<?php
/**
  * Ahead WebSoft Technologies Pvt Ltd.
  * @copyright  Copyright 2006-2026 Ahead WebSoft Technologies Pvt Ltd.
  * @license    https://www.socialengine.com/policies
*/
error_reporting(E_ALL);
ini_set('display_errors', 1);
// vim: foldmethod=marker

/* Generic exception class
 */
if(!class_exists('OAuthToken')){

    if (1) {
        if(!class_exists('OAuthException')) {
            class OAuthException extends Exception
            {
                // pass
            }
        }
        if(!class_exists('OAuthConsumer')) {
            class OAuthConsumer
            {

                public $key;
                public $secret;

                function __construct($key, $secret, $callback_url = NULL)
                {
                    $this->key = $key;
                    $this->secret = $secret;
                    $this->callback_url = $callback_url;
                }

                function __toString()
                {
                    return "OAuthConsumer[key=$this->key,secret=$this->secret]";
                }

            }
        }
        if(!class_exists('OAuthToken')) {
            class OAuthToken
            {

                // access tokens and request tokens
                public $key;
                public $secret;

                /**
                 * key = the token
                 * secret = the token secret
                 */
                function __construct($key, $secret)
                {
                    $this->key = $key;
                    $this->secret = $secret;
                }

                /**
                 * generates the basic string serialization of a token that a server
                 * would respond to request_token and access_token calls with
                 */
                function to_string()
                {
                    return "oauth_token=" .
                        OAuthUtil::urlencode_rfc3986($this->key) .
                        "&oauth_token_secret=" .
                        OAuthUtil::urlencode_rfc3986($this->secret);
                }

                function __toString()
                {
                    return $this->to_string();
                }

            }
        }
        /**
         * A class for implementing a Signature Method
         * See section 9 ("Signing Requests") in the spec
         */
        if(!class_exists('OAuthSignatureMethod')) {
            abstract class OAuthSignatureMethod
            {

                /**
                 * Needs to return the name of the Signature Method (ie HMAC-SHA1)
                 * @return string
                 */
                abstract public function get_name();

                /**
                 * Build up the signature
                 * NOTE: The output of this function MUST NOT be urlencoded.
                 * the encoding is handled in OAuthRequest when the final
                 * request is serialized
                 * @param OAuthRequest $request
                 * @param OAuthConsumer $consumer
                 * @param OAuthToken $token
                 * @return string
                 */
                abstract public function build_signature($request, $consumer, $token);

                /**
                 * Verifies that a given signature is correct
                 * @param OAuthRequest $request
                 * @param OAuthConsumer $consumer
                 * @param OAuthToken $token
                 * @param string $signature
                 * @return bool
                 */
                public function check_signature($request, $consumer, $token, $signature)
                {
                    $built = $this->build_signature($request, $consumer, $token);
                    return $built == $signature;
                }

            }
        }
        /**
         * The HMAC-SHA1 signature method uses the HMAC-SHA1 signature algorithm as defined in [RFC2104]
         * where the Signature Base String is the text and the key is the concatenated values (each first
         * encoded per Parameter Encoding) of the Consumer Secret and Token Secret, separated by an '&'
         * character (ASCII code 38) even if empty.
         *   - Chapter 9.2 ("HMAC-SHA1")
         */
        if(!class_exists('OAuthSignatureMethod_HMAC_SHA1')) {
            class OAuthSignatureMethod_HMAC_SHA1 extends OAuthSignatureMethod
            {

                function get_name()
                {
                    return "HMAC-SHA1";
                }

                public function build_signature($request, $consumer, $token)
                {
                    $base_string = $request->get_signature_base_string();
                    $request->base_string = $base_string;

                    $key_parts = array(
                        $consumer->secret,
                        ($token) ? $token->secret : ""
                    );

                    $key_parts = OAuthUtil::urlencode_rfc3986($key_parts);
                    $key = implode('&', $key_parts);

                    return base64_encode(hash_hmac('sha1', $base_string, $key, true));
                }

            }
        }
        /**
         * The PLAINTEXT method does not provide any security protection and SHOULD only be used
         * over a secure channel such as HTTPS. It does not use the Signature Base String.
         *   - Chapter 9.4 ("PLAINTEXT")
         */
        if(!class_exists('OAuthSignatureMethod_PLAINTEXT')) {
            class OAuthSignatureMethod_PLAINTEXT extends OAuthSignatureMethod
            {

                public function get_name()
                {
                    return "PLAINTEXT";
                }

                /**
                 * oauth_signature is set to the concatenated encoded values of the Consumer Secret and
                 * Token Secret, separated by a '&' character (ASCII code 38), even if either secret is
                 * empty. The result MUST be encoded again.
                 *   - Chapter 9.4.1 ("Generating Signatures")
                 *
                 * Please note that the second encoding MUST NOT happen in the SignatureMethod, as
                 * OAuthRequest handles this!
                 */
                public function build_signature($request, $consumer, $token)
                {
                    $key_parts = array(
                        $consumer->secret,
                        ($token) ? $token->secret : ""
                    );

                    $key_parts = OAuthUtil::urlencode_rfc3986($key_parts);
                    $key = implode('&', $key_parts);
                    $request->base_string = $key;

                    return $key;
                }

            }
        }
        /**
         * The RSA-SHA1 signature method uses the RSASSA-PKCS1-v1_5 signature algorithm as defined in
         * [RFC3447] section 8.2 (more simply known as PKCS#1), using SHA-1 as the hash function for
         * EMSA-PKCS1-v1_5. It is assumed that the Consumer has provided its RSA public key in a
         * verified way to the Service Provider, in a manner which is beyond the scope of this
         * specification.
         *   - Chapter 9.3 ("RSA-SHA1")
         */
        if(!class_exists('OAuthSignatureMethod_RSA_SHA1')) {
            abstract class OAuthSignatureMethod_RSA_SHA1 extends OAuthSignatureMethod
            {

                public function get_name()
                {
                    return "RSA-SHA1";
                }

                // Up to the SP to implement this lookup of keys. Possible ideas are:
                // (1) do a lookup in a table of trusted certs keyed off of consumer
                // (2) fetch via http using a url provided by the requester
                // (3) some sort of specific discovery code based on request
                //
                // Either way should return a string representation of the certificate
                protected abstract function fetch_public_cert(&$request);

                // Up to the SP to implement this lookup of keys. Possible ideas are:
                // (1) do a lookup in a table of trusted certs keyed off of consumer
                //
                // Either way should return a string representation of the certificate
                protected abstract function fetch_private_cert(&$request);

                public function build_signature($request, $consumer, $token)
                {
                    $base_string = $request->get_signature_base_string();
                    $request->base_string = $base_string;

                    // Fetch the private key cert based on the request
                    $cert = $this->fetch_private_cert($request);

                    // Pull the private key ID from the certificate
                    $privatekeyid = openssl_get_privatekey($cert);

                    // Sign using the key
                    $ok = openssl_sign($base_string, $signature, $privatekeyid);

                    // Release the key resource
                    openssl_free_key($privatekeyid);

                    return base64_encode($signature);
                }

                public function check_signature($request, $consumer, $token, $signature)
                {
                    $decoded_sig = base64_decode($signature);

                    $base_string = $request->get_signature_base_string();

                    // Fetch the public key cert based on the request
                    $cert = $this->fetch_public_cert($request);

                    // Pull the public key ID from the certificate
                    $publickeyid = openssl_get_publickey($cert);

                    // Check the computed signature against the one passed in the query
                    $ok = openssl_verify($base_string, $decoded_sig, $publickeyid);

                    // Release the key resource
                    openssl_free_key($publickeyid);

                    return $ok == 1;
                }

            }
        }
        if(!class_exists('OAuthRequest')) {
            class OAuthRequest
            {

                protected $parameters;
                protected $http_method;
                protected $http_url;
                // for debug purposes
                public $base_string;
                public static $version = '1.0';
                public static $POST_INPUT = 'php://input';

                function __construct($http_method, $http_url, $parameters = NULL)
                {
                    $parameters = ($parameters) ? $parameters : array();
                    $parameters = array_merge(OAuthUtil::parse_parameters(parse_url($http_url, PHP_URL_QUERY)), $parameters);
                    $this->parameters = $parameters;
                    $this->http_method = $http_method;
                    $this->http_url = $http_url;
                }

                /**
                 * attempt to build up a request from what was passed to the server
                 */
                public static function from_request($http_method = NULL, $http_url = NULL, $parameters = NULL)
                {
                    $scheme = (!isset($_SERVER['HTTPS']) || $_SERVER['HTTPS'] != "on") ? 'http' : 'https';
                    $http_url = ($http_url) ? $http_url : $scheme .
                        '://' . $_SERVER['HTTP_HOST'] .
                        ':' .
                        $_SERVER['SERVER_PORT'] .
                        $_SERVER['REQUEST_URI'];
                    $http_method = ($http_method) ? $http_method : $_SERVER['REQUEST_METHOD'];

                    // We weren't handed any parameters, so let's find the ones relevant to
                    // this request.
                    // If you run XML-RPC or similar you should use this to provide your own
                    // parsed parameter-list
                    if (!$parameters) {
                        // Find request headers
                        $request_headers = OAuthUtil::get_headers();

                        // Parse the query-string to find GET parameters
                        $parameters = OAuthUtil::parse_parameters($_SERVER['QUERY_STRING']);

                        // It's a POST request of the proper content-type, so parse POST
                        // parameters and add those overriding any duplicates from GET
                        if ($http_method == "POST" && isset($request_headers['Content-Type']) && strstr($request_headers['Content-Type'], 'application/x-www-form-urlencoded')
                        ) {
                            $post_data = OAuthUtil::parse_parameters(
                                file_get_contents(self::$POST_INPUT)
                            );
                            $parameters = array_merge($parameters, $post_data);
                        }

                        // We have a Authorization-header with OAuth data. Parse the header
                        // and add those overriding any duplicates from GET or POST
                        if (isset($request_headers['Authorization']) && substr($request_headers['Authorization'], 0, 6) == 'OAuth ') {
                            $header_parameters = OAuthUtil::split_header(
                                $request_headers['Authorization']
                            );
                            $parameters = array_merge($parameters, $header_parameters);
                        }
                    }

                    return new OAuthRequest($http_method, $http_url, $parameters);
                }

                /**
                 * pretty much a helper function to set up the request
                 */
                public static function from_consumer_and_token($consumer, $token, $http_method, $http_url, $parameters = NULL)
                {
                    $parameters = ($parameters) ? $parameters : array();
                    $defaults = array("oauth_version" => OAuthRequest::$version,
                        "oauth_nonce" => OAuthRequest::generate_nonce(),
                        "oauth_timestamp" => OAuthRequest::generate_timestamp(),
                        "oauth_consumer_key" => $consumer->key);
                    if ($token)
                        $defaults['oauth_token'] = $token->key;

                    $parameters = array_merge($defaults, $parameters);

                    return new OAuthRequest($http_method, $http_url, $parameters);
                }

                public function set_parameter($name, $value, $allow_duplicates = true)
                {
                    if ($allow_duplicates && isset($this->parameters[$name])) {
                        // We have already added parameter(s) with this name, so add to the list
                        if (is_scalar($this->parameters[$name])) {
                            // This is the first duplicate, so transform scalar (string)
                            // into an array so we can add the duplicates
                            $this->parameters[$name] = array($this->parameters[$name]);
                        }

                        $this->parameters[$name][] = $value;
                    } else {
                        $this->parameters[$name] = $value;
                    }
                }

                public function get_parameter($name)
                {
                    return isset($this->parameters[$name]) ? $this->parameters[$name] : null;
                }

                public function get_parameters()
                {
                    return $this->parameters;
                }

                public function unset_parameter($name)
                {
                    unset($this->parameters[$name]);
                }

                /**
                 * The request parameters, sorted and concatenated into a normalized string.
                 * @return string
                 */
                public function get_signable_parameters()
                {
                    // Grab all parameters
                    $params = $this->parameters;

                    // Remove oauth_signature if present
                    // Ref: Spec: 9.1.1 ("The oauth_signature parameter MUST be excluded.")
                    if (isset($params['oauth_signature'])) {
                        unset($params['oauth_signature']);
                    }

                    return OAuthUtil::build_http_query($params);
                }

                /**
                 * Returns the base string of this request
                 *
                 * The base string defined as the method, the url
                 * and the parameters (normalized), each urlencoded
                 * and the concated with &.
                 */
                public function get_signature_base_string()
                {
                    $parts = array(
                        $this->get_normalized_http_method(),
                        $this->get_normalized_http_url(),
                        $this->get_signable_parameters()
                    );

                    $parts = OAuthUtil::urlencode_rfc3986($parts);

                    return implode('&', $parts);
                }

                /**
                 * just uppercases the http method
                 */
                public function get_normalized_http_method()
                {
                    return strtoupper($this->http_method);
                }

                /**
                 * parses the url and rebuilds it to be
                 * scheme://host/path
                 */
                public function get_normalized_http_url()
                {
                    $parts = parse_url($this->http_url);

                    $scheme = (isset($parts['scheme'])) ? $parts['scheme'] : 'http';
                    $port = (isset($parts['port'])) ? $parts['port'] : (($scheme == 'https') ? '443' : '80');
                    $host = (isset($parts['host'])) ? $parts['host'] : '';
                    $path = (isset($parts['path'])) ? $parts['path'] : '';

                    if (($scheme == 'https' && $port != '443') || ($scheme == 'http' && $port != '80')) {
                        $host = "$host:$port";
                    }
                    return "$scheme://$host$path";
                }

                /**
                 * builds a url usable for a GET request
                 */
                public function to_url()
                {
                    $post_data = $this->to_postdata();
                    $out = $this->get_normalized_http_url();
                    if ($post_data) {
                        $out .= '?' . $post_data;
                    }
                    return $out;
                }

                /**
                 * builds the data one would send in a POST request
                 */
                public function to_postdata()
                {
                    return OAuthUtil::build_http_query($this->parameters);
                }

                /**
                 * builds the Authorization: header
                 */
                public function to_header($realm = null)
                {
                    $first = true;
                    if ($realm) {
                        $out = 'Authorization: OAuth realm="' . OAuthUtil::urlencode_rfc3986($realm) . '"';
                        $first = false;
                    } else
                        $out = 'Authorization: OAuth';

                    $total = array();
                    foreach ($this->parameters as $k => $v) {
                        if (substr($k, 0, 5) != "oauth")
                            continue;
                        if (is_array($v)) {
                            throw new OAuthException('Arrays not supported in headers');
                        }
                        $out .= ($first) ? ' ' : ',';
                        $out .= OAuthUtil::urlencode_rfc3986($k) .
                            '="' .
                            OAuthUtil::urlencode_rfc3986($v) .
                            '"';
                        $first = false;
                    }
                    return $out;
                }

                public function __toString()
                {
                    return $this->to_url();
                }

                public function sign_request($signature_method, $consumer, $token)
                {
                    $this->set_parameter(
                        "oauth_signature_method", $signature_method->get_name(), false
                    );
                    $signature = $this->build_signature($signature_method, $consumer, $token);
                    $this->set_parameter("oauth_signature", $signature, false);
                }

                public function build_signature($signature_method, $consumer, $token)
                {
                    $signature = $signature_method->build_signature($this, $consumer, $token);
                    return $signature;
                }

                /**
                 * util function: current timestamp
                 */
                private static function generate_timestamp()
                {
                    return time();
                }

                /**
                 * util function: current nonce
                 */
                private static function generate_nonce()
                {
                    $mt = microtime();
                    $rand = mt_rand();

                    return md5($mt . $rand); // md5s look nicer than numbers
                }

            }
        }
        if(!class_exists('OAuthServer')) {
            class OAuthServer
            {

                protected $timestamp_threshold = 300; // in seconds, five minutes
                protected $version = '1.0';             // hi blaine
                protected $signature_methods = array();
                protected $data_store;

                function __construct($data_store)
                {
                    $this->data_store = $data_store;
                }

                public function add_signature_method($signature_method)
                {
                    $this->signature_methods[$signature_method->get_name()] = $signature_method;
                }

                // high level functions

                /**
                 * process a request_token request
                 * returns the request token on success
                 */
                public function fetch_request_token(&$request)
                {
                    $this->get_version($request);

                    $consumer = $this->get_consumer($request);

                    // no token required for the initial token request
                    $token = NULL;

                    $this->check_signature($request, $consumer, $token);

                    // Rev A change
                    $callback = $request->get_parameter('oauth_callback');
                    $new_token = $this->data_store->new_request_token($consumer, $callback);

                    return $new_token;
                }

                /**
                 * process an access_token request
                 * returns the access token on success
                 */
                public function fetch_access_token(&$request)
                {
                    $this->get_version($request);

                    $consumer = $this->get_consumer($request);

                    // requires authorized request token
                    $token = $this->get_token($request, $consumer, "request");

                    $this->check_signature($request, $consumer, $token);

                    // Rev A change
                    $verifier = $request->get_parameter('oauth_verifier');
                    $new_token = $this->data_store->new_access_token($token, $consumer, $verifier);

                    return $new_token;
                }

                /**
                 * verify an api call, checks all the parameters
                 */
                public function verify_request(&$request)
                {
                    $this->get_version($request);
                    $consumer = $this->get_consumer($request);
                    $token = $this->get_token($request, $consumer, "access");
                    $this->check_signature($request, $consumer, $token);
                    return array($consumer, $token);
                }

                // Internals from here

                /**
                 * version 1
                 */
                private function get_version(&$request)
                {
                    $version = $request->get_parameter("oauth_version");
                    if (!$version) {
                        // Service Providers MUST assume the protocol version to be 1.0 if this parameter is not present.
                        // Chapter 7.0 ("Accessing Protected Ressources")
                        $version = '1.0';
                    }
                    if ($version !== $this->version) {
                        throw new OAuthException("OAuth version '$version' not supported");
                    }
                    return $version;
                }

                /**
                 * figure out the signature with some defaults
                 */
                private function get_signature_method($request)
                {
                    $signature_method = $request instanceof OAuthRequest ? $request->get_parameter("oauth_signature_method") : NULL;

                    if (!$signature_method) {
                        // According to chapter 7 ("Accessing Protected Ressources") the signature-method
                        // parameter is required, and we can't just fallback to PLAINTEXT
                        throw new OAuthException('No signature method parameter. This parameter is required');
                    }

                    if (!engine_in_array($signature_method, array_keys($this->signature_methods))) {
                        throw new OAuthException(
                            "Signature method '$signature_method' not supported " .
                            "try one of the following: " .
                            implode(", ", array_keys($this->signature_methods))
                        );
                    }
                    return $this->signature_methods[$signature_method];
                }

                /**
                 * try to find the consumer for the provided request's consumer key
                 */
                private function get_consumer($request)
                {
                    $consumer_key = $request instanceof OAuthRequest ? $request->get_parameter("oauth_consumer_key") : NULL;

                    if (!$consumer_key) {
                        throw new OAuthException("Invalid consumer key");
                    }

                    $consumer = $this->data_store->lookup_consumer($consumer_key);
                    if (!$consumer) {
                        throw new OAuthException("Invalid consumer");
                    }

                    return $consumer;
                }

                /**
                 * try to find the token for the provided request's token key
                 */
                private function get_token($request, $consumer, $token_type = "access")
                {
                    $token_field = $request instanceof OAuthRequest ? $request->get_parameter('oauth_token') : NULL;

                    $token = $this->data_store->lookup_token(
                        $consumer, $token_type, $token_field
                    );
                    if (!$token) {
                        throw new OAuthException("Invalid $token_type token: $token_field");
                    }
                    return $token;
                }

                /**
                 * all-in-one function to check the signature on a request
                 * should guess the signature method appropriately
                 */
                private function check_signature($request, $consumer, $token)
                {
                    // this should probably be in a different method
                    $timestamp = $request instanceof OAuthRequest ? $request->get_parameter('oauth_timestamp') : NULL;
                    $nonce = $request instanceof OAuthRequest ? $request->get_parameter('oauth_nonce') : NULL;

                    $this->check_timestamp($timestamp);
                    $this->check_nonce($consumer, $token, $nonce, $timestamp);

                    $signature_method = $this->get_signature_method($request);

                    $signature = $request->get_parameter('oauth_signature');
                    $valid_sig = $signature_method->check_signature(
                        $request, $consumer, $token, $signature
                    );

                    if (!$valid_sig) {
                        throw new OAuthException("Invalid signature");
                    }
                }

                /**
                 * check that the timestamp is new enough
                 */
                private function check_timestamp($timestamp)
                {
                    if (!$timestamp)
                        throw new OAuthException(
                            'Missing timestamp parameter. The parameter is required'
                        );

                    // verify that timestamp is recentish
                    $now = time();
                    if (abs($now - $timestamp) > $this->timestamp_threshold) {
                        throw new OAuthException(
                            "Expired timestamp, yours $timestamp, ours $now"
                        );
                    }
                }

                /**
                 * check that the nonce is not repeated
                 */
                private function check_nonce($consumer, $token, $nonce, $timestamp)
                {
                    if (!$nonce)
                        throw new OAuthException(
                            'Missing nonce parameter. The parameter is required'
                        );

                    // verify that the nonce is uniqueish
                    $found = $this->data_store->lookup_nonce(
                        $consumer, $token, $nonce, $timestamp
                    );
                    if ($found) {
                        throw new OAuthException("Nonce already used: $nonce");
                    }
                }

            }
        }
        if(!class_exists('OAuthDataStore')) {
            class OAuthDataStore
            {

                function lookup_consumer($consumer_key)
                {
                    // implement me
                }

                function lookup_token($consumer, $token_type, $token)
                {
                    // implement me
                }

                function lookup_nonce($consumer, $token, $nonce, $timestamp)
                {
                    // implement me
                }

                function new_request_token($consumer, $callback = null)
                {
                    // return a new token attached to this consumer
                }

                function new_access_token($token, $consumer, $verifier = null)
                {
                    // return a new access token attached to this consumer
                    // for the user associated with this token if the request token
                    // is authorized
                    // should also invalidate the request token
                }

            }
        }
        if(!class_exists('OAuthUtil')) {
            class OAuthUtil
            {

                public static function urlencode_rfc3986($input)
                {
                    if (is_array($input)) {
                        return array_map(array('OAuthUtil', 'urlencode_rfc3986'), $input);
                    } else if (is_scalar($input)) {
                        return str_replace(
                            '+', ' ', str_replace('%7E', '~', rawurlencode($input))
                        );
                    } else {
                        return '';
                    }
                }

                // This decode function isn't taking into consideration the above
                // modifications to the encoding process. However, this method doesn't
                // seem to be used anywhere so leaving it as is.
                public static function urldecode_rfc3986($string)
                {
                    return urldecode($string);
                }

                // Utility function for turning the Authorization: header into
                // parameters, has to do some unescaping
                // Can filter out any non-oauth parameters if needed (default behaviour)
                // May 28th, 2010 - method updated to tjerk.meesters for a speed improvement.
                //                  see http://code.google.com/p/oauth/issues/detail?id=163
                public static function split_header($header, $only_allow_oauth_parameters = true)
                {
                    $params = array();
                    if (preg_match_all('/(' . ($only_allow_oauth_parameters ? 'oauth_' : '') . '[a-z_-]*)=(:?"([^"]*)"|([^,]*))/', $header, $matches)) {
                        foreach ($matches[1] as $i => $h) {
                            $params[$h] = OAuthUtil::urldecode_rfc3986(empty($matches[3][$i]) ? $matches[4][$i] : $matches[3][$i]);
                        }
                        if (isset($params['realm'])) {
                            unset($params['realm']);
                        }
                    }
                    return $params;
                }

                // helper to try to sort out headers for people who aren't running apache
                public static function get_headers()
                {
                    if (function_exists('apache_request_headers')) {
                        // we need this to get the actual Authorization: header
                        // because apache tends to tell us it doesn't exist
                        $headers = apache_request_headers();

                        // sanitize the output of apache_request_headers because
                        // we always want the keys to be Cased-Like-This and arh()
                        // returns the headers in the same case as they are in the
                        // request
                        $out = array();
                        foreach ($headers AS $key => $value) {
                            $key = str_replace(
                                " ", "-", ucwords(strtolower(str_replace("-", " ", $key)))
                            );
                            $out[$key] = $value;
                        }
                    } else {
                        // otherwise we don't have apache and are just going to have to hope
                        // that $_SERVER actually contains what we need
                        $out = array();
                        if (isset($_SERVER['CONTENT_TYPE']))
                            $out['Content-Type'] = $_SERVER['CONTENT_TYPE'];
                        if (isset($_ENV['CONTENT_TYPE']))
                            $out['Content-Type'] = $_ENV['CONTENT_TYPE'];

                        foreach ($_SERVER as $key => $value) {
                            if (substr($key, 0, 5) == "HTTP_") {
                                // this is chaos, basically it is just there to capitalize the first
                                // letter of every word that is not an initial HTTP and strip HTTP
                                // code from przemek
                                $key = str_replace(
                                    " ", "-", ucwords(strtolower(str_replace("_", " ", substr($key, 5))))
                                );
                                $out[$key] = $value;
                            }
                        }
                    }
                    return $out;
                }

                // This function takes a input like a=b&a=c&d=e and returns the parsed
                // parameters like this
                // array('a' => array('b','c'), 'd' => 'e')
                public static function parse_parameters($input)
                {
                    if (!isset($input) || !$input)
                        return array();

                    $pairs = explode('&', $input);

                    $parsed_parameters = array();
                    foreach ($pairs as $pair) {
                        $split = explode('=', $pair, 2);
                        $parameter = OAuthUtil::urldecode_rfc3986($split[0]);
                        $value = isset($split[1]) ? OAuthUtil::urldecode_rfc3986($split[1]) : '';

                        if (isset($parsed_parameters[$parameter])) {
                            // We have already recieved parameter(s) with this name, so add to the list
                            // of parameters with this name

                            if (is_scalar($parsed_parameters[$parameter])) {
                                // This is the first duplicate, so transform scalar (string) into an array
                                // so we can add the duplicates
                                $parsed_parameters[$parameter] = array($parsed_parameters[$parameter]);
                            }

                            $parsed_parameters[$parameter][] = $value;
                        } else {
                            $parsed_parameters[$parameter] = $value;
                        }
                    }
                    return $parsed_parameters;
                }

                public static function build_http_query($params)
                {
                    if (!$params)
                        return '';

                    // Urlencode both keys and values
                    $keys = OAuthUtil::urlencode_rfc3986(array_keys($params));
                    $values = OAuthUtil::urlencode_rfc3986(array_values($params));
                    $params = array_combine($keys, $values);

                    // Parameters are sorted by name, using lexicographical byte value ordering.
                    // Ref: Spec: 9.1.1 (1)
                    uksort($params, 'strcmp');

                    $pairs = array();
                    foreach ($params as $parameter => $value) {
                        if (is_array($value)) {
                            // If two or more parameters share the same name, they are sorted by their value
                            // Ref: Spec: 9.1.1 (1)
                            // June 12th, 2010 - changed to sort because of issue 164 by hidetaka
                            sort($value, SORT_STRING);
                            foreach ($value as $duplicate_value) {
                                $pairs[] = $parameter . '=' . $duplicate_value;
                            }
                        } else {
                            $pairs[] = $parameter . '=' . $value;
                        }
                    }
                    // For each parameter, the name is separated from the corresponding value by an '=' character (ASCII code 61)
                    // Each name-value pair is separated by an '&' character (ASCII code 38)
                    return implode('&', $pairs);
                }

            }
        }
    }
}
?>
