<?php
/*
 *  sac-a-push - Obj/transports.phh
 *
 *  Copyright (C) 2012 Matteo Nastasi
 *                          mailto: nastasi@alternativeoutput.it
 *                                  matteo.nastasi@milug.org
 *                          web: http://www.alternativeoutput.it
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABLILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details. You should have received a
 * copy of the GNU General Public License along with this program; if
 * not, write to the Free Software Foundation, Inc, 59 Temple Place -
 * Suite 330, Boston, MA 02111-1307, USA.
 *
 */

/*
 *  test: SO x Browser
 *  Values: Y: works, N: not works, @: continuous download,
 *          D: continuous download after first reload
 *
 *  Stream IFRAME:
 *
 * Iframe| IW | FF | Ch | Op | Ko | IE
 * ------+----+----+----+----+----+----
 *   Lnx | D  |    | @  |    | @  | x
 *   Win | x  | D  | @  | @  |    | D
 *   Mac | x  |    |    |    |    |
 *
 *
 *   WS  | IW | FF | Ch | Op | Ko | IE
 * ------+----+----+----+----+----+----
 *   Lnx |    |    |    |    |    |
 *   Win |    |    |    |    |    |
 *   Mac |    |    |    |    |    |
 *
 *
 *   XHR | IW | FF | Ch | Op | Ko | IE
 * ------+----+----+----+----+----+----
 *   Lnx | Y  |    | ^D |    | Y  | x
 *   Win | x  | Y  | Y  |    |    | N
 *   Mac | x  |    |    |    |    |
 *
 *
 * HtmlFl| IW | FF | Ch | Op | Ko | IE
 * ------+----+----+----+----+----+----
 *   Lnx | N  |    |    |    | N  |
 *   Win | x  | N  | N  |    |    | Y* (* seems delay between click and load of a new page)
 *   Mac | x  |    |    |    |    |
 *
 *
 */

class Transport_template {

    function Transport_template() {
    }

    // return string value is appended to the content of the returned page
    // return FALSE if fails
    // check with '===' operator to disambiguation between "" and FALSE return value
    function init($enc, $header, &$header_out, $init_string, $base, $step)
    {
    }

    function close()
    {
    }

    function chunk($step, $cont)
    {
    }

    function is_chunked()
    {
    }

    // return string to add to the stream to perform something to the engine
    static function fini($init_string, $base, $blockerr)
    {
        return "";
    }
}

class Transport_websocket {
    protected $magicGUID = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";

    function Transport_websocket($secure = FALSE) {
        $this->type = ($secure == FALSE ? "websocket" : "websocketsec");
        $this->headerOriginRequired                 = false;
        $this->headerSecWebSocketProtocolRequired   = false;
        $this->headerSecWebSocketExtensionsRequired = false;

        $this->sendingContinuous = false;

        $this->handlingPartialPacket = false;
        $this->partialMessage = "";

        $this->hasSentClose = false;
    }

    protected function extractHeaders($message) {
        $header = array('fin'     => $message[0] & chr(128),
                        'rsv1'    => $message[0] & chr(64),
                        'rsv2'    => $message[0] & chr(32),
                        'rsv3'    => $message[0] & chr(16),
                        'opcode'  => ord($message[0]) & 15,
                        'hasmask' => $message[1] & chr(128),
                        'length'  => 0,
                        'mask'    => "");
        $header['length'] = (ord($message[1]) >= 128) ? ord($message[1]) - 128 : ord($message[1]);

        if ($header['length'] == 126) {
            if ($header['hasmask']) {
                $header['mask'] = $message[4] . $message[5] . $message[6] . $message[7];
            }
            $header['length'] = ord($message[2]) * 256
                + ord($message[3]);
        } elseif ($header['length'] == 127) {
            if ($header['hasmask']) {
                $header['mask'] = $message[10] . $message[11] . $message[12] . $message[13];
            }
            $header['length'] = ord($message[2]) * 65536 * 65536 * 65536 * 256
                + ord($message[3]) * 65536 * 65536 * 65536
                + ord($message[4]) * 65536 * 65536 * 256
                + ord($message[5]) * 65536 * 65536
                + ord($message[6]) * 65536 * 256
                + ord($message[7]) * 65536
                + ord($message[8]) * 256
                + ord($message[9]);
        } elseif ($header['hasmask']) {
            $header['mask'] = $message[2] . $message[3] . $message[4] . $message[5];
        }
        //echo $this->strtohex($message);
        //$this->printHeaders($header);
        return $header;
    }

    protected function extractPayload($message,$headers) {
        $offset = 2;
        if ($headers['hasmask']) {
            $offset += 4;
        }
        if ($headers['length'] > 65535) {
            $offset += 8;
        } elseif ($headers['length'] > 125) {
            $offset += 2;
        }
        return substr($message,$offset);
    }

    protected function applyMask($headers,$payload) {
        $effectiveMask = "";
        if ($headers['hasmask']) {
            $mask = $headers['mask'];
        } else {
            return $payload;
        }

        while (mb_strlen($effectiveMask, "ASCII") < mb_strlen($payload, "ASCII")) {
            $effectiveMask .= $mask;
        }
        while (mb_strlen($effectiveMask, "ASCII") > mb_strlen($payload, "ASCII")) {
            $effectiveMask = substr($effectiveMask,0,-1);
        }
        return $effectiveMask ^ $payload;
    }

    protected function checkRSVBits($headers,$user) { // override this method if you are using an extension where the RSV bits are used.
        if (ord($headers['rsv1']) + ord($headers['rsv2']) + ord($headers['rsv3']) > 0) {
            //$this->disconnect($user); // todo: fail connection
            return true;
        }
        return false;
    }

    protected function strtohex($str) {
        $strout = "";
        for ($i = 0; $i < mb_strlen($str, "ASCII"); $i++) {
            $strout .= (ord($str[$i])<16) ? "0" . dechex(ord($str[$i])) : dechex(ord($str[$i]));
            $strout .= " ";
            if ($i%32 == 7) {
                $strout .= ": ";
            }
            if ($i%32 == 15) {
                $strout .= ": ";
            }
            if ($i%32 == 23) {
                $strout .= ": ";
            }
            if ($i%32 == 31) {
                $strout .= "\n";
            }
        }
        return $strout . "\n";
    }

    function unchunk($cont)
    {
        // fprintf(STDERR, "CHUNK: [%s]\n", $cont);
        return $this->deframe($cont);
    }

    function chunk($step, $cont)
    {
        // fprintf(STDERR, "CHUNK: [%s]\n", $cont);
        return $this->frame('@BEGIN@'.$cont.'@END@'); // , 'text', TRUE);
    }

    protected function frame($message, $messageType='text', $messageContinues=false) {
        switch ($messageType) {
        case 'continuous':
            $b1 = 0;
            break;
        case 'text':
            $b1 = ($this->sendingContinuous) ? 0 : 1;
            break;
        case 'binary':
            $b1 = ($this->sendingContinuous) ? 0 : 2;
            break;
        case 'close':
            $b1 = 8;
            break;
        case 'ping':
            $b1 = 9;
            break;
        case 'pong':
            $b1 = 10;
            break;
        }
        if ($messageContinues) {
            $this->sendingContinuous = true;
        } else {
            $b1 += 128;
            $this->sendingContinuous = false;
        }

        $length = mb_strlen($message, "ASCII");
        $lengthField = "";
        if ($length < 126) {
            $b2 = $length;
        } elseif ($length <= 65536) {
            $b2 = 126;
            $hexLength = dechex($length);
            //$this->stdout("Hex Length: $hexLength");
            if (mb_strlen($hexLength, "ASCII")%2 == 1) {
                $hexLength = '0' . $hexLength;
            }
            $n = mb_strlen($hexLength, "ASCII") - 2;

            for ($i = $n; $i >= 0; $i=$i-2) {
                $lengthField = chr(hexdec(substr($hexLength, $i, 2))) . $lengthField;
            }
            while (mb_strlen($lengthField, "ASCII") < 2) {
                $lengthField = chr(0) . $lengthField;
            }
        } else {
            $b2 = 127;
            $hexLength = dechex($length);
            if (mb_strlen($hexLength, "ASCII")%2 == 1) {
                $hexLength = '0' . $hexLength;
            }
            $n = mb_strlen($hexLength, "ASCII") - 2;

            for ($i = $n; $i >= 0; $i=$i-2) {
                $lengthField = chr(hexdec(substr($hexLength, $i, 2))) . $lengthField;
            }
            while (mb_strlen($lengthField, "ASCII") < 8) {
                $lengthField = chr(0) . $lengthField;
            }
        }

        return chr($b1) . chr($b2) . $lengthField . $message;
    }

    protected function deframe($message) {
        //echo $this->strtohex($message);
        $headers = $this->extractHeaders($message);
        $pongReply = false;
        $willClose = false;
        switch($headers['opcode']) {
        case 0:
        case 1:
        case 2:
            break;
        case 8:
            // todo: close the connection
            $this->hasSentClose = true;
            return "";
        case 9:
            $pongReply = true;
        case 10:
            break;
        default:
            //$this->disconnect($user); // todo: fail connection
            $willClose = true;
            break;
        }

        if ($this->handlingPartialPacket) {
            $message = $this->partialBuffer . $message;
            $this->handlingPartialPacket = false;
            return $this->deframe($message);
        }

        if ($this->checkRSVBits($headers,$this)) {
            return false;
        }

        if ($willClose) {
            // todo: fail the connection
            return false;
        }

        $payload = $this->partialMessage . $this->extractPayload($message,$headers);

        if ($pongReply) {
            $reply = $this->frame($payload,$this,'pong');
            // TODO FIXME ALL socket_write management
            socket_write($user->socket,$reply,mb_strlen($reply, "ASCII"));
            return false;
        }
        if (extension_loaded('mbstring')) {
            if ($headers['length'] > mb_strlen($payload, "ASCII")) {
                $this->handlingPartialPacket = true;
                $this->partialBuffer = $message;
                return false;
            }
        } else {
            if ($headers['length'] > mb_strlen($payload, "ASCII")) {
                $this->handlingPartialPacket = true;
                $this->partialBuffer = $message;
                return false;
            }
        }

        $payload = $this->applyMask($headers,$payload);

        if ($headers['fin']) {
            $this->partialMessage = "";
            return $payload;
        }
        $this->partialMessage = $payload;
        return false;
    }


    protected function checkHost($hostName) {
        return true; // Override and return false if the host is not one that you would expect.
        // Ex: You only want to accept hosts from the my-domain.com domain,
        // but you receive a host from malicious-site.com instead.
    }

    protected function checkOrigin($origin) {
        return true; // Override and return false if the origin is not one that you would expect.
    }

    protected function checkWebsocProtocol($protocol) {
        return true; // Override and return false if a protocol is not found that you would expect.
    }

    protected function checkWebsocExtensions($extensions) {
        return true; // Override and return false if an extension is not found that you would expect.
    }

    protected function processProtocol($protocol) {
        return ""; // return either "Sec-WebSocket-Protocol: SelectedProtocolFromClientList\r\n" or return an empty string.
        // The carriage return/newline combo must appear at the end of a non-empty string, and must not
        // appear at the beginning of the string nor in an otherwise empty string, or it will be considered part of
        // the response body, which will trigger an error in the client as it will not be formatted correctly.
    }

    protected function processExtensions($extensions) {
        return ""; // return either "Sec-WebSocket-Extensions: SelectedExtensions\r\n" or return an empty string.
    }

    function init($enc, $headers, &$headers_out, $init_string, $base, $step)
    {
        if (0) { // TODO: what is ?
            if (isset($headers['get'])) {
                $this->requestedResource = $headers['get'];
            } else {
                // todo: fail the connection
                $headers_out['HTTP-Response'] = "405 Method Not Allowed";
            }
        }

        if (!isset($headers['Host']) || !$this->checkHost($headers['Host'])) {
            // error_log('bad 1');
            $headers_out['HTTP-Response'] = "400 Bad Request";
        }
        if (!isset($headers['Upgrade']) || strtolower($headers['Upgrade']) != 'websocket') {
            // error_log('bad 2 ' . $headers['Upgrade']);
            $headers_out['HTTP-Response'] = "400 Bad Request";
        }
        if (!isset($headers['Connection']) || strpos(strtolower($headers['Connection']), 'upgrade') === FALSE) {
            // error_log('bad 3');
            $headers_out['HTTP-Response'] = "400 Bad Request";
        }
        if (!isset($headers['Sec-Websocket-Key'])) {
            // error_log('bad 4');
            $headers_out['HTTP-Response'] = "400 Bad Request";
        } else {
        }

        if (!isset($headers['Sec-Websocket-Version']) || strtolower($headers['Sec-Websocket-Version']) != 13) {
            $headers_out['HTTP-Response'] = "426 Upgrade Required";
            $headers_out['Sec-WebSocketVersion'] = "13";
        }
        if ( ($this->headerOriginRequired && !isset($headers['Origin']) )
             || ($this->headerOriginRequired && !$this->checkOrigin($headers['Origin'])) ) {
            $headers_out['HTTP-Response'] = "403 Forbidden";
        }
        if ( ($this->headerSecWebSocketProtocolRequired && !isset($headers['Sec-Websocket-Protocol']))
             || ($this->headerSecWebSocketProtocolRequired &&
                 !$this->checkWebsocProtocol($headers['Sec-Websocket-Protocol']))) {
            // error_log('bad 5');
            $headers_out['HTTP-Response'] = "400 Bad Request";
        }
        if ( ($this->headerSecWebSocketExtensionsRequired  && !isset($headers['Sec-Websocket-Extensions']))
             || ($this->headerSecWebSocketExtensionsRequired &&
                 !$this->checkWebsocExtensions($headers['Sec-Websocket-Extensions'])) ) {
            // error_log('bad 6');
            $headers_out['HTTP-Response'] = "400 Bad Request";
        }

        if (isset($headers_out['HTTP-Response'])) {
            // TODO: check return management
            return (FALSE);
        }

        // TODO: verify both variables
        // here there is a change of the socket status from start to handshaked
        // th headers are saved too but without any further access so we skip it


        $inno = 'x3JJHMbDL1EzLkh9GBhXDw==';
        $outo = sha1($inno . $this->magicGUID);
        $rawToken = "";
        for ($i = 0; $i < 20; $i++) {
            $rawToken .= chr(hexdec(substr($outo,$i*2, 2)));
        }

        $outo = base64_encode($rawToken);

        $webSocketKeyHash = sha1($headers['Sec-Websocket-Key'] . $this->magicGUID);
        $rawToken = "";
        for ($i = 0; $i < 20; $i++) {
            $rawToken .= chr(hexdec(substr($webSocketKeyHash,$i*2, 2)));
        }
        $handshakeToken = base64_encode($rawToken);
        $subProtocol = (isset($headers['Sec-Websocket-Protocol'])) ?
            $this->processProtocol($headers['Sec-Websocket-Protocol']) : "";
        $extensions = (isset($headers['Sec-Websocket-Extensions'])) ?
            $this->processExtensions($headers['Sec-Websocket-Extensions']) : "";

        $headers_out['HTTP-Response'] = "101 Switching Protocols";
        $headers_out['Upgrade']       = 'websocket';
        $headers_out['Connection']    = 'Upgrade';
        $headers_out['Sec-WebSocket-Accept'] = "$handshakeToken$subProtocol$extensions";

        return ("");
    }

    static function close()
    {
        return(chr(0x88).chr(0x02).chr(0xe8).chr(0x03));
    }

    static function fini($init_string, $base, $blockerr)
    {
        return (sprintf('@BEGIN@ %s window.onbeforeunload = null; window.onunload = null; document.location.assign("%sindex.php"); @END@',  ($blockerr ? 'xstm.stop(); ' : ''), $base).self::close());
    }

    function is_chunked()
    {
        return FALSE;
    }

}

class Transport_xhr {

    function Transport_xhr() {
        $this->type = 'xhr';
    }

    function init($enc, $header, &$header_out, $init_string, $base, $step)
    {
        $ret = sprintf("@BEGIN@ /* %s */ @END@", $init_string);
        if ($enc != 'plain')
            $header_out['Content-Encoding'] = $enc;
        $header_out['Cache-Control'] = 'no-cache, must-revalidate';     // HTTP/1.1
        $header_out['Expires']       = 'Mon, 26 Jul 1997 05:00:00 GMT'; // Date in the past
        $header_out['Content-type']  = 'application/xml; charset="utf-8"';

        return ($ret);
    }

    function close()
    {
        return "";
    }

    static function fini($init_string, $base, $blockerr)
    {
        return (sprintf('@BEGIN@ %s window.onbeforeunload = null; window.onunload = null; document.location.assign("%sindex.php"); @END@',  ($blockerr ? 'xstm.stop(); ' : ''), $base));
        return ("");
    }

    function chunk($step, $cont)
    {
        // fprintf(STDERR, "CHUNK: [%s]\n", $cont);
        return ("@BEGIN@".$cont."@END@");
    }

    function is_chunked()
    {
        return TRUE;
    }
}

class Transport_iframe {

    function Transport_iframe() {
        $this->type = 'iframe';
    }

    function init($enc, $header, &$header_out, $init_string, $base, $step)
    {
        $ret = "";

        if ($enc != 'plain')
            $header_out['Content-Encoding'] = $enc;
        $header_out['Cache-Control'] = 'no-cache, must-revalidate';     // HTTP/1.1
        $header_out['Expires']       = 'Mon, 26 Jul 1997 05:00:00 GMT'; // Date in the past
        $header_out['Content-type']  = 'text/html; charset="utf-8"';

        $ret .= sprintf("<html>
<head>
<script type=\"text/javascript\" src=\"%scommons.js\"></script>
<script type=\"text/javascript\" src=\"%sxynt-streaming-ifra.js\"></script>
<script type=\"text/javascript\">
var xynt_streaming = \"ready\";", $base, $base);
        if ($step > 0)
            $ret .= sprintf("last_clean = %d;\n", ($step-1));
        $ret .= sprintf("
window.onload = function () { try { if (xynt_streaming != \"ready\") { xynt_streaming.transp.stopped = true; } } catch(e) { /* console.log(\"catcha\"); */ } };
</script>
</head>
<body>");
        $ret .= sprintf("<!-- \n%s -->\n", $init_string);

        return ($ret);
    }

    function close()
    {
        return "";
    }

    static function fini($init_string, $base, $blockerr)
    {
        $ret = "";
        $ret .= sprintf("<html>
<head>
<script type=\"text/javascript\" src=\"%scommons.js\"></script>
<script type=\"text/javascript\" src=\"%sxynt-streaming-ifra.js\"></script>
<script type=\"text/javascript\">
var xynt_streaming = \"ready\";", $base, $base);
        $ret .= sprintf("
window.onload = function () { try { if (xynt_streaming != \"ready\") { xynt_streaming.reload(); } } catch(e) { /* console.log(\"catcha\"); */ } };
</script>
</head>
<body>");
        $ret .= sprintf("<!-- \n%s -->\n", $init_string);
        $ret .= sprintf("<script id='hs%d' type='text/javascript'><!--
push(\"%s\");
// -->
</script>", 0, escpush($blockerr) );
        return ($ret);
    }

    function chunk($step, $cont)
    {
        // fprintf(STDERR, "CHUNK: [%s]\n", $cont);
        if ($cont == NULL) {
            return sprintf("<script id='hs%d' type='text/javascript'><!--
push(null);\n// -->\n</script>", $step);
        }
        else {
            return sprintf("<script id='hs%d' type='text/javascript'><!--
push(\"%s\");\n// -->\n</script>", $step, escpush($cont) );
        }
    }

    function is_chunked()
    {
        return TRUE;
    }
}

class Transport_htmlfile extends Transport_iframe {
    function Transport_htmlfile() {
        $this->type = 'htmlfile';
    }
}

class Transport {
    function Transport()
    {
    }

    static function create($transp)
    {
        if ($transp == 'websocket' || $transp == 'websocketsec') {
            return new Transport_websocket($transp == 'websocketsec');
        }
        else if ($transp == 'xhr') {
            return new Transport_xhr();
        }
        else if ($transp == 'htmlfile') {
            return new Transport_htmlfile();
        }
        else  {
            return new Transport_iframe();
        }
    }
    static function gettype($transp)
    {
        if ($transp == 'websocket' || $transp == 'xhr' || $transp == 'htmlfile') {
            return "Transport_".$transp;
        }
        else {
            return 'Transport_iframe';
        }
    }
}
?>