Python Subprocess module
hey folks, A simple question hopefully. despite all my searching I have not found a satisfactory response. The goal. Interact with a command line program. Simple enough, but the key is INTERACT. I tried the shell and comand approaches but that initiates, it does not allow interaction with the programs. So then I went with Popen and such... which then led to the subprocess module. I can create the object and read a few lines of output. but if I go too far then the program hangs. the number of lines will differ depandening on many function including the format of an input file so I can;t hardcode how many lines to read. I want to read all of STDOUT without failing because I went out of range. next I want to read the final line of the output because it tells me what is required for the next line of input. I am supposed to be able to entre 'y' and return for the program to continue if I agree with what I see in the stdout. A problem exists though that I have tried 'y' 'y\n' 'y\r' and nothing seems to get the program going again for I still cant; read past the same point in the standard output. then I have to kill and start over. So the next approach included looking at Pexpect, which got realy confusing realy fast and despite running fedora core and python 2.4.4 I would like my application to be cross platform and there is no Pexpect for Windows That I can see. I have checked out many mailing lists and posts and tutorials but they all admit to not be samples of complex interactivity. I guess I am having that special case. ASPN Python cookbok provided some code for a new Popen Class that allows for interaction but I don't think I need to go that root I am essentialy trying to build and Python wrapper for a coomand line program that i want to build a GUI around. Any links or suggestions would be great. Unfortunaetly I don't understand that abstract concepts in the manual reference. I am fresh in the python world and find examples better than technical abstracts. Cheers -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Subprocess module
On Jul 13, 7:50 pm, Dan Stromberg - Datallegro <[EMAIL PROTECTED]> wrote: > You could start up a pty and do your own Pexpect-like thing, using > read/readline/write. > > However, this may not be portable to windows. Maybe if you get the python > that comes with cygwin, or build your own python under the cygwin thanks for the suggestion. I will follow up on Noah's pexpect sugestion bellow. thanks for the input, cross platform is key with low overhead. -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Subprocess module
send keys for the p.c. you can use a try: except: concept and on the > windows platform there is also a way to use autoit in python using > pywin. thanks for the uggestion about sendkeys. I might be able to build that into the wrapper. So you're sugesting: NIX = Pexpect WINDOZE = sendkeys Correct? -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Subprocess module
Thanks for your response. It;s good to see you're promtoing Pexpect. I was actualy wokring on a project at work that could have used Pexpect to automate the creation of maps by tieing togethr a bunch of processes through SSH and Pexpect looked like the money shot. however it was enough of a battle to bring Python into the game since it is government that bringing CYGWIN was a battle not worth fighting. Which is unfortunate because I think Pexpect was exactly what we needed in that case > > You need Pexpect. > > There is nothing you can do about this when using a pipe. > This is because stdio will change the type of buffering when sending > stdout and stderr to a pipe. From the client side there is no way you > can change the buffer mode (you CAN change the mode, but it only > changes > it on YOUR side of the pipe -- not your child application's side). I obviously lack skills and understanding in many aspects of programming. After all I'm a geographer / recreologist not a comp-sci professional. I understand the CONCEPT of pipes but don't know how to use or implement.. the bigest things I ever do is something like dmesg | grep wlan0 Where | is my pipe... but that is the extent of my knowledge and skill. Pexpect may very well be the option I need, and having a project that supports the module is great. I am curous what is stopping Pexpect from becoming cross platform. Above, a user suggested implementing send keys in windows. Why not include that as an try/except in Pexpect instead of my wrapper? That way it can benifit many more people? Cheers -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Subprocess module
> You probably > mean:http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/440554 > > Why is that not sufficient? It will allow interaction with a called > subprocess, in a cross-platform manner, etc. > > - Josiah Sorry maybe 'not sufficient' was the wrong excuse. Maybe the right thing to say is that when I look at it I don't know if I'm supposed to copy paste in my own module, or paste into a seprate module, or use it in a pre-existing module. Does the liscence for the content through ASPN even allow reuse of code. or Am I supposed to modify it? If I use, how is it to be used?. Wher eare the exmpales and documentation. By sufficient I mean I don't have sufficient info from the site to implement it. And I don't have sufficient know how to implement it base don the comments in the source code. IN SHORT... IT'S SCARY So if you can answer any of those questions I am open. -- http://mail.python.org/mailman/listinfo/python-list
