calling python script from node.js

Question

I want to call python script from node.js

Here is my script : my.py

def printme( str ):
# print str;
return str;
printme("I'm first call to user defined function!");
printme("Again second call to the same function");

My node script : testpy.js

var PythonShell = require('python-shell');
var pyshell = new PythonShell('my.py');
pyshell.on('message', function(message) {
console.log(message);
});

but getting error

events.js:85
throw er; // Unhandled 'error' event
Error: spawn python ENOENT
at exports._errnoException (util.js:746:11)
at Process.ChildProcess._handle.onexit (child_process.js:1046:32)
at child_process.js:1137:20
at process._tickCallback (node.js:355:11)
at Function.Module.runMain (module.js:503:11)
at startup (node.js:129:16)
at node.js:814:3

P.S I have install Python shell

Also if I want to execute individual function from node.js to python script. can I do that ?Help

• sinanspd: hmm maybe it is because the script is not executable by default ? I am not really sure how shell library works but maybe try adding this ? Also wrap things in a main function maybe #!/usr/local/bin/python

Answer 1

You can simply write the 'my.py' file like this-

def printme(str):
 return str;
print(printme("I'm first call to user defined function!"));

Check if the path given is correct and check for indentation errors.

Answer 2

Your print statement (my.py line 2) is commented out so nothing will be output and the message event will therefore never fire. Uncomment your print statement, the Node PythonShell object will redirect the stdout (which print writes to) and fire a message event with the output.

As for your error, it looks like the python script isn't being found in the current directory. See https://docs.python.org/2/library/errno.html for error codes and what they mean. Make sure your script is in the right directory or set your python shell to the correct directory using os.chdir.

• priyank jain: thanks for reply but I also tried that one too...but stll same error is coming.

Answer 3

I think that you need to set up the python script to take in standard input like this import sys for v in sys.argv[1:]: print v

Also when setting up the code the way you have it you need to do a PyhtonShell.send('message'), but I would need to see more of your code because I don't see how you are sending data to the python shell through Node.js.

Answer 4

You can simply import Npm Pythonshell using let keyword instead of const Keyword.

let {PythonShell} = require('python-shell')

this works for me