/// <summary>
/// Parse bytes for a CONNECT message
/// </summary>
/// <param name="fixedHeaderFirstByte">First fixed header byte</param>
/// <param name="protocolVersion">Protocol Version</param>
/// <param name="channel">Channel connected to the broker</param>
/// <returns>CONNECT message instance</returns>
public static MqttConnectMessage Parse(byte fixedHeaderFirstByte, byte protocolVersion, IMqttNetworkChannel channel)
{
byte[] buffer;
int index = 0;
int protNameUtf8Length;
byte[] protNameUtf8;
bool isUsernameFlag;
bool isPasswordFlag;
int clientIdUtf8Length;
byte[] clientIdUtf8;
int willTopicUtf8Length;
byte[] willTopicUtf8;
int willMessageUtf8Length;
byte[] willMessageUtf8;
int usernameUtf8Length;
byte[] usernameUtf8;
int passwordUtf8Length;
byte[] passwordUtf8;
MqttConnectMessage msg = new MqttConnectMessage();
// get remaining length and allocate buffer
int remainingLength = MqttMessage.DecodeRemainingLength(channel);
buffer = new byte[remainingLength];
// read bytes from socket...
channel.Receive(buffer);
// protocol name
protNameUtf8Length = ((buffer[index++] << 8) & 0xFF00);
protNameUtf8Length |= buffer[index++];
protNameUtf8 = new byte[protNameUtf8Length];
Array.Copy(buffer, index, protNameUtf8, 0, protNameUtf8Length);
index += protNameUtf8Length;
msg.protocolName = new string(Encoding.UTF8.GetChars(protNameUtf8));
// [v3.1.1] wrong protocol name
if (!msg.protocolName.Equals(PROTOCOL_NAME_V3_1) && !msg.protocolName.Equals(PROTOCOL_NAME_V3_1_1))
{
throw new MqttClientException(MqttClientErrorCode.InvalidProtocolName);
}
// protocol version
msg.protocolVersion = buffer[index];
index += PROTOCOL_VERSION_SIZE;
// connect flags
// [v3.1.1] check lsb (reserved) must be 0
if ((msg.protocolVersion == PROTOCOL_VERSION_V3_1_1) &&
((buffer[index] & RESERVED_FLAG_MASK) != 0x00))
{
throw new MqttClientException(MqttClientErrorCode.InvalidConnectFlags);
}
isUsernameFlag = (buffer[index] & USERNAME_FLAG_MASK) != 0x00;
isPasswordFlag = (buffer[index] & PASSWORD_FLAG_MASK) != 0x00;
msg.willRetain = (buffer[index] & WILL_RETAIN_FLAG_MASK) != 0x00;
msg.willQosLevel = (byte)((buffer[index] & WILL_QOS_FLAG_MASK) >> WILL_QOS_FLAG_OFFSET);
msg.willFlag = (buffer[index] & WILL_FLAG_MASK) != 0x00;
msg.cleanSession = (buffer[index] & CLEAN_SESSION_FLAG_MASK) != 0x00;
index += CONNECT_FLAGS_SIZE;
// keep alive timer
msg.keepAlivePeriod = (ushort)((buffer[index++] << 8) & 0xFF00);
msg.keepAlivePeriod |= buffer[index++];
// client identifier [v3.1.1] it may be zero bytes long (empty string)
clientIdUtf8Length = ((buffer[index++] << 8) & 0xFF00);
clientIdUtf8Length |= buffer[index++];
clientIdUtf8 = new byte[clientIdUtf8Length];
Array.Copy(buffer, index, clientIdUtf8, 0, clientIdUtf8Length);
index += clientIdUtf8Length;
msg.clientId = new string(Encoding.UTF8.GetChars(clientIdUtf8));
// [v3.1.1] if client identifier is zero bytes long, clean session must be true
if ((msg.protocolVersion == PROTOCOL_VERSION_V3_1_1) && (clientIdUtf8Length == 0) && (!msg.cleanSession))
{
throw new MqttClientException(MqttClientErrorCode.InvalidClientId);
}
// will topic and will message
if (msg.willFlag)
{
willTopicUtf8Length = ((buffer[index++] << 8) & 0xFF00);
willTopicUtf8Length |= buffer[index++];
willTopicUtf8 = new byte[willTopicUtf8Length];
Array.Copy(buffer, index, willTopicUtf8, 0, willTopicUtf8Length);
index += willTopicUtf8Length;
msg.willTopic = new string(Encoding.UTF8.GetChars(willTopicUtf8));
willMessageUtf8Length = ((buffer[index++] << 8) & 0xFF00);
willMessageUtf8Length |= buffer[index++];
willMessageUtf8 = new byte[willMessageUtf8Length];
Array.Copy(buffer, index, willMessageUtf8, 0, willMessageUtf8Length);
index += willMessageUtf8Length;
msg.willMessage = new string(Encoding.UTF8.GetChars(willMessageUtf8));
}
// username
if (isUsernameFlag)
{
usernameUtf8Length = ((buffer[index++] << 8) & 0xFF00);
usernameUtf8Length |= buffer[index++];
usernameUtf8 = new byte[usernameUtf8Length];
Array.Copy(buffer, index, usernameUtf8, 0, usernameUtf8Length);
index += usernameUtf8Length;
msg.username = new string(Encoding.UTF8.GetChars(usernameUtf8));
}
// password
if (isPasswordFlag)
{
passwordUtf8Length = ((buffer[index++] << 8) & 0xFF00);
passwordUtf8Length |= buffer[index++];
passwordUtf8 = new byte[passwordUtf8Length];
Array.Copy(buffer, index, passwordUtf8, 0, passwordUtf8Length);
index += passwordUtf8Length;
msg.password = new string(Encoding.UTF8.GetChars(passwordUtf8));
}
return(msg);
}
/// <summary>
/// Initializes a new instance of the <see cref="MqttConnectEventArgs"/> class.
/// </summary>
/// <param name="msg">CONNECT message received from client</param>
public MqttConnectEventArgs(MqttConnectMessage msg)
{
this.Message = msg;
}