recv and recvfrom, socket programming using python

Question

i am new to python and new to socket programming as well.

I am confused about about socket.recvfrom() and socket.recv()

I understan

Answer 1

I think people usually use recvfrom for UDP. Because in TCP, once the connection gets established, the address information does not change and hence recvfrom always returns None for connection-information field.

And in the above code, it will error out in this line:

message2, clientAddress2 = serverSocketTCP.recv(1024)

Because: recvfrom() returns (data, connection_information), and recv() returns just the data. So it will raise ValueError because you are trying to unpack a non-tuple value.

1024, or 2048 just defines the buffer size but it does not wait for exactly that much amount of data before returning. For example:

#One side, 'receiver' is a socket
receiver.recv(2048)

#Second side, 'sender' is a socket
sender.send('abc'.encode('utf-8'))

Clearly the data sent by 'sender' is much less than 2048 bytes but the 'recv' call will return immediately after it receives the data sent to it from 'sender'