
+        if (function_exists('curl_init')
+            && (!in_array('https', stream_get_wrappers()) || !ini_get('safe_mode') && !ini_get('open_basedir'))
+        ) {
+            return $this->request_curl($url, $method, $params);
+        }
+        return $this->request_streams($url, $method, $params);
+    }
+
+    protected function build_url($url, $parts)
+    {
+        if (isset($url['query'], $parts['query'])) {
+            $parts['query'] = $url['query'] . '&' . $parts['query'];
+        }
+
+        $url = $parts + $url;
+        $url = $url['scheme'] . '://'
+             . (empty($url['username'])?''
+                 :(empty($url['password'])? "{$url['username']}@"
+                 :"{$url['username']}:{$url['password']}@"))
+             . $url['host']
+             . (empty($url['port'])?'':":{$url['port']}")
+             . (empty($url['path'])?'':$url['path'])
+             . (empty($url['query'])?'':"?{$url['query']}")
+             . (empty($url['fragment'])?'':"#{$url['fragment']}");
+        return $url;
+    }
+
+    /**
+     * Helper function used to scan for <meta>/<link> tags and extract information
+     * from them
+     */
+    protected function htmlTag($content, $tag, $attrName, $attrValue, $valueName)
+    {
+        preg_match_all("#<{$tag}[^>]*$attrName=['\"].*?$attrValue.*?['\"][^>]*$valueName=['\"](.+?)['\"][^>]*/?>#i", $content, $matches1);
+        preg_match_all("#<{$tag}[^>]*$valueName=['\"](.+?)['\"][^>]*$attrName=['\"].*?$attrValue.*?['\"][^>]*/?>#i", $content, $matches2);
+
+        $result = array_merge($matches1[1], $matches2[1]);
+        return empty($result)?false:$result[0];
+    }
+
+    /**
+     * Performs Yadis and HTML discovery. Normally not used.
+     * @param $url Identity URL.
+     * @return String OP Endpoint (i.e. OpenID provider address).
+     * @throws ErrorException
+     */
+    function discover($url)
+    {
+        if (!$url) throw new ErrorException('No identity supplied.');
+        # Use xri.net proxy to resolve i-name identities
+        if (!preg_match('#^https?:#', $url)) {
+            $url = "https://xri.net/$url";
+        }
+
+        # We save the original url in case of Yadis discovery failure.
+        # It can happen when we'll be lead to an XRDS document
+        # which does not have any OpenID2 services.
+        $originalUrl = $url;
+
+        # A flag to disable yadis discovery in case of failure in headers.
+        $yadis = true;
+
+        # We'll jump a maximum of 5 times, to avoid endless redirections.
+        for ($i = 0; $i < 5; $i ++) {
+            if ($yadis) {
+                $headers = $this->request($url, 'HEAD');
+
+                $next = false;
+                if (isset($headers['x-xrds-location'])) {
+                    $url = $this->build_url(parse_url($url), parse_url(trim($headers['x-xrds-location'])));
+                    $next = true;
+                }
+
+                if (isset($headers['content-type'])
+                    && (strpos($headers['content-type'], 'application/xrds+xml') !== false
+                        || strpos($headers['content-type'], 'text/xml') !== false)
+                ) {
+                    # Apparently, some providers return XRDS documents as text/html.
+                    # While it is against the spec, allowing this here shouldn't break
+                    # compatibility with anything.
+                    # ---
+                    # Found an XRDS document, now let's find the server, and optionally delegate.
+                    $content = $this->request($url, 'GET');
+
+                    preg_match_all('#<Service.*?>(.*?)</Service>#s', $content, $m);
+                    foreach($m[1] as $content) {
+                        $content = ' ' . $content; # The space is added, so that strpos doesn't return 0.
+
+                        # OpenID 2
+                        $ns = preg_quote('http://specs.openid.net/auth/2.0/');
+                        if(preg_match('#<Type>\s*'.$ns.'(server|signon)\s*</Type>#s', $content, $type)) {
+                            if ($type[1] == 'server') $this->identifier_select = true;
+
+                            preg_match('#<URI.*?>(.*)</URI>#', $content, $server);
+                            preg_match('#<(Local|Canonical)ID>(.*)</\1ID>#', $content, $delegate);
+                            if (empty($server)) {
+                                return false;
+                            }
+                            # Does the server advertise support for either AX or SREG?
+                            $this->ax   = (bool) strpos($content, '<Type>http://openid.net/srv/ax/1.0</Type>');
+                            $this->sreg = strpos($content, '<Type>http://openid.net/sreg/1.0</Type>')
+                                       || strpos($content, '<Type>http://openid.net/extensions/sreg/1.1</Type>');
+
+                            $server = $server[1];
+                            if (isset($delegate[2])) $this->identity = trim($delegate[2]);
+                            $this->version = 2;
+
+                            $this->server = $server;
+                            return $server;
+                        }
+
+                        # OpenID 1.1
+                        $ns = preg_quote('http://openid.net/signon/1.1');
+                        if (preg_match('#<Type>\s*'.$ns.'\s*</Type>#s', $content)) {
+
+                            preg_match('#<URI.*?>(.*)</URI>#', $content, $server);
+                            preg_match('#<.*?Delegate>(.*)</.*?Delegate>#', $content, $delegate);
+                            if (empty($server)) {
+                                return false;
+                            }
+                            # AX can be used only with OpenID 2.0, so checking only SREG
+                            $this->sreg = strpos($content, '<Type>http://openid.net/sreg/1.0</Type>')
+                                       || strpos($content, '<Type>http://openid.net/extensions/sreg/1.1</Type>');
+
+                            $server = $server[1];
+                            if (isset($delegate[1])) $this->identity = $delegate[1];
+                            $this->version = 1;
+
+                            $this->server = $server;
+                            return $server;
+                        }
+                    }
+
+                    $next = true;
+                    $yadis = false;
+                    $url = $originalUrl;
+                    $content = null;
+                    break;
+                }
+                if ($next) continue;
+
+                # There are no relevant information in headers, so we search the body.
+                $content = $this->request($url, 'GET');
+                $location = $this->htmlTag($content, 'meta', 'http-equiv', 'X-XRDS-Location', 'content');
+                if ($location) {
+                    $url = $this->build_url(parse_url($url), parse_url($location));
+                    continue;
+                }
+            }
+
+            if (!$content) $content = $this->request($url, 'GET');
+
+            # At this point, the YADIS Discovery has failed, so we'll switch
+            # to openid2 HTML discovery, then fallback to openid 1.1 discovery.
+            $server   = $this->htmlTag($content, 'link', 'rel', 'openid2.provider', 'href');
+            $delegate = $this->htmlTag($content, 'link', 'rel', 'openid2.local_id', 'href');
+            $this->version = 2;
+
+            if (!$server) {
+                # The same with openid 1.1
+                $server   = $this->htmlTag($content, 'link', 'rel', 'openid.server', 'href');
+                $delegate = $this->htmlTag($content, 'link', 'rel', 'openid.delegate', 'href');
+                $this->version = 1;
+            }
+
+            if ($server) {
+                # We found an OpenID2 OP Endpoint
+                if ($delegate) {
+                    # We have also found an OP-Local ID.
+                    $this->identity = $delegate;
+                }
+                $this->server = $server;
+                return $server;
+            }
+
+            throw new ErrorException("No OpenID Server found at $url", 404);
+        }
+        throw new ErrorException('Endless redirection!', 500);
+    }
+
+    protected function sregParams()
+    {
+        $params = array();
+        # We always use SREG 1.1, even if the server is advertising only support for 1.0.
+        # That's because it's fully backwards compatibile with 1.0, and some providers
+        # advertise 1.0 even if they accept only 1.1. One such provider is myopenid.com
+        $params['openid.ns.sreg'] = 'http://openid.net/extensions/sreg/1.1';
+        if ($this->required) {
+            $params['openid.sreg.required'] = array();
+            foreach ($this->required as $required) {
+                if (!isset(self::$ax_to_sreg[$required])) continue;
+                $params['openid.sreg.required'][] = self::$ax_to_sreg[$required];
+            }
+            $params['openid.sreg.required'] = implode(',', $params['openid.sreg.required']);
+        }
+
+        if ($this->optional) {
+            $params['openid.sreg.optional'] = array();
+            foreach ($this->optional as $optional) {
+                if (!isset(self::$ax_to_sreg[$optional])) continue;
+                $params['openid.sreg.optional'][] = self::$ax_to_sreg[$optional];
+            }
+            $params['openid.sreg.optional'] = implode(',', $params['openid.sreg.optional']);
+        }
+        return $params;
+    }
+
+    protected function axParams()
+    {
+        $params = array();
+        if ($this->required || $this->optional) {
+            $params['openid.ns.ax'] = 'http://openid.net/srv/ax/1.0';
+            $params['openid.ax.mode'] = 'fetch_request';
+            $this->aliases  = array();
+            $counts   = array();
+            $required = array();
+            $optional = array();
+            foreach (array('required','optional') as $type) {
+                foreach ($this->$type as $alias => $field) {
+                    if (is_int($alias)) $alias = strtr($field, '/', '_');
+                    $this->aliases[$alias] = 'http://axschema.org/' . $field;
+                    if (empty($counts[$alias])) $counts[$alias] = 0;
+                    $counts[$alias] += 1;
+                    ${$type}[] = $alias;
+                }
+            }
+            foreach ($this->aliases as $alias => $ns) {
+                $params['openid.ax.type.' . $alias] = $ns;
+            }
+            foreach ($counts as $alias => $count) {
+                if ($count == 1) continue;
+                $params['openid.ax.count.' . $alias] = $count;
+            }
+
+            # Don't send empty ax.requied and ax.if_available.
+            # Google and possibly other providers refuse to support ax when one of these is empty.
+            if($required) {
+                $params['openid.ax.required'] = implode(',', $required);
+            }
+            if($optional) {
+                $params['openid.ax.if_available'] = implode(',', $optional);
+            }
+        }
+        return $params;
+    }
+
+    protected function authUrl_v1($immediate)
+    {
+	$returnUrl = $this->returnUrl;
+        # If we have an openid.delegate that is different from our claimed id,
+        # we need to somehow preserve the claimed id between requests.
+        # The simplest way is to just send it along with the return_to url.
+        if($this->identity != $this->claimed_id) {
+            $returnUrl .= (strpos($returnUrl, '?') ? '&' : '?') . 'openid.claimed_id=' . $this->claimed_id;
+        }
+
+        $params = array(
+            'openid.return_to'  => $returnUrl,
+            'openid.mode'       => $immediate ? 'checkid_immediate' : 'checkid_setup',
+            'openid.identity'   => $this->identity,
+            'openid.trust_root' => $this->trustRoot,
+            ) + $this->sregParams();
+
+        return $this->build_url(parse_url($this->server)
+                               , array('query' => http_build_query($params, '', '&')));
+    }
+
+    protected function authUrl_v2($immediate)
+    {
+        $params = array(
+            'openid.ns'          => 'http://specs.openid.net/auth/2.0',
+            'openid.mode'        => $immediate ? 'checkid_immediate' : 'checkid_setup',
+            'openid.return_to'   => $this->returnUrl,
+            'openid.realm'       => $this->trustRoot,
+        );
+        if ($this->ax) {
+            $params += $this->axParams();
+        }
+        if ($this->sreg) {
+            $params += $this->sregParams();
+        }
+        if (!$this->ax && !$this->sreg) {
+            # If OP doesn't advertise either SREG, nor AX, let's send them both
+            # in worst case we don't get anything in return.
+            $params += $this->axParams() + $this->sregParams();
+        }
+
+        if ($this->identifier_select) {
+            $params['openid.identity'] = $params['openid.claimed_id']
+                 = 'http://specs.openid.net/auth/2.0/identifier_select';
+        } else {
+            $params['openid.identity'] = $this->identity;
+            $params['openid.claimed_id'] = $this->claimed_id;
+        }
+
+        return $this->build_url(parse_url($this->server)
+                               , array('query' => http_build_query($params, '', '&')));
+    }
+
+    /**
+     * Returns authentication url. Usually, you want to redirect your user to it.
+     * @return String The authentication url.
+     * @param String $select_identifier Whether to request OP to select identity for an user in OpenID 2. Does not affect OpenID 1.
+     * @throws ErrorException
+     */
+    function authUrl($immediate = false)
+    {
+        if ($this->setup_url && !$immediate) return $this->setup_url;
+        if (!$this->server) $this->discover($this->identity);
+
+        if ($this->version == 2) {
+            return $this->authUrl_v2($immediate);
+        }
+        return $this->authUrl_v1($immediate);
+    }
+
+    /**
+     * Performs OpenID verification with the OP.
+     * @return Bool Whether the verification was successful.
+     * @throws ErrorException
+     */
+    function validate()
+    {
+        # If the request was using immediate mode, a failure may be reported
+        # by presenting user_setup_url (for 1.1) or reporting
+        # mode 'setup_needed' (for 2.0). Also catching all modes other than
+        # id_res, in order to avoid throwing errors.
+        if(isset($this->data['openid_user_setup_url'])) {
+            $this->setup_url = $this->data['openid_user_setup_url'];
+            return false;
+        }
+        if($this->mode != 'id_res') {
+            return false;
+        }
+
+        $this->claimed_id = isset($this->data['openid_claimed_id'])?$this->data['openid_claimed_id']:$this->data['openid_identity'];
+        $params = array(
+            'openid.assoc_handle' => $this->data['openid_assoc_handle'],
+            'openid.signed'       => $this->data['openid_signed'],
+            'openid.sig'          => $this->data['openid_sig'],
+            );
+
+        if (isset($this->data['openid_ns'])) {
+            # We're dealing with an OpenID 2.0 server, so let's set an ns
+            # Even though we should know location of the endpoint,
+            # we still need to verify it by discovery, so $server is not set here
+            $params['openid.ns'] = 'http://specs.openid.net/auth/2.0';
+        } elseif (isset($this->data['openid_claimed_id'])
+            && $this->data['openid_claimed_id'] != $this->data['openid_identity']
+        ) {
+            # If it's an OpenID 1 provider, and we've got claimed_id,
+            # we have to append it to the returnUrl, like authUrl_v1 does.
+            $this->returnUrl .= (strpos($this->returnUrl, '?') ? '&' : '?')
+                             .  'openid.claimed_id=' . $this->claimed_id;
+        }
+
+        if ($this->data['openid_return_to'] != $this->returnUrl) {
+            # The return_to url must match the url of current request.
+            # I'm assuing that noone will set the returnUrl to something that doesn't make sense.
+            return false;
+        }
+
+        $server = $this->discover($this->claimed_id);
+
+        foreach (explode(',', $this->data['openid_signed']) as $item) {
+            # Checking whether magic_quotes_gpc is turned on, because
+            # the function may fail if it is. For example, when fetching
+            # AX namePerson, it might containg an apostrophe, which will be escaped.
+            # In such case, validation would fail, since we'd send different data than OP
+            # wants to verify. stripslashes() should solve that problem, but we can't
+            # use it when magic_quotes is off.
+            $value = $this->data['openid_' . str_replace('.','_',$item)];
+            $params['openid.' . $item] = get_magic_quotes_gpc() ? stripslashes($value) : $value;
+
+        }
+
+        $params['openid.mode'] = 'check_authentication';
+
+        $response = $this->request($server, 'POST', $params);
+
+        return preg_match('/is_valid\s*:\s*true/i', $response);
+    }
+
+    protected function getAxAttributes()
+    {
+        $alias = null;
+        if (isset($this->data['openid_ns_ax'])
+            && $this->data['openid_ns_ax'] != 'http://openid.net/srv/ax/1.0'
+        ) { # It's the most likely case, so we'll check it before
+            $alias = 'ax';
+        } else {
+            # 'ax' prefix is either undefined, or points to another extension,
+            # so we search for another prefix
+            foreach ($this->data as $key => $val) {
+                if (substr($key, 0, strlen('openid_ns_')) == 'openid_ns_'
+                    && $val == 'http://openid.net/srv/ax/1.0'
+                ) {
+                    $alias = substr($key, strlen('openid_ns_'));
+                    break;
+                }
+            }
+        }
+        if (!$alias) {
+            # An alias for AX schema has not been found,
+            # so there is no AX data in the OP's response
+            return array();
+        }
+
+        $attributes = array();
+        foreach (explode(',', $this->data['openid_signed']) as $key) {
+            $keyMatch = $alias . '.value.';
+            if (substr($key, 0, strlen($keyMatch)) != $keyMatch) {
+                continue;
+            }
+            $key = substr($key, strlen($keyMatch));
+            if (!isset($this->data['openid_' . $alias . '_type_' . $key])) {
+                # OP is breaking the spec by returning a field without
+                # associated ns. This shouldn't happen, but it's better
+                # to check, than cause an E_NOTICE.
+                continue;
+            }
+            $value = $this->data['openid_' . $alias . '_value_' . $key];
+            $key = substr($this->data['openid_' . $alias . '_type_' . $key],
+                          strlen('http://axschema.org/'));
+
+            $attributes[$key] = $value;
+        }
+        return $attributes;
+    }
+
+    protected function getSregAttributes()
+    {
+        $attributes = array();
+        $sreg_to_ax = array_flip(self::$ax_to_sreg);
+        foreach (explode(',', $this->data['openid_signed']) as $key) {
+            $keyMatch = 'sreg.';
+            if (substr($key, 0, strlen($keyMatch)) != $keyMatch) {
+                continue;
+            }
+            $key = substr($key, strlen($keyMatch));
+            if (!isset($sreg_to_ax[$key])) {
+                # The field name isn't part of the SREG spec, so we ignore it.
+                continue;
+            }
+            $attributes[$sreg_to_ax[$key]] = $this->data['openid_sreg_' . $key];
+        }
+        return $attributes;
+    }
+
+    /**
+     * Gets AX/SREG attributes provided by OP. should be used only after successful validaton.
+     * Note that it does not guarantee that any of the required/optional parameters will be present,
+     * or that there will be no other attributes besides those specified.
+     * In other words. OP may provide whatever information it wants to.
+     *     * SREG names will be mapped to AX names.
+     *     * @return Array Array of attributes with keys being the AX schema names, e.g. 'contact/email'
+     * @see http://www.axschema.org/types/
+     */
+    function getAttributes()
+    {
+        if (isset($this->data['openid_ns'])
+            && $this->data['openid_ns'] == 'http://specs.openid.net/auth/2.0'
+        ) { # OpenID 2.0
+            # We search for both AX and SREG attributes, with AX taking precedence.
+            return $this->getAxAttributes() + $this->getSregAttributes();
+        }
+        return $this->getSregAttributes();
+    }
+}