Reactive Cocoa: Response from HTTPRequest using RACCommand

Question

I'm completely new to the Reactive Cocoa Framework and i'm just doing some simple tests but i'm encountering a problem that i would like to understand.

Basically i'm just doing an API call to fetch a JSON object from my server, i want to do this with RAC. So my steps are the following:

First i build the RACCommand this way:

RACCommand *getLatestVersionCommand = [[RACCommand alloc] initWithSignalBlock:^RACSignal *(id input) {
    return [[[API sharedInstance] getLatestAppVersion]
                materialize];
}];

Now i create the signal and subscribe to it this way:

RACSignal *versionCodeSignal = [[getLatestVersionCommand.executionSignals flatten] deliverOn:[RACScheduler mainThreadScheduler]];
[[versionCodeSignal
    map:^id(NSDictionary *responseObject) {
        return responseObject;
    }]
    subscribeNext:^(NSDictionary *responseObject) {
        NSArray *allVersions = [[NSArray alloc] initWithArray:[responseObject objectForKey:KEY_VERSIONS]];
        for(NSDictionary *version in allVersions) {
            NSString *device = [version objectForKey:KEY_DEVICE];
            if([device isEqualToString:KEY_IOS]) {
                NSString *latestVersionName = [[version objectForKey:KEY_VERSION] objectForKey:KEY_NAME];
                if([APP_VERSION compare:latestVersionName options:NSNumericSearch] == NSOrderedAscending) {
                    //There is a new version!
                    NSLog(@"There is a new version!!!");
                }
            }
        }
    }];

Finally I execute the command this way

[getLatestVersionCommand execute:self];

The problem i'm facing is that in the subscribeNext block, the object i receive is an RACEvent object and not the dictionary i'm expecting. I know i'm doing something wrong and not understanding the full flow correctly, i tried adding the map function that i thought i didn't need just to test and nothing.

The only way i found is to convert the response in the map block to a RACEvent and return its value but that doesn't seem to me the right way to go.

Any light will be greatly appreciated.

Answer 1

Remove the call to -[RACSignal materialize] from your command's signal block.