Import JSON object/array into RestKit

File.swift

// Imports comment JSON into RestKit
let json: RestKitJSON = ["some_key": "some_value"] // [NSObject: AnyObject]
importObject(json, finished: { (model: YourModel?) -> () in
	print("YourModel - \(model)")
})

RestKitManagedObjectExtensions.swift

import Foundation

typealias RestKitJSON = [NSObject: AnyObject]

func importObject<T: NSManagedObject>(object: RestKitJSON?, objectStore: RKManagedObjectStore = RKManagedObjectStore.defaultStore(), finished: (object: T?) -> ()) {
	
	guard let object = object else {
		finished(object: nil)
		return
	}
	
	importObjects([object], objectStore: objectStore, finished: { (objects: [T]?) -> () in
		finished(object: objects?.first)
	})
}

func importObjects<T: NSManagedObject>(objects: [RestKitJSON]?, objectStore: RKManagedObjectStore = RKManagedObjectStore.defaultStore(), finished: (objects: [T]?) -> ()) {
	
	guard let objects = objects else {
		finished(objects: nil)
		return
	}
	
	// Get mappings for class
	var mappings = [NSObject: AnyObject]()
	let descriptors = RKObjectManager.sharedManager().responseDescriptors as? [RKResponseDescriptor] ?? []
	for descriptor in descriptors {
		if let mapping = descriptor.mapping as? RKEntityMapping
			where mapping.objectClass === T.self {
			mappings[descriptor.keyPath] = mapping
		}
	}

	// Get the mapper
	guard let mapper = RKMapperOperation(representation: objects, mappingsDictionary: mappings) else {
		finished(objects: nil)
		return
	}

	// Get datasource
	let datasource = RKManagedObjectMappingOperationDataSource(
		managedObjectContext: objectStore.persistentStoreManagedObjectContext,
		cache: objectStore.managedObjectCache
	)
	mapper.mappingOperationDataSource = datasource

	// Create queue for mapping operation to run
	let queue = NSOperationQueue()
	queue.addOperation(mapper)
	queue.waitUntilAllOperationsAreFinished()
	
	// Run and wait for the mapping to run in the context
	let context = RKManagedObjectStore.defaultStore().persistentStoreManagedObjectContext
	context.performBlock({ () -> Void in
		do {
			try context.saveToPersistentStore()
			let objects = mapper.mappingResult.array() as? [T]
			
			finished(objects: objects)
		} catch _ {
			finished(objects: nil)
		}
	})
}