Question

I found the code here: Send a file through sockets in Python (the selected answer)

But I will jut post it here again..

server.py
import socket
import sys
s = socket.socket()
s.bind(("localhost",9999))
s.listen(10) 
while True:
    sc, address = s.accept()

    print address
    i=1
    f = open('file_'+ str(i)+".txt",'wb') #open in binary
    i=i+1
    while (True):       
        l = sc.recv(1024)
        while (l):
            print l #<--- i can see the data here
            f.write(l) #<--- here is the issue.. the file is blank
            l = sc.recv(1024)
    f.close()

    sc.close()

s.close()



client.py

import socket
import sys

s = socket.socket()
s.connect(("localhost",9999))
f=open ("test.txt", "rb") 
l = f.read(1024)
while (l):
    print l
    s.send(l)
    l = f.read(1024)
s.close()

On server code, the print l line prints the file contents..so that means that content is being transferred..
but then the file is empty??

what am i missing?
thanks

Answer 1

You are probably trying to inspect the file while the program is running. The file is being buffered, so you likely won’t see any output in it until the f.close() line is executed, or until a large amount of data is written. Add a call to f.flush() after the f.write(l) line to see output in real time. Note that it will hurt performance somewhat.