Question :
I have a C++ program and a Python script that I want to incorporate into my node.js web app.
I want to use them to parse the files that are uploaded to my site; it may take a few seconds to process, so I would avoid to block the app as well.
How can I just accept the file then just run the C++ program and script in a sub-process from a node.js controller?
Answer #1:
see child_process. here is an example using spawn, which allows you to write to stdin and read from stderr/stdout as data is output. If you have no need to write to stdin and you can handle all output when the process completes, child_process.exec offers a slightly shorter syntax to execute a command.
// with express 3.x
var express = require('express');
var app = express();
app.use(express.logger('dev'));
app.use(express.bodyParser());
app.use(app.router);
app.post('/upload', function(req, res){
if(req.files.myUpload){
var python = require('child_process').spawn(
'python',
// second argument is array of parameters, e.g.:
["/home/me/pythonScript.py"
, req.files.myUpload.path
, req.files.myUpload.type]
);
var output = "";
python.stdout.on('data', function(data){ output += data });
python.on('close', function(code){
if (code !== 0) {
return res.send(500, code);
}
return res.send(200, output);
});
} else { res.send(500, 'No file found') }
});
require('http').createServer(app).listen(3000, function(){
console.log('Listening on 3000');
});
Answer #2:
Might be a old question but some of these references will provide more details and different ways of including python in 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/
