How do you read from stdin in python from a pipe which has no ending

Question

I've problem to read from Standard input or pipe in python when the pipe is from a "open" (do not know right name) file.

I have as example pipetest.py:

import sys import time k = 0 try:    for line in sys.stdin:       k = k + 1       print line except KeyboardInterrupt:    sys.stdout.flush()    pass print k 

I run a program that have continues output and Ctrl+c after a while

$ ping 127.0.0.1 | python pipetest.py ^C0 

I get no output. But if I go via an ordinary file it works.

$ ping 127.0.0.1 > testfile.txt 

this is ended by Ctrl+c after a short while

$ cat testfile.txt |  python pipetest.py  PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data. 64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.017 ms 64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.015 ms 64 bytes from 127.0.0.1: icmp_seq=3 ttl=64 time=0.014 ms 64 bytes from 127.0.0.1: icmp_seq=4 ttl=64 time=0.013 ms 64 bytes from 127.0.0.1: icmp_seq=5 ttl=64 time=0.012 ms  --- 127.0.0.1 ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 3998ms rtt min/avg/max/mdev = 0.012/0.014/0.017/0.003 ms 10 

How do I do to get any output before the program ends, in this case ping has ended?

Answer 1

Try this:

import sys import time k = 0 try:     buff = ''     while True:         buff += sys.stdin.read(1)         if buff.endswith('\n'):             print buff[:-1]             buff = ''             k = k + 1 except KeyboardInterrupt:    sys.stdout.flush()    pass print k