<?php
// vim: foldmethod=marker

/* Generic exception class
 */
class OAuthException extends Exception { 
    // pass 
} 

class OAuthConsumer { 
    public $key; 
    public $secret; 

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

    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(); 
    } 
} 

/** 
 * @ignore 
 */ 
class OAuthSignatureMethod { 
    public function check_signature(&$request, $consumer, $token, $signature) { 
        $built = $this->build_signature($request, $consumer, $token); 
        return $built == $signature; 
    } 
} 

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)); 
    } 
} 

class OAuthSignatureMethod_PLAINTEXT extends OAuthSignatureMethod { 
    public function get_name() { 
        return "PLAINTEXT"; 
    } 

    public function build_signature($request, $consumer, $token) { 
        $sig = array( 
            OAuthUtil::urlencode_rfc3986($consumer->secret) 
        ); 

        if ($token) { 
            array_push($sig, OAuthUtil::urlencode_rfc3986($token->secret)); 
        } else { 
            array_push($sig, ''); 
        } 

        $raw = implode("&", $sig); 
        // for debug purposes 
        $request->base_string = $raw; 

        return OAuthUtil::urlencode_rfc3986($raw); 
    } 
} 

/** 
 * @ignore 
 */ 
class OAuthSignatureMethod_RSA_SHA1 extends OAuthSignatureMethod { 
    public function get_name() { 
        return "RSA-SHA1"; 
    } 

    protected function fetch_public_cert(&$request) { 
        // not implemented yet, 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 
        throw Exception("fetch_public_cert not implemented"); 
    } 

    protected function fetch_private_cert(&$request) { 
        // not implemented yet, 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 
        throw Exception("fetch_private_cert not implemented"); 
    } 

    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 { 
    private $parameters; 
    private $http_method; 
    private $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 or $parameters = array(); 
        $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 or $http_url = $scheme . 
            '://' . $_SERVER['HTTP_HOST'] . 
            ':' . 
            $_SERVER['SERVER_PORT'] . 
            $_SERVER['REQUEST_URI']; 
        @$http_method or $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 ($http_method == "POST" 
                && @strstr($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 (@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 or $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 pic 
        if (isset($params['pic'])) { 
            unset($params['pic']); 
        }
        
          if (isset($params['image'])) 
         { 
            unset($params['image']); 
        }

        // 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); 

        $port = @$parts['port']; 
        $scheme = $parts['scheme']; 
        $host = $parts['host']; 
        $path = @$parts['path']; 

        $port or $port = ($scheme == 'https') ? '443' : '80'; 

        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( $multi = false ) {
    //echo "multi=" . $multi . '`';
    if( $multi )
    	return OAuthUtil::build_http_query_multi($this->parameters); 
    else 
        return OAuthUtil::build_http_query($this->parameters); 
    } 

    /** 
     * builds the Authorization: header 
     */ 
    public function to_header() { 
        $out ='Authorization: OAuth realm=""'; 
        $total = array(); 
        foreach ($this->parameters as $k => $v) { 
            if (substr($k, 0, 5) != "oauth") continue; 
            if (is_array($v)) { 
                throw new OAuthException('Arrays not supported in headers'); 
            } 
            $out .= ',' . 
                OAuthUtil::urlencode_rfc3986($k) . 
                '="' . 
                OAuthUtil::urlencode_rfc3986($v) . 
                '"'; 
        } 
        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 BJTIMESTAMP;
    } 

    /** 
     * 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); 

        $new_token = $this->data_store->new_request_token($consumer); 

        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); 

        $new_token = $this->data_store->new_access_token($token, $consumer); 

        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) { 
            $version = '1.0'; 
        } 
        if ($version && $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->get_parameter("oauth_signature_method"); 

        if (!$signature_method) { 
            $signature_method = "PLAINTEXT"; 
        } 
        if (!in_array($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 
     */ 
    private function get_consumer(&$request) { 
        $consumer_key = @$request->get_parameter("oauth_consumer_key"); 
        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->get_parameter('oauth_token'); 
        $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->get_parameter('oauth_timestamp'); 
        $nonce = @$request->get_parameter('oauth_nonce'); 

        $this->check_timestamp($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) { 
        // verify that timestamp is recentish 
        $now = BJTIMESTAMP;
        if ($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) { 
        // 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) { 
        // return a new token attached to this consumer 
    } 

    function new_access_token($token, $consumer) { 
        // 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 $boundary = '';

    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) 
    public static function split_header($header, $only_allow_oauth_parameters = true) { 
        $pattern = '/(([-_a-z]*)=("([^"]*)"|([^,]*)),?)/'; 
        $offset = 0; 
        $params = array(); 
        while (preg_match($pattern, $header, $matches, PREG_OFFSET_CAPTURE, $offset) > 0) { 
            $match = $matches[0]; 
            $header_name = $matches[2][0]; 
            $header_content = (isset($matches[5])) ? $matches[5][0] : $matches[4][0]; 
            if (preg_match('/^oauth_/', $header_name) || !$only_allow_oauth_parameters) { 
                $params[$header_name] = OAuthUtil::urldecode_rfc3986($header_content); 
            } 
            $offset = $match[1] + strlen($match[0]); 
        } 

        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 
            return apache_request_headers(); 
        } 
        // otherwise we don't have apache and are just going to have to hope 
        // that $_SERVER actually contains what we need 
        $out = array(); 
        foreach ($_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_multi($params) { 
        if (!$params) return ''; 
		
		//print_r( $params );
		//return null;
        
        // Urlencode both keys and values 
        $keys = array_keys($params);
        $values = array_values($params);
        //$keys = OAuthUtil::urlencode_rfc3986(array_keys($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(); 
        
        self::$boundary = $boundary = uniqid('------------------');
		$MPboundary = '--'.$boundary;
		$endMPboundary = $MPboundary. '--';
		$multipartbody = '';

        foreach ($params as $parameter => $value) { 
            
        //if( $parameter == 'pic' && $value{0} == '@' )
		if( in_array($parameter,array("pic","image")) )
        {
			if(is_array($value)) {
				$content = $value[2];
        	    $filename = $value[1];
        	    $mime = $value[0]; 
			} else {
			    $url = ltrim($value , '@');
			    //$content = file_get_contents($url);
				$content = get_url_contents($url);
			    $filename = reset(explode('?' , basename($url)));
			    $mime = self :: get_image_mime($url);
			}

        	$multipartbody .= $MPboundary . "\r\n";
			$multipartbody .= 'Content-Disposition: form-data; name="' . $parameter . '"; filename="' . $filename . '"'. "\r\n";
			$multipartbody .= 'Content-Type: '. $mime . "\r\n\r\n";
			$multipartbody .= $content. "\r\n";
        }
        else
        {
        	$multipartbody .= $MPboundary . "\r\n";
			$multipartbody .= 'content-disposition: form-data; name="'.$parameter."\"\r\n\r\n";
			$multipartbody .= $value."\r\n";
			
        }
        } 
        
        $multipartbody .=  "$endMPboundary\r\n";
        // 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 $multipartbody; 
    } 

    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) 
                natsort($value); 
                foreach ($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); 
    } 
    
    public static function get_image_mime( $file )
    {
    	$ext = strtolower(pathinfo( $file , PATHINFO_EXTENSION ));
    	switch( $ext )
    	{
    		case 'jpg':
    		case 'jpeg':
    			$mime = 'image/jpg';
    			break;
    		 	
    		case 'png';
    			$mime = 'image/png';
    			break;
    			
    		case 'gif';
    		default:
    			$mime = 'image/gif';
    			break;    		
    	}
    	return $mime;
    }
}

?>