How to call python script from NodeJs

There are multiple ways of doing this.

• first way is by doing npm install python-shell

and here's the code

var PythonShell = require('python-shell');
//you can use error handling to see if there are any errors
PythonShell.run('my_script.py', options, function (err, results) { 
//your code

you can send a message to python shell using pyshell.send('hello');

you can find the API reference here- https://github.com/extrabacon/python-shell

• second way - another package you can refer to is node python , you have to do npm install node-python

• third way - you can refer to this question where you can find an example of using a child process- How to invoke external scripts/programs from node.js

a few more references - https://www.npmjs.com/package/python

if you want to use service-oriented architecture - http://ianhinsdale.com/code/2013/12/08/communicating-between-nodejs-and-python/

• install python-shell :- npm install python-shell

  Index.js

  let {PythonShell} = require('python-shell')
  
  function runPy(){
      return new Promise(async function(resolve, reject){
            let options = {
            mode: 'text',
            pythonOptions: ['-u'],
            scriptPath: './test.py',//Path to your script
            args: [JSON.stringify({"name": ["xyz", "abc"], "age": ["28","26"]})]//Approach to send JSON as when I tried 'json' in mode I was getting error.
           };
  
            await PythonShell.run('test.py', options, function (err, results) {
            //On 'results' we get list of strings of all print done in your py scripts sequentially. 
            if (err) throw err;
            console.log('results: ');
            for(let i of results){
                  console.log(i, "---->", typeof i)
            }
        resolve(results[1])//I returned only JSON(Stringified) out of all string I got from py script
       });
     })
   } 
  
  function runMain(){
      return new Promise(async function(resolve, reject){
          let r =  await runPy()
          console.log(JSON.parse(JSON.stringify(r.toString())), "Done...!@")//Approach to parse string to JSON.
      })
   }
  
  runMain() //run main function
  

test.py

    import sys #You will get input from node in sys.argv(list)
    import json
    import pandas as pd #Import just to check if you dont have pandas module you can comment it or install pandas using pip install pandas

    def add_two(a, b):
        sum = 0
        for i in range(a, b):
            sum += i
        print(sum)  

    if __name__ == "__main__":
        print("Here...!")
        # print(sys.argv)
        j = json.loads(sys.argv[1]) #sys.argv[0] is filename
        print(j)
        add_two(20000, 5000000) #I make this function just to check 
    # So for all print done here you will get a list for all print in node, here-> console.log(i, "---->", typeof i)