How to avoid unsubscribe after catch error or resubscribe

[vincentsong]

Hi Guys,

I have a some code like below

RAC(self, A) = [RACObserve(self, B) flattenMap:^id(id param) {
    return [self doSomthingToGetA:param];// this may throw an error
}] catch:^RACSignal *(NSError *error){

    //do some other things
    return [RACSignal return:nil];
}

when the error happened, next time I cannot get the signal for B anymore. So my question is there any way to avoid unsubscribe after catch error? Or do I need to use any other methods such as then: or something else?

[erikprice]

You can put -repeat at the end of your signal chain if you want to automatically have the signal be resubscribed-to if it completes. You can put -retry at the end of your signal chain if you want to automatically have the signal be resubscribed-to if it errors.

[vincentsong]

Hi Erik,

If I put repeat at the end, the block in flattenMap will be called after error happened and then it falls to a infinite loop.

[erikprice]

What signal do you want A to be subscribed to if an error occurs?

[mdiep]

If you put the -catch: inside the -flattenMap:, then the outer signal won't error.

RAC(self, A) = [RACObserve(self, B)
    flattenMap:^(id param) {
        return [[self
            doSomthingToGetA:param]; // this may throw an error
            catch:^(NSError *error){
                //do some other things
                return [RACSignal return:nil];
            }];
    }];

[vincentsong]

Thanks mdlep, that fixed my problem.

[ChaosLin]

Excellent solution!Thank mdiep :)@mdiep