The answers to these questions vary depending on whether you are using a stream socket (SOCK_STREAM) or a datagram socket (SOCK_DGRAM) – within TCP/IP, the former corresponds to TCP and the latter to UDP. How do you know how big to make the buffer passed to recv()? SOCK_STREAM: It doesn’t really matter too much. If … Read more
It depends on the protocol. Some protocols like UDP send messages and exactly 1 message is returned per recv. Assuming you are talking about TCP specifically, there are several factors involved. TCP is stream oriented and because of things like the amount of currently outstanding send/recv data, lost/reordered packets on the wire, delayed acknowledgement of … Read more
Your mySQL connections are timing out before your connection pool recognizes them. There are multiple ways to fix this: Increase the timeout value in mysql config file (my.ini) Reduce the idle time in your connection pool, so that it will discard the connection before mysql will close it Add a validate connection query in your … Read more
The answer by Larry Hastings has some great general advice about sockets, but there are a couple of mistakes as it pertains to how the recv(bufsize) method works in the Python socket module. So, to clarify, since this may be confusing to others looking to this for help: The bufsize param for the recv(bufsize) method … Read more
In the case of a non blocking socket that has no data available, recv will throw the socket.error exception and the value of the exception will have the errno of either EAGAIN or EWOULDBLOCK. Example: import sys import socket import fcntl, os import errno from time import sleep s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect((‘127.0.0.1’,9999)) fcntl.fcntl(s, fcntl.F_SETFL, … Read more
This is a very bad idea. Binary data should always be sent in a way that: Handles different endianness Handles different padding Handles differences in the byte-sizes of intrinsic types Don’t ever write a whole struct in a binary way, not to a file, not to a socket. Always write each field separately, and read … Read more