node-minecraft-protocol/src/client.js

var EventEmitter = require('events').EventEmitter
  , util = require('util')
  , protocol = require('./protocol')
  , createPacketBuffer = protocol.createPacketBuffer
  , compressPacketBuffer = protocol.compressPacketBuffer
  , oldStylePacket = protocol.oldStylePacket
  , newStylePacket = protocol.newStylePacket
  , parsePacketData = protocol.parsePacketData
  , parseNewStylePacket = protocol.parseNewStylePacket
  , packetIds = protocol.packetIds
  , packetNames = protocol.packetNames
  , states = protocol.states
  , debug = require('./debug')
  ;

module.exports = Client;

function Client(isServer) {
  EventEmitter.call(this);

  this._state = states.HANDSHAKING;
  Object.defineProperty(this, "state", {
    get: function() {
      return this._state;
    },
    set: function(newProperty) {
      var oldProperty = this._state;
      this._state = newProperty;
      this.emit('state', newProperty, oldProperty);
    }
  });
  this.isServer = !!isServer;
  this.socket = null;
  this.encryptionEnabled = false;
  this.cipher = null;
  this.decipher = null;
  this.compressionThreshold = -2;
  this.packetsToParse = {};
  this.on('newListener', function(event, listener) {
    var direction = this.isServer ? 'toServer' : 'toClient';
    if(protocol.packetStates[direction].hasOwnProperty(event) || event === "packet") {
      if(typeof this.packetsToParse[event] === "undefined") this.packetsToParse[event] = 1;
      else this.packetsToParse[event] += 1;
    }
  });
  this.on('removeListener', function(event, listener) {
    var direction = this.isServer ? 'toServer' : 'toClient';
    if(protocol.packetStates[direction].hasOwnProperty(event) || event === "packet") {
      this.packetsToParse[event] -= 1;
    }
  });
}

util.inherits(Client, EventEmitter);

// Transform weird "packet" types into string representing their type. Should be mostly retro-compatible
Client.prototype.on = function(type, func) {
  var direction = this.isServer ? 'toServer' : 'toClient';
  if(Array.isArray(type)) {
    arguments[0] = protocol.packetNames[type[0]][direction][type[1]];
  } else if(typeof type === "number") {
    arguments[0] = protocol.packetNames[this.state][direction][type];
  }
  EventEmitter.prototype.on.apply(this, arguments);
};

Client.prototype.onRaw = function(type, func) {
  var arg = "raw.";
  if(Array.isArray(type)) {
    arg += protocol.packetNames[type[0]][direction][type[1]];
  } else if(typeof type === "number") {
    arg += protocol.packetNames[this.state][direction][type];
  } else {
    arg += type;
  }
  arguments[0] = arg;
  EventEmitter.prototype.on.apply(this, arguments);
};

Client.prototype.setSocket = function(socket) {
  var self = this;

  function afterParse(err, parsed) {
    if(err || (parsed && parsed.error)) {
      self.emit('error', err || parsed.error);
      self.end("ProtocolError");
      return;
    }
    if(!parsed) {
      return;
    }
    var packet = parsed.results;
    //incomingBuffer = incomingBuffer.slice(parsed.size); TODO: Already removed in prepare

    var packetName = protocol.packetNames[self.state][self.isServer ? 'toServer' : 'toClient'][packet.id];
    var packetState = self.state;
    self.emit(packetName, packet);
    self.emit('packet', packet);
    self.emit('raw.' + packetName, parsed.buffer, packetState);
    self.emit('raw', parsed.buffer, packetState);
    prepareParse();
  }

  function prepareParse() {
    var packetLengthField = protocol.types["varint"][0](incomingBuffer, 0);
    if(packetLengthField && packetLengthField.size + packetLengthField.value <= incomingBuffer.length) {
      var buf = incomingBuffer.slice(packetLengthField.size, packetLengthField.size + packetLengthField.value);
      // TODO : Slice as early as possible to avoid processing same data twice.
      incomingBuffer = incomingBuffer.slice(packetLengthField.size + packetLengthField.value);
      if(self.compressionThreshold == -2) {
        afterParse(null, parsePacketData(buf, self.state, self.isServer, self.packetsToParse));
      } else {
        parseNewStylePacket(buf, self.state, self.isServer, self.packetsToParse, afterParse);
      }
    }
  }

  self.socket = socket;
  if(self.socket.setNoDelay)
    self.socket.setNoDelay(true);
  var incomingBuffer = new Buffer(0);
  self.socket.on('data', function(data) {
    if(self.encryptionEnabled) data = new Buffer(self.decipher.update(data), 'binary');
    incomingBuffer = Buffer.concat([incomingBuffer, data]);
    prepareParse()
  });

  self.socket.on('connect', function() {
    self.emit('connect');
  });

  self.socket.on('error', onError);
  self.socket.on('close', endSocket);
  self.socket.on('end', endSocket);
  self.socket.on('timeout', endSocket);

  function onError(err) {
    self.emit('error', err);
    endSocket();
  }

  var ended = false;

  function endSocket() {
    if(ended) return;
    ended = true;
    self.socket.removeListener('close', endSocket);
    self.socket.removeListener('end', endSocket);
    self.socket.removeListener('timeout', endSocket);
    self.emit('end', self._endReason);
  }
};

Client.prototype.end = function(reason) {
  this._endReason = reason;
  this.socket.end();
};

Client.prototype.write = function(packetId, params) {
  if(Array.isArray(packetId)) {
    if(packetId[0] !== this.state)
      return false;
    packetId = packetId[1];
  }
  if(typeof packetId === "string")
    packetId = packetIds[this.state][this.isServer ? "toClient" : "toServer"][packetId];
  var that = this;

  var finishWriting = function(err, buffer) {
    if(err) {
      console.log(err);
      throw err; // TODO : Handle errors gracefully, if possible
    }
    var packetName = packetNames[that.state][that.isServer ? "toClient" : "toServer"][packetId];
    debug("writing packetId " + that.state + "." + packetName + " (0x" + packetId.toString(16) + ")");
    debug(params);
    var out = that.encryptionEnabled ? new Buffer(that.cipher.update(buffer), 'binary') : buffer;
    that.socket.write(out);
    return true;
  }

  var buffer = createPacketBuffer(packetId, this.state, params, this.isServer);
  if(this.compressionThreshold >= 0 && buffer.length >= this.compressionThreshold) {
    debug("Compressing packet");
    compressPacketBuffer(buffer, finishWriting);
  } else if(this.compressionThreshold >= -1) {
    debug("New-styling packet");
    newStylePacket(buffer, 0, finishWriting);
  } else {
    debug("Old-styling packet");
    oldStylePacket(buffer, finishWriting);
  }
};

// TODO : Perhaps this should only accept buffers without length, so we can
// handle compression ourself ? Needs to ask peopl who actually use this feature
// like @deathcap
Client.prototype.writeRaw = function(buffer) {
  var self = this;

  var finishWriting = function(error, buffer) {
    if(error)
      throw error; // TODO : How do we handle this error ?
    var out = self.encryptionEnabled ? new Buffer(self.cipher.update(buffer), 'binary') : buffer;
    self.socket.write(out);
  };
  if(this.compressionThreshold >= 0 && buffer.length >= this.compressionThreshold) {
    compressPacketBuffer(buffer, finishWriting);
  } else if(this.compressionThreshold >= -1) {
    newStylePacket(buffer, 0, finishWriting);
  } else {
    oldStylePacket(buffer, finishWriting);
  }
};