Python "Send2Pd" doesn't reach Pure Data's "Netreceive"

Question

I need to send messages from Python to Pure Data, so I followed this article. It was working fine until one day suddenly it stopped working. Pure Data doesn't receive anything anymore and I have tried this on Mac and Linux environment

I have uploaded script plus patch here: but a equivalent code is:

import os
os.system("echo '1;' | pdsend 3000")

and Puredata should receive the message with a simple netreceive 3000

Looks like Python and Pure Data can't find a path to communicate. after i tried so change pdsend with it's absoulute path as follow:

import os
os.system("echo '1;' | /Users/path_to_pure_data/PureData.app/Contents/Resources/bin/pdsend 3000")

it works.

at this point i don't know why Python doesn't automatically find it's path, and how to fix it.

Answer 1

How would Python know that it should look for executables in /Users/path_to_pure_data/PureData.app/Contents/Resources/bin/?

For security (and perfomance) reasons, the system will only search for executables in a few select locations, that are defined in the PATH environment variable.

You could either add /Users/path_to_pure_data/PureData.app/Contents/Resources/bin/ to your PATH, or put pdsend into a path that is already searched for.

However, this seems to be an overkill in any case, as calling an external application is rather costly, and using os.system is probably one of the worst options.

Python is a powerful programming language, and it is very easy to build the client code in Python itself. Eg this code does not have any external dependencies, performs faster, and is safer (and I'd say. it's easier to read as well):

import socket

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(("localhost", 3000))
s.sendall(b'1;')
s.close()