Always fresh data in your mobile application

Transcript

2. ALWAYS FRESH DATA IN YOUR MOBILE APPLICATION Romain Menetrier @romemore +RomainMenetrier
3. THE PROBLEM notification (online) open app (offline)
4. It’s a synchronization problem !
5. It’s a synchronization problem ! kind of… mobile connection is not a network plug ! connection is not always available connection is shared : (very) variable bitrate
6. your app is not always running (hopefully) It’s a synchronization problem ! kind of…
8. Polling Server side push Permanent connection SOME SOLUTIONS
9. the application asks the data he wants, when he wants POLLING
10. PRO simple, well known model we ask for data only when we need it (application opened ?) CONS the data is not here when user want it what happens when no data or (worst) slow data when you open the app ? POLLING
11. Not server friendly Imagine 10000 apps making 1 request by minute to the same server ? POLLING
12. Not mobile friendly Imagine your app waking up network every minute ? POLLING
13. the server send the data he wants, when he wants SERVER SIDE PUSH
14. PRO push only when we have data data can be received in background by the app CONS server side filtering and triggering > server side dev we have to have a schema for datas to react on > update client AND server SERVER SIDE PUSH
15. NOT MOBILE DEV FRIENDLY server side development SERVER SIDE PUSH
16. clients and server are always connected PERMANENT CONNECTION
17. client and server are always connected (not really) mobile phone are sometimes often connected PERMANENT CONNECTION
18. PRO bidirectional push instant data transfer large data allowed (files, …) CONS permanent connection to maintain server resources (sockets) PERMANENT CONNECTION
19. NOT SERVER FRIENDLY work to allow many connection by server or cost to use a SAAS (Firebase, …) NOT MOBILE FRIENDLY you have to keep your app running to maintain the connection connection use a lot of battery PERMANENT CONNECTION
20. Polling Server side push Permanent connection SOME SOLUTIONS
21. Continuous queries
22. An SDK based on Parse to get only the interesting data 'au fil de l'eau', as it has been saved on server ONE SOLUTION
23. GOALS interesting data network friendly device friendly no server side development ! only data we care about freshest data topics we are interested in (filtered data)
24. interesting data network friendly device friendly no server side development ! GOALS no request if no interesting data one request to get all the data data as small as possible (only newest data)
25. interesting data network friendly device friendly no server side development ! GOALS only active when server have interesting data no permanent connection to server
26. interesting data network friendly device friendly no server side development ! just forget about it GOALS
27. Polling, triggered by server side push, using the (already) available permanent connection. aka ’’triggered polling’’ ONE SOLUTION
28. Mobile app subscribe to topic(s) On server side, when new data is saved or data modified, notify subscribed mobile apps Mobile apps receive the notification and download the new data Triggered polling ONE SOLUTION
29. Google Play services maintain a permanent connection, that we can use to send push notification (GCM) on data changes. When the app receive this push notification, it can download the changes in background. Triggered polling ONE SOLUTION
30. We can use a hook when we save data on Parse, and send pushes to mobiles who have subscribed to this data. Triggered polling ONE SOLUTION
31. CQRS Event sourcing Background (inspiration) ONE SOLUTION
32. Command hook on « save » to trigger notification Query get data triggered by the notification CQRS ONE SOLUTION
33. Delete is a flag on the object Can replay modifications on data since a time reference (last sync) Event sourcing ONE SOLUTION
34. IMPLEMENTATION We use Parse to have : a central datastore hooks on data store ("AfterSave(object)") push notifications Server side
35. Android because everything is easier on Android Parse SDK as we use Parse on server side (push + queries) GCM for push notifications Event bus because I just like it Client side IMPLEMENTATION
36. IMPLEMENTATION
37. /**
 * register to an object type
 * @param type
 */
 static public void register(String type) {
 ParseInstallation i = ParseInstallation.getCurrentInstallation();
 i.addUnique("sushi", type);
 i.saveInBackground();
 } // Dynamically register to class of data (can register many)
 Sushi.register("MyClassOfObject");
 CODE
38. /**
 * Wrappers around Parse save methods
 */
 
 static public Task<Void> saveEventually(ParseObject obj) {
 Task<Void> result = obj.saveEventually();
 updateLastMod(obj.getClassName());
 return result;
 } /**
 * send the update trigger to the server
 * @param className the class of saved object
 */
 static private void updateLastMod(String className) {
 ParseObject ev = new ParseObject("SushiUpdates");
 ev.put("objectName", className);
 ev.saveEventually();
 } CODE
39. Parse.Cloud.afterSave("SushiUpdates", function(request) {
 var objectName = ""+request.object.get("objectName");
 
 Parse.Cloud.useMasterKey();
 
 //send push to clients
 var pushQuery = new Parse.Query(Parse.Installation);
 pushQuery.equalTo("channels", "Sushi");
 pushQuery.equalTo("sushi", objectName);
 Parse.Push.send({
 where: pushQuery,
 data: {
 class: objectName
 }
 }, {
 success: function() {
 console.log("push sent for class " + objectName);
 },
 error: function(error) {
 console.error("push not sent : " + error.message);
 }
 });
 
 });
 CODE
40. @Override
 protected void onPushReceive(Context context, Intent intent) {
 boolean isSushiEvent = false;
 if (intent != null) {
 String channel = intent.getExtras().getString("com.parse.Channel");
 if(channel != null && channel.equalsIgnoreCase("sushi")) {
 isSushiEvent = true;
 onSushiEvent( intent.getExtras().getString("com.parse.Data") );
 }
 }
 if(!isSushiEvent)
 super.onPushReceive(context, intent);
 }
 
 protected void onSushiEvent(String data) {
 try {
 JSONObject json = new JSONObject(data);
 String updatedObject = json.getString("class");
 Log.i(TAG, "updated " + updatedObject);
 EventBus.getDefault().post(new SushiUpdateEvent(updatedObject));
 } catch (JSONException e) {
 Log.d(TAG, "JSONException: " + e.getMessage());
 }
 } CODE
41. DEMO
42. IMPROVEMENTS //@todo Multiple push prevent multiple push to a same client for same class of data if he didn’t already query for the data Sync point the client must query new data since last sync Continuous query add parameters to subscription
43. OPEN iOS push notifications + background fetch Git hook on push
44. THANKS ! Questions ?
45. http://en.wikipedia.org/wiki/File:Fresh_%26_easy_semitrailer_truck.jpg http://commons.wikimedia.org/wiki/File:Tewkesbury_Medieval_Festival_2009_-_Archers.jpg http://cdn.appstorm.net/android.appstorm.net/files/2011/03/graph.jpg http://pixabay.com/fr/l-eau-filtre-entonnoir-306142/ http://commons.wikimedia.org/wiki/File:Love_Heart_symbol.svg http://pixabay.com/fr/trace-de-l-impulsion-163708/ http://pixabay.com/fr/burnout-%C3%A9puis%C3%A9-seul-solitude-384080/ http://pixabay.com/fr/rouleau-de-sushi-sushi-alimentaire-295089/