AFNetworking and No Internet Connection scenario

Question

I use AFNetworking in my app for every request (like login, get data from url, etc).

Take this for example: an user click on the login button and there's no connection, how to instantly display a UIAlertView that says the error? The only way is to wait the request timeout and execute the failure block? Isn't there a way that instantly check if there's connection or not?

Thanks!

score 56 · Accepted Answer · answered Feb 13 '12 at 05:03

56

As of 0.9, AFHTTPClient actually has network reachability built-in (a simpler interface to Apple's aforementioned Reachability code). Just include the SystemConfiguration framework and use -setReachabilityStatusChangeBlock: to specify a response when the reachability state changes.

answered Feb 13 '12 at 05:03

mattt

19,544
7
73
84

1

Hi mattt and thanks for you reply. But your suggestion is to check for current status of internet connection before **every** method that uses internet and if there's no connection displays an alert? – Fred Collins Feb 13 '12 at 05:22
3

No, not at all. `AFHTTPClient` monitors for reachability changes and executes the specified block when that happens. The block has a single argument, which is a boolean for whether or not the `baseURL` is reachable. – mattt Feb 13 '12 at 05:33
1

I've subclassed `AFHTTPClient` and I've overridden `-setReachabilityStatusChangeBlock:` with an `NSLog(@"test")` inside but the statement is never executed. Why? – Fred Collins Feb 15 '12 at 05:01
@FredCollins Check that you've included the SystemConfiguration framework. If that's not linked to the project, that code won't run. – mattt Feb 16 '12 at 21:41
@mattt could you add some sample code so I could see what should I do. Thanks – Simon Apr 24 '12 at 23:17
1

@FredCollins You don't override the method, you call it on your subclass and pass in a block which contains the code you want to run. Make sure you take out your override or it WILL NOT WORK. – Lance May 21 '12 at 23:39
9

Add `#import ` to the header prefix of the project (Prefix.pch). This is required step after adding SystemConfiguration framework. – Avinash Jun 26 '12 at 08:17
3

@mattt I have set `setReachabilityStatusChangeBlock:` before setting up a `JSONRequestOperationWithRequest:success:failure`, is this the right way to do it? if that's the case, when I get a status of `AFNetworkReachabilityStatusNotReachable`, how do I cancel the operation, or would the failure block be automatically called when it sees a `AFNetworkReachabilityStatusNotReachable`? – minovsky Oct 27 '12 at 08:18

score 28 · Answer 2 · edited Jan 06 '15 at 06:12

With AFNetworking these are the steps that one has to follow in order to take advantage of setReachabilityStatusChangeBlock: after adding the AFNetworing classes -

Add SystemConfiguration.framework to your project
In pch file add #import <SystemConfiguration/SystemConfiguration.h>
Assuming that you have a subclass of AFHTTPClient in this subclass add below lines of code in init function -

[self setReachabilityStatusChangeBlock:^(AFNetworkReachabilityStatus status) {
        NSLog(@"changed %d", status);
        //your code here
    }];

score 2 · Answer 3 · edited Aug 14 '14 at 08:58

I use the AFNetworkingOperationDidFinishNotification. Every time a http request will fail, the alert pops up and informs the user

- (void)addNetworkObserver
{
   [[NSNotificationCenter defaultCenter] addObserver:self
                                            selector:@selector(HTTPOperationDidFinish:) 
                                                name:AFNetworkingOperationDidFinishNotification 
                                              object:nil];
}

- (void)HTTPOperationDidFinish:(NSNotification *)notification 
{
   AFHTTPRequestOperation *operation = (AFHTTPRequestOperation *)[notification object];
   if (![operation isKindOfClass:[AFHTTPRequestOperation class]]) {
       return;
   }
   if (operation.error) {
       UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Connection error"
                                                       message:@"Missing connection to the internet"
                                                      delegate:nil
                                             cancelButtonTitle:@"OK"
                                             otherButtonTitles:nil];

       [alert show];
   }
}

score 2 · Answer 4 · answered Feb 12 '12 at 23:11

Maybe you could use "Reachability" to determine if the device is connected to the network. Here is the link to the Apple Doc. : Reachability

For example :

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleNetworkChange:) name:kReachabilityChangedNotification object:nil];
reachability = [Reachability reachabilityForInternetConnection];
[reachability startNotifier];
NetworkStatus remoteHostStatus = [reachability currentReachabilityStatus];
if(remoteHostStatus == NotReachable) {
  //Your UIAlertView
}

score 0 · Answer 5 · edited May 23 '17 at 12:31

0

How about using Reachability?

You can check whether you have a plausible reason for trying a connection before you do it.

Looks like the Apple Sample Project for Reachability shows how to get an initial status.

edited May 23 '17 at 12:31

Community

1
1

answered Feb 12 '12 at 23:03

Adam Eberbach

12,309
6
62
114

For any case where reachability returns no, won't any socket i/o fail immediately, too? – smparkes Feb 12 '12 at 23:04
Yes, that's how Reachability works but it gives you extras like the ability to receive notifications when reachability changes - interrupts, not polling. – Adam Eberbach Feb 12 '12 at 23:18
Excuse me Adam, but if the network is not used but the device is connected and I check for network status, Reachability tell me I've no connection. This answer explain what I would say in a better way: http://stackoverflow.com/a/9186073/719127 – Fred Collins Feb 12 '12 at 23:22
Right. I guess my point was for the question at hand, using reachability isn't any better than just trying to make the connection. – smparkes Feb 12 '12 at 23:27
Updated with a link to the code sample - checking reachability before making your actual request can be done. – Adam Eberbach Feb 12 '12 at 23:40
Thanks guy, I'll try to implement it in while and I come back with the response. :-) – Fred Collins Feb 13 '12 at 01:18

AFNetworking and No Internet Connection scenario

5 Answers5

Linked