@jmhobbs

I make a website for dogs.

packdog.com / velvetcache.org / whatcheer.com

I'm also starting a tiny farm.

/buttercupfarmomaha    @buttercupfarmomaha

Node.js

Fetch JPEG

var http_callback = function(response) {
  var img = '';
 
  response.setEncoding('binary');
 
  response.on('data', function (chunk) { img += chunk; });
 
  response.on('end', function () {
    latest_image = img;
    latest_image_timestamp = +(new Date());
    setTimeout(updateImage, REFRESH_INTERVAL);
  });
};

function updateImage () {
  if(( +(new Date()) - last_request ) > PAUSE_TIMEOUT) {
    setTimeout(updateImage, PAUSE_INTERVAL);
  }
  else {
    http
      .request(http_options, http_callback)
      .on('error', function (e) {
        setTimeout(updateImage, BACKOFF_INTERVAL);
      })
      .end();
  }
}

Serve Image

var server = http.createServer(function (request, response) {
  if( DEBUG ) { console.log('Incoming Request:', request.url); }

  if(request.url === '/') {
    // ...
  }
  else if (request.url.substr(0, 6) === '/image') {
    last_request = +(new Date());
    frames_served++;
    response.writeHead(200, {"Content-Type": "image/jpeg"});
    response.end(latest_image, 'binary');
  }
  else {
    response.writeHead(404, {'Content-Type': 'text/plain'});
    response.end('404 - Not Found');
  }
});

Front End

$chicken_cam.on('load', function () {
  $('#error-message, #sad').hide();
  $chicken_cam.show();
  setTimeout(update, {{UPDATE_INTERVAL}});
});

$chicken_cam.on('error', function () {
  $('#error-message, #sad').show();
  $chicken_cam.hide();
  setTimeout(update, {{ERROR_RETRY_TIMEOUT}});
});

function update () {
  $chicken_cam.attr('src', '/image?t=' + (+new Date()));
}

update();

DEMO

http://chicken-cam.herokuapp.com/