Python套接字文件服务器

Question

There are many questions on stackoverflow discussing the client server model for sending and receiving files with python.

My question is a little different in that I want to create a python 'server socket', which listens on some port and then pushes a file to whoeever connects to that port.

I'm using the code below, however when I connect to the socket I do not receive the file.

s = socket.socket()        
s.bind((socket.gethostname(), 2048))
f = open('/tmp/test','rb')
s.listen(5)           
while True:
    c, addr = s.accept()
    print 'Connection from ', addr
    l = f.read(1024)
    while (l):
       print "Sending"
       s.send(l)
       l = f.read(1024)
    f.close()
    s.shutdown(socket.SHUT_WR)
    c.close()

Can anyone explain why this doesn't work?

Answer 1

You have four problems here.

s.bind((socket.gethostname(), 2048))

gethostname() returns the name of your machine, not an address you can bind to. If you want to bind to all interfaces, just like s.bind(('', 2048)) .

s.send(l)

You're trying to send on the listener socket, not the connected client socket. Use c.send(l) . You make the same mistake later by calling s.shutdown instead of c.shutdown ; you need it to fix it there, too.

s.send(l)

You're using send instead of sendall , and not checking the return value. You'll usually get away with this when your buffers are this small, but why accept "usually"?

f.close()

Since you only open the file once, before accepting the first connection, and then you close it for each connection, the second client is just going to cause an exception as you try to read from a closed file. Either move the open into the loop, or replace the f.close() with f.seek(0) .

Answer 2

You are trying to send on the server socket s , while you need to do that on the newly accepted client socket c .

Listening socket ( s here) can only accept new connections. By definition it does not have the other end to exchange data with.