将消息从python-shell发送到Node Express App中的浏览器

Question

I have an express app and I would like to be able to trigger python scripts via routes and emit the log into the browser.

I have created a route which triggers the python scripts correctly and outputs the log into the node console using python-shell module. How can I push this log to the browser in real time.

I have a button on an index.html page which triggers an Ajax post request to a /python route below. I have tried to implement this with socket.io but haven't managed to get my head around it. Is socket.io the way forward, please point me in the right direction or can someone recommend an alternative?

My file layout is:

server.js

var express      = require('express');
var path         = require('path');
var app          = express();
var port         = process.env.PORT || 3000;
var http         = require('http');
var server       = http.createServer(app);
var io           = require('socket.io').listen(server);

/* A bit inbetween */

server.listen(port)

app/routes.js

var PythonShell = require('python-shell');
var config      = require('../config/config');

module.exports = function(app) {
      app.get('/', function(req, res) {
        res.render('pages/index.ejs', {
            pageTitle: 'Index'
        }); // load the index.ejs file
      });

      app.post('/test', function(req, res) {

          var options = {
               mode: 'text',
               pythonPath: config.pythonPath,
               pythonOptions: ['-u'],
               scriptPath: config.pythonScriptsDirectory
             };

             var pyshell = new PythonShell('printRange.py', options);

             pyshell.on('message', function (message) {
               console.log(message);
             });

         res.sendStatus(200)
      });

}

Thanks in advance

Answer 1

socket.io is a good solution. This will take care of passing the messages from the server to the client. You just post the message to on the server side, and have a callback react to it on the client side

On the server side you'll have something like this:

var app = require('express')();
var server = require('http').createServer(app);
var io = require('socket.io')(server);
io.on('connection', function(){ 
  console.log('connected');
});
server.listen(3000);

...

var pyshell = new PythonShell('printRange.py', options);
pyshell.on('message', function (message) {
  if (connected)
     io.emit('logentry',message);
});

On the client side, you'll have something like this:

<script src='/socket.io/socket.io.js'></script>

<script>
  var socket = io();
  socket.on('logentry',function(log_entry){
    add_to_html(log_entry); // You need to implement this function.
  });
</script>