<?php
/**
 * The object of this class are generic jsonRPC 1.0 clients
 * http://json-rpc.org/wiki/specification
 *
 * @author sergio <jsonrpcphp@inservibile.org>
 */
class jsonRPCClient {

        /**
         * Debug state
         *
         * @var boolean
         */
        private $debug;

        /**
         * The server URL
         *
         * @var string
         */
        private $url;
        /**
         * The request id
         *
         * @var integer
         */
        private $id;
        /**
         * If true, notifications are performed instead of requests
         *
         * @var boolean
         */
        private $notification = false;

        /**
         * Takes the connection parameters
         *
         * @param string $url
         * @param boolean $debug
         */
        public function __construct($url,$debug = false) {
                // server URL
                $this->url = $url;
                // proxy
                empty($proxy) ? $this->proxy = '' : $this->proxy = $proxy;
                // debug state
                empty($debug) ? $this->debug = false : $this->debug = true;
                // message id
                $this->id = 1;
        }

        /**
         * Sets the notification state of the object. In this state, notifications are performed, instead of requests.
         *
         * @param boolean $notification
         */
        public function setRPCNotification($notification) {
                empty($notification) ?
                                                        $this->notification = false
                                                        :
                                                        $this->notification = true;
        }

        /**
         * Performs a jsonRCP request and gets the results as an array
         *
         * @param string $method
         * @param array $params
         * @return array
         */
        public function __call($method,$params) {

                // check
                if (!is_scalar($method)) {
                        throw new Exception('Method name has no scalar value');
                }

                // check
                if (is_array($params)) {
                        // no keys
                        $params = array_values($params);
                } else {
                        throw new Exception('Params must be given as array');
                }

                // sets notification or request task
                if ($this->notification) {
                        $currentId = NULL;
                } else {
                        $currentId = $this->id;
                }

                // prepares the request
                $request = array(
                                                'method' => $method,
                                                'params' => $params,
                                                'id' => $currentId
                                                );
                $request = json_encode($request);
                $this->debug && $this->debug.='***** Request *****'."\n".$request."\n".'***** End Of request *****'."\n\n";

                // performs the HTTP POST
                $opts = array ('http' => array (
                                                        'method'  => 'POST',
                                                        'header'  => 'Content-type: application/json',
                                                        'content' => $request
                                                        ));
                $context  = stream_context_create($opts);
                if ($fp = fopen($this->url, 'r', false, $context)) {
                        $response = '';
                        while($row = fgets($fp)) {
                                $response.= trim($row)."\n";
                        }
                        $this->debug && $this->debug.='***** Server response *****'."\n".$response.'***** End of server response *****'."\n";
                        $response = json_decode($response,true);
                } else {
                        throw new Exception('Unable to connect to '.$this->url);
                }

                // debug output
                if ($this->debug) {
                        echo nl2br($debug);
                }

                // final checks and return
                if (!$this->notification) {
                        // check
                        if ($response['id'] != $currentId) {
                                throw new Exception('Incorrect response id (request id: '.$currentId.', response id: '.$response['id'].')');
                        }
                        if (!is_null($response['error'])) {
                                throw new Exception('Request error: '.$response['error']);
                        }

                        return $response['result'];

                } else {
                        return true;
                }
        }
}
?>