I am building an android app that exchanges data with our server through http api calls. In many cases users are complaining that the app is slow or doesn't work at all.
The most common cause of that is bad network connectivity (low 3g/wifi signal or congested public wifi).
What is the best way to detect bad connections? Once i can detect bad connectivity an icon or toast message can be used to inform the user about the situation.
I am using HttpUrlConnection for the api calls.
I think you can make use of ConnectivityManager. Call getActiveNetworkInfo() and then call getDetailedState() on the NetworkInfo object received. You can check the state of the connection and whether it is VERIFYING_POOR_LINK, though I don't know in which conditions this state is active.
Also you might want to listen to network changes as described in Detect Connection Changes.
I'd probably use latency. Save the time when you get the request, and when the request finishes. If you're seeing numbers that are too high, pop up the warning. If you're downloading large files, you may wish to switch to throughput (how many kbps you're transfering).
as far as i remember http is "connectionless"..
you should try concentrating on minimizing the size of your traffic.. (compress, divide.. etc)
if you really want to test connectivity i guess you should do pings.. every x seconds.. then if the ping is bad you could warn the user..
Related
I am having an Android app which needs continuous network monitoring and I require to be notified when I have internet and when not. I have tried Android connectivity manager, which only tells if the internet wifi is connected or not, but doesn't tell if there is reachability. So I used the following ping method to check the reachability.
private fun isOnline(): Boolean {
return try {
val timeoutMs = 1500
val sock = Socket()
val socketAddress = InetSocketAddress("8.8.8.8", 53)
sock.connect(socketAddress, timeoutMs)
sock.close()
true
} catch (e: IOException) {
Logger.e(TAG, e.toString())
false
}
}
Now to keep checking this every 1 minute I am using a fixedRateTimer which will call this method every 1 minute and notify accordingly.
Now the problem I am facing is, this works fine for few hours and I get proper connection status. But after few hours the ping starts timing out. I get a timeout exception every alternate ping.
I want to understand few things,
First thing, is it okay to ping for every 1 minute to check the network?
Can the client be blocked by Google for frequent pings?
Or is it anything related to the ISP?
Is there a better approach in android to achieve what I want?
Any advice would be appreciated. Thanks in advance!
PS : I have also tried onCapabilitiesChanged and the callbacks are not immediate for every connection and disconnection, though the google documentation says callbacks will be immediate.
but doesn't tell if there is reachability. So I used the following ping method to check the reachability
First, that is not a ping. That is opening and closing a socket.
Second, it can only tell you if you can open a socket connection to that IP address. It does not tell you if you can access anything else. So, this is subject to false positives (you can reach 8.8.8.8 but not your real server) and false negatives (8.8.8.8 is blocked by network management, but your real server is not).
Now to keep checking this every 1 minute I am using a fixedRateTimer which will call this method every 1 minute and notify accordingly.
That will only work so long as your process is running, and only until you lose Internet access due to Doze mode/app standby/manufacturer-specific power management solutions.
First thing, is it okay to ping for every 1 minute to check the network?
It has flaws. "Okay" is a subjective measure; only you can decide whether it is "okay" for you.
Can the client be blocked by Google for frequent pings?
This is not a ping. It is certainly within Google's power to take action for buggy clients like this.
Or is it anything related to the ISP?
There are lots of pieces involved in an Android device reaching 8.8.8.8:
The network management for whatever WiFi network the phone is using for connectivity (where relevant)
The mobile carrier or ISP
The various other ISPs between you and Google
Google's own network management
Any of them could take steps, if they so chose.
Is there a better approach in android to achieve what I want?
I would aim to eliminate the "need" entirely, as Android and device manufacturers will be fighting you every step of the way.
At minimum:
Do a valid expected operation, such as an actual ping; and
Do it against a relevant server
IIRC, 8.8.8.8 is a DNS server. If your app is a DNS client, you are welcome perform a valid, useful DNS operation against 8.8.8.8. If your app is not a DNS client, quit messing with somebody else's server. Run your own server and test reaching it. For example, you could run a Web server and test whether you can retrieve your robots.txt file.
Most of the question has been answered, but I want to pick up on the most important one.
First thing, is it okay to ping for every 1 minute to check the network?
No. It is not OK.
It is wasteful
You are consuming Google's resources. Resources that you are not paying for. If everyone did what you are doing it would cost Google a lot of money ... to run a much larger fleet of DNS servers, etc to cope with bazillions of vacuous connections.
You are also consuming resources in the along the route from the user's app to Google with the (unnecessary) network traffic.
This would also apply if you were doing real (ICMP) pings, though not to the same extent.
And bear in mind, this is also consuming electricity. And that means more fossil fuel is burned.
It may be incurring costs for the user
Depending on the what their mobile phone plan is, this may be costing the user of your app network charges. Each of those connections your App is making probably being metered. If they are not aware of this ... or they can't turn this (mis-)feature off, they could get rather annoyed about this. (I would be!)
It doesn't actually work
What you are doing doesn't actually test if the internet is available. What you are actually doing is seeing if your App can connect to the Google DNS services. But the fact that the DNS server is accepting connections doesn't mean that the real services that the user wants to use will be accessible and working. (And vice versa!)
As you noted, connections will occasionally fail for reasons that are probably due to transient problems that resolve themselves. There is nothing you can do about that. That could be a false negative for the internet being "up".
Even if there was a reliable way to find out if the internet is "working", your "pinging" is only giving you a single sample. The internet could go "down" (or come back "up") any time in the up to 60 seconds between your pings. More false negatives and positives.
And as noted, Google DNS is not the same as "the internet", and "the internet" is not the same as the service that the user of you App is really interested in.
Your app doesn't REALLY need this information
The user does not need to know minute by minute that the internet is available.
Most of the time a typical user is doing something else.
They only actually need to know if they are actively using some service. And even then, knowing that the internet was up 60 seconds ago is probably no help to them.
Unfortunately, the only way that the user can tell if the service they are talking to is available right now ... is to actually try to use it.
So what is the real solution?
IMO, there are two approaches:
Forget it. In most cases, the user really doesn't need to know. It is not actually going to materially effect the user if your App does not distinguish "service down" from "internet down".
If you can't forget it.
Implement an end-point on your service that you can ping ... and pay the bills!
If you are trying to implement this in an App where you are talking to someone else's services, stop free-loading on Google. If you want an "internet is up/down" feature in your App, implement your own service for doing this ... and pay the bills.
Note that you will still have false positives and false negatives to deal with. There is no solution to that. It is a fundamental property of the internet.
I'm using Connectivity library to see the internet(Wifi or network data) is active and saving the data in Storage if there is no connectivity(Offline) and synchronize with server when connected to internet. I'm having issues in public places where the internet is consistently unstable(esp. in basements, offices, stores, Coffee shops etc., where there is internet connects in and out). When I check the Connectivity is active but by the time I started synchronizing internet goes offline (Something like this). this leads inconsistent /partial updates to the server. Also, in coffee shops and Airports where wifi gets connected but there will be "Agree Terms and Conditions" page to connect. Not all the browsers will take you to that page directly after joining the Wifi. In that case I see the wifi is active in Mobile but actually it is not activated until I accept the terms and Conditions in IE or some specific browser. Any one else having difficulty in handling these kind of issue from Mobile App?
My App - Hangs on Login screen if I'm trying to login when there is in-stable/in consistent internet.It thinks wifi is there but not.
IF I'm on a screen where I will display list, screen will show blank for infinite time. Adding timeout for server request/response or something will help such scenario.
I know I'm not handling this case in code to show some kind of error message but I need some guidance to detect these conditions suing CN1 API to handle through my app.Please advise.
Code:
public boolean isOffline() {
if (Connectivity.isConnected() && forceOffline) {
relogin();
}
return forceOffline || !Connectivity.isConnected();
}
The problem is that it's impossible to detect online/offline properly as you might be connected to a local wifi/network but it might be a bad connection that won't let you reach the server. As far as the library is concerned you are connected... But in reality you don't have a connection.
First set the timeout values in NetworkManager to lower values to improve the experience although this won't solve a situation where data starts downloading and stops in the middle.
Next you need to handle these cases one by one and provide the user with a way to toggle the offline mode. Unfortunately there is no silver bullet for network reliability. You just need to go through every path and try to detect these things.
i am trying to develop a cordova(3.5.0) project in android platform and in that i have to check network connection availability before each API call. for that i am using 'navigator.connection.type',and some times it return 0. why this is happening? plz help me for solving this trouble
Without some more details I can only guess.. There are some conditions which may cause this.
navigator.connection.type = 0 -> connection type unknown.
So you may have a connection, you may not it simply hasn't been determined yet, or because of privileges the device isn't saying.
Are you calling this check too early? ie before deviceready
In our app we do not check the connection each time but we handle it this way:
by making the API request anyway, knowing that its possible to fail, we set a timeout and error handling. If it fails by error or timeout we check connection type and then ping the server with a simple "hello" "acknowledge" request. Its a super small request that we figure will work or if it timeouts again the connection must be so poor it might as well be disconnected.
This is because there are really two types of connection you need to check. Many miss this!
And also because its navigator totally lies some times... :/
Just because wifi is on and connected and navigator tells you this, it doesn't mean you will have a connection to the outside world. You need to check the network hardware (which is all navigator will tell you) but you must also check network connectivity, if this is something you are sensitive about.
In my Android application I first get the users location using either GPS, the GSM network or a text value that is manually input via a Settings screen.
At first I used the Geocoder class to get the users locale with latitude and longitude provided by GPS or GSM but it seemed unreliable, now I used Google's web API to get the locale by making a HTTP request and parsing the XML document returned. This is using the following URL:
http://maps.googleapis.com/maps/api/geocode/xmllatlng=blahblahlat,blahblahlong&sensor=true
After getting the users locale I then send another HTTP request to free.worldweatheronline.com's weather API and parse the XML returned. With a stable internet connection the application runs fine, however my house has a rubbish signal and even worse mobile data connection.
I am aware there is a simple method to check if the device has a mobile data connection, however what I want to know is whether there is a way of measuring the signal strength as the problem arises when there is a connection, but it is too bad to successfully run. For example, if there is a way to get mobile data signal strength which returns a value from 0 (no signal) to 100 (full signal), I can then only carry out the location and weather retrieval if signal strength is above a certain amount.
Would it be best to just surround the location and weather retrieval code with a try/catch so it doesn't cause a runtime exception, allowing it to just fail gracefully then update when a better signal is acquired? Any ideas on how to accomplish this, or any other suggestions to make my app more friendly for users with bad signal?
Thanks in advance!
You can check it but remember to handle, in any case, drop of connections.
In my apps I had some problems while writing files or stuff like that with an open connection, so just remember that a fail may always occur (for example switching from gprs to wifi).
If you can easily check the signal strength I would do both.
Give a look at the SignalStrength class (never used it btw). Here a nice explanation.
You can check cell service signal strength by creating a PhoneStateListener and handle the onSignalStrengthChanged callback. For more info look at this question How to get cell service signal strength in Android?
EDIT :
You can pause PhoneStateListener by calling telephony.listen(listener, PhoneStateListener.LISTEN_NONE); to not receive updates when you don't need them.
I perform some large downloads. I start a download being connected to 3G, all is fine. Then, I switch to WiFi connection, but the request returns a timeout exception. I have used HttpClient library. I have implemented a retry mechanism, so, when the request returns an exception, it sleeps for 0.5 seconds and tries to execute again and again. I would expect that, after connecting to a WiFi, the Http request could execute. But it seems that the Http execute method returns a null response, all the time after that. Very strange, if I commute again to 3G, the execute method returns again a good response. Can anyone help me please :) ?
First, it seems that it may be more convenient to use DownloadManager for large files - it handles retry and everything.
As for HttpClient - it's known to have some issues, but i'm not sure if you bumped into one of them or just overlooked something. It's been deprecated as of Gingerbread, you may want to try HttpUrlConnection instead, it's said to have less problems than HttpClient.
Also, when switching between WIFI and cell connections, HttpClient may need to be reinitialized completely, there's http range header to tell server which byte you want to continue downloading from. But again, I suggest you give DownloadManager a try, it may save you a lot of time.
This might be a routing problem:
when switching between different network types usually the local ip address and, more important, the local routing table changes, due to a different gateway being used. This means that packages that traveled fine between client and server wont reach any destination after a network change, if they are send the same route. Most likely your client implementation has to be notified of the change or even restartet completely, so that the routing strategy is reinitilized.
If the documentation of the implementation components you use dont reveal anything you could try to track this down using a package sniffer like wireshark. Typically packages running into nirwhana show up easily there.