Python receive data from tcp socket

Question

Say we have:

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
data = s.recv(1024)

what if we receive messages, but the last message is not 1024 bytes. Will we still receive it or will we wait forever? How to receive the last message if it doesn't fill up a buffer or what not?

In Node.js, streams have "flush" behavior, where flush is called internally (not sure when), looks like this: https://github.com/ORESoftware/json-parser/blob/master/src/index.ts

What's unclear about the [documentation](https://docs.python.org/3/library/socket.html)? ("The maximum amount of data to be received at once is specified by `bufsize`." ) — molbdnilo, Mar 10 '19 at 09:19
@zwer yeah that's what I am concerned about...can you add an answer explaining how to mitigate that? — Alexander Mills, Mar 10 '19 at 09:22
@AlexanderMills - Check [this answer](https://stackoverflow.com/a/16745561). — zwer, Mar 10 '19 at 09:25

score 0 · Answer 1 · answered Mar 10 '19 at 09:23

It is not 1024

Can mean a lot of things, it can mean:

It's smaller than 1024 bytes: you will receive the partial data anyway this time, and if there is other things to be received it will come when you do another recv(..)
It's bigger than 1024 bytes: you will receive 1024 bytes of the data coming, the rest is buffered waiting for another trigger to recv(..)
There is no receive data: recv(..) will wait until there is a recv data, can be changed by setting a timeout

Python receive data from tcp socket

1 Answers1