How to send multiple responses from Node js using res.write, so that the data appears live in the client?

Question

I want to send data immediately to the client from res.write, but the data is being sent exactly once in one response. How can i send multiple responses so the data is sent live to the client?

app.get('/api/simulator', (req,res) => {


    res.setHeader('Content-Type','text/html');
    var spawn = require('child_process').spawn,
ls = spawn('../abc.sh');

ls.stdout.on('data', function (data) {
  console.log('stdout: ' + data.toString());
  res.write(data.toString());
});

ls.stderr.on('data', function (data) {
  console.log('stderr: ' + data.toString());
});

ls.on('exit', function (code) {
    console.log('child process exited with code ' + code.toString());
    res.end();
  });

    });

There can only be a single response to a single request, you will have to make multiple requests for multiple responses. The better solution is to use Socket.io for streaming. — Don
– Don, Commented Apr 3, 2020 at 5:29
The problem is that, in nearly all cases, the browser is waiting for the completion of the http request before it will display anything or return anything to the ajax call. So, even though you may be incrementally sending data with res.write(), the client in the browser typically won't show the data until it has all arrived. If you can be more specific about exactly what you're trying to do, perhaps we could help in more detail. A webSocket connection would allow you to send individual chunks of data that would be received by the client immediately. — jfriend00
– jfriend00, Commented Apr 3, 2020 at 6:03

Tri Bui Quang · Accepted Answer · 2020-05-11 10:09:07Z

0

I think you just add another line res.write(): - Example:

ls.stdout.on('data', function (data) {
  console.log('stdout: ' + data.toString());
  res.write(data.toString());
  response.write("foo");
  response.write("bar");
});

answered May 11, 2020 at 10:09

Tri Bui Quang

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