Node.js and Python communication

README.md

Node.js + Python

Using the Node.js child_process module to create and use a python3 process to do a sum over an array.

Usage

node father.js

father.js

/* Generate a python process using nodejs child_process module */
var spawn = require('child_process').spawn,
    py_process = spawn('python3', ['son.py']),
    data = getData(),
    dataResult = '';

/* Define what to do on everytime node application receives data from py_process */
py_process.stdout.on('data', function(data){
    dataResult += data.toString();
});

/* At the end, show the result from py_process computing (stored in 'dataResult') */
py_process.stdout.on('end', function(){
    console.log('Sum result: ', dataResult);
});

/* Stringify the array before send to py_process */
py_process.stdin.write(JSON.stringify(data));

/* Close the stream */
py_process.stdin.end();

function getData() {
    return [1, 8, 16, 32, 64, 128, 256];
}

son.py

import sys
import json


# Read data from the Writable Stream
def read_in():
    lines = sys.stdin.readlines()
    return json.loads(lines[0])


# Work work
def compute_sum(data):
    return sum(data)


def main():
    # Store the data as an array in 'data_input'
    data_input = read_in()

    # Compute the sum
    sum_result = compute_sum(data_input)

    # Return the sum
    sys.stdout.write(str(sum_result))

# Start the process
if __name__ == '__main__':
    main()