1<?php
2// vim: foldmethod=marker
3
4/* Generic exception class
5 */
6class OAuthException extends Exception {
7  // pass
8}
9
10class OAuthConsumer {
11  public $key;
12  public $secret;
13
14  function __construct($key, $secret, $callback_url=NULL) {
15    $this->key = $key;
16    $this->secret = $secret;
17    $this->callback_url = $callback_url;
18  }
19
20  function __toString() {
21    return "OAuthConsumer[key=$this->key,secret=$this->secret]";
22  }
23}
24
25class OAuthToken {
26  // access tokens and request tokens
27  public $key;
28  public $secret;
29
30  /**
31   * key = the token
32   * secret = the token secret
33   */
34  function __construct($key, $secret) {
35    $this->key = $key;
36    $this->secret = $secret;
37  }
38
39  /**
40   * generates the basic string serialization of a token that a server
41   * would respond to request_token and access_token calls with
42   */
43  function to_string() {
44    return "oauth_token=" .
45           OAuthUtil::urlencode_rfc3986($this->key) .
46           "&oauth_token_secret=" .
47           OAuthUtil::urlencode_rfc3986($this->secret);
48  }
49
50  function __toString() {
51    return $this->to_string();
52  }
53}
54
55/**
56 * A class for implementing a Signature Method
57 * See section 9 ("Signing Requests") in the spec
58 */
59abstract class OAuthSignatureMethod {
60  /**
61   * Needs to return the name of the Signature Method (ie HMAC-SHA1)
62   * @return string
63   */
64  abstract public function get_name();
65
66  /**
67   * Build up the signature
68   * NOTE: The output of this function MUST NOT be urlencoded.
69   * the encoding is handled in OAuthRequest when the final
70   * request is serialized
71   * @param OAuthRequest $request
72   * @param OAuthConsumer $consumer
73   * @param OAuthToken $token
74   * @return string
75   */
76  abstract public function build_signature($request, $consumer, $token);
77
78  /**
79   * Verifies that a given signature is correct
80   * @param OAuthRequest $request
81   * @param OAuthConsumer $consumer
82   * @param OAuthToken $token
83   * @param string $signature
84   * @return bool
85   */
86  public function check_signature($request, $consumer, $token, $signature) {
87    $built = $this->build_signature($request, $consumer, $token);
88    return $built == $signature;
89  }
90}
91
92/**
93 * The HMAC-SHA1 signature method uses the HMAC-SHA1 signature algorithm as defined in [RFC2104]
94 * where the Signature Base String is the text and the key is the concatenated values (each first
95 * encoded per Parameter Encoding) of the Consumer Secret and Token Secret, separated by an '&'
96 * character (ASCII code 38) even if empty.
97 *   - Chapter 9.2 ("HMAC-SHA1")
98 */
99class OAuthSignatureMethod_HMAC_SHA1 extends OAuthSignatureMethod {
100  function get_name() {
101    return "HMAC-SHA1";
102  }
103
104  public function build_signature($request, $consumer, $token) {
105    $base_string = $request->get_signature_base_string();
106    $request->base_string = $base_string;
107
108    $key_parts = array(
109      $consumer->secret,
110      ($token) ? $token->secret : ""
111    );
112
113    $key_parts = OAuthUtil::urlencode_rfc3986($key_parts);
114    $key = implode('&', $key_parts);
115
116    return base64_encode(hash_hmac('sha1', $base_string, $key, true));
117  }
118}
119
120/**
121 * The PLAINTEXT method does not provide any security protection and SHOULD only be used
122 * over a secure channel such as HTTPS. It does not use the Signature Base String.
123 *   - Chapter 9.4 ("PLAINTEXT")
124 */
125class OAuthSignatureMethod_PLAINTEXT extends OAuthSignatureMethod {
126  public function get_name() {
127    return "PLAINTEXT";
128  }
129
130  /**
131   * oauth_signature is set to the concatenated encoded values of the Consumer Secret and
132   * Token Secret, separated by a '&' character (ASCII code 38), even if either secret is
133   * empty. The result MUST be encoded again.
134   *   - Chapter 9.4.1 ("Generating Signatures")
135   *
136   * Please note that the second encoding MUST NOT happen in the SignatureMethod, as
137   * OAuthRequest handles this!
138   */
139  public function build_signature($request, $consumer, $token) {
140    $key_parts = array(
141      $consumer->secret,
142      ($token) ? $token->secret : ""
143    );
144
145    $key_parts = OAuthUtil::urlencode_rfc3986($key_parts);
146    $key = implode('&', $key_parts);
147    $request->base_string = $key;
148
149    return $key;
150  }
151}
152
153/**
154 * The RSA-SHA1 signature method uses the RSASSA-PKCS1-v1_5 signature algorithm as defined in
155 * [RFC3447] section 8.2 (more simply known as PKCS#1), using SHA-1 as the hash function for
156 * EMSA-PKCS1-v1_5. It is assumed that the Consumer has provided its RSA public key in a
157 * verified way to the Service Provider, in a manner which is beyond the scope of this
158 * specification.
159 *   - Chapter 9.3 ("RSA-SHA1")
160 */
161abstract class OAuthSignatureMethod_RSA_SHA1 extends OAuthSignatureMethod {
162  public function get_name() {
163    return "RSA-SHA1";
164  }
165
166  // Up to the SP to implement this lookup of keys. Possible ideas are:
167  // (1) do a lookup in a table of trusted certs keyed off of consumer
168  // (2) fetch via http using a url provided by the requester
169  // (3) some sort of specific discovery code based on request
170  //
171  // Either way should return a string representation of the certificate
172  protected abstract function fetch_public_cert(&$request);
173
174  // Up to the SP to implement this lookup of keys. Possible ideas are:
175  // (1) do a lookup in a table of trusted certs keyed off of consumer
176  //
177  // Either way should return a string representation of the certificate
178  protected abstract function fetch_private_cert(&$request);
179
180  public function build_signature($request, $consumer, $token) {
181    $base_string = $request->get_signature_base_string();
182    $request->base_string = $base_string;
183
184    // Fetch the private key cert based on the request
185    $cert = $this->fetch_private_cert($request);
186
187    // Pull the private key ID from the certificate
188    $privatekeyid = openssl_get_privatekey($cert);
189
190    // Sign using the key
191    $ok = openssl_sign($base_string, $signature, $privatekeyid);
192
193    // Release the key resource
194    openssl_free_key($privatekeyid);
195
196    return base64_encode($signature);
197  }
198
199  public function check_signature($request, $consumer, $token, $signature) {
200    $decoded_sig = base64_decode($signature);
201
202    $base_string = $request->get_signature_base_string();
203
204    // Fetch the public key cert based on the request
205    $cert = $this->fetch_public_cert($request);
206
207    // Pull the public key ID from the certificate
208    $publickeyid = openssl_get_publickey($cert);
209
210    // Check the computed signature against the one passed in the query
211    $ok = openssl_verify($base_string, $decoded_sig, $publickeyid);
212
213    // Release the key resource
214    openssl_free_key($publickeyid);
215
216    return $ok == 1;
217  }
218}
219
220class OAuthRequest {
221  private $parameters;
222  private $http_method;
223  private $http_url;
224  // for debug purposes
225  public $base_string;
226  public static $version = '1.0';
227  public static $POST_INPUT = 'php://input';
228
229  function __construct($http_method, $http_url, $parameters=NULL) {
230    @$parameters or $parameters = array();
231    $parameters = array_merge( OAuthUtil::parse_parameters(parse_url($http_url, PHP_URL_QUERY)), $parameters);
232    $this->parameters = $parameters;
233    $this->http_method = $http_method;
234    $this->http_url = $http_url;
235  }
236
237
238  /**
239   * attempt to build up a request from what was passed to the server
240   */
241  public static function from_request($http_method=NULL, $http_url=NULL, $parameters=NULL) {
242    $scheme = (!isset($_SERVER['HTTPS']) || $_SERVER['HTTPS'] != "on")
243              ? 'http'
244              : 'https';
245    @$http_url or $http_url = $scheme .
246                              '://' . $_SERVER['HTTP_HOST'] .
247                              ':' .
248                              $_SERVER['SERVER_PORT'] .
249                              $_SERVER['REQUEST_URI'];
250    @$http_method or $http_method = $_SERVER['REQUEST_METHOD'];
251
252    // We weren't handed any parameters, so let's find the ones relevant to
253    // this request.
254    // If you run XML-RPC or similar you should use this to provide your own
255    // parsed parameter-list
256    if (!$parameters) {
257      // Find request headers
258      $request_headers = OAuthUtil::get_headers();
259
260      // Parse the query-string to find GET parameters
261      $parameters = OAuthUtil::parse_parameters($_SERVER['QUERY_STRING']);
262
263      // It's a POST request of the proper content-type, so parse POST
264      // parameters and add those overriding any duplicates from GET
265      if ($http_method == "POST"
266          && @strstr($request_headers["Content-Type"],
267                     "application/x-www-form-urlencoded")
268          ) {
269        $post_data = OAuthUtil::parse_parameters(
270          file_get_contents(self::$POST_INPUT)
271        );
272        $parameters = array_merge($parameters, $post_data);
273      }
274
275      // We have a Authorization-header with OAuth data. Parse the header
276      // and add those overriding any duplicates from GET or POST
277      if (@substr($request_headers['Authorization'], 0, 6) == "OAuth ") {
278        $header_parameters = OAuthUtil::split_header(
279          $request_headers['Authorization']
280        );
281        $parameters = array_merge($parameters, $header_parameters);
282      }
283
284    }
285
286    return new OAuthRequest($http_method, $http_url, $parameters);
287  }
288
289  /**
290   * pretty much a helper function to set up the request
291   */
292  public static function from_consumer_and_token($consumer, $token, $http_method, $http_url, $parameters=NULL) {
293    @$parameters or $parameters = array();
294    $defaults = array("oauth_version" => OAuthRequest::$version,
295                      "oauth_nonce" => OAuthRequest::generate_nonce(),
296                      "oauth_timestamp" => OAuthRequest::generate_timestamp(),
297                      "oauth_consumer_key" => $consumer->key);
298    if ($token)
299      $defaults['oauth_token'] = $token->key;
300
301    $parameters = array_merge($defaults, $parameters);
302
303    return new OAuthRequest($http_method, $http_url, $parameters);
304  }
305
306  public function set_parameter($name, $value, $allow_duplicates = true) {
307    if ($allow_duplicates && isset($this->parameters[$name])) {
308      // We have already added parameter(s) with this name, so add to the list
309      if (is_scalar($this->parameters[$name])) {
310        // This is the first duplicate, so transform scalar (string)
311        // into an array so we can add the duplicates
312        $this->parameters[$name] = array($this->parameters[$name]);
313      }
314
315      $this->parameters[$name][] = $value;
316    } else {
317      $this->parameters[$name] = $value;
318    }
319  }
320
321  public function get_parameter($name) {
322    return isset($this->parameters[$name]) ? $this->parameters[$name] : null;
323  }
324
325  public function get_parameters() {
326    return $this->parameters;
327  }
328
329  public function unset_parameter($name) {
330    unset($this->parameters[$name]);
331  }
332
333  /**
334   * The request parameters, sorted and concatenated into a normalized string.
335   * @return string
336   */
337  public function get_signable_parameters() {
338    // Grab all parameters
339    $params = $this->parameters;
340
341    // Remove oauth_signature if present
342    // Ref: Spec: 9.1.1 ("The oauth_signature parameter MUST be excluded.")
343    if (isset($params['oauth_signature'])) {
344      unset($params['oauth_signature']);
345    }
346
347    return OAuthUtil::build_http_query($params);
348  }
349
350  /**
351   * Returns the base string of this request
352   *
353   * The base string defined as the method, the url
354   * and the parameters (normalized), each urlencoded
355   * and the concated with &.
356   */
357  public function get_signature_base_string() {
358    $parts = array(
359      $this->get_normalized_http_method(),
360      $this->get_normalized_http_url(),
361      $this->get_signable_parameters()
362    );
363
364    $parts = OAuthUtil::urlencode_rfc3986($parts);
365
366    return implode('&', $parts);
367  }
368
369  /**
370   * just uppercases the http method
371   */
372  public function get_normalized_http_method() {
373    return strtoupper($this->http_method);
374  }
375
376  /**
377   * parses the url and rebuilds it to be
378   * scheme://host/path
379   */
380  public function get_normalized_http_url() {
381    $parts = parse_url($this->http_url);
382
383    $port = @$parts['port'];
384    $scheme = $parts['scheme'];
385    $host = $parts['host'];
386    $path = @$parts['path'];
387
388    $port or $port = ($scheme == 'https') ? '443' : '80';
389
390    if (($scheme == 'https' && $port != '443')
391        || ($scheme == 'http' && $port != '80')) {
392      $host = "$host:$port";
393    }
394    return "$scheme://$host$path";
395  }
396
397  /**
398   * builds a url usable for a GET request
399   */
400  public function to_url() {
401    $post_data = $this->to_postdata();
402    $out = $this->get_normalized_http_url();
403    if ($post_data) {
404      $out .= '?'.$post_data;
405    }
406    return $out;
407  }
408
409  /**
410   * builds the data one would send in a POST request
411   */
412  public function to_postdata() {
413    return OAuthUtil::build_http_query($this->parameters);
414  }
415
416  /**
417   * builds the Authorization: header
418   */
419  public function to_header($realm=null) {
420    $first = true;
421	if($realm) {
422      $out = 'Authorization: OAuth realm="' . OAuthUtil::urlencode_rfc3986($realm) . '"';
423      $first = false;
424    } else
425      $out = 'Authorization: OAuth';
426
427    $total = array();
428    foreach ($this->parameters as $k => $v) {
429      if (substr($k, 0, 5) != "oauth") continue;
430      if (is_array($v)) {
431        throw new OAuthException('Arrays not supported in headers');
432      }
433      $out .= ($first) ? ' ' : ',';
434      $out .= OAuthUtil::urlencode_rfc3986($k) .
435              '="' .
436              OAuthUtil::urlencode_rfc3986($v) .
437              '"';
438      $first = false;
439    }
440    return $out;
441  }
442
443  public function __toString() {
444    return $this->to_url();
445  }
446
447
448  public function sign_request($signature_method, $consumer, $token) {
449    $this->set_parameter(
450      "oauth_signature_method",
451      $signature_method->get_name(),
452      false
453    );
454    $signature = $this->build_signature($signature_method, $consumer, $token);
455    $this->set_parameter("oauth_signature", $signature, false);
456  }
457
458  public function build_signature($signature_method, $consumer, $token) {
459    $signature = $signature_method->build_signature($this, $consumer, $token);
460    return $signature;
461  }
462
463  /**
464   * util function: current timestamp
465   */
466  private static function generate_timestamp() {
467    return time();
468  }
469
470  /**
471   * util function: current nonce
472   */
473  private static function generate_nonce() {
474    $mt = microtime();
475    $rand = mt_rand();
476
477    return md5($mt . $rand); // md5s look nicer than numbers
478  }
479}
480
481class OAuthServer {
482  protected $timestamp_threshold = 300; // in seconds, five minutes
483  protected $version = '1.0';             // hi blaine
484  protected $signature_methods = array();
485
486  protected $data_store;
487
488  function __construct($data_store) {
489    $this->data_store = $data_store;
490  }
491
492  public function add_signature_method($signature_method) {
493    $this->signature_methods[$signature_method->get_name()] =
494      $signature_method;
495  }
496
497  // high level functions
498
499  /**
500   * process a request_token request
501   * returns the request token on success
502   */
503  public function fetch_request_token(&$request) {
504    $this->get_version($request);
505
506    $consumer = $this->get_consumer($request);
507
508    // no token required for the initial token request
509    $token = NULL;
510
511    $this->check_signature($request, $consumer, $token);
512
513    // Rev A change
514    $callback = $request->get_parameter('oauth_callback');
515    $new_token = $this->data_store->new_request_token($consumer, $callback);
516
517    return $new_token;
518  }
519
520  /**
521   * process an access_token request
522   * returns the access token on success
523   */
524  public function fetch_access_token(&$request) {
525    $this->get_version($request);
526
527    $consumer = $this->get_consumer($request);
528
529    // requires authorized request token
530    $token = $this->get_token($request, $consumer, "request");
531
532    $this->check_signature($request, $consumer, $token);
533
534    // Rev A change
535    $verifier = $request->get_parameter('oauth_verifier');
536    $new_token = $this->data_store->new_access_token($token, $consumer, $verifier);
537
538    return $new_token;
539  }
540
541  /**
542   * verify an api call, checks all the parameters
543   */
544  public function verify_request(&$request) {
545    $this->get_version($request);
546    $consumer = $this->get_consumer($request);
547    $token = $this->get_token($request, $consumer, "access");
548    $this->check_signature($request, $consumer, $token);
549    return array($consumer, $token);
550  }
551
552  // Internals from here
553  /**
554   * version 1
555   */
556  private function get_version(&$request) {
557    $version = $request->get_parameter("oauth_version");
558    if (!$version) {
559      // Service Providers MUST assume the protocol version to be 1.0 if this parameter is not present.
560      // Chapter 7.0 ("Accessing Protected Ressources")
561      $version = '1.0';
562    }
563    if ($version !== $this->version) {
564      throw new OAuthException("OAuth version '$version' not supported");
565    }
566    return $version;
567  }
568
569  /**
570   * figure out the signature with some defaults
571   */
572  private function get_signature_method(&$request) {
573    $signature_method =
574        @$request->get_parameter("oauth_signature_method");
575
576    if (!$signature_method) {
577      // According to chapter 7 ("Accessing Protected Ressources") the signature-method
578      // parameter is required, and we can't just fallback to PLAINTEXT
579      throw new OAuthException('No signature method parameter. This parameter is required');
580    }
581
582    if (!in_array($signature_method,
583                  array_keys($this->signature_methods))) {
584      throw new OAuthException(
585        "Signature method '$signature_method' not supported " .
586        "try one of the following: " .
587        implode(", ", array_keys($this->signature_methods))
588      );
589    }
590    return $this->signature_methods[$signature_method];
591  }
592
593  /**
594   * try to find the consumer for the provided request's consumer key
595   */
596  private function get_consumer(&$request) {
597    $consumer_key = @$request->get_parameter("oauth_consumer_key");
598    if (!$consumer_key) {
599      throw new OAuthException("Invalid consumer key");
600    }
601
602    $consumer = $this->data_store->lookup_consumer($consumer_key);
603    if (!$consumer) {
604      throw new OAuthException("Invalid consumer");
605    }
606
607    return $consumer;
608  }
609
610  /**
611   * try to find the token for the provided request's token key
612   */
613  private function get_token(&$request, $consumer, $token_type="access") {
614    $token_field = @$request->get_parameter('oauth_token');
615    $token = $this->data_store->lookup_token(
616      $consumer, $token_type, $token_field
617    );
618    if (!$token) {
619      throw new OAuthException("Invalid $token_type token: $token_field");
620    }
621    return $token;
622  }
623
624  /**
625   * all-in-one function to check the signature on a request
626   * should guess the signature method appropriately
627   */
628  private function check_signature(&$request, $consumer, $token) {
629    // this should probably be in a different method
630    $timestamp = @$request->get_parameter('oauth_timestamp');
631    $nonce = @$request->get_parameter('oauth_nonce');
632
633    $this->check_timestamp($timestamp);
634    $this->check_nonce($consumer, $token, $nonce, $timestamp);
635
636    $signature_method = $this->get_signature_method($request);
637
638    $signature = $request->get_parameter('oauth_signature');
639    $valid_sig = $signature_method->check_signature(
640      $request,
641      $consumer,
642      $token,
643      $signature
644    );
645
646    if (!$valid_sig) {
647      throw new OAuthException("Invalid signature");
648    }
649  }
650
651  /**
652   * check that the timestamp is new enough
653   */
654  private function check_timestamp($timestamp) {
655    if( ! $timestamp )
656      throw new OAuthException(
657        'Missing timestamp parameter. The parameter is required'
658      );
659
660    // verify that timestamp is recentish
661    $now = time();
662    if (abs($now - $timestamp) > $this->timestamp_threshold) {
663      throw new OAuthException(
664        "Expired timestamp, yours $timestamp, ours $now"
665      );
666    }
667  }
668
669  /**
670   * check that the nonce is not repeated
671   */
672  private function check_nonce($consumer, $token, $nonce, $timestamp) {
673    if( ! $nonce )
674      throw new OAuthException(
675        'Missing nonce parameter. The parameter is required'
676      );
677
678    // verify that the nonce is uniqueish
679    $found = $this->data_store->lookup_nonce(
680      $consumer,
681      $token,
682      $nonce,
683      $timestamp
684    );
685    if ($found) {
686      throw new OAuthException("Nonce already used: $nonce");
687    }
688  }
689
690}
691
692class OAuthDataStore {
693  function lookup_consumer($consumer_key) {
694    // implement me
695  }
696
697  function lookup_token($consumer, $token_type, $token) {
698    // implement me
699  }
700
701  function lookup_nonce($consumer, $token, $nonce, $timestamp) {
702    // implement me
703  }
704
705  function new_request_token($consumer, $callback = null) {
706    // return a new token attached to this consumer
707  }
708
709  function new_access_token($token, $consumer, $verifier = null) {
710    // return a new access token attached to this consumer
711    // for the user associated with this token if the request token
712    // is authorized
713    // should also invalidate the request token
714  }
715
716}
717
718class OAuthUtil {
719  public static function urlencode_rfc3986($input) {
720  if (is_array($input)) {
721    return array_map(array('OAuthUtil', 'urlencode_rfc3986'), $input);
722  } else if (is_scalar($input)) {
723    return str_replace(
724      '+',
725      ' ',
726      str_replace('%7E', '~', rawurlencode($input))
727    );
728  } else {
729    return '';
730  }
731}
732
733
734  // This decode function isn't taking into consideration the above
735  // modifications to the encoding process. However, this method doesn't
736  // seem to be used anywhere so leaving it as is.
737  public static function urldecode_rfc3986($string) {
738    return urldecode($string);
739  }
740
741  // Utility function for turning the Authorization: header into
742  // parameters, has to do some unescaping
743  // Can filter out any non-oauth parameters if needed (default behaviour)
744  public static function split_header($header, $only_allow_oauth_parameters = true) {
745    $pattern = '/(([-_a-z]*)=("([^"]*)"|([^,]*)),?)/';
746    $offset = 0;
747    $params = array();
748    while (preg_match($pattern, $header, $matches, PREG_OFFSET_CAPTURE, $offset) > 0) {
749      $match = $matches[0];
750      $header_name = $matches[2][0];
751      $header_content = (isset($matches[5])) ? $matches[5][0] : $matches[4][0];
752      if (preg_match('/^oauth_/', $header_name) || !$only_allow_oauth_parameters) {
753        $params[$header_name] = OAuthUtil::urldecode_rfc3986($header_content);
754      }
755      $offset = $match[1] + strlen($match[0]);
756    }
757
758    if (isset($params['realm'])) {
759      unset($params['realm']);
760    }
761
762    return $params;
763  }
764
765  // helper to try to sort out headers for people who aren't running apache
766  public static function get_headers() {
767    if (function_exists('apache_request_headers')) {
768      // we need this to get the actual Authorization: header
769      // because apache tends to tell us it doesn't exist
770      $headers = apache_request_headers();
771
772      // sanitize the output of apache_request_headers because
773      // we always want the keys to be Cased-Like-This and arh()
774      // returns the headers in the same case as they are in the
775      // request
776      $out = array();
777      foreach( $headers AS $key => $value ) {
778        $key = str_replace(
779            " ",
780            "-",
781            ucwords(strtolower(str_replace("-", " ", $key)))
782          );
783        $out[$key] = $value;
784      }
785    } else {
786      // otherwise we don't have apache and are just going to have to hope
787      // that $_SERVER actually contains what we need
788      $out = array();
789      if( isset($_SERVER['CONTENT_TYPE']) )
790        $out['Content-Type'] = $_SERVER['CONTENT_TYPE'];
791      if( isset($_ENV['CONTENT_TYPE']) )
792        $out['Content-Type'] = $_ENV['CONTENT_TYPE'];
793
794      foreach ($_SERVER as $key => $value) {
795        if (substr($key, 0, 5) == "HTTP_") {
796          // this is chaos, basically it is just there to capitalize the first
797          // letter of every word that is not an initial HTTP and strip HTTP
798          // code from przemek
799          $key = str_replace(
800            " ",
801            "-",
802            ucwords(strtolower(str_replace("_", " ", substr($key, 5))))
803          );
804          $out[$key] = $value;
805        }
806      }
807    }
808    return $out;
809  }
810
811  // This function takes a input like a=b&a=c&d=e and returns the parsed
812  // parameters like this
813  // array('a' => array('b','c'), 'd' => 'e')
814  public static function parse_parameters( $input ) {
815    if (!isset($input) || !$input) return array();
816
817    $pairs = explode('&', $input);
818
819    $parsed_parameters = array();
820    foreach ($pairs as $pair) {
821      $split = explode('=', $pair, 2);
822      $parameter = OAuthUtil::urldecode_rfc3986($split[0]);
823      $value = isset($split[1]) ? OAuthUtil::urldecode_rfc3986($split[1]) : '';
824
825      if (isset($parsed_parameters[$parameter])) {
826        // We have already recieved parameter(s) with this name, so add to the list
827        // of parameters with this name
828
829        if (is_scalar($parsed_parameters[$parameter])) {
830          // This is the first duplicate, so transform scalar (string) into an array
831          // so we can add the duplicates
832          $parsed_parameters[$parameter] = array($parsed_parameters[$parameter]);
833        }
834
835        $parsed_parameters[$parameter][] = $value;
836      } else {
837        $parsed_parameters[$parameter] = $value;
838      }
839    }
840    return $parsed_parameters;
841  }
842
843  public static function build_http_query($params) {
844    if (!$params) return '';
845
846    // Urlencode both keys and values
847    $keys = OAuthUtil::urlencode_rfc3986(array_keys($params));
848    $values = OAuthUtil::urlencode_rfc3986(array_values($params));
849    $params = array_combine($keys, $values);
850
851    // Parameters are sorted by name, using lexicographical byte value ordering.
852    // Ref: Spec: 9.1.1 (1)
853    uksort($params, 'strcmp');
854
855    $pairs = array();
856    foreach ($params as $parameter => $value) {
857      if (is_array($value)) {
858        // If two or more parameters share the same name, they are sorted by their value
859        // Ref: Spec: 9.1.1 (1)
860        natsort($value);
861        foreach ($value as $duplicate_value) {
862          $pairs[] = $parameter . '=' . $duplicate_value;
863        }
864      } else {
865        $pairs[] = $parameter . '=' . $value;
866      }
867    }
868    // For each parameter, the name is separated from the corresponding value by an '=' character (ASCII code 61)
869    // Each name-value pair is separated by an '&' character (ASCII code 38)
870    return implode('&', $pairs);
871  }
872}
873
874?>
875