OAuth.php

<?php
// vim: foldmethod=marker
/**
 * The MIT License
 *
 * Copyright (c) 2007 Andy Smith
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files ( the "Software" ), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
*/
/* Generic exception class
 */
class OAuthException extends Exception {
	// pass
}

class OAuthConsumer {
	public $key;
	public $secret;
	public $callback_url;

	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]";
	}
}

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
 */
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, $signature ) {
		wfDebugLog( 'OAuth', __METHOD__ . ": Expecting: '$signature'" );
		$built = $this->build_signature( $request, $consumer, $token );
		wfDebugLog( 'OAuth', __METHOD__ . ": Built: '$built'" );
		// Check for zero length, although unlikely here
		if ( strlen( $built ) == 0 || strlen( $signature ) == 0 ) {
			return false;
		}

		if ( strlen( $built ) != strlen( $signature ) ) {
			return false;
		}

		// Avoid a timing leak with a ( hopefully ) time insensitive compare
		$result = 0;
		for ( $i = 0; $i < strlen( $signature ); $i++ ) {
			$result |= ord( $built{$i} ) ^ ord( $signature{$i} );
		}

		return $result == 0;
	}
}

/**
 * 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" )
 */
class OAuthSignatureMethod_HMAC_SHA1 extends OAuthSignatureMethod {
	function get_name() {
		return "HMAC-SHA1";
	}

	public function build_signature( $request, $consumer, $token ) {
		$base_string = $request->get_signature_base_string();
		wfDebugLog( 'OAuth', __METHOD__ . ": Base string: '$base_string'" );
		$request->base_string = $base_string;

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

		$key_parts = OAuthUtil::urlencode_rfc3986( $key_parts );
		$key = implode( '&', $key_parts );
		wfDebugLog( 'OAuth', __METHOD__ . ": HMAC Key: '$key'" );
		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" )
 */
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" )
 */
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;
	}
}

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['SERVER_NAME'] .
			':' .
			$_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() {
		//wfDebugLog( 'OAuth', __METHOD__ . ": Generating base string when this->paramters:\n" . print_r( $this->parameters, true ) );
		$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'] ) ) ? strtolower( $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
	}
}

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
	 */
	protected 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 ( !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
	 */
	protected function get_consumer( $request ) {
		$consumer_key = $request instanceof OAuthRequest
				? $request->get_parameter( "oauth_consumer_key" )
				: NULL;

		if ( !$consumer_key ) {
			throw new OAuthException( "Invalid consumer key" );
		}
		wfDebugLog( 'OAuth', __METHOD__ . ": getting consumer for '$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
	 */
	protected 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
	 */
	protected 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 ) {
			wfDebugLog( 'OAuth', __METHOD__ . ': Signature check (' . get_class( $signature_method ) . ') failed' );
			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" );
		}
	}

}

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
	}

}

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, $only_allow_oauth_parameters = true ) {
		wfDebugLog( 'OAuth', __METHOD__ . ": pulling headers from '$header'" );
		$params = array();
		if ( preg_match_all( '/(' . ( $only_allow_oauth_parameters ? 'oauth_' : '' ) . '[a-z_-]*)=(:?"([^"]*)"|([^,]*))/', $header, $matches ) ) {
			foreach ( $matches[1] as $i => $h ) {
				wfDebugLog( 'OAuth', __METHOD__ . ": '$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 ) {
		wfDebugLog( 'OAuth', __METHOD__ . " called with params:\n" . print_r( $params, true ) );
		if ( !$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 );
	}
}

?>