Hi i'm relatively new to android programming and am trying to do the following. I want to create a messaging system in which immediate response is not (at least for now necessary). I am completely new to networking / socket programming but have followed this:
http://www.tutorialspoint.com/python/python_networking.htm
and have kinda got my head around it.
I have the following question with regards to best practice.
What are the advantages/disadvantages of method A and B.
Method A:
Have a server and client running on the app.
Method B:
Have a client running on the app and pinging the server every minute for data.
Apart from the obvious that Method B doesn't allow real time which is better suggested? Does a server application take too much memory / CPU / battery etc? I know a lot of IM apps exist, how do they work?
Thank you in advance
Why not use push notifications?
http://developer.android.com/guide/google/gcm/index.html
I would recommend Google Cloud Messaging but last time I checked you needed a dedicated server to install it. Or Am i wrong? I only had a shared server so:
method A: the difficult part, considering its a mobile device, would be to keep the connection alive when your phone changes IP (another wifi network for example) and
method B: you could make small simple messages in order to check if there is something new and update in that case. My app sent around 500 bytes every 30 seconds and I didnt have any battery related problems. It also didnt slow the phone down.
Related
I started with a application where you can chat.
Now im in the position to start with the chat.
The problem I'm facing is that I don't want to use
resources from "outside". With outside I mean:
Firebase, Socket.io and so on.
I do simply rent a webspace. And I'm asking you now,
how is it possible to realize an live chat without
using extern services like firebase.
Is it possible with only using an Webspace?
What is required to make an live chat?
And there comes the second question:
How do I realize to stay connected to a server to check if there is a new message without using much battery or network ressources?
I'm not asking without hardly trying by my self.
Two days ago I started with the research of possibility, but I didn't found anything which would work I guess.
Thanks folks...
You need to connect to the Web Server using a Socket and keep that connection open to receive new messages with little delay (see for example http://srchea.com/build-a-real-time-application-using-html5-websockets) This keeps the phone active and uses much battery.
The very purpose of Firebase is to bundle this work for all services which need this type of communication (E-Mail, Push messages of newspapers, Chats) such that the phone only has to query one server. Therefore, I see no way for you to find another solution which uses little battery.
I'm developing an ASP.NET MVC 5 application which is supposed to receive and send messages to Android smartphones. The way I have currently implemented it is by using a message broker (RabbitMQ in this case) and let that broker handle the communications between the backend and the smartphones.
In the ASP.NET code I am creating a thread which is run at the beginning of the application in global.asax (I have seen some people who recommends this, maybe I am doing it wrong...). This thread is in charge of listening to the messages that the broker receives and then process them.
My question is: is this a good practice in terms of handling external messages in an ASP.NET application? This is the first time I program this kind of applications and I don't know if I am doing the things right. Does anybody know another ways to receive messages from an external device in ASP.NET? Again, keep in mind I'm very new to ASP.NET, maybe I am asking something stupid but I just need some information about this.
Thanks!
In case someone has a similar question I will answer how I made it work. At the end I used HangFire (http://hangfire.io/), it is quite easy to configure, just need to add this code below in Startup.Auth file:
GlobalConfiguration.Configuration.UseSqlServerStorage("db_name");
app.UseHangfireServer();
app.UseHangfireDashboard();
And the following code to start the background task:
var storage = new SqlServerStorage("db_name");
var client = new BackgroundJobClient(storage);
client.Enqueue(() => rabbitInstance.MethodXYZ());
I hope this solution is helpful for more people.
If two (or more) devices are connected to the same network, and each has my apk installed, how might one device efficiently 'talk' to the other? Google Play services, Wifi Direct, and bluetooth is unfortunately not available on these devices.
I thought of using a 3rd party push notification service, but ideally I need the response between either device to be as fast as possible, and long-lived.
I have managed to get two devices sending messages to one another using the old client-server Network Discovery Sample app in the docs. However, if either of the apps is closed or leaves memory, the connection is obviously broken. Therefore I'm trying to figure out if this is possible through a Service, which I understand exists outside of the Activity lifecycle.
I understand how an Activity might connect to a Service to send a message (good sample on that located here), but from what I gather this all happens locally on the device. Is it possible to have this exchange happen over a local network, from one app to another? I guess what I'm saying is how can I set up a basic client server socket relationship between two apps that won't die?
It has been a long time but it should still work.
The problem here, as I understand it, is to have something that keeps running when the app is gone.
I remember using IntentService for this purpose. In the onHandleIntent() we made it loop while(!stopCondition) {...}
It was a stable solution then but it was around kitkat's time.
I'd try with the solution in your first paragraph being executed and managed by the IntentService which should keep it available.
To start of, i should mention that i'm a newbie in Android (Not that much experience in Java at all tbh), so be easy on me.
I am making an app that continuously pulls data from a server, and then returns data through a http post request. The question is, what is the best way to handle the actual pulling from the server? Should i be using AsyncTask or create another thread and let it run on that? Are there better methods for this purpose?
I will be pulling data every 5 minutes. (I am aware that this will drain the battery very fast, and i should definately be using Androids C2DM framework. But i have no experience in it before and i'm on a deadline, so this'll have to do until i have time to learn how to implement it.)
I'm grateful for any advice!
As an alternative to C2DM, you can do the persistent TCP connection between your device and the server. Then every 5 minutes your server can push a tickle to the device. Upon being tickled, the device can request the information via Http post.
Here is some sample code on how to do that.The connection stays open in a background thread even after the app has exited
Creating and Managing a persistent TCP socket: http://openmobster.googlecode.com/svn/trunk/cloud/android/connection/src/main/java/org/openmobster/core/mobileCloud/android/module/connection/NotificationListener.java
Full Disclosure: I am the Chief Engineer of OpenMobster and I wrote this code. Please feel free to use whatever you like or just get an idea if thats what you need
Thanks
Do you need to pull the data in background (even if your app is not "opened" and the android device is sleeping)? I suppose thats what you want because you mentioned C2DM. If so..the buzzwords are AlarmManager (with repeating time)/BroadCastReceiver and maybe NotificationManager to notify the user. With AlarmManager you schedule your events (every 5 minutes) and with BroadcastReceiver you receive those events and do what you want to do every 5 minutes :)
I have developed android apps, and have a web server application which serves REST style JSON, to the apps.
My apps are strongly dependent on that web services but as traffic gets higher, users' complaint started, as force close problems. I am not sure but maybe my server (AWS small instance) may not answer all requests correctly or in time.
I am planning to retry the web request when a problem on getting json response arise instead giving the error/net-connection alert.
I guess there are many developers who integrates apps with web services, so what is the good practice on handling network problems?
Or is the frequency of such network problems acceptable?
I take about 10-20 problem per day.
I have about 200.000+ web requests per day, for a AWS small instance (1.7 RAM), dedicated to server Tomcat. I analyze the logs there is no clue, no error log. Also the errors are spreaded.
You need to start with analyzing the problem, and determine the root cause or root causes of your issues. You always need to take into account that
a network connection might drop
a users switches from 3G / WiFi
the android devices "thinks" it's connected while in fact it's not
Also, be very sceptical when using the Android ConnectivityManager / NetworkInfo. Only trust it when it states that it is not connected. If it is connected, check it yourself (as sometimes, user is on a hotspot and the only connectivity he has is with a login page).
The application needs to handle all these scenarios properly. The way it's presented to the user depends on the use-case (do you want the user to be informed of the error, do you silently ignore it and just retry, ....)
In terms of retrying webservice connections, there are several ways to implement this :
exponential backoff
periodic rescheduling
event-driven triggering
retry-after moratorium intervals
You need to start by putting sufficient logging both on the client (Android) and on the server (AWS) so that you can analyze the issues and draw the proper conclusions.
I think the answer to your problem lies in the design of your android app.
You need to take into consideration the worst case scenario and redesign your application to take that into account and recover. Dealing with the chaos monkey - jeff atwood.
Personally I never allow an android app to be in a state where it needs to force close. For any or all network connection I assume that the connection is down, lossy, not all data can be retreived and (finally) up and working correctly.
That way my app will degenerate gracefully. If it needs web access it'll make an attempt in a background thread allowing the user to continue using the app, it will cache previous requests and will retry until it gets a connection or gives a nice toast to the end user.