function connect()

in digital-shadow/demo-car/js/aws-iot/aws-iot.js [9884:10024]

• 112 lines of code
• 48 McCabe index (conditional complexity)

function connect(opts) {
  var opts = opts || {}
    , protocolId = opts.protocolId || 'MQTT'
    , protocolVersion = opts.protocolVersion || 4
    , will = opts.will
    , clean = opts.clean
    , keepalive = opts.keepalive || 0
    , clientId = opts.clientId || ""
    , username = opts.username
    , password = opts.password

  if (clean === undefined) {
    clean = true
  }

  var length = 0

  if (!protocolId ||
     (typeof protocolId !== "string" && !Buffer.isBuffer(protocolId))) {
    throw new Error('Invalid protocol id')
  } else {
    length += protocolId.length + 2
  }

  if (!protocolVersion ||
      'number' !== typeof protocolVersion ||
      protocolVersion > 255 ||
      protocolVersion < 0) {

    throw new Error('Invalid protocol version')
  } else {
    length += 1
  }

  if ((typeof clientId === "string" || Buffer.isBuffer(clientId)) &&
     (clientId || protocolVersion == 4) &&
     (clientId || clean)) {

    length += clientId.length + 2
  } else {

    if(protocolVersion < 4) {

      throw new Error('clientId must be supplied before 3.1.1');
    }

    if(clean == 0) {

      throw new Error('clientId must be given if cleanSession set to 0');
    }
  }

  if ('number' !== typeof keepalive ||
      keepalive < 0 ||
      keepalive > 65535) {
    throw new Error('Invalid keepalive')
  } else {
    length += 2
  }

  length += 1

  if (will) {
    if ('object' !== typeof will) {
      throw new Error('Invalid will')
    }
    if (!will.topic || 'string' !== typeof will.topic) {
      throw new Error('Invalid will topic')
    } else {
      length += Buffer.byteLength(will.topic) + 2
    }

    if (will.payload && will.payload) {
      if (will.payload.length >= 0) {
        if ('string' === typeof will.payload) {
          length += Buffer.byteLength(will.payload) + 2
        } else {
          length += will.payload.length + 2
        }
      } else {
        throw new Error('Invalid will payload')
      }
    } else {
      length += 2
    }
  }

  if (username) {
    if (username.length) {
      length += Buffer.byteLength(username) + 2
    } else {
      throw new Error('Invalid username')
    }
  }

  if (password) {
    if (password.length) {
      length += byteLength(password) + 2
    } else {
      throw new Error('Invalid password')
    }
  }

  var buffer = new Buffer(1 + calcLengthLength(length) + length)
    , pos = 0

  buffer.writeUInt8(protocol.codes['connect'] << protocol.CMD_SHIFT, pos++, true)

  pos += writeLength(buffer, pos, length)

  pos += writeStringOrBuffer(buffer, pos, protocolId)
  buffer.writeUInt8(protocolVersion, pos++, true)

  var flags = 0
  flags |= username ? protocol.USERNAME_MASK : 0
  flags |= password ? protocol.PASSWORD_MASK : 0
  flags |= (will && will.retain) ? protocol.WILL_RETAIN_MASK : 0
  flags |= (will && will.qos) ?
    will.qos << protocol.WILL_QOS_SHIFT : 0
  flags |= will ? protocol.WILL_FLAG_MASK : 0
  flags |= clean ? protocol.CLEAN_SESSION_MASK : 0

  buffer.writeUInt8(flags, pos++, true)

  pos += writeNumber(buffer, pos, keepalive)

  pos += writeStringOrBuffer(buffer, pos, clientId)

  if (will) {
  	pos += writeString(buffer, pos, will.topic)
    pos += writeStringOrBuffer(buffer, pos, will.payload)
  }

  if (username)
    pos += writeStringOrBuffer(buffer, pos, username)

  if (password)
    pos += writeStringOrBuffer(buffer, pos, password)

  return buffer
}