Is there any way to keep LG WebOS service alive?

Question

I’m trying to create a JS service on WebOS 3.0 followed the official documentation.

I can send data between JS service and my application, but sometimes the JS service does not respond to the request if it’s idled for like 20 seconds. I’ve also tried to increase the timeout per this. Unfortunately, it does not seemed to be working.

Here’s my code

Application Side

const request = webOS.service.request('luna://com.myapp.service', {
        method : 'fetch',
        parameters : { url, method, headers, body },
        onFailure : (err) => {
          reject(err)
        },
        onSuccess : (s) => {
          console.log('request success', s)
        },
        onComplete : (resp) => {
          const isSuccess = resp.data.status >= 200 && resp.data.status < 400
          var payload = {
            json : () => Promise.resolve(JSON.parse(resp.data.body)),
            ok : isSuccess,
            headers : resp.data.headers,
            status : resp.data.status,
            error : isSuccess
              ? null
              : resp.data.body
          }
          resolve(payload)
        }
      })
    })

Service Side

var Service = require('webos-service')
var service = new Service('com.myapp.service')

service.register('fetch', function(message) {
var payload = message.payload
  if(!payload) {
    message.respond({
      returnValue : true,
      error : 'Message does not have a `payload`'
    })
    return
  }
  var url = payload.url,
      headers = payload.headers,
      method = payload.method,
      body = payload.body
  var request = http.request({
    method : method,
    hostname : URL.parse(url).hostname,
    path : URL.parse(url).path,
    headers : headers,
  }, function(res) {
    var data = ''
    res.on('data', function(chunk) { data+=chunk })
    res.on('end', function() {
      message.respond({
        returnValue : true,
        data : {
          status : res.statusCode,
          statusText : res.statusMessage,
          headers : res.headers,
          body : data,
        }
      })
    })
  })
  request.on('error', function(err) {
    console.log(err)
    message.respond({
      returnValue : true,
      error : err
    })
  })
  request.end()
})

Answer 1

I recently wrote a JavaScript application for LG Smart-TVs and would highly recommend using socket.io for all communication between client and server. It's a bit tricky getting it to work initially, but works flawlessly.

Here's how the connection looks ...

    var socket = io("http://10.27.101.95");
    idUser = getCookie("idUser");   // Retrieved from device and set to cookie.

// ┌────────────────────────────────────────────────────────────────┐
// │   Socket.io: Connect/Emit                                      │

    socket.on('connect', function() {
        socket.emit("addUser", {
            "idUser": idUser
        });
        reconnectHideData = false;
    });

    // Hide data if server cannot be reached.
    var reconnectCount = 0;
    var reconnectHideData = false;
    socket.on('reconnect_error', function() {
        if (reconnectCount < 10 && reconnectHideData == false) {
            // console.log( '---=== Reconnect attempt: ' + reconnectCount + ' ===---' );
            setTimeout(function(){
                reconnectCount++;
            }, 3000);
        }
        if (reconnectCount == 10 && reconnectHideData == false) {
            // console.log( '-----===== Cleared Data =====-----' );
            $('.section ').addClass(' u-hide ');
            $('.greeting').addClass(' u-hide ');
            reconnectHideData = true;
            reconnectCount = 0;
        }
        else {
            return;
        }
    });

    // Necessary to trigger event to be emitted server side.
    setInterval(function(){
        socket.emit("reqData");
    }, 5000);

// └────────────────────────────────────────────────────────────────┘

After that, it's all a matter of processing and formatting the returned data.