How to execute a python script via javascript file in an electronjs app?

Question

I am trying to call and execute a python script via the following javascript code in an electronjs app

function getProgramstatus(){
    
    const { exec } = require('child_process');

    exec('python python\\getProgramstatus.py', (error, stdout, stderr) => {
    });
    
    let jsonData = require('.\\js\\programstatus.json');
    let itemData = JSON.stringify(jsonData);
    let programstatus = JSON.parse(itemData);
    
    sessionStorage.setItem('programstatus check', programstatus.status);
}

The goal of the python script is to write a value at a json file.

data1={
    "status": "12",
    "time" : time.ctime(start)
}
json_object = json.dumps( data1, indent = 4)

with open('..\js\programstatus.json', 'w') as outfile:
    outfile.write(json_object)


#print("2")
sys.exit("2")

When i execute the python script via terminal it writes at json file, but when i call it from javascript it doen't write at json file. Any ideas;

you can write to json file using electronjs, check this => https://stackoverflow.com/questions/38067298/saving-files-locally-with-electron — Stack, Jun 25 '22 at 17:55
@Stack the data written at json file is the outcome of some other python code. I just need to pass data from python to electronjs and thoughout via a json file would be east — John D, Jun 25 '22 at 18:15
https://stackoverflow.com/a/23452742/8150371 try moving the js code of reading json file inside `pythonProcess.stdout.on` — Stack, Jun 25 '22 at 18:29

Erwin van Hoof · Accepted Answer · 2022-06-26T07:10:05.010

Try outputting the response for hints, like this:

function getProgramstatus(){
    
    const { exec } = require('child_process');

    exec('python python\\getProgramstatus.py', (error, stdout, stderr) => {
        if (error) {
            console.error(`exec error: ${error}`);
            return;
        }
        console.log(`stdout: ${stdout}`);
        console.error(`stderr: ${stderr}`);
    });
    
    let jsonData = require('.\\js\\programstatus.json');
    let itemData = JSON.stringify(jsonData);
    let programstatus = JSON.parse(itemData);
    
    sessionStorage.setItem('programstatus check', programstatus.status);
}

And please share the output.

Also the code execution continues while getProgramstatus.py is still running, you want to use execSync / move the code below exec inside the callback or create a promise, so that let jsonData = require('.\\js\\programstatus.json'); gets executed when the python script has finished.

Thank you for the advice, it helped me find the answer. The response was: "No such file or directory: '..\\js\\programstatus.json' — John D, Jun 26 '22 at 08:44

score 0 · Answer 2 · answered Jun 26 '22 at 08:39

I found the answer, why the json file was not written when the python script was called by the application and not by me at the terminal.

The problem is the folder/file location. It should be relative to the main.js of the electron app.

So I changed the following:

with open('..\js\programstatus.json', 'w') as outfile:
    outfile.write(json_object)

To: with open('.\js\programstatus.json', 'w') as outfile: outfile.write(json_object)

and work fine.

How to execute a python script via javascript file in an electronjs app?

2 Answers2