How can you tell if there exists a network connection of any kind ?

To be more specific, how can one be sure to use the methods of classes like Network (Connect, InitializeServer, etc ) when there is no LAN, Wifi or ethernet connection ?

In this case (where no connection is available on the target device) nasty errors occur when trying to Initialize a server or to poll for a host list.

The more general question would be how can one manage in code this type of situation ?

Try catch statements don't help because for example Network.Connect() makes the device connect only after a while so the error "Cannot resolve connection tester address, you must be connected to the internet before performing this or set the address to something accessible to you" pops out after the code in the try block has executed as normal.

I think the solution is implementing some sort of polling system that checks in every frame if there is a network connection since this information is critical for any operations with the Network so it has to be as up-to-date as possible.

I have found (on this forum) a not so satisfying solution that constantly checks if there is internet availability.

The code is bellow, if anyone wants to use it:

Code (csharp):

1. bool thereIsConnection = false;
2. IEnumerator TestConnection()
3.     {
4.  
5.  
6.         float timeTaken = 0.0F;
7.         float maxTime = 2.0F;
8.  
9.         while ( true )
10.         {
11.             Ping testPing = new Ping( "74.125.79.99" );
12.  
13.             timeTaken = 0.0F;
14.  
15.             while ( !testPing.isDone )
16.             {
17.  
18.                 timeTaken += Time.deltaTime;
19.  
20.  
21.                 if ( timeTaken > maxTime )
22.                 {
23.                     // if time has exceeded the max
24.                     // time, break out and return false
25.                     thereIsConnection = false;
26.                     break;
27.                 }
28.  
29.                 yield return null;
30.             }
31.             if ( timeTaken <= maxTime ) thereIsConnection = true;
32.             yield return null;
33.         }
34.     }

This Coroutine Pings the www.google.com address and checks for a response. This works well in determining whether or not one has internet access but this condition is not allways valid since wifi networks can be local, withoug access to the internet and games can still be played in such networks (ex: for iPhone - it can detect a wifi network with no internet access but it can still play wifi games with locally connected devices in that network... i think )

My game is for the iPhone so I guess another approach would be to code smth directly in XCode but I would really appreciate it if there would be a more elegant, accessible and C-sharpy solution to this

Any help would be awesome,

Thx alot, guys.

Paul

 

Does this command not work?

iPhoneNetworkReachability.ReachableViaWiFiNetwork

 

Thanks for the answer spire,

I knew about this function from iPhoneSettings.internetReachability but it didn't work when I was testing with the Unity editor - it returned Reachable allways even if there wasn't actually any wifi available.

I realized that it only worked when I installed it on the device since the class name is iPhoneSettings, not UnityEditorSettings

So, this solves my problem for now but I am eager to know a way to generally detect wifi networks regardless of the device it is installed on (web player, android or xbox) since I want my game to be played on multiple platforms.

This type of issue was dealt with very elegantly by Unity when they deprecated the class iPhoneTouch and made the general class Touch.

Thx again for the help,
Paul

 

One way you could do that is simply ping the master server, and if you get a response back, than you *should* be connected ;-)

 

Sounds interresting and it's probably a good idea. Can you tell me exactly how to ping the master server ? Is it like polling it for hosts ?
Thx

 

Hey-- I'm actually working on some networking things myself.

For the time being, I am using code like this:

Code (csharp):

1.  
2.         //excerpt from code
3.     lastIsConnectedToInternet = isConnectedToInternet;
4.     isConnectedToInternet = false;
5.    
6. #if UNITY_EDITOR
7.     if (Network.player.ipAddress.ToString() != "127.0.0.1")
8.     {
9.         isConnectedToInternet = true;      
10.     }
11. #endif
12. #if UNITY_IPHONE
13.     if (iPhoneSettings.internetReachability == iPhoneNetworkReachability.ReachableViaWiFiNetwork)
14.     {
15.         isConnectedToInternet = true;
16.     }
17. #endif
18. #if UNITY_ANDROID
19.     if (iPhoneSettings.internetReachability == iPhoneNetworkReachability.ReachableViaWiFiNetwork)
20.     {
21.         isConnectedToInternet = true;
22.     }
23. #endif
24. #if (!UNITY_IPHONE  !UNITY_ANDROID)
25.     if (Network.player.ipAddress.ToString() != "127.0.0.1")
26.     {
27.         isConnectedToInternet = true;
28.  
29.     }
30. #endif
31.  
32.     if (lastIsConnectedToInternet != isConnectedToInternet)
33.     {
34.         wasNotifiedNetwork = false;
35.     }
36.  

This works pretty decent in web player-- I can receive notifications when the network changes, and I just set the screen resolution to that of an iPhone, so it is a pretty good simulation.

I'm about to try the above code out on the iPhone to see what happens. I can confirm that the above code does NOT work for the android, since for some reason the IP address ALWAYS returns 127.0.0.1, even if you ARE connected to a network.

I'll let you know in a few.

 

For anyone considering using the Ping technique, I just want to point out that the C# Ping class is not available in web player builds due to security sandboxing. See: http://unity3d.com/support/documentation/ScriptReference/MonoCompatibility.html

I didn't realize this at first and spent a bit of time wondering why the compiler was complaining about not finding the System.Net.NetworkInformation namespace.

 

try Application.internetReachability
http://docs.unity3d.com/Documentation/ScriptReference/Application-internetReachability.html

 

Not suggested:
Do not use this property to determine the actual connectivity. E.g. the device can be connected to a hot spot, but not have the actual route to the network. Non-handhelds are considered to always be capable of NetworkReachability.ReachableViaLocalAreaNetwork.

 

Neo - What are we supposed to use then? All the other Networking functionality for reachability seems to be deprecated and Application.internetReachability seems to be the only option now.

 

Application.internetReachability actually only checks if there is a networking capability. It returns a member of an enum NetworkReachability, that is, either no connection, a data packet connection, or a wifi/ethernet connection possibility . It doesn't check if the device is connected to a network with the device.

It could be named better.

 

To truly know you're online, you need to implement "captive portal detection", to know if you're e.g. hitting a public WiFi login page. So just checking Application.internetReachability or doing a Ping to some address doesn't guarantee you can successfully make connections or make WWW requests.

I have made an easy asset called Internet Reachability Verifier. It keeps you up-to-date whether you have verified internet access (WWW requests can be done).
More info here: http://j.mp/IRVUN

 

Please stop advertising your own products...

 

Just in case somebody finds the thread like I did, the above answers are quite old, I think a legit solution is to ping the masterserver asynchronous, my solution looks like this:

Code (CSharp):

1. private IEnumerator CheckConnectionToMasterServer() {
2.         Ping pingMasterServer = new Ping("67.225.180.24");
3.         Debug.Log(pingMasterServer.ip);
4.         float startTime = Time.time;
5.         while (!pingMasterServer.isDone && Time.time < startTime + 5.0f) {
6.             yield return new WaitForSeconds(0.1f);
7.         }
8.         if(pingMasterServer.isDone && pingMasterServer.time >= 0) {
9.             new InternetConnectionMessage();
10.         } else {
11.             new NoInternetConnectionMessage();
12.         }
13.     }

It tries to ping the masterserver for 5 seconds or until it gets a response and afterwards sends a message whether there is a connection. (Should work for all platforms)
Oh and you call the method like that:

Code (CSharp):

1. StartCoroutine(CheckConnectionToMasterServer());

 

@Johannski thanks for posting example code. But, for better reliability, it's probably best to combine your way with the "captive portal detection", because those public-wifi-login-systems may still let a simple Ping get through even if they block actual access.

 

@tonic Hm, you have a point there. I didn't try it, but there are probably systems out there, which let pings trough, but nothing else. I think for most purposes my code will be enough to check if there is a connection, but it won't handle all border cases.

 

Hi
i am also try to find a simple way of testing network connectivity.
what do the new InternetConnectionMessage();/new NoInternetConnectionMessage(); do?
In general how is a good way to get feedback results from an asychronous function?

Thanks

 

Hi @Johannski
Just one question, the IP you're using... where is it from? Is it from a server of yours? Or is it something like Google? So that I know that I can rely on that one IP. Thanks!

 

Hi @jrobertomar, this address is from a server of mine, because the servers were also needed to play the game and so I could check two things at once. If you just want to know if you got Internet, I recommend to use 8.8.8.8. It is the address of Google, so it will be pingable unless the world ends or you have no Internet connection

 

any fixes yet ?
or still need these workarounds?

 

hi all,

I am working on the same thing, I have to check two servers by ping. so calling web services from one of those live server.

my ping works fine in unity editor and it inyellugently switch between available server

issues comes on android build, the ping.time always returns -1 for both servers. even frim available server.

any help appreciated in advance.