Category on NSManagedObject

NSManagedObject+MVVM.m

#import "NSManagedObject+MVVM.h"
#import <RBCoreDataStack/NSManagedObject+RBCoreDataStack.h>

@implementation NSManagedObject (MVVM)

+ (RACSignal *)fetchAllSignalInContext:(NSManagedObjectContext *)context {
    return [self fetchAllSignalWithPredicate:nil inContext:context];
}

+ (RACSignal *)fetchAllSignalWithPredicate:(NSPredicate *)predicate inContext:(NSManagedObjectContext *)context {
    
    NSParameterAssert(context);
    
    return [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
        
        NSFetchRequest * request = [self fetchRequest];
        request.predicate = predicate;
        
        [context performBlock:^{
            
            NSError * error = nil;
            NSArray * results = [context executeFetchRequest:request error:&error];
            
            if (results) {
                [subscriber sendNext:results];
            }
            else {
                [subscriber sendError:error];
            }
            
            [subscriber sendCompleted];
        }];
        
        return [RACDisposable disposableWithBlock:^{}];
    }];
}

@end

NSManagedObjectContext+MVVM.m

#import "NSManagedObjectContext+MVVM.h"

@implementation NSManagedObjectContext (MVVM)

- (RACSignal *)saveContextSignal {
    
    return [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
        
        [self performBlock:^{
            
            NSError * error = nil;
            BOOL success = [self save:&error];
            
            if (success) {
                [subscriber sendNext:self];
            }
            else {
                [subscriber sendError:error];
            }
            
            [subscriber sendCompleted];
        }];
        
        return [RACDisposable disposableWithBlock:^{}];
    }];
}