<?php
/*
PHP-Websockets Project - https://github.com/ghedipunk/PHP-Websockets
Copyright (c) 2012, Adam Alexander
All rights reserved.

Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice, this
  list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice, this
  list of conditions and the following disclaimer in the documentation and/or
  other materials provided with the distribution.
* Neither the name of PHP WebSockets nor the names of its contributors may be
  used to endorse or promote products derived from this software without
  specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
abstract class WebSocketServer {

  protected $userClass = 'WebSocketUser'; // redefine this if you want a custom user class.  The custom user class should inherit from WebSocketUser.
  protected $maxBufferSize;        
  protected $master;
  protected $sockets                              = array();
  protected $users                                = array();
  protected $heldMessages                         = array();
  protected $interactive                          = true;
  protected $headerOriginRequired                 = false;
  protected $headerSecWebSocketProtocolRequired   = false;
  protected $headerSecWebSocketExtensionsRequired = false;

  function __construct($addr, $port, $bufferLength = 2048) {
    $this->maxBufferSize = $bufferLength;
    $this->master = socket_create(AF_INET, SOCK_STREAM, SOL_TCP)  or die("Failed: socket_create()");
    socket_set_option($this->master, SOL_SOCKET, SO_REUSEADDR, 1) or die("Failed: socket_option()");
    socket_bind($this->master, $addr, $port)                      or die("Failed: socket_bind()");
    socket_listen($this->master,20)                               or die("Failed: socket_listen()");
    $this->sockets['m'] = $this->master;
    $this->stdout("Server started\nListening on: $addr:$port\nMaster socket: ".$this->master);

    
  }

  abstract protected function process($user,$message); // Called immediately when the data is recieved. 
  abstract protected function connected($user);        // Called after the handshake response is sent to the client.
  abstract protected function closed($user);           // Called after the connection is closed.

  protected function connecting($user) {
    // Override to handle a connecting user, after the instance of the User is created, but before
    // the handshake has completed.
  }
  
  protected function send($user, $message) {
    if ($user->handshake) {
      $message = $this->frame($message,$user);
      $result = @socket_write($user->socket, $message, strlen($message));
    }
    else {
      // User has not yet performed their handshake.  Store for sending later.
      $holdingMessage = array('user' => $user, 'message' => $message);
      $this->heldMessages[] = $holdingMessage;
    }
  }

  protected function tick() {
    // Override this for any process that should happen periodically.  Will happen at least once
    // per second, but possibly more often.
  }

  protected function _tick() {
    // Core maintenance processes, such as retrying failed messages.
    foreach ($this->heldMessages as $key => $hm) {
      $found = false;
      foreach ($this->users as $currentUser) {
        if ($hm['user']->socket == $currentUser->socket) {
          $found = true;
          if ($currentUser->handshake) {
            unset($this->heldMessages[$key]);
            $this->send($currentUser, $hm['message']);
          }
        }
      }
      if (!$found) {
        // If they're no longer in the list of connected users, drop the message.
        unset($this->heldMessages[$key]);
      }
    }
  }

  /**
   * Main processing loop
   */
  public function run() {
    while(true) {
      if (empty($this->sockets)) {
        $this->sockets['m'] = $this->master;
      }
      $read = $this->sockets;
      $write = $except = null;
      $this->_tick();
      $this->tick();
      @socket_select($read,$write,$except,1);
      foreach ($read as $socket) {
        if ($socket == $this->master) {
          $client = socket_accept($socket);
          if ($client < 0) {
            $this->stderr("Failed: socket_accept()");
            continue;
          } 
          else {
            $this->connect($client);
            $this->stdout("Client connected. " . $client);
          }
        } 
        else {
          $numBytes = @socket_recv($socket, $buffer, $this->maxBufferSize, 0); 
          if ($numBytes === false) {
            $sockErrNo = socket_last_error($socket);
            switch ($sockErrNo)
            {
              case 102: // ENETRESET    -- Network dropped connection because of reset
              case 103: // ECONNABORTED -- Software caused connection abort
              case 104: // ECONNRESET   -- Connection reset by peer
              case 108: // ESHUTDOWN    -- Cannot send after transport endpoint shutdown -- probably more of an error on our part, if we're trying to write after the socket is closed.  Probably not a critical error, though.
              case 110: // ETIMEDOUT    -- Connection timed out
              case 111: // ECONNREFUSED -- Connection refused -- We shouldn't see this one, since we're listening... Still not a critical error.
              case 112: // EHOSTDOWN    -- Host is down -- Again, we shouldn't see this, and again, not critical because it's just one connection and we still want to listen to/for others.
              case 113: // EHOSTUNREACH -- No route to host
              case 121: // EREMOTEIO    -- Rempte I/O error -- Their hard drive just blew up.
              case 125: // ECANCELED    -- Operation canceled
                
                $this->stderr("Unusual disconnect on socket " . $socket);
                $this->disconnect($socket, true, $sockErrNo); // disconnect before clearing error, in case someone with their own implementation wants to check for error conditions on the socket.
                break;
              default:

                $this->stderr('Socket error: ' . socket_strerror($sockErrNo));
            }
            
          }
          elseif ($numBytes == 0) {
            $this->disconnect($socket);
            $this->stderr("Client disconnected. TCP connection lost: " . $socket);
          } 
          else {
            $user = $this->getUserBySocket($socket);
            if (!$user->handshake) {
              $tmp = str_replace("\r", '', $buffer);
              if (strpos($tmp, "\n\n") === false ) {
                continue; // If the client has not finished sending the header, then wait before sending our upgrade response.
              }
              $this->doHandshake($user,$buffer);
            } 
            else {
              //split packet into frame and send it to deframe
              $this->split_packet($numBytes,$buffer, $user);
            }
          }
        }
      }
    }
  }

  protected function connect($socket) {
    $user = new $this->userClass(uniqid('u'), $socket);
    $this->users[$user->id] = $user;
    $this->sockets[$user->id] = $socket;
    $this->connecting($user);
  }

  protected function disconnect($socket, $triggerClosed = true, $sockErrNo = null) {
    $disconnectedUser = $this->getUserBySocket($socket);
    
    if ($disconnectedUser !== null) {
      unset($this->users[$disconnectedUser->id]);
        
      if (array_key_exists($disconnectedUser->id, $this->sockets)) {
        unset($this->sockets[$disconnectedUser->id]);
      }
      
      if (!is_null($sockErrNo)) {
        socket_clear_error($socket);
      }

      if ($triggerClosed) {
        $this->closed($disconnectedUser);
        socket_close($disconnectedUser->socket);
      }
      else {
        $message = $this->frame('', $disconnectedUser, 'close');
        @socket_write($disconnectedUser->socket, $message, strlen($message));
      }
    }
  }

  protected function doHandshake($user, $buffer) {
    $magicGUID = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
    $headers = array();
    $lines = explode("\n",$buffer);
    foreach ($lines as $line) {
      if (strpos($line,":") !== false) {
        $header = explode(":",$line,2);
        $headers[strtolower(trim($header[0]))] = trim($header[1]);
      }
      elseif (stripos($line,"get ") !== false) {
        preg_match("/GET (.*) HTTP/i", $buffer, $reqResource);
        $headers['get'] = trim($reqResource[1]);
      }
    }
    if (isset($headers['get'])) {
      $user->requestedResource = $headers['get'];
    } 
    else {
      // todo: fail the connection
      $handshakeResponse = "HTTP/1.1 405 Method Not Allowed\r\n\r\n";     
    }
    if (!isset($headers['host']) || !$this->checkHost($headers['host'])) {
      $handshakeResponse = "HTTP/1.1 400 Bad Request";
    }
    if (!isset($headers['upgrade']) || strtolower($headers['upgrade']) != 'websocket') {
      $handshakeResponse = "HTTP/1.1 400 Bad Request";
    } 
    if (!isset($headers['connection']) || strpos(strtolower($headers['connection']), 'upgrade') === FALSE) {
      $handshakeResponse = "HTTP/1.1 400 Bad Request";
    }
    if (!isset($headers['sec-websocket-key'])) {
      $handshakeResponse = "HTTP/1.1 400 Bad Request";
    } 
    else {

    }
    if (!isset($headers['sec-websocket-version']) || strtolower($headers['sec-websocket-version']) != 13) {
      $handshakeResponse = "HTTP/1.1 426 Upgrade Required\r\nSec-WebSocketVersion: 13";
    }
    if (($this->headerOriginRequired && !isset($headers['origin']) ) || ($this->headerOriginRequired && !$this->checkOrigin($headers['origin']))) {
      $handshakeResponse = "HTTP/1.1 403 Forbidden";
    }
    if (($this->headerSecWebSocketProtocolRequired && !isset($headers['sec-websocket-protocol'])) || ($this->headerSecWebSocketProtocolRequired && !$this->checkWebsocProtocol($headers['sec-websocket-protocol']))) {
      $handshakeResponse = "HTTP/1.1 400 Bad Request";
    }
    if (($this->headerSecWebSocketExtensionsRequired && !isset($headers['sec-websocket-extensions'])) || ($this->headerSecWebSocketExtensionsRequired && !$this->checkWebsocExtensions($headers['sec-websocket-extensions']))) {
      $handshakeResponse = "HTTP/1.1 400 Bad Request";
    }

    // Done verifying the _required_ headers and optionally required headers.

    if (isset($handshakeResponse)) {
      socket_write($user->socket,$handshakeResponse,strlen($handshakeResponse));
      $this->disconnect($user->socket);
      return;
    }

    $user->headers = $headers;
    $user->handshake = $buffer;

    $webSocketKeyHash = sha1($headers['sec-websocket-key'] . $magicGUID);

    $rawToken = "";
    for ($i = 0; $i < 20; $i++) {
      $rawToken .= chr(hexdec(substr($webSocketKeyHash,$i*2, 2)));
    }
    $handshakeToken = base64_encode($rawToken) . "\r\n";

    $subProtocol = (isset($headers['sec-websocket-protocol'])) ? $this->processProtocol($headers['sec-websocket-protocol']) : "";
    $extensions = (isset($headers['sec-websocket-extensions'])) ? $this->processExtensions($headers['sec-websocket-extensions']) : "";

    $handshakeResponse = "HTTP/1.1 101 Switching Protocols\r\nUpgrade: websocket\r\nConnection: Upgrade\r\nSec-WebSocket-Accept: $handshakeToken$subProtocol$extensions\r\n";
    socket_write($user->socket,$handshakeResponse,strlen($handshakeResponse));
    $this->connected($user);
  }

  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.
  }

  protected function getUserBySocket($socket) {
    foreach ($this->users as $user) {
      if ($user->socket == $socket) {
        return $user;
      }
    }
    return null;
  }

  public function stdout($message) {
    if ($this->interactive) {
      echo "$message\n";
    }
  }

  public function stderr($message) {
    if ($this->interactive) {
      echo "$message\n";
    }
  }

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

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

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

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

    return chr($b1) . chr($b2) . $lengthField . $message;
  }
  
  //check packet if he have more than one frame and process each frame individually
  protected function split_packet($length,$packet, $user) {
    //add PartialPacket and calculate the new $length
    if ($user->handlingPartialPacket) {
      $packet = $user->partialBuffer . $packet;
      $user->handlingPartialPacket = false;
      $length=strlen($packet);
    }
    $fullpacket=$packet;
    $frame_pos=0;
    $frame_id=1;

    while($frame_pos<$length) {
      $headers = $this->extractHeaders($packet);
      $headers_size = $this->calcoffset($headers);
      $framesize=$headers['length']+$headers_size;
      
      //split frame from packet and process it
      $frame=substr($fullpacket,$frame_pos,$framesize);

      if (($message = $this->deframe($frame, $user,$headers)) !== FALSE) {
        if ($user->hasSentClose) {
          $this->disconnect($user->socket);
        } else {
          if (preg_match('//u', $message)) {
            //$this->stdout("Is UTF-8\n".$message); 
            $this->process($user, $message);
          } else {
            $this->stderr("not UTF-8\n");
          }
        }
      } 
      //get the new position also modify packet data
      $frame_pos+=$framesize;
      $packet=substr($fullpacket,$frame_pos);
      $frame_id++;
    }
  }

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

  protected function deframe($message, &$user) {
    //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
        $user->hasSentClose = true;
        return "";
      case 9:
        $pongReply = true;
      case 10:
        break;
      default:
        //$this->disconnect($user); // todo: fail connection
        $willClose = true;
        break;
    }

    /* Deal by split_packet() as now deframe() do only one frame at a time.
    if ($user->handlingPartialPacket) {
      $message = $user->partialBuffer . $message;
      $user->handlingPartialPacket = false;
      return $this->deframe($message, $user);
    }
    */
    
    if ($this->checkRSVBits($headers,$user)) {
      return false;
    }

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

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

    if ($pongReply) {
      $reply = $this->frame($payload,$user,'pong');
      socket_write($user->socket,$reply,strlen($reply));
      return false;
    }
    if (extension_loaded('mbstring')) {
      if ($headers['length'] > mb_strlen($this->applyMask($headers,$payload))) {
        $user->handlingPartialPacket = true;
        $user->partialBuffer = $message;
        return false;
      }
    } 
    else {
      if ($headers['length'] > strlen($this->applyMask($headers,$payload))) {
        $user->handlingPartialPacket = true;
        $user->partialBuffer = $message;
        return false;
      }
    }

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

    if ($headers['fin']) {
      $user->partialMessage = "";
      return $payload;
    }
    $user->partialMessage = $payload;
    return 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 (strlen($effectiveMask) < strlen($payload)) {
      $effectiveMask .= $mask;
    }
    while (strlen($effectiveMask) > strlen($payload)) {
      $effectiveMask = substr($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; $i < strlen($str); $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";
  }

  protected function printHeaders($headers) {
    echo "Array\n(\n";
    foreach ($headers as $key => $value) {
      if ($key == 'length' || $key == 'opcode') {
        echo "\t[$key] => $value\n\n";
      } 
      else {
        echo "\t[$key] => ".$this->strtohex($value)."\n";

      }

    }
    echo ")\n";
  }
}

class WebSocketUser {

  public $socket;
  public $id;
  public $headers = array();
  public $handshake = false;

  public $handlingPartialPacket = false;
  public $partialBuffer = "";

  public $sendingContinuous = false;
  public $partialMessage = "";
  
  public $hasSentClose = false;

  function __construct($id, $socket) {
    $this->id = $id;
    $this->socket = $socket;
  }
}
?>