Python 3 writing to a pipe -

i'm trying write code put data pipe, , i'd solution python 2.6+ , 3.x compatible. example:

from __future__ import print_function  import subprocess import sys  if(sys.version_info > (3,0)):     print ("using python3")     def raw_input(*prmpt):         """in python3, input behaves raw_input in python2"""         return input(*prmpt)  class pipe(object):     def __init__(self,openstr):         self.gnuprocess=subprocess.popen(openstr.split(),                                          stdin=subprocess.pipe)      def putinpipe(self,mystr):         print(mystr, file=self.gnuprocess.stdin)  if(__name__=="__main__"):     print("this simple program echoes (control-d exit)")     p=pipe("cat -")     while(true):         try:             inpt=raw_input()         except eoferror:             break         print('putting in pipe:%s'%inpt)         p.putinpipe(inpt) 

the above code works on python 2.6 fails in python 3.2 (note above code generated 2to3 -- messed little make python 2.6 compatible.)

traceback (most recent call last):   file "test.py", line 30, in <module>    p.putinpipe(inpt)   file "test.py", line 18, in putinpipe    print(mystr, file=self.gnuprocess.stdin) typeerror: 'str' not support buffer interface 

i've tried bytes function (e.g. print(bytes(mystr,'ascii')) suggested here, typeerror: 'str' not support buffer interface doesn't seem work. suggestions?

the print function converts arguments string representation, , outputs string representation given file. string representation of type str both, python 2.x , python 3.x. in python 3.x, pipe accepts bytes or buffer objects, won't work. (even if pass bytes object print, converted str.)

a solution use write() method instead (and flushing after writing):

self.gnuprocess.stdin.write(bytes(mystr + "\n", "ascii")) self.gnuprocess.stdin.flush()