<?php

namespace PhpXmlRpc;

use PhpXmlRpc\Helper\Logger;

/**
 * Used to represent a client of an XML-RPC server.
 */
class Client
{
    /// @todo: do these need to be public?
    public $method = 'http';
    public $server;
    public $port = 0;
    public $path;

    public $errno;
    public $errstr;
    public $debug = 0;

    public $username = '';
    public $password = '';
    public $authtype = 1;

    public $cert = '';
    public $certpass = '';
    public $cacert = '';
    public $cacertdir = '';
    public $key = '';
    public $keypass = '';
    public $verifypeer = true;
    public $verifyhost = 2;
    public $sslversion = 0; // corresponds to CURL_SSLVERSION_DEFAULT

    public $proxy = '';
    public $proxyport = 0;
    public $proxy_user = '';
    public $proxy_pass = '';
    public $proxy_authtype = 1;

    public $cookies = array();
    public $extracurlopts = array();

    /**
     * @var bool
     *
     * This determines whether the multicall() method will try to take advantage of the system.multicall xmlrpc method
     * to dispatch to the server an array of requests in a single http roundtrip or simply execute many consecutive http
     * calls. Defaults to FALSE, but it will be enabled automatically on the first failure of execution of
     * system.multicall.
     */
    public $no_multicall = false;

    /**
     * List of http compression methods accepted by the client for responses.
     * NB: PHP supports deflate, gzip compressions out of the box if compiled w. zlib.
     *
     * NNB: you can set it to any non-empty array for HTTP11 and HTTPS, since
     * in those cases it will be up to CURL to decide the compression methods
     * it supports. You might check for the presence of 'zlib' in the output of
     * curl_version() to determine wheter compression is supported or not
     */
    public $accepted_compression = array();

    /**
     * Name of compression scheme to be used for sending requests.
     * Either null, gzip or deflate.
     */

    public $request_compression = '';
    /**
     * CURL handle: used for keep-alive connections (PHP 4.3.8 up, see:
     * http://curl.haxx.se/docs/faq.html#7.3).
     */
    public $xmlrpc_curl_handle = null;

    /// Whether to use persistent connections for http 1.1 and https
    public $keepalive = false;

    /// Charset encodings that can be decoded without problems by the client
    public $accepted_charset_encodings = array();

    /**
     * The charset encoding that will be used for serializing request sent by the client.
     * It defaults to NULL, which means using US-ASCII and encoding all characters outside of the ASCII range using
     * their xml character entity representation (this has the benefit that line end characters will not be mangled in
     * the transfer, a CR-LF will be preserved as well as a singe LF).
     *  Valid values are 'US-ASCII', 'UTF-8' and 'ISO-8859-1'
     */
    public $request_charset_encoding = '';

    /**
     * Decides the content of Response objects returned by calls to send() and multicall().
     * Valid values are 'xmlrpcvals', 'phpvals' or 'xml'.
     *
     * Determines whether the value returned inside an Response object as results of calls to the send() and multicall()
     * methods will be a Value object, a plain php value or a raw xml string.
     * Allowed values are 'xmlrpcvals' (the default), 'phpvals' and 'xml'.
     * To allow the user to differentiate between a correct and a faulty response, fault responses will be returned as
     * Response objects in any case.
     * Note that the 'phpvals' setting will yield faster execution times, but some of the information from the original
     * response will be lost. It will be e.g. impossible to tell whether a particular php string value was sent by the
     * server as an xmlrpc string or base64 value.
     */
    public $return_type = 'xmlrpcvals';

    /**
     * Sent to servers in http headers.
     */
    public $user_agent;

    /**
     * @param string $path either the PATH part of the xmlrpc server URL, or complete server URL (in which case you
     *                     should use and empty string for all other parameters)
     *                     e.g. /xmlrpc/server.php
     *                     e.g. http://phpxmlrpc.sourceforge.net/server.php
     *                     e.g. https://james:bond@secret.service.com:443/xmlrpcserver?agent=007
     * @param string $server the server name / ip address
     * @param integer $port the port the server is listening on, when omitted defaults to 80 or 443 depending on
     *                      protocol used
     * @param string $method the http protocol variant: defaults to 'http'; 'https' and 'http11' can be used if CURL is
     *                       installed. The value set here can be overridden in any call to $this->send().
     */
    public function __construct($path, $server = '', $port = '', $method = '')
    {
        // allow user to specify all params in $path
        if ($server == '' and $port == '' and $method == '') {
            $parts = parse_url($path);
            $server = $parts['host'];
            $path = isset($parts['path']) ? $parts['path'] : '';
            if (isset($parts['query'])) {
                $path .= '?' . $parts['query'];
            }
            if (isset($parts['fragment'])) {
                $path .= '#' . $parts['fragment'];
            }
            if (isset($parts['port'])) {
                $port = $parts['port'];
            }
            if (isset($parts['scheme'])) {
                $method = $parts['scheme'];
            }
            if (isset($parts['user'])) {
                $this->username = $parts['user'];
            }
            if (isset($parts['pass'])) {
                $this->password = $parts['pass'];
            }
        }
        if ($path == '' || $path[0] != '/') {
            $this->path = '/' . $path;
        } else {
            $this->path = $path;
        }
        $this->server = $server;
        if ($port != '') {
            $this->port = $port;
        }
        if ($method != '') {
            $this->method = $method;
        }

        // if ZLIB is enabled, let the client by default accept compressed responses
        if (function_exists('gzinflate') || (
                function_exists('curl_init') && (($info = curl_version()) &&
                    ((is_string($info) && strpos($info, 'zlib') !== null) || isset($info['libz_version'])))
            )
        ) {
            $this->accepted_compression = array('gzip', 'deflate');
        }

        // keepalives: enabled by default
        $this->keepalive = true;

        // by default the xml parser can support these 3 charset encodings
        $this->accepted_charset_encodings = array('UTF-8', 'ISO-8859-1', 'US-ASCII');

        // Add all charsets which mbstring can handle, but remove junk not found in IANA registry at
        // in http://www.iana.org/assignments/character-sets/character-sets.xhtml
        // NB: this is disabled to avoid making all the requests sent huge... mbstring supports more than 80 charsets!
        /*if (function_exists('mb_list_encodings')) {

            $encodings = array_diff(mb_list_encodings(), array('pass', 'auto', 'wchar', 'BASE64', 'UUENCODE', 'ASCII',
                'HTML-ENTITIES', 'Quoted-Printable', '7bit','8bit', 'byte2be', 'byte2le', 'byte4be', 'byte4le'));
            $this->accepted_charset_encodings = array_unique(array_merge($this->accepted_charset_encodings, $encodings));
        }*/

        // initialize user_agent string
        $this->user_agent = PhpXmlRpc::$xmlrpcName . ' ' . PhpXmlRpc::$xmlrpcVersion;
    }

    /**
     * Enable/disable the echoing to screen of the xmlrpc responses received. The default is not no output anything.
     *
     * The debugging information at level 1 includes the raw data returned from the XML-RPC server it was querying
     * (including bot HTTP headers and the full XML payload), and the PHP value the client attempts to create to
     * represent the value returned by the server
     * At level2, the complete payload of the xmlrpc request is also printed, before being sent t the server.
     *
     * This option can be very useful when debugging servers as it allows you to see exactly what the client sends and
     * the server returns.
     *
     * @param integer $in values 0, 1 and 2 are supported (2 = echo sent msg too, before received response)
     */
    public function setDebug($level)
    {
        $this->debug = $level;
    }

    /**
     * Sets the username and password for authorizing the client to the server.
     *
     * With the default (HTTP) transport, this information is used for HTTP Basic authorization.
     * Note that username and password can also be set using the class constructor.
     * With HTTP 1.1 and HTTPS transport, NTLM and Digest authentication protocols are also supported. To enable them use
     * the constants CURLAUTH_DIGEST and CURLAUTH_NTLM as values for the auth type parameter.
     *
     * @param string $user username
     * @param string $password password
     * @param integer $authType auth type. See curl_setopt man page for supported auth types. Defaults to CURLAUTH_BASIC
     *                          (basic auth). Note that auth types NTLM and Digest will only work if the Curl php
     *                          extension is enabled.
     */
    public function setCredentials($user, $password, $authType = 1)
    {
        $this->username = $user;
        $this->password = $password;
        $this->authtype = $authType;
    }

    /**
     * Set the optional certificate and passphrase used in SSL-enabled communication with a remote server.
     *
     * Note: to retrieve information about the client certificate on the server side, you will need to look into the
     * environment variables which are set up by the webserver. Different webservers will typically set up different
     * variables.
     *
     * @param string $cert the name of a file containing a PEM formatted certificate
     * @param string $certPass the password required to use it
     */
    public function setCertificate($cert, $certPass = '')
    {
        $this->cert = $cert;
        $this->certpass = $certPass;
    }

    /**
     * Add a CA certificate to verify server with in SSL-enabled communication when SetSSLVerifypeer has been set to TRUE.
     *
     * See the php manual page about CURLOPT_CAINFO for more details.
     *
     * @param string $caCert certificate file name (or dir holding certificates)
     * @param bool $isDir set to true to indicate cacert is a dir. defaults to false
     */
    public function setCaCertificate($caCert, $isDir = false)
    {
        if ($isDir) {
            $this->cacertdir = $caCert;
        } else {
            $this->cacert = $caCert;
        }
    }

    /**
     * Set attributes for SSL communication: private SSL key.
     *
     * NB: does not work in older php/curl installs.
     * Thanks to Daniel Convissor.
     *
     * @param string $key The name of a file containing a private SSL key
     * @param string $keyPass The secret password needed to use the private SSL key
     */
    public function setKey($key, $keyPass)
    {
        $this->key = $key;
        $this->keypass = $keyPass;
    }

    /**
     * Set attributes for SSL communication: verify the remote host's SSL certificate, and cause the connection to fail
     * if the cert verification fails.
     *
     * By default, verification is enabled.
     * To specify custom SSL certificates to validate the server with, use the setCaCertificate method.
     *
     * @param bool $i enable/disable verification of peer certificate
     */
    public function setSSLVerifyPeer($i)
    {
        $this->verifypeer = $i;
    }

    /**
     * Set attributes for SSL communication: verify the remote host's SSL certificate's common name (CN).
     *
     * Note that support for value 1 has been removed in cURL 7.28.1
     *
     * @param int $i Set to 1 to only the existence of a CN, not that it matches
     */
    public function setSSLVerifyHost($i)
    {
        $this->verifyhost = $i;
    }

    /**
     * Set attributes for SSL communication: SSL version to use. Best left at 0 (default value ): let cURL decide
     *
     * @param int $i
     */
    public function setSSLVersion($i)
    {
        $this->sslversion = $i;
    }

    /**
     * Set proxy info.
     *
     * NB: CURL versions before 7.11.10 cannot use a proxy to communicate with https servers.
     *
     * @param string $proxyHost
     * @param string $proxyPort Defaults to 8080 for HTTP and 443 for HTTPS
     * @param string $proxyUsername Leave blank if proxy has public access
     * @param string $proxyPassword Leave blank if proxy has public access
     * @param int $proxyAuthType defaults to CURLAUTH_BASIC (Basic authentication protocol); set to constant CURLAUTH_NTLM
     *                           to use NTLM auth with proxy (has effect only when the client uses the HTTP 1.1 protocol)
     */
    public function setProxy($proxyHost, $proxyPort, $proxyUsername = '', $proxyPassword = '', $proxyAuthType = 1)
    {
        $this->proxy = $proxyHost;
        $this->proxyport = $proxyPort;
        $this->proxy_user = $proxyUsername;
        $this->proxy_pass = $proxyPassword;
        $this->proxy_authtype = $proxyAuthType;
    }

    /**
     * Enables/disables reception of compressed xmlrpc responses.
     *
     * This requires the "zlib" extension to be enabled in your php install. If it is, by default xmlrpc_client
     * instances will enable reception of compressed content.
     * Note that enabling reception of compressed responses merely adds some standard http headers to xmlrpc requests.
     * It is up to the xmlrpc server to return compressed responses when receiving such requests.
     *
     * @param string $compMethod either 'gzip', 'deflate', 'any' or ''
     */
    public function setAcceptedCompression($compMethod)
    {
        if ($compMethod == 'any') {
            $this->accepted_compression = array('gzip', 'deflate');
        } elseif ($compMethod == false) {
            $this->accepted_compression = array();
        } else {
            $this->accepted_compression = array($compMethod);
        }
    }

    /**
     * Enables/disables http compression of xmlrpc request.
     *
     * This requires the "zlib" extension to be enabled in your php install.
     * Take care when sending compressed requests: servers might not support them (and automatic fallback to
     * uncompressed requests is not yet implemented).
     *
     * @param string $compMethod either 'gzip', 'deflate' or ''
     */
    public function setRequestCompression($compMethod)
    {
        $this->request_compression = $compMethod;
    }

    /**
     * Adds a cookie to list of cookies that will be sent to server with every further request (useful e.g. for keeping
     * session info outside of the xml-rpc payload).
     *
     * NB: By default cookies are sent using the 'original/netscape' format, which is also the same as the RFC 2965;
     * setting any param but name and value will turn the cookie into a 'version 1' cookie (i.e. RFC 2109 cookie) that
     * might not be fully supported by the server. Note that RFC 2109 has currently 'historic' status...
     *
     * @param string $name nb: will not be escaped in the request's http headers. Take care not to use CTL chars or
     *                     separators!
     * @param string $value
     * @param string $path leave this empty unless the xml-rpc server only accepts RFC 2109 cookies
     * @param string $domain leave this empty unless the xml-rpc server only accepts RFC 2109 cookies
     * @param int $port leave this empty unless the xml-rpc server only accepts RFC 2109 cookies
     *
     * @todo check correctness of urlencoding cookie value (copied from php way of doing it, but php is generally sending
     *       response not requests. We do the opposite...)
     * @todo strip invalid chars from cookie name? As per RFC6265, we should follow RFC2616, Section 2.2
     */
    public function setCookie($name, $value = '', $path = '', $domain = '', $port = null)
    {
        $this->cookies[$name]['value'] = urlencode($value);
        if ($path || $domain || $port) {
            $this->cookies[$name]['path'] = $path;
            $this->cookies[$name]['domain'] = $domain;
            $this->cookies[$name]['port'] = $port;
            $this->cookies[$name]['version'] = 1;
        } else {
            $this->cookies[$name]['version'] = 0;
        }
    }

    /**
     * Directly set cURL options, for extra flexibility (when in cURL mode).
     *
     * It allows eg. to bind client to a specific IP interface / address.
     *
     * @param array $options
     */
    public function setCurlOptions($options)
    {
        $this->extracurlopts = $options;
    }

    /**
     * Set user-agent string that will be used by this client instance in http headers sent to the server.
     *
     * The default user agent string includes the name of this library and the version number.
     *
     * @param string $agentString
     */
    public function setUserAgent($agentString)
    {
        $this->user_agent = $agentString;
    }

    /**
     * Send an xmlrpc request to the server.
     *
     * @param Request|Request[]|string $req The Request object, or an array of requests for using multicall, or the
     *                                      complete xml representation of a request.
     *                                      When sending an array of Request objects, the client will try to make use of
     *                                      a single 'system.multicall' xml-rpc method call to forward to the server all
     *                                      the requests in a single HTTP round trip, unless $this->no_multicall has
     *                                      been previously set to TRUE (see the multicall method below), in which case
     *                                      many consecutive xmlrpc requests will be sent. The method will return an
     *                                      array of Response objects in both cases.
     *                                      The third variant allows to build by hand (or any other means) a complete
     *                                      xmlrpc request message, and send it to the server. $req should be a string
     *                                      containing the complete xml representation of the request. It is e.g. useful
     *                                      when, for maximal speed of execution, the request is serialized into a
     *                                      string using the native php xmlrpc functions (see http://www.php.net/xmlrpc)
     * @param integer $timeout Connection timeout, in seconds, If unspecified, a platform specific timeout will apply.
     *                         This timeout value is passed to fsockopen(). It is also used for detecting server
     *                         timeouts during communication (i.e. if the server does not send anything to the client
     *                         for $timeout seconds, the connection will be closed).
     * @param string $method valid values are 'http', 'http11' and 'https'. If left unspecified, the http protocol
     *                       chosen during creation of the object will be used.
     *
     *
     * @return Response|Response[] Note that the client will always return a Response object, even if the call fails
     */
    public function send($req, $timeout = 0, $method = '')
    {
        // if user does not specify http protocol, use native method of this client
        // (i.e. method set during call to constructor)
        if ($method == '') {
            $method = $this->method;
        }

        if (is_array($req)) {
            // $req is an array of Requests
            $r = $this->multicall($req, $timeout, $method);

            return $r;
        } elseif (is_string($req)) {
            $n = new Request('');
            $n->payload = $req;
            $req = $n;
        }

        // where req is a Request
        $req->setDebug($this->debug);

        if ($method == 'https') {
            $r = $this->sendPayloadHTTPS(
                $req,
                $this->server,
                $this->port,
                $timeout,
                $this->username,
                $this->password,
                $this->authtype,
                $this->cert,
                $this->certpass,
                $this->cacert,
                $this->cacertdir,
                $this->proxy,
                $this->proxyport,
                $this->proxy_user,
                $this->proxy_pass,
                $this->proxy_authtype,
                $this->keepalive,
                $this->key,
                $this->keypass,
                $this->sslversion
            );
        } elseif ($method == 'http11') {
            $r = $this->sendPayloadCURL(
                $req,
                $this->server,
                $this->port,
                $timeout,
                $this->username,
                $this->password,
                $this->authtype,
                null,
                null,
                null,
                null,
                $this->proxy,
                $this->proxyport,
                $this->proxy_user,
                $this->proxy_pass,
                $this->proxy_authtype,
                'http',
                $this->keepalive
            );
        } else {
            $r = $this->sendPayloadHTTP10(
                $req,
                $this->server,
                $this->port,
                $timeout,
                $this->username,
                $this->password,
                $this->authtype,
                $this->proxy,
                $this->proxyport,
                $this->proxy_user,
                $this->proxy_pass,
                $this->proxy_authtype,
                $method
            );
        }

        return $r;
    }

    /**
     * @param Request $req
     * @param string $server
     * @param int $port
     * @param int $timeout
     * @param string $username
     * @param string $password
     * @param int $authType
     * @param string $proxyHost
     * @param int $proxyPort
     * @param string $proxyUsername
     * @param string $proxyPassword
     * @param int $proxyAuthType
     * @param string $method
     * @return Response
     */
    protected function sendPayloadHTTP10($req, $server, $port, $timeout = 0, $username = '', $password = '',
        $authType = 1, $proxyHost = '', $proxyPort = 0, $proxyUsername = '', $proxyPassword = '', $proxyAuthType = 1,
        $method='http')
    {
        if ($port == 0) {
            $port = ( $method === "https" ) ? 443 : 80;
        }

        // Only create the payload if it was not created previously
        if (empty($req->payload)) {
            $req->createPayload($this->request_charset_encoding);
        }

        $payload = $req->payload;
        // Deflate request body and set appropriate request headers
        if (function_exists('gzdeflate') && ($this->request_compression == 'gzip' || $this->request_compression == 'deflate')) {
            if ($this->request_compression == 'gzip') {
                $a = @gzencode($payload);
                if ($a) {
                    $payload = $a;
                    $encodingHdr = "Content-Encoding: gzip\r\n";
                }
            } else {
                $a = @gzcompress($payload);
                if ($a) {
                    $payload = $a;
                    $encodingHdr = "Content-Encoding: deflate\r\n";
                }
            }
        } else {
            $encodingHdr = '';
        }

        // thanks to Grant Rauscher <grant7@firstworld.net> for this
        $credentials = '';
        if ($username != '') {
            $credentials = 'Authorization: Basic ' . base64_encode($username . ':' . $password) . "\r\n";
            if ($authType != 1) {
                error_log('XML-RPC: ' . __METHOD__ . ': warning. Only Basic auth is supported with HTTP 1.0');
            }
        }

        $acceptedEncoding = '';
        if (is_array($this->accepted_compression) && count($this->accepted_compression)) {
            $acceptedEncoding = 'Accept-Encoding: ' . implode(', ', $this->accepted_compression) . "\r\n";
        }

        $proxyCredentials = '';
        if ($proxyHost) {
            if ($proxyPort == 0) {
                $proxyPort = 8080;
            }
            $connectServer = $proxyHost;
            $connectPort = $proxyPort;
            $transport = "tcp";
            $uri = 'http://' . $server . ':' . $port . $this->path;
            if ($proxyUsername != '') {
                if ($proxyAuthType != 1) {
                    error_log('XML-RPC: ' . __METHOD__ . ': warning. Only Basic auth to proxy is supported with HTTP 1.0');
                }
                $proxyCredentials = 'Proxy-Authorization: Basic ' . base64_encode($proxyUsername . ':' . $proxyPassword) . "\r\n";
            }
        } else {
            $connectServer = $server;
            $connectPort = $port;
            /// @todo if supporting https, we should support all its current options as well: peer name verification etc...
            $transport = ( $method === "https" ) ? "tls" : "tcp";
            $uri = $this->path;
        }

        // Cookie generation, as per rfc2965 (version 1 cookies) or
        // netscape's rules (version 0 cookies)
        $cookieHeader = '';
        if (count($this->cookies)) {
            $version = '';
            foreach ($this->cookies as $name => $cookie) {
                if ($cookie['version']) {
                    $version = ' $Version="' . $cookie['version'] . '";';
                    $cookieHeader .= ' ' . $name . '="' . $cookie['value'] . '";';
                    if ($cookie['path']) {
                        $cookieHeader .= ' $Path="' . $cookie['path'] . '";';
                    }
                    if ($cookie['domain']) {
                        $cookieHeader .= ' $Domain="' . $cookie['domain'] . '";';
                    }
                    if ($cookie['port']) {
                        $cookieHeader .= ' $Port="' . $cookie['port'] . '";';
                    }
                } else {
                    $cookieHeader .= ' ' . $name . '=' . $cookie['value'] . ";";
                }
            }
            $cookieHeader = 'Cookie:' . $version . substr($cookieHeader, 0, -1) . "\r\n";
        }

        // omit port if 80
        $port = ($port == 80) ? '' : (':' . $port);

        $op = 'POST ' . $uri . " HTTP/1.0\r\n" .
            'User-Agent: ' . $this->user_agent . "\r\n" .
            'Host: ' . $server . $port . "\r\n" .
            $credentials .
            $proxyCredentials .
            $acceptedEncoding .
            $encodingHdr .
            'Accept-Charset: ' . implode(',', $this->accepted_charset_encodings) . "\r\n" .
            $cookieHeader .
            'Content-Type: ' . $req->content_type . "\r\nContent-Length: " .
            strlen($payload) . "\r\n\r\n" .
            $payload;

        if ($this->debug > 1) {
            Logger::instance()->debugMessage("---SENDING---\n$op\n---END---");
        }

        if ($timeout > 0) {
            $fp = @stream_socket_client("$transport://$connectServer:$connectPort", $this->errno, $this->errstr, $timeout);
        } else {
            $fp = @stream_socket_client("$transport://$connectServer:$connectPort", $this->errno, $this->errstr);
        }
        if ($fp) {
            if ($timeout > 0) {
                stream_set_timeout($fp, $timeout);
            }
        } else {
            $this->errstr = 'Connect error: ' . $this->errstr;
            $r = new Response(0, PhpXmlRpc::$xmlrpcerr['http_error'], $this->errstr . ' (' . $this->errno . ')');

            return $r;
        }

        if (!fputs($fp, $op, strlen($op))) {
            fclose($fp);
            $this->errstr = 'Write error';
            $r = new Response(0, PhpXmlRpc::$xmlrpcerr['http_error'], $this->errstr);

            return $r;
        } else {
            // reset errno and errstr on successful socket connection
            $this->errstr = '';
        }
        // G. Giunta 2005/10/24: close socket before parsing.
        // should yield slightly better execution times, and make easier recursive calls (e.g. to follow http redirects)
        $ipd = '';
        do {
            // shall we check for $data === FALSE?
            // as per the manual, it signals an error
            $ipd .= fread($fp, 32768);
        } while (!feof($fp));
        fclose($fp);
        $r = $req->parseResponse($ipd, false, $this->return_type);

        return $r;
    }

    /**
     * @param Request $req
     * @param string $server
     * @param int $port
     * @param int $timeout
     * @param string $username
     * @param string $password
     * @param int $authType
     * @param string $cert
     * @param string $certPass
     * @param string $caCert
     * @param string $caCertDir
     * @param string $proxyHost
     * @param int $proxyPort
     * @param string $proxyUsername
     * @param string $proxyPassword
     * @param int $proxyAuthType
     * @param bool $keepAlive
     * @param string $key
     * @param string $keyPass
     * @param int $sslVersion
     * @return Response
     */
    protected function sendPayloadHTTPS($req, $server, $port, $timeout = 0, $username = '',  $password = '',
        $authType = 1, $cert = '', $certPass = '', $caCert = '', $caCertDir = '', $proxyHost = '', $proxyPort = 0,
        $proxyUsername = '', $proxyPassword = '', $proxyAuthType = 1, $keepAlive = false, $key = '', $keyPass = '',
        $sslVersion = 0)
    {
        return $this->sendPayloadCURL($req, $server, $port, $timeout, $username,
            $password, $authType, $cert, $certPass, $caCert, $caCertDir, $proxyHost, $proxyPort,
            $proxyUsername, $proxyPassword, $proxyAuthType, 'https', $keepAlive, $key, $keyPass, $sslVersion);
    }

    /**
     * Contributed by Justin Miller <justin@voxel.net>
     * Requires curl to be built into PHP
     * NB: CURL versions before 7.11.10 cannot use proxy to talk to https servers!
     *
     * @param Request $req
     * @param string $server
     * @param int $port
     * @param int $timeout
     * @param string $username
     * @param string $password
     * @param int $authType
     * @param string $cert
     * @param string $certPass
     * @param string $caCert
     * @param string $caCertDir
     * @param string $proxyHost
     * @param int $proxyPort
     * @param string $proxyUsername
     * @param string $proxyPassword
     * @param int $proxyAuthType
     * @param string $method
     * @param bool $keepAlive
     * @param string $key
     * @param string $keyPass
     * @param int $sslVersion
     * @return Response
     */
    protected function sendPayloadCURL($req, $server, $port, $timeout = 0, $username = '', $password = '',
        $authType = 1, $cert = '', $certPass = '', $caCert = '', $caCertDir = '', $proxyHost = '', $proxyPort = 0,
        $proxyUsername = '', $proxyPassword = '', $proxyAuthType = 1, $method = 'https', $keepAlive = false, $key = '',
        $keyPass = '', $sslVersion = 0)
    {
        if (!function_exists('curl_init')) {
            $this->errstr = 'CURL unavailable on this install';
            return new Response(0, PhpXmlRpc::$xmlrpcerr['no_curl'], PhpXmlRpc::$xmlrpcstr['no_curl']);
        }
        if ($method == 'https') {
            if (($info = curl_version()) &&
                ((is_string($info) && strpos($info, 'OpenSSL') === null) || (is_array($info) && !isset($info['ssl_version'])))
            ) {
                $this->errstr = 'SSL unavailable on this install';
                return new Response(0, PhpXmlRpc::$xmlrpcerr['no_ssl'], PhpXmlRpc::$xmlrpcstr['no_ssl']);
            }
        }

        if ($port == 0) {
            if ($method == 'http') {
                $port = 80;
            } else {
                $port = 443;
            }
        }

        // Only create the payload if it was not created previously
        if (empty($req->payload)) {
            $req->createPayload($this->request_charset_encoding);
        }

        // Deflate request body and set appropriate request headers
        $payload = $req->payload;
        if (function_exists('gzdeflate') && ($this->request_compression == 'gzip' || $this->request_compression == 'deflate')) {
            if ($this->request_compression == 'gzip') {
                $a = @gzencode($payload);
                if ($a) {
                    $payload = $a;
                    $encodingHdr = 'Content-Encoding: gzip';
                }
            } else {
                $a = @gzcompress($payload);
                if ($a) {
                    $payload = $a;
                    $encodingHdr = 'Content-Encoding: deflate';
                }
            }
        } else {
            $encodingHdr = '';
        }

        if ($this->debug > 1) {
            Logger::instance()->debugMessage("---SENDING---\n$payload\n---END---");
        }

        if (!$keepAlive || !$this->xmlrpc_curl_handle) {
            $curl = curl_init($method . '://' . $server . ':' . $port . $this->path);
            if ($keepAlive) {
                $this->xmlrpc_curl_handle = $curl;
            }
        } else {
            $curl = $this->xmlrpc_curl_handle;
        }

        // results into variable
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);

        if ($this->debug > 1) {
            curl_setopt($curl, CURLOPT_VERBOSE, true);
            /// @todo allow callers to redirect curlopt_stderr to some stream which can be buffered
        }
        curl_setopt($curl, CURLOPT_USERAGENT, $this->user_agent);
        // required for XMLRPC: post the data
        curl_setopt($curl, CURLOPT_POST, 1);
        // the data
        curl_setopt($curl, CURLOPT_POSTFIELDS, $payload);

        // return the header too
        curl_setopt($curl, CURLOPT_HEADER, 1);

        // NB: if we set an empty string, CURL will add http header indicating
        // ALL methods it is supporting. This is possibly a better option than
        // letting the user tell what curl can / cannot do...
        if (is_array($this->accepted_compression) && count($this->accepted_compression)) {
            //curl_setopt($curl, CURLOPT_ENCODING, implode(',', $this->accepted_compression));
            // empty string means 'any supported by CURL' (shall we catch errors in case CURLOPT_SSLKEY undefined ?)
            if (count($this->accepted_compression) == 1) {
                curl_setopt($curl, CURLOPT_ENCODING, $this->accepted_compression[0]);
            } else {
                curl_setopt($curl, CURLOPT_ENCODING, '');
            }
        }
        // extra headers
        $headers = array('Content-Type: ' . $req->content_type, 'Accept-Charset: ' . implode(',', $this->accepted_charset_encodings));
        // if no keepalive is wanted, let the server know it in advance
        if (!$keepAlive) {
            $headers[] = 'Connection: close';
        }
        // request compression header
        if ($encodingHdr) {
            $headers[] = $encodingHdr;
        }

        curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);
        // timeout is borked
        if ($timeout) {
            curl_setopt($curl, CURLOPT_TIMEOUT, $timeout == 1 ? 1 : $timeout - 1);
        }

        if ($username && $password) {
            curl_setopt($curl, CURLOPT_USERPWD, $username . ':' . $password);
            if (defined('CURLOPT_HTTPAUTH')) {
                curl_setopt($curl, CURLOPT_HTTPAUTH, $authType);
            } elseif ($authType != 1) {
                error_log('XML-RPC: ' . __METHOD__ . ': warning. Only Basic auth is supported by the current PHP/curl install');
            }
        }

        if ($method == 'https') {
            // set cert file
            if ($cert) {
                curl_setopt($curl, CURLOPT_SSLCERT, $cert);
            }
            // set cert password
            if ($certPass) {
                curl_setopt($curl, CURLOPT_SSLCERTPASSWD, $certPass);
            }
            // whether to verify remote host's cert
            curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, $this->verifypeer);
            // set ca certificates file/dir
            if ($caCert) {
                curl_setopt($curl, CURLOPT_CAINFO, $caCert);
            }
            if ($caCertDir) {
                curl_setopt($curl, CURLOPT_CAPATH, $caCertDir);
            }
            // set key file (shall we catch errors in case CURLOPT_SSLKEY undefined ?)
            if ($key) {
                curl_setopt($curl, CURLOPT_SSLKEY, $key);
            }
            // set key password (shall we catch errors in case CURLOPT_SSLKEY undefined ?)
            if ($keyPass) {
                curl_setopt($curl, CURLOPT_SSLKEYPASSWD, $keyPass);
            }
            // whether to verify cert's common name (CN); 0 for no, 1 to verify that it exists, and 2 to verify that it matches the hostname used
            curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, $this->verifyhost);
            // allow usage of different SSL versions
            curl_setopt($curl, CURLOPT_SSLVERSION, $sslVersion);
        }

        // proxy info
        if ($proxyHost) {
            if ($proxyPort == 0) {
                $proxyPort = 8080; // NB: even for HTTPS, local connection is on port 8080
            }
            curl_setopt($curl, CURLOPT_PROXY, $proxyHost . ':' . $proxyPort);
            if ($proxyUsername) {
                curl_setopt($curl, CURLOPT_PROXYUSERPWD, $proxyUsername . ':' . $proxyPassword);
                if (defined('CURLOPT_PROXYAUTH')) {
                    curl_setopt($curl, CURLOPT_PROXYAUTH, $proxyAuthType);
                } elseif ($proxyAuthType != 1) {
                    error_log('XML-RPC: ' . __METHOD__ . ': warning. Only Basic auth to proxy is supported by the current PHP/curl install');
                }
            }
        }

        // NB: should we build cookie http headers by hand rather than let CURL do it?
        // the following code does not honour 'expires', 'path' and 'domain' cookie attributes
        // set to client obj the the user...
        if (count($this->cookies)) {
            $cookieHeader = '';
            foreach ($this->cookies as $name => $cookie) {
                $cookieHeader .= $name . '=' . $cookie['value'] . '; ';
            }
            curl_setopt($curl, CURLOPT_COOKIE, substr($cookieHeader, 0, -2));
        }

        foreach ($this->extracurlopts as $opt => $val) {
            curl_setopt($curl, $opt, $val);
        }

        $result = curl_exec($curl);

        if ($this->debug > 1) {
            $message = "---CURL INFO---\n";
            foreach (curl_getinfo($curl) as $name => $val) {
                if (is_array($val)) {
                    $val = implode("\n", $val);
                }
                $message .= $name . ': ' . $val . "\n";
            }
            $message .= "---END---";
            Logger::instance()->debugMessage($message);
        }

        if (!$result) {
            /// @todo we should use a better check here - what if we get back '' or '0'?

            $this->errstr = 'no response';
            $resp = new Response(0, PhpXmlRpc::$xmlrpcerr['curl_fail'], PhpXmlRpc::$xmlrpcstr['curl_fail'] . ': ' . curl_error($curl));
            curl_close($curl);
            if ($keepAlive) {
                $this->xmlrpc_curl_handle = null;
            }
        } else {
            if (!$keepAlive) {
                curl_close($curl);
            }
            $resp = $req->parseResponse($result, true, $this->return_type);
            // if we got back a 302, we can not reuse the curl handle for later calls
            if ($resp->faultCode() == PhpXmlRpc::$xmlrpcerr['http_error'] && $keepAlive) {
                curl_close($curl);
                $this->xmlrpc_curl_handle = null;
            }
        }

        return $resp;
    }

    /**
     * Send an array of requests and return an array of responses.
     *
     * Unless $this->no_multicall has been set to true, it will try first to use one single xmlrpc call to server method
     * system.multicall, and revert to sending many successive calls in case of failure.
     * This failure is also stored in $this->no_multicall for subsequent calls.
     * Unfortunately, there is no server error code universally used to denote the fact that multicall is unsupported,
     * so there is no way to reliably distinguish between that and a temporary failure.
     * If you are sure that server supports multicall and do not want to fallback to using many single calls, set the
     * fourth parameter to FALSE.
     *
     * NB: trying to shoehorn extra functionality into existing syntax has resulted
     * in pretty much convoluted code...
     *
     * @param Request[] $reqs an array of Request objects
     * @param integer $timeout connection timeout (in seconds). See the details in the docs for the send() method
     * @param string $method the http protocol variant to be used. See the details in the docs for the send() method
     * @param boolean fallback When true, upon receiving an error during multicall, multiple single calls will be
     *                         attempted
     *
     * @return Response[]
     */
    public function multicall($reqs, $timeout = 0, $method = '', $fallback = true)
    {
        if ($method == '') {
            $method = $this->method;
        }
        if (!$this->no_multicall) {
            $results = $this->_try_multicall($reqs, $timeout, $method);
            if (is_array($results)) {
                // System.multicall succeeded
                return $results;
            } else {
                // either system.multicall is unsupported by server,
                // or call failed for some other reason.
                if ($fallback) {
                    // Don't try it next time...
                    $this->no_multicall = true;
                } else {
                    if (is_a($results, '\PhpXmlRpc\Response')) {
                        $result = $results;
                    } else {
                        $result = new Response(0, PhpXmlRpc::$xmlrpcerr['multicall_error'], PhpXmlRpc::$xmlrpcstr['multicall_error']);
                    }
                }
            }
        } else {
            // override fallback, in case careless user tries to do two
            // opposite things at the same time
            $fallback = true;
        }

        $results = array();
        if ($fallback) {
            // system.multicall is (probably) unsupported by server:
            // emulate multicall via multiple requests
            foreach ($reqs as $req) {
                $results[] = $this->send($req, $timeout, $method);
            }
        } else {
            // user does NOT want to fallback on many single calls:
            // since we should always return an array of responses,
            // return an array with the same error repeated n times
            foreach ($reqs as $req) {
                $results[] = $result;
            }
        }

        return $results;
    }

    /**
     * Attempt to boxcar $reqs via system.multicall.
     *
     * Returns either an array of Response, a single error Response or false (when received response does not respect
     * valid multicall syntax).
     *
     * @param Request[] $reqs
     * @param int $timeout
     * @param string $method
     * @return Response[]|bool|mixed|Response
     */
    private function _try_multicall($reqs, $timeout, $method)
    {
        // Construct multicall request
        $calls = array();
        foreach ($reqs as $req) {
            $call['methodName'] = new Value($req->method(), 'string');
            $numParams = $req->getNumParams();
            $params = array();
            for ($i = 0; $i < $numParams; $i++) {
                $params[$i] = $req->getParam($i);
            }
            $call['params'] = new Value($params, 'array');
            $calls[] = new Value($call, 'struct');
        }
        $multiCall = new Request('system.multicall');
        $multiCall->addParam(new Value($calls, 'array'));

        // Attempt RPC call
        $result = $this->send($multiCall, $timeout, $method);

        if ($result->faultCode() != 0) {
            // call to system.multicall failed
            return $result;
        }

        // Unpack responses.
        $rets = $result->value();

        if ($this->return_type == 'xml') {
            return $rets;
        } elseif ($this->return_type == 'phpvals') {
            /// @todo test this code branch...
            $rets = $result->value();
            if (!is_array($rets)) {
                return false;       // bad return type from system.multicall
            }
            $numRets = count($rets);
            if ($numRets != count($reqs)) {
                return false;       // wrong number of return values.
            }

            $response = array();
            for ($i = 0; $i < $numRets; $i++) {
                $val = $rets[$i];
                if (!is_array($val)) {
                    return false;
                }
                switch (count($val)) {
                    case 1:
                        if (!isset($val[0])) {
                            return false;       // Bad value
                        }
                        // Normal return value
                        $response[$i] = new Response($val[0], 0, '', 'phpvals');
                        break;
                    case 2:
                        /// @todo remove usage of @: it is apparently quite slow
                        $code = @$val['faultCode'];
                        if (!is_int($code)) {
                            return false;
                        }
                        $str = @$val['faultString'];
                        if (!is_string($str)) {
                            return false;
                        }
                        $response[$i] = new Response(0, $code, $str);
                        break;
                    default:
                        return false;
                }
            }

            return $response;
        } else {
            // return type == 'xmlrpcvals'

            $rets = $result->value();
            if ($rets->kindOf() != 'array') {
                return false;       // bad return type from system.multicall
            }
            $numRets = $rets->count();
            if ($numRets != count($reqs)) {
                return false;       // wrong number of return values.
            }

            $response = array();
            foreach($rets as $val) {
                switch ($val->kindOf()) {
                    case 'array':
                        if ($val->count() != 1) {
                            return false;       // Bad value
                        }
                        // Normal return value
                        $response[] = new Response($val[0]);
                        break;
                    case 'struct':
                        $code = $val['faultCode'];
                        if ($code->kindOf() != 'scalar' || $code->scalartyp() != 'int') {
                            return false;
                        }
                        $str = $val['faultString'];
                        if ($str->kindOf() != 'scalar' || $str->scalartyp() != 'string') {
                            return false;
                        }
                        $response[] = new Response(0, $code->scalarval(), $str->scalarval());
                        break;
                    default:
                        return false;
                }
            }

            return $response;
        }
    }
}
