ProtocolBuffer missing required fields but they are filled in - c++

Question

I'm creating a client-server environment and I have just implemented UDP. I was only working and testing with a TCP connection before and then everything worked fine.
Now, if I try to send packets to the server from the client I get an error that some required fields weren't filled in which they cleary are (see code later on). I don't really have an idea why this is happening since it worked before.
One thing I guess that can be important, the receive method of the TCP socket and the UDP socket are on a different thread. (the server uses multithreading)
So, Here's some code:
The TCP Receive (part of it):
iResult = recv(m_Connections[t].socket, m_TCPRecvbuf, m_TCPRecvbuflen, 0);
// Deserialize the data
MessageID* receivedData = new MessageID();
receivedData->ParseFromArray((char*)m_TCPRecvbuf, receivedData->packetsize());
I did the size in ParseFromArray with iResult at first (which seemed to work) but I changed it so I put the size in the data itself. (which has now become receivedData->packetsize())
The UDP Receive (part of it) on a different thread:
iResult = recvfrom(m_UDPListenSocket, m_UDPRecvbuf, m_UDPRecvbuflen, 0, (struct sockaddr *)&address, &addrlen);
// Deserialize the data
MessageID* receivedData = new MessageID();
receivedData->ParseFromArray((char*)m_TCPRecvbuf, receivedData->packetsize());
This is the first creation of a packet that gets sent:
void NetworkInterface::SendLoginData(string username, string password)
{
// Create base message
// -----------------
MessageID message;
message.set_type(MessageID::Type::MessageID_Type_LOGINDATA);
// Create logindata
// ------------------
LoginData data = message.logindata();
data.set_username(username);
data.set_password(password);
// Create packet
// ----------------------
int size = message.ByteSize();
void* buffer = malloc(size);
message.set_packetsize(size);
message.set_clientid(0);
message.SerializeToArray(buffer, size);
if (m_pTCPNetworkingObject != nullptr)
m_pTCPNetworkingObject->SendData(buffer, size);
else
printf("NetworkInterface [ERROR]: No connection data was found. Please use CreateConnectionObject() first!\n");
}
The error that it gives after this is that the Type, ClientID and packetSize fields are missing but you can see those are filled in
Here's the SendData() method:
void SendData(void* data, int size)
{
// SEND DATA
int iResult;
iResult = send(m_TCPConnectSocket, (char*)data, size, 0 );
if (iResult == SOCKET_ERROR)
printf("send failed with error: %d\n", WSAGetLastError());
}
This is about all the information I can give. Any help is appreciated.

Answer 1

There are multiple problems:
1) deserialization:
receivedData->ParseFromArray((char*)m_TCPRecvbuf, receivedData->packetsize());
You call packetSize before it gets filled by parseFromArray, use iResult instead.
2) LoginData:
LoginData data = message.logindata();
This reads a copy of messages empty loginData, you never change message. Use
LoginData* data = message.mutable_logindata();
to get a pointer to messages loginData an modify it within message.
3) serialization:
int size = message.ByteSize();
void* buffer = malloc(size);
this uses the size of an empty message (since loginData is not set). So you never send the full message.
You have to call ByteSize() after all properties are set. This contradicts with the packetSize within your message.
Since you can't use it for deserialization anyway (see 1) you should remove this entry.