index.js

const PythonShell = require('python-shell')['PythonShell'];
const static = require('node-static');
const http = require('http');
const fs = require('fs');

var static_serve = new(static.Server)('./static');

const server = http.createServer(function (req, res) {
    static_serve.serve(req, res);
})

const io = require('socket.io')(server);
io.on('connection', (socket) => {
    console.log("Socket Connected");
    
    function run_python_script() {
        try {
            let pyshell = new PythonShell('run.py');

            socket.on('disconnect', () =>  {
                console.log("Socket Disconnected");
                try {
                    pyshell.kill();
                } catch (e) {
                    console.log('Cannot send any more to pyshell', e);
                }
            });

            socket.on('command_entered', (command) =>  {
                console.log("Socket Command: ", command);
                try {
                    pyshell.send(command);
                } catch (e) {
                    console.log('Cannot send any more to pyshell', e);
                }
            });


            // sends a message to the Python script via stdin

            pyshell.on('message',  (message) => {
                // received a message sent from the Python script (a simple "print" statement)
                console.log('process Out: ', message);
                try {
                    socket.emit("console_output", message);
                } catch (e) {
                    console.log('Cannot write to socket', e);
                }
            });

            pyshell.on('close', () => {
                console.log('Process ended');
            });

            pyshell.on('error', (message) => {
                console.log('Process error:', message);
                try {
                    socket.emit("console_output", message.traceback.replace('\n', '\r\n'));
                } catch (e) {
                    console.log('Cannot write to socket', e);
                }
            });
        } catch (e) {
            console.error("Exception running", e);
        }
    }

    if (process.env.CREDS != null) {
        fs.writeFile('creds.json', process.env.CREDS, 'utf8', function(err) {
            if (err) {
                console.log('Error writing file: ', err);
                socket.emit("console_output", "Error saving credentials: " + err);
            } else {
                run_python_script();
            }
        });
    } else {
        run_python_script();
    }
});

console.log('Starting node on port', process.env.PORT);
server.listen(process.env.PORT);