ios - Reactive Cocoa and multiple AFNetworking requests in short period of time -

i'm struggeling way handle multiple requests web service afnetworking , reactive cocoa. in scenario user asking api deliver bunch of suggestions character/integer search input pick city out of list.

here's code:

first method gets executed user types in more 3 characters/integers

- (void)fetchdata:(nsstring *)searchtext {     nslog(@"%@", searchtext);      if ([searchtext validatestringwithpattern:bkpostcoderegex]) {         self.searchurl = [nsstring stringwithformat:@"%@location/postalcode/%@/%@", bkbaseurl, self.countrycode, searchtext];     } else if ([searchtext validatestringwithpattern:bkcityregex]) {         self.searchurl = [nsstring stringwithformat:@"%@location/city/%@/%@", bkbaseurl, self.countrycode, searchtext];     } else {         nslog(@"error alert - no valid input");         return;     }      rac(self, searchresults) = [[[self postrequest] map:^(nsdictionary *json) {         nsarray *results = json[@"data"][@"locations"];         return results;     }] catch:^(nserror *error) {         return [racsignal return:@[]];     }]; } 

now create signal , pass self.searchresults:

- (racsignal *)postrequest {     return [[[racsignal createsignal:^racdisposable *(id<racsubscriber> subscriber) {          [self.requestoperationmanager get:self.searchurl parameters:self.params success:^(afhttprequestoperation *operation, id responseobject) {             [subscriber sendnext:responseobject];             [subscriber sendcompleted];         }failure:^(afhttprequestoperation *operation, nserror *error) {             [subscriber senderror:error];         }];          return [racdisposable disposablewithblock:^{             [self.requestoperationmanager.operationqueue cancelalloperations];         }];      }] doerror:^(nserror *error) {         nslog(@"error: %@", [error description]);     }] throttle:0.5]; } 

i think problem is, start subscribing signal before signal prior current signal has been completed , cause exception i'm trying subscribe again.

* terminating app due uncaught exception 'nsinternalinconsistencyexception', reason: 'signal name: [[[[+createsignal:] -doerror:] -throttle: 0.500000] -map:] -catch: bound key path "searchresults" on object , adding signal name: [[[[+createsignal:] -doerror:] -throttle: 0.500000] -map:] -catch: undefined behavior'

my guess have try in postrequest method doesn't seem work out of box:

if (self.requestoperationmanager.operationqueue.operationcount == 1) {   nslog(@"cancel operations");   [self.requestoperationmanager.operationqueue cancelalloperations];   [subscriber sendcompleted]; } 

you can call rac() once on given object's key path. looks -fetchdata: can called more once, result in rac() being called multiple times on same object , key path.

typically, call rac() in sort of setup method (such initializer or -[uiviewcontroller loadview]) gets called once. instead of waiting until user types more 3 characters , calling -fetchdata:, think how create signal sends value when user types more 3 characters, , assign signal rac()'d property. example (completely untested):

- (void)someinitializationmethod {     racsignal *morethan3 = [[mytextfield rac_textsignal] filter:^(nsstring *text) {         return [text length] > 2;     }];      rac(self, searchresults) = [self rac_liftselector:@selector(fetchdata:) withsignals:morethan3]; }  - (void)fetchdata:(nsstring *)searchtext {     if ([searchtext validatestringwithpattern:bkpostcoderegex]) {         // ... etc ...     }      return [[[self postrequest] map:^(nsdictionary *json) {         nsarray *results = json[@"data"][@"locations"];         return results;     }] catch:^(nserror *error) {         return [racsignal return:@[]];     }]; }  - (racsignal *)postrequest {     // ... etc ...