gistfile1.m

// The following code only needs to be called once, and only requires to be called before user input is expected
// It performs some very basic logic to handle search queries

RACSignal* searchTextChanged = [self rac_signalForSelector:@selector(searchBar:textDidChange:)
						fromProtocol:@protocol(UISearchBarDelegate)];
	
__block NSInteger minimumSearchLength = 3;

[[[[searchTextChanged
map:^id(RACTuple *tuple) {
	// Grab searchText from method call, searchText is the second argument
	NSString* searchText = tuple.second;
	return searchText;
	
}] doNext:^(NSString* searchText){
	// Implement some view logic
	if (searchText.length <= minimumSearchLength && self.navController.viewControllers[0] != self.spotsDrillDown) {
		[self.navController setViewControllers:@[self.spotsDrillDown] animated:YES];
	}
	
}] filter:^BOOL(NSString* searchText){
	// Limit searching to queries with at least a length of minimumSearchLength
	return searchText.length >= minimumSearchLength;
	
}] subscribeNext:^(NSString* searchText){
	// Present searchResults controller, perform search
	if (self.navController.viewControllers[0] != self.spotSelectViewController) {
		[self.navController setViewControllers:@[self.spotSelectViewController] animated:YES];
	}
	self.spotSelectViewController.spots = [self.spotManager spotsMatchingQuery:searchText];
}];



///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// This is the traditional alternative


- (void)viewDidLoad { // or similar
	self.searchBar.delegate = self
}

#pragma mark - UISearchBarDelegate

- (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText {
	NSInteger minimumSearchLength = 3;

	if (searchText.length > minimumSearchLength) {
		self.searching = YES;
		self.spotSelectViewController.spots = [self.spotManager spotsMatchingQuery:searchText];
	} else {
		self.searching = NO;
		[searchBar resignFirstResponder];
	}
}

#pragma mark - Setters

- (void)setSearching:(BOOL)searching {
	if (searching != _searching) {
		_searching = searching;
		
		if (_searching) {
			[self.navController setViewControllers:@[self.spotSelectViewController] animated:YES];
		} else {
			[self.navController setViewControllers:@[self.spotsDrillDown] animated:YES];
		}
	}
}