image polling

image-poll.js

/** =========================== SERVER =================================== */
var express = require('express');
var MjpegCamera = require('mjpeg-camera');
var app = express();

// Create an MjpegCamera instance
var camera = new MjpegCamera({
  name: 'backdoor',
  url: 'http://192.168.7.1/video'
});
 
// Start streaming
camera.start();

app.get('/frame', function(req, res) {
  res.set('Content-Type', 'image/jpeg');
  res.status(200).send(camera.frame);
});

app.listen(3000);

/** =========================== BROWSER =================================== */
function startImageFeed(imageUrl, id) {
  var img = document.getElementById(id);
  var stop = false;
  (function setSrc() {
    if (stop) return;
    img.src = imageUrl;
  })();
  img.onload = setSrc;
  img.onerror = setSrc;
  return function() {
    stop = true;
  };
};

var stop = startImageFeed('/frame', 'video-image');
// Stop "video" feed after 30 seconds
setTimeout(stop, 30000);

Hi, Friend!
How it can be scale for many cameras app.get ('/ frame / CameraID')
Start stream only when requested and stop after N minutes

This code is untested, but the approach should work.

class Streamer {

  constructor(cameraOptions, opt_stopAfterMinutes) {
    this.camera = new MjpegCamera(cameraOptions);

    this.stopAfter = (opt_stopAfterMinutes || 5) * 60 * 1000; // hold in ms
    this.timeout = null;
  }

  getFrame() {
    clearTimeout(this.timeout);
    return new Promise((resolve, reject) => {
      if (this.camera.connection) {
        resolve(this.camera.frame);
      } else {
        this.camera.start()
        this.camera.once('data', (frame) => { resolve(frame); });
        this.camera.once('error', (err) => { reject(err); });
      }
      this.timeout = setTimeout(() => { this.camera.stop(); }, this.stopAfter);
    });
  }

}

const streamer = new Streamer(cameraOptions, 5 /** Stop after 5 minutes of streaming if no new requests come in */);
app.get('/frame', function(req, res) {
  streamer.getFrame()
    .then(frame => {
      res.set('Content-Type', 'image/jpeg');
      res.status(200).send(frame);
    })
    .catch(err => {
      res.set('Content-Type', 'text/plain');
      res.status(500).send(err.toString());
    });
});