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Differences Between: [Versions 310 and 311] [Versions 310 and 400] [Versions 310 and 401] [Versions 310 and 402] [Versions 310 and 403]

   1  <?php
   2  // vim: foldmethod=marker
   3  
   4  $OAuth_last_computed_siguature = false;
   5  
   6  /* Generic exception class
   7   */
   8  class OAuthException extends \Exception {
   9    // pass
  10  }
  11  
  12  class OAuthConsumer {
  13    public $key;
  14    public $secret;
  15  
  16    function __construct($key, $secret, $callback_url=NULL) {
  17      $this->key = $key;
  18      $this->secret = $secret;
  19      $this->callback_url = $callback_url;
  20    }
  21  
  22    function __toString() {
  23      return "OAuthConsumer[key=$this->key,secret=$this->secret]";
  24    }
  25  }
  26  
  27  class OAuthToken {
  28    // access tokens and request tokens
  29    public $key;
  30    public $secret;
  31  
  32    /**
  33     * key = the token
  34     * secret = the token secret
  35     */
  36    function __construct($key, $secret) {
  37      $this->key = $key;
  38      $this->secret = $secret;
  39    }
  40  
  41    /**
  42     * generates the basic string serialization of a token that a server
  43     * would respond to request_token and access_token calls with
  44     */
  45    function to_string() {
  46      return "oauth_token=" .
  47             OAuthUtil::urlencode_rfc3986($this->key) .
  48             "&oauth_token_secret=" .
  49             OAuthUtil::urlencode_rfc3986($this->secret);
  50    }
  51  
  52    function __toString() {
  53      return $this->to_string();
  54    }
  55  }
  56  
  57  class OAuthSignatureMethod {
  58    public function check_signature(&$request, $consumer, $token, $signature) {
  59      $built = $this->build_signature($request, $consumer, $token);
  60      return $built == $signature;
  61    }
  62  }
  63  
  64  class OAuthSignatureMethod_HMAC_SHA1 extends OAuthSignatureMethod {
  65    function get_name() {
  66      return "HMAC-SHA1";
  67    }
  68  
  69    public function build_signature($request, $consumer, $token) {
  70      global $OAuth_last_computed_signature;
  71      $OAuth_last_computed_signature = false;
  72  
  73      $base_string = $request->get_signature_base_string();
  74      $request->base_string = $base_string;
  75  
  76      $key_parts = array(
  77        $consumer->secret,
  78        ($token) ? $token->secret : ""
  79      );
  80  
  81      $key_parts = OAuthUtil::urlencode_rfc3986($key_parts);
  82      $key = implode('&', $key_parts);
  83  
  84      $computed_signature = base64_encode(hash_hmac('sha1', $base_string, $key, true));
  85      $OAuth_last_computed_signature = $computed_signature;
  86      return $computed_signature;
  87    }
  88  
  89  }
  90  
  91  class OAuthSignatureMethod_PLAINTEXT extends OAuthSignatureMethod {
  92    public function get_name() {
  93      return "PLAINTEXT";
  94    }
  95  
  96    public function build_signature($request, $consumer, $token) {
  97      $sig = array(
  98        OAuthUtil::urlencode_rfc3986($consumer->secret)
  99      );
 100  
 101      if ($token) {
 102        array_push($sig, OAuthUtil::urlencode_rfc3986($token->secret));
 103      } else {
 104        array_push($sig, '');
 105      }
 106  
 107      $raw = implode("&", $sig);
 108      // for debug purposes
 109      $request->base_string = $raw;
 110  
 111      return OAuthUtil::urlencode_rfc3986($raw);
 112    }
 113  }
 114  
 115  class OAuthSignatureMethod_RSA_SHA1 extends OAuthSignatureMethod {
 116    public function get_name() {
 117      return "RSA-SHA1";
 118    }
 119  
 120    protected function fetch_public_cert(&$request) {
 121      // not implemented yet, ideas are:
 122      // (1) do a lookup in a table of trusted certs keyed off of consumer
 123      // (2) fetch via http using a url provided by the requester
 124      // (3) some sort of specific discovery code based on request
 125      //
 126      // either way should return a string representation of the certificate
 127      throw Exception("fetch_public_cert not implemented");
 128    }
 129  
 130    protected function fetch_private_cert(&$request) {
 131      // not implemented yet, ideas are:
 132      // (1) do a lookup in a table of trusted certs keyed off of consumer
 133      //
 134      // either way should return a string representation of the certificate
 135      throw Exception("fetch_private_cert not implemented");
 136    }
 137  
 138    public function build_signature(&$request, $consumer, $token) {
 139      $base_string = $request->get_signature_base_string();
 140      $request->base_string = $base_string;
 141  
 142      // Fetch the private key cert based on the request
 143      $cert = $this->fetch_private_cert($request);
 144  
 145      // Pull the private key ID from the certificate
 146      $privatekeyid = openssl_get_privatekey($cert);
 147  
 148      // Sign using the key
 149      $ok = openssl_sign($base_string, $signature, $privatekeyid);
 150  
 151      // Release the key resource
 152      openssl_free_key($privatekeyid);
 153  
 154      return base64_encode($signature);
 155    }
 156  
 157    public function check_signature(&$request, $consumer, $token, $signature) {
 158      $decoded_sig = base64_decode($signature);
 159  
 160      $base_string = $request->get_signature_base_string();
 161  
 162      // Fetch the public key cert based on the request
 163      $cert = $this->fetch_public_cert($request);
 164  
 165      // Pull the public key ID from the certificate
 166      $publickeyid = openssl_get_publickey($cert);
 167  
 168      // Check the computed signature against the one passed in the query
 169      $ok = openssl_verify($base_string, $decoded_sig, $publickeyid);
 170  
 171      // Release the key resource
 172      openssl_free_key($publickeyid);
 173  
 174      return $ok == 1;
 175    }
 176  }
 177  
 178  class OAuthRequest {
 179    private $parameters;
 180    private $http_method;
 181    private $http_url;
 182    // for debug purposes
 183    public $base_string;
 184    public static $version = '1.0';
 185    public static $POST_INPUT = 'php://input';
 186  
 187    function __construct($http_method, $http_url, $parameters=NULL) {
 188      @$parameters or $parameters = array();
 189      $this->parameters = $parameters;
 190      $this->http_method = $http_method;
 191      $this->http_url = $http_url;
 192    }
 193  
 194  
 195    /**
 196     * attempt to build up a request from what was passed to the server
 197     */
 198    public static function from_request($http_method=NULL, $http_url=NULL, $parameters=NULL) {
 199      $scheme = (!isset($_SERVER['HTTPS']) || $_SERVER['HTTPS'] != "on")
 200                ? 'http'
 201                : 'https';
 202      $port = "";
 203      if ( $_SERVER['SERVER_PORT'] != "80" && $_SERVER['SERVER_PORT'] != "443" &&
 204          strpos(':', $_SERVER['HTTP_HOST']) < 0 ) {
 205        $port =  ':' . $_SERVER['SERVER_PORT'] ;
 206      }
 207      @$http_url or $http_url = $scheme .
 208                                '://' . $_SERVER['HTTP_HOST'] .
 209                                $port .
 210                                $_SERVER['REQUEST_URI'];
 211      @$http_method or $http_method = $_SERVER['REQUEST_METHOD'];
 212  
 213      // We weren't handed any parameters, so let's find the ones relevant to
 214      // this request.
 215      // If you run XML-RPC or similar you should use this to provide your own
 216      // parsed parameter-list
 217      if (!$parameters) {
 218        // Find request headers
 219        $request_headers = OAuthUtil::get_headers();
 220  
 221        // Parse the query-string to find GET parameters
 222        $parameters = OAuthUtil::parse_parameters($_SERVER['QUERY_STRING']);
 223  
 224        $ourpost = $_POST;
 225        // Deal with magic_quotes
 226        // http://www.php.net/manual/en/security.magicquotes.disabling.php
 227        if ( get_magic_quotes_gpc() ) {
 228           $outpost = array();
 229           foreach ($_POST as $k => $v) {
 230              $v = stripslashes($v);
 231              $ourpost[$k] = $v;
 232           }
 233        }
 234       // Add POST Parameters if they exist
 235        $parameters = array_merge($parameters, $ourpost);
 236  
 237        // We have a Authorization-header with OAuth data. Parse the header
 238        // and add those overriding any duplicates from GET or POST
 239        if (@substr($request_headers['Authorization'], 0, 6) == "OAuth ") {
 240          $header_parameters = OAuthUtil::split_header(
 241            $request_headers['Authorization']
 242          );
 243          $parameters = array_merge($parameters, $header_parameters);
 244        }
 245  
 246      }
 247  
 248      return new OAuthRequest($http_method, $http_url, $parameters);
 249    }
 250  
 251    /**
 252     * pretty much a helper function to set up the request
 253     */
 254    public static function from_consumer_and_token($consumer, $token, $http_method, $http_url, $parameters=NULL) {
 255      @$parameters or $parameters = array();
 256      $defaults = array("oauth_version" => OAuthRequest::$version,
 257                        "oauth_nonce" => OAuthRequest::generate_nonce(),
 258                        "oauth_timestamp" => OAuthRequest::generate_timestamp(),
 259                        "oauth_consumer_key" => $consumer->key);
 260      if ($token)
 261        $defaults['oauth_token'] = $token->key;
 262  
 263      $parameters = array_merge($defaults, $parameters);
 264  
 265      // Parse the query-string to find and add GET parameters
 266      $parts = parse_url($http_url);
 267      if ( !empty($parts['query']) ) {
 268        $qparms = OAuthUtil::parse_parameters($parts['query']);
 269        $parameters = array_merge($qparms, $parameters);
 270      }
 271  
 272  
 273      return new OAuthRequest($http_method, $http_url, $parameters);
 274    }
 275  
 276    public function set_parameter($name, $value, $allow_duplicates = true) {
 277      if ($allow_duplicates && isset($this->parameters[$name])) {
 278        // We have already added parameter(s) with this name, so add to the list
 279        if (is_scalar($this->parameters[$name])) {
 280          // This is the first duplicate, so transform scalar (string)
 281          // into an array so we can add the duplicates
 282          $this->parameters[$name] = array($this->parameters[$name]);
 283        }
 284  
 285        $this->parameters[$name][] = $value;
 286      } else {
 287        $this->parameters[$name] = $value;
 288      }
 289    }
 290  
 291    public function get_parameter($name) {
 292      return isset($this->parameters[$name]) ? $this->parameters[$name] : null;
 293    }
 294  
 295    public function get_parameters() {
 296      return $this->parameters;
 297    }
 298  
 299    public function unset_parameter($name) {
 300      unset($this->parameters[$name]);
 301    }
 302  
 303    /**
 304     * The request parameters, sorted and concatenated into a normalized string.
 305     * @return string
 306     */
 307    public function get_signable_parameters() {
 308      // Grab all parameters
 309      $params = $this->parameters;
 310  
 311      // Remove oauth_signature if present
 312      // Ref: Spec: 9.1.1 ("The oauth_signature parameter MUST be excluded.")
 313      if (isset($params['oauth_signature'])) {
 314        unset($params['oauth_signature']);
 315      }
 316  
 317      return OAuthUtil::build_http_query($params);
 318    }
 319  
 320    /**
 321     * Returns the base string of this request
 322     *
 323     * The base string defined as the method, the url
 324     * and the parameters (normalized), each urlencoded
 325     * and the concated with &.
 326     */
 327    public function get_signature_base_string() {
 328      $parts = array(
 329        $this->get_normalized_http_method(),
 330        $this->get_normalized_http_url(),
 331        $this->get_signable_parameters()
 332      );
 333  
 334      $parts = OAuthUtil::urlencode_rfc3986($parts);
 335  
 336      return implode('&', $parts);
 337    }
 338  
 339    /**
 340     * just uppercases the http method
 341     */
 342    public function get_normalized_http_method() {
 343      return strtoupper($this->http_method);
 344    }
 345  
 346    /**
 347     * parses the url and rebuilds it to be
 348     * scheme://host/path
 349     */
 350    public function get_normalized_http_url() {
 351      $parts = parse_url($this->http_url);
 352  
 353      $port = @$parts['port'];
 354      $scheme = $parts['scheme'];
 355      $host = $parts['host'];
 356      $path = @$parts['path'];
 357  
 358      $port or $port = ($scheme == 'https') ? '443' : '80';
 359  
 360      if (($scheme == 'https' && $port != '443')
 361          || ($scheme == 'http' && $port != '80')) {
 362        $host = "$host:$port";
 363      }
 364      return "$scheme://$host$path";
 365    }
 366  
 367    /**
 368     * builds a url usable for a GET request
 369     */
 370    public function to_url() {
 371      $post_data = $this->to_postdata();
 372      $out = $this->get_normalized_http_url();
 373      if ($post_data) {
 374        $out .= '?'.$post_data;
 375      }
 376      return $out;
 377    }
 378  
 379    /**
 380     * builds the data one would send in a POST request
 381     */
 382    public function to_postdata() {
 383      return OAuthUtil::build_http_query($this->parameters);
 384    }
 385  
 386    /**
 387     * builds the Authorization: header
 388     */
 389    public function to_header() {
 390      $out ='Authorization: OAuth realm=""';
 391      $total = array();
 392      foreach ($this->parameters as $k => $v) {
 393        if (substr($k, 0, 5) != "oauth") continue;
 394        if (is_array($v)) {
 395          throw new OAuthException('Arrays not supported in headers');
 396        }
 397        $out .= ',' .
 398                OAuthUtil::urlencode_rfc3986($k) .
 399                '="' .
 400                OAuthUtil::urlencode_rfc3986($v) .
 401                '"';
 402      }
 403      return $out;
 404    }
 405  
 406    public function __toString() {
 407      return $this->to_url();
 408    }
 409  
 410  
 411    public function sign_request($signature_method, $consumer, $token) {
 412      $this->set_parameter(
 413        "oauth_signature_method",
 414        $signature_method->get_name(),
 415        false
 416      );
 417      $signature = $this->build_signature($signature_method, $consumer, $token);
 418      $this->set_parameter("oauth_signature", $signature, false);
 419    }
 420  
 421    public function build_signature($signature_method, $consumer, $token) {
 422      $signature = $signature_method->build_signature($this, $consumer, $token);
 423      return $signature;
 424    }
 425  
 426    /**
 427     * util function: current timestamp
 428     */
 429    private static function generate_timestamp() {
 430      return time();
 431    }
 432  
 433    /**
 434     * util function: current nonce
 435     */
 436    private static function generate_nonce() {
 437      $mt = microtime();
 438      $rand = mt_rand();
 439  
 440      return md5($mt . $rand); // md5s look nicer than numbers
 441    }
 442  }
 443  
 444  class OAuthServer {
 445    protected $timestamp_threshold = 300; // in seconds, five minutes
 446    protected $version = 1.0;             // hi blaine
 447    protected $signature_methods = array();
 448  
 449    protected $data_store;
 450  
 451    function __construct($data_store) {
 452      $this->data_store = $data_store;
 453    }
 454  
 455    public function add_signature_method($signature_method) {
 456      $this->signature_methods[$signature_method->get_name()] =
 457        $signature_method;
 458    }
 459  
 460    // high level functions
 461  
 462    /**
 463     * process a request_token request
 464     * returns the request token on success
 465     */
 466    public function fetch_request_token(&$request) {
 467      $this->get_version($request);
 468  
 469      $consumer = $this->get_consumer($request);
 470  
 471      // no token required for the initial token request
 472      $token = NULL;
 473  
 474      $this->check_signature($request, $consumer, $token);
 475  
 476      $new_token = $this->data_store->new_request_token($consumer);
 477  
 478      return $new_token;
 479    }
 480  
 481    /**
 482     * process an access_token request
 483     * returns the access token on success
 484     */
 485    public function fetch_access_token(&$request) {
 486      $this->get_version($request);
 487  
 488      $consumer = $this->get_consumer($request);
 489  
 490      // requires authorized request token
 491      $token = $this->get_token($request, $consumer, "request");
 492  
 493  
 494      $this->check_signature($request, $consumer, $token);
 495  
 496      $new_token = $this->data_store->new_access_token($token, $consumer);
 497  
 498      return $new_token;
 499    }
 500  
 501    /**
 502     * verify an api call, checks all the parameters
 503     */
 504    public function verify_request(&$request) {
 505      global $OAuth_last_computed_signature;
 506      $OAuth_last_computed_signature = false;
 507      $this->get_version($request);
 508      $consumer = $this->get_consumer($request);
 509      $token = $this->get_token($request, $consumer, "access");
 510      $this->check_signature($request, $consumer, $token);
 511      return array($consumer, $token);
 512    }
 513  
 514    // Internals from here
 515    /**
 516     * version 1
 517     */
 518    private function get_version(&$request) {
 519      $version = $request->get_parameter("oauth_version");
 520      if (!$version) {
 521        $version = 1.0;
 522      }
 523      if ($version && $version != $this->version) {
 524        throw new OAuthException("OAuth version '$version' not supported");
 525      }
 526      return $version;
 527    }
 528  
 529    /**
 530     * figure out the signature with some defaults
 531     */
 532    private function get_signature_method(&$request) {
 533      $signature_method =
 534          @$request->get_parameter("oauth_signature_method");
 535      if (!$signature_method) {
 536        $signature_method = "PLAINTEXT";
 537      }
 538      if (!in_array($signature_method,
 539                    array_keys($this->signature_methods))) {
 540        throw new OAuthException(
 541          "Signature method '$signature_method' not supported " .
 542          "try one of the following: " .
 543          implode(", ", array_keys($this->signature_methods))
 544        );
 545      }
 546      return $this->signature_methods[$signature_method];
 547    }
 548  
 549    /**
 550     * try to find the consumer for the provided request's consumer key
 551     */
 552    private function get_consumer(&$request) {
 553      $consumer_key = @$request->get_parameter("oauth_consumer_key");
 554      if (!$consumer_key) {
 555        throw new OAuthException("Invalid consumer key");
 556      }
 557  
 558      $consumer = $this->data_store->lookup_consumer($consumer_key);
 559      if (!$consumer) {
 560        throw new OAuthException("Invalid consumer");
 561      }
 562  
 563      return $consumer;
 564    }
 565  
 566    /**
 567     * try to find the token for the provided request's token key
 568     */
 569    private function get_token(&$request, $consumer, $token_type="access") {
 570      $token_field = @$request->get_parameter('oauth_token');
 571      if ( !$token_field) return false;
 572      $token = $this->data_store->lookup_token(
 573        $consumer, $token_type, $token_field
 574      );
 575      if (!$token) {
 576        throw new OAuthException("Invalid $token_type token: $token_field");
 577      }
 578      return $token;
 579    }
 580  
 581    /**
 582     * all-in-one function to check the signature on a request
 583     * should guess the signature method appropriately
 584     */
 585    private function check_signature(&$request, $consumer, $token) {
 586      // this should probably be in a different method
 587      global $OAuth_last_computed_signature;
 588      $OAuth_last_computed_signature = false;
 589  
 590      $timestamp = @$request->get_parameter('oauth_timestamp');
 591      $nonce = @$request->get_parameter('oauth_nonce');
 592  
 593      $this->check_timestamp($timestamp);
 594      $this->check_nonce($consumer, $token, $nonce, $timestamp);
 595  
 596      $signature_method = $this->get_signature_method($request);
 597  
 598      $signature = $request->get_parameter('oauth_signature');
 599      $valid_sig = $signature_method->check_signature(
 600        $request,
 601        $consumer,
 602        $token,
 603        $signature
 604      );
 605  
 606      if (!$valid_sig) {
 607        $ex_text = "Invalid signature";
 608        if ( $OAuth_last_computed_signature ) {
 609            $ex_text = $ex_text . " ours= $OAuth_last_computed_signature yours=$signature";
 610        }
 611        throw new OAuthException($ex_text);
 612      }
 613    }
 614  
 615    /**
 616     * check that the timestamp is new enough
 617     */
 618    private function check_timestamp($timestamp) {
 619      // verify that timestamp is recentish
 620      $now = time();
 621      if ($now - $timestamp > $this->timestamp_threshold) {
 622        throw new OAuthException(
 623          "Expired timestamp, yours $timestamp, ours $now"
 624        );
 625      }
 626    }
 627  
 628    /**
 629     * check that the nonce is not repeated
 630     */
 631    private function check_nonce($consumer, $token, $nonce, $timestamp) {
 632      // verify that the nonce is uniqueish
 633      $found = $this->data_store->lookup_nonce(
 634        $consumer,
 635        $token,
 636        $nonce,
 637        $timestamp
 638      );
 639      if ($found) {
 640        throw new OAuthException("Nonce already used: $nonce");
 641      }
 642    }
 643  
 644  }
 645  
 646  class OAuthDataStore {
 647    function lookup_consumer($consumer_key) {
 648      // implement me
 649    }
 650  
 651    function lookup_token($consumer, $token_type, $token) {
 652      // implement me
 653    }
 654  
 655    function lookup_nonce($consumer, $token, $nonce, $timestamp) {
 656      // implement me
 657    }
 658  
 659    function new_request_token($consumer) {
 660      // return a new token attached to this consumer
 661    }
 662  
 663    function new_access_token($token, $consumer) {
 664      // return a new access token attached to this consumer
 665      // for the user associated with this token if the request token
 666      // is authorized
 667      // should also invalidate the request token
 668    }
 669  
 670  }
 671  
 672  class OAuthUtil {
 673    public static function urlencode_rfc3986($input) {
 674    if (is_array($input)) {
 675      return array_map(array('OAuthUtil', 'urlencode_rfc3986'), $input);
 676    } else if (is_scalar($input)) {
 677      return str_replace(
 678        '+',
 679        ' ',
 680        str_replace('%7E', '~', rawurlencode($input))
 681      );
 682    } else {
 683      return '';
 684    }
 685  }
 686  
 687  
 688    // This decode function isn't taking into consideration the above
 689    // modifications to the encoding process. However, this method doesn't
 690    // seem to be used anywhere so leaving it as is.
 691    public static function urldecode_rfc3986($string) {
 692      return urldecode($string);
 693    }
 694  
 695    // Utility function for turning the Authorization: header into
 696    // parameters, has to do some unescaping
 697    // Can filter out any non-oauth parameters if needed (default behaviour)
 698    public static function split_header($header, $only_allow_oauth_parameters = true) {
 699      $pattern = '/(([-_a-z]*)=("([^"]*)"|([^,]*)),?)/';
 700      $offset = 0;
 701      $params = array();
 702      while (preg_match($pattern, $header, $matches, PREG_OFFSET_CAPTURE, $offset) > 0) {
 703        $match = $matches[0];
 704        $header_name = $matches[2][0];
 705        $header_content = (isset($matches[5])) ? $matches[5][0] : $matches[4][0];
 706        if (preg_match('/^oauth_/', $header_name) || !$only_allow_oauth_parameters) {
 707          $params[$header_name] = OAuthUtil::urldecode_rfc3986($header_content);
 708        }
 709        $offset = $match[1] + strlen($match[0]);
 710      }
 711  
 712      if (isset($params['realm'])) {
 713        unset($params['realm']);
 714      }
 715  
 716      return $params;
 717    }
 718  
 719    // helper to try to sort out headers for people who aren't running apache
 720    public static function get_headers() {
 721      if (function_exists('apache_request_headers')) {
 722        // we need this to get the actual Authorization: header
 723        // because apache tends to tell us it doesn't exist
 724        return apache_request_headers();
 725      }
 726      // otherwise we don't have apache and are just going to have to hope
 727      // that $_SERVER actually contains what we need
 728      $out = array();
 729      foreach ($_SERVER as $key => $value) {
 730        if (substr($key, 0, 5) == "HTTP_") {
 731          // this is chaos, basically it is just there to capitalize the first
 732          // letter of every word that is not an initial HTTP and strip HTTP
 733          // code from przemek
 734          $key = str_replace(
 735            " ",
 736            "-",
 737            ucwords(strtolower(str_replace("_", " ", substr($key, 5))))
 738          );
 739          $out[$key] = $value;
 740        }
 741      }
 742      return $out;
 743    }
 744  
 745    // This function takes a input like a=b&a=c&d=e and returns the parsed
 746    // parameters like this
 747    // array('a' => array('b','c'), 'd' => 'e')
 748    public static function parse_parameters( $input ) {
 749      if (!isset($input) || !$input) return array();
 750  
 751      $pairs = explode('&', $input);
 752  
 753      $parsed_parameters = array();
 754      foreach ($pairs as $pair) {
 755        $split = explode('=', $pair, 2);
 756        $parameter = OAuthUtil::urldecode_rfc3986($split[0]);
 757        $value = isset($split[1]) ? OAuthUtil::urldecode_rfc3986($split[1]) : '';
 758  
 759        if (isset($parsed_parameters[$parameter])) {
 760          // We have already recieved parameter(s) with this name, so add to the list
 761          // of parameters with this name
 762  
 763          if (is_scalar($parsed_parameters[$parameter])) {
 764            // This is the first duplicate, so transform scalar (string) into an array
 765            // so we can add the duplicates
 766            $parsed_parameters[$parameter] = array($parsed_parameters[$parameter]);
 767          }
 768  
 769          $parsed_parameters[$parameter][] = $value;
 770        } else {
 771          $parsed_parameters[$parameter] = $value;
 772        }
 773      }
 774      return $parsed_parameters;
 775    }
 776  
 777    public static function build_http_query($params) {
 778      if (!$params) return '';
 779  
 780      // Urlencode both keys and values
 781      $keys = OAuthUtil::urlencode_rfc3986(array_keys($params));
 782      $values = OAuthUtil::urlencode_rfc3986(array_values($params));
 783      $params = array_combine($keys, $values);
 784  
 785      // Parameters are sorted by name, using lexicographical byte value ordering.
 786      // Ref: Spec: 9.1.1 (1)
 787      uksort($params, 'strcmp');
 788  
 789      $pairs = array();
 790      foreach ($params as $parameter => $value) {
 791        if (is_array($value)) {
 792          // If two or more parameters share the same name, they are sorted by their value
 793          // Ref: Spec: 9.1.1 (1)
 794          natsort($value);
 795          foreach ($value as $duplicate_value) {
 796            $pairs[] = $parameter . '=' . $duplicate_value;
 797          }
 798        } else {
 799          $pairs[] = $parameter . '=' . $value;
 800        }
 801      }
 802      // For each parameter, the name is separated from the corresponding value by an '=' character (ASCII code 61)
 803      // Each name-value pair is separated by an '&' character (ASCII code 38)
 804      return implode('&', $pairs);
 805    }
 806  }
 807  
 808  ?>