network-programming

问题 Why doesn't the recv system call just block until all the data is received? Every time I have seen a recv call, it's in a while loop which just keeps on calling recv until all the data is there. Why not just have recv block in the first place? 回答1: You can request that recv block until all data is received, with the MSG_WAITALL flag. However, if a signal arrives, a system call that has performed some work (ie, receiving part of the data) cannot be automatically restarted to receive the rest.

问题 Why doesn't the recv system call just block until all the data is received? Every time I have seen a recv call, it's in a while loop which just keeps on calling recv until all the data is there. Why not just have recv block in the first place? 回答1: You can request that recv block until all data is received, with the MSG_WAITALL flag. However, if a signal arrives, a system call that has performed some work (ie, receiving part of the data) cannot be automatically restarted to receive the rest.

问题 Why doesn't the recv system call just block until all the data is received? Every time I have seen a recv call, it's in a while loop which just keeps on calling recv until all the data is there. Why not just have recv block in the first place? 回答1: You can request that recv block until all data is received, with the MSG_WAITALL flag. However, if a signal arrives, a system call that has performed some work (ie, receiving part of the data) cannot be automatically restarted to receive the rest.

问题 I have a live video chat application and I use a TURN server which supports STUN/TURN and both UPD/TCP transmission. Sometimes users can be connected to the network which blocks that much ports and protocols that WebRTC connection just cannot happen (usually those are corporate networks). I would like to check if a WebRTC connection is possible before users try to connect to each other (actually, perform a technical check ). How can I do it? Ideas I have in my head: Try to download a hosted

问题 I need to 'disconnect' a UDP socket in python(and not close it!). Is it possible to do the equivalent of: int disconnect_udp_sock(int fd) { struct sockaddr_in sin; memset((char *)&sin, 0, sizeof(sin)); sin.sin_family = AF_UNSPEC; return (connect(fd, (struct sockaddr *)&sin, sizeof(sin))); } taken from here in python without interfacing the function? 回答1: Looking at socketmodule.c in the Python 2.7 sources, it doesn't seem possible. You really need to define and call the C function above. 来源：

问题 I need to 'disconnect' a UDP socket in python(and not close it!). Is it possible to do the equivalent of: int disconnect_udp_sock(int fd) { struct sockaddr_in sin; memset((char *)&sin, 0, sizeof(sin)); sin.sin_family = AF_UNSPEC; return (connect(fd, (struct sockaddr *)&sin, sizeof(sin))); } taken from here in python without interfacing the function? 回答1: Looking at socketmodule.c in the Python 2.7 sources, it doesn't seem possible. You really need to define and call the C function above. 来源：

问题 Minimal demonstration example: import asyncio async def main(): c1_reader, c1_writer = await asyncio.open_connection(host='google.com', port=80) c1_socket = c1_writer.get_extra_info('socket') c1_socket.close() c2_reader, c2_writer = await asyncio.open_connection(host='google.com', port=80) asyncio.run(main()) Running this program gives this error: $ python3 asyncio_fd_used.py Traceback (most recent call last): File "/opt/local/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7

问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 4 years ago . Improve this question Is there a way that Python 3 can tell me about network state of my machine? Specifically: The SSID that my machine is currently connected to. Internet connectivity state Uptime/Downtime Most important for my use case is the SSID, but the others are nice to

问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 4 years ago . Improve this question Is there a way that Python 3 can tell me about network state of my machine? Specifically: The SSID that my machine is currently connected to. Internet connectivity state Uptime/Downtime Most important for my use case is the SSID, but the others are nice to

问题 I am new to socket programming. My sockets work with localhost or local ip. But why can't I create a socket server with my public ip? When I try to do this in python, it complains "cannot assign requested address". import socket s=socket.socket() host="address" port=5000 s.bind((host, port)) s.listen(5) while True: c, addr=s.accept() result=c.recv(1024) print(result.decode('utf-8')) c.send(""" test """.encode('utf-8')) c.close() My IP I got from this website:http://whatismyip.host/ 回答1: A