AFNetworking checking Availability

Question

I've implemented AFNetworking without subclassing AFHTTPClient, in part using the following code in my DownloadQueueManager:

-(void)downloadPodcastAt:(NSString *)url toPath:(NSString *)path
{
    NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:url]
                                             cachePolicy:NSURLRequestReturnCacheDataElseLoad
                                         timeoutInterval:60.0];
    AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];

    operation.outputStream = [NSOutputStream outputStreamToFileAtPath:path append:NO];

    [operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject)
    {
        [self saveQueuedItemInformation];
    } failure:^(AFHTTPRequestOperation *operation, NSError *error)
    {
        // Other stuff
    }];

    [operation start];
}

My question is manifold. I've googled til' my fingers went numb, and have yet to find a decent code sample that simply and easily checks for Reachability status using AFNetworking. (Oddly, there is plenty of discussion about importing SystemConfiguration.framework, which seems like a no-brainer). So if my user wants to minimize their data usage, and only download using wifi, how do I check for wifi, and only download if wifi is available?

Second, it seems like AFNetworking wants to be a user-friendly front-end. But I could actually use a front-end to this front-end, because there's a LOT of stuff in there that one has to weed through to get to the stuff one needs. I just need to access a url, download an xml file (based on reachability), and do stuff with it. Am I missing something that makes this a simple task ?

When I make sense of this, I'm totally building a front-end or five to simplify implementation (assuming I'm not just an idiot). Thanks in advance for any responses.

Answer 1

Actually contrary to what A-Live said Reachability IS a part of AFNetworking. It's implemented in AFHTTPClient.h here. You need the correct imports in your .pch file as discussed here in order to use it.

To use it you'll probably want to have a subclass of AFHTTPClient so you can use setReachabilityStatusChangeBlock defined here. Here's a simple example without using a subclass.

AFHTTPClient *client = [AFHTTPClient clientWithBaseURL:[NSURL URLWithString:@"http://google.com"]];
[client setReachabilityStatusChangeBlock:^(AFNetworkReachabilityStatus status) {
    if (status == AFNetworkReachabilityStatusNotReachable) {
        // Not reachable
    } else {
        // Reachable
    }

    if (status == AFNetworkReachabilityStatusReachableViaWiFi) {
        // On wifi
    }
}];

If you don't like how this reachability setup works then I would recommend Tony Million's fork of Apple's Reachability. Simple example:

Reachability *reach = [Reachability reachabilityWithHostname:@"google.com"];
if ([reach isReachable]) {
    // Reachable
    if ([reach isReachableViaWiFi]) {
        // On WiFi
    }
} else {
    // Isn't reachable

    [reach setReachableBlock:^(Reachability *reachblock)
    {
        // Now reachable
    }];

    [reach setUnreachableBlock:^(Reachability*reach)
    {
        // Now unreachable
    }];
}

Answer 2

With AFNetworking 2.0 and above, one can check for availability like this,

    [[AFNetworkReachabilityManager sharedManager] setReachabilityStatusChangeBlock:^(AFNetworkReachabilityStatus status) {
    switch (status) {
        case AFNetworkReachabilityStatusUnknown:
        case AFNetworkReachabilityStatusReachableViaWWAN:
        case AFNetworkReachabilityStatusReachableViaWiFi:
            //available
            break;
        case AFNetworkReachabilityStatusNotReachable:
            //not available
            break;
        default:
            break;
    }

    NSLog(@"Reachability: %@", AFStringFromNetworkReachabilityStatus(status));

}];

//start monitoring
[[AFNetworkReachabilityManager sharedManager] startMonitoring];

To get current status

[AFNetworkReachabilityManager sharedManager].reachable

Answer 3

Just an update, the newer version of AFNetworking has deprecated AFHTTPClient.

You can use AFHTTPRequestOperationManager.h instead

Something small taken from the github page itself:

AFHTTPRequestOperationManager *manager = [[AFHTTPRequestOperationManager alloc] initWithBaseURL:url]; //url can be google.com or something you want to reach

NSOperationQueue *operationQueue = manager.operationQueue;
[manager.reachabilityManager setReachabilityStatusChangeBlock:^(AFNetworkReachabilityStatus status)

{
    switch (status)
    {
        case AFNetworkReachabilityStatusReachableViaWWAN:
        case AFNetworkReachabilityStatusReachableViaWiFi:
        {
            NSLog(@"SO REACHABLE");
            [operationQueue setSuspended:NO]; // or do whatever you want
            break;
        }

        case AFNetworkReachabilityStatusNotReachable:
        default:
        {
            NSLog(@"SO UNREACHABLE");
            [operationQueue setSuspended:YES]; 
            //not reachable,inform user perhaps
            break;
        }
    }
}];
[manager.reachabilityManager startMonitoring];