qws/out/release/lib/frame.js

An HTML5 Web Sockets Server Module

// Generated by CoffeeScript 1.6.3
var Frame, crypto, inflate, opcodes, opcodesMap, pack, unmask, unpack, zlib;

zlib = require('zlib');

crypto = require('crypto');

unmask = function(data, mask) {
  var d1, i, mod, _i, _ref;
  d1 = new Buffer(data.length);
  for (i = _i = 0, _ref = data.length; _i < _ref; i = _i += 4) {
    d1[i + 3] = data[i + 3] ^ mask[3];
    d1[i + 2] = data[i + 2] ^ mask[2];
    d1[i + 1] = data[i + 1] ^ mask[1];
    d1[i] = data[i] ^ mask[0];
  }
  mod = data.length % 4;
  if (mod > 0) {
    d1[i] = data[i] ^ mask[0];
  }
  if (mod > 1) {
    d1[i + 1] = data[i + 1] ^ mask[0];
  }
  if (mod > 2) {
    d1[i + 2] = data[i + 2] ^ mask[0];
  }
  return d1;
};

inflate = function(frame, stream, cb) {
  var b, len;
  if (!frame.rsv1) {
    return cb(null, frame);
  }
  stream.once('error', function(err) {
    return cb(err);
  });
  stream.once('data', function(data) {
    frame.data = data;
    return cb(null, frame);
  });
  len = frame.data.length;
  b = new Buffer(len + 4);
  b[len] = 0x00;
  b[len + 1] = 0x00;
  b[len + 2] = 0xff;
  b[len + 3] = 0xff;
  frame.data.copy(b);
  stream.write(b);
};

opcodes = ['continue', 'text', 'binary', 'non-control 3', 'non-control 4', 'non-control 5', 'non-control 6', ' non-control 7', 'close', 'ping', 'pong', 'control B', 'control C', 'control D', 'control E', ' control F'];

unpack = function(buf, frame) {
  var b1, b2, idx;
  if (frame) {
    if (buf.length > frame.left) {
      frame.data.push(buf.slice(0, frame.left));
      buf = buf.slice(frame.left);
      frame.left = 0;
    } else {
      frame.data.push(buf);
      frame.left -= buf.length;
      buf = null;
    }
  } else {
    b1 = buf[0];
    b2 = buf[1];
    frame = {
      fin: 0 < (b1 & 0x80),
      rsv1: 0 < (b1 & 0x40),
      rsv2: 0 < (b1 & 0x20),
      rsv3: 0 < (b1 & 0x10),
      opcode: opcodes[b1 & 0xf],
      mask: 0 < (b2 & 128),
      length: b2 & 127,
      data: [],
      left: 0,
      done: false
    };
    idx = 2;
    if (frame.length > 0) {
      if (frame.length === 126) {
        frame.length = buf.readUInt16BE(2, true);
        idx = 4;
      } else if (frame.length === 127) {
        frame.length = buf.readUInt32BE(2, true) * 0xffffffff + buf.readUInt32BE(6, true);
        idx = 10;
      }
      if (frame.mask) {
        frame.maskKey = buf.slice(idx, idx += 4);
      }
      frame.data.push(buf.slice(idx, idx += frame.length));
      frame.left = frame.length - frame.data[0].length;
    }
    if (buf.length > idx) {
      buf = buf.slice(idx);
    } else {
      buf = null;
    }
  }
  if (frame.left === 0) {
    if (frame.length > 0) {
      frame.data = Buffer.concat(frame.data);
      if (frame.mask && frame.length > 0) {
        frame.data = unmask(frame.data, frame.maskKey);
      }
    } else {
      frame.data = null;
    }
    frame.done = true;
    delete frame.left;
  }
  return [frame, buf];
};

pack = function(frame, data) {
  var b1, b2, buf, dlen, lenFix, plen;
  b1 = opcodesMap[frame.opcode];
  if (frame.rsv3) {
    b1 |= 0x10;
  }
  if (frame.rsv2) {
    b1 |= 0x20;
  }
  if (frame.rsv1) {
    b1 |= 0x40;
  }
  if (frame.fin) {
    b1 |= 0x80;
  }
  dlen = data != null ? data.length : 0;
  if (dlen > 0xffff) {
    lenFix = 10;
    plen = 127;
  } else if (dlen >= 126) {
    lenFix = 4;
    plen = 126;
  } else {
    lenFix = 2;
    plen = dlen;
  }
  if (dlen === 0) {
    frame.mask = false;
  }
  b2 = plen;
  if (frame.mask) {
    b2 |= 0x80;
    buf = new Buffer(lenFix + 4 + dlen);
    frame.maskKey = crypto.randomBytes(4);
    frame.maskKey.copy(buf, lenFix);
    lenFix += 4;
    data = unmask(data, frame.maskKey);
  } else {
    buf = new Buffer(lenFix + dlen);
  }
  buf[0] = b1;
  buf[1] = b2;
  if (dlen > 0xffff) {
    buf.writeUInt32BE(Math.floor(dlen / 0xffffffff), 2, true);
    buf.writeUInt32BE(dlen % 0xffffffff, 6, true);
  } else if (dlen >= 126) {
    buf.writeUInt16BE(dlen, 2, true);
  }
  if (dlen > 0) {
    data.copy(buf, lenFix);
  }
  return buf;
};

opcodesMap = {
  'continue': 0,
  'text': 1,
  'binary': 2,
  'close': 8,
  'ping': 9,
  'pong': 10
};

Frame = (function() {
  function Frame(prop) {
    var k;
    this.minDeflateLength = 32;
    this.opcode = 'text';
    this.fin = false;
    this.rsv1 = false;
    this.rsv2 = false;
    this.rsv3 = false;
    this.mask = false;
    this.data = null;
    for (k in prop) {
      if (prop) {
        this[k] = prop[k];
      }
    }
  }

  Frame.prototype.pack = function(deflate, cb) {
    var data,
      _this = this;
    if (opcodesMap[this.opcode] == null) {
      return cb(new Error("Opcode Not Found \"" + this.opcode + "\""));
    }
    if (this.data == null) {
      data = null;
    } else if (this.data instanceof Buffer) {
      data = this.data;
    } else {
      data = new Buffer(typeof this.data === 'string' ? this.data : this.data.toString());
    }
    if (deflate && data.length < this.minDeflateLength) {
      deflate = false;
    }
    if (deflate) {
      this.rsv1 = true;
      zlib.deflateRaw(data, function(err, data) {
        cb(null, pack(_this, data));
      });
    } else {
      this.rsv1 = false;
      cb(null, pack(this, data));
    }
  };

  return Frame;

})();

exports.unpack = unpack;

exports.inflate = inflate;

exports.Frame = Frame;