How to save normal array into realm in background thread swift - ios

Question

I have a RealmManager class as bellow:
class RealmManager {
static func save<T: Object>(obj: [T]) {
let personRef = ThreadSafeReference(to: obj)
DispatchQueue.global(qos: .background).async {
autoreleasepool {
let realm = try! Realm()
try! realm.write({
realm.add(obj, update: .modified)
})
}
}
}
}
I'm trying to save a obj array into Realm database but my code do not compile getting this error:
Referencing initializer 'init(to:)' on 'ThreadSafeReference' requires
that '[_]' conform to 'ThreadConfined'
Any help?
Code update:
class RealmManager {
static func save<T: Object>(obj: [T]) {
let realm = try! Realm()
realm.asyncSaveArray(obj: obj)
}
static func get<T: Object>(type: T.Type) -> [T]? {
let realm = try! Realm()
return realm.objects(T.self).toArray(type: T.self)
}
}
extension Results {
func toArray<T>(type: T.Type) -> [T] {
return compactMap { $0 as? T }
}
}
extension Realm {
func asyncWrite<T : ThreadConfined>(obj: T, errorHandler: #escaping ((_ error : Swift.Error) -> Void) = { _ in return }, block: #escaping ((Realm, T?) -> Void)) {
let wrappedObj = ThreadSafeReference(to: obj)
let config = self.configuration
DispatchQueue.global(qos: .background).async {
autoreleasepool {
do {
let realm = try Realm(configuration: config)
let obj = realm.resolve(wrappedObj)
try realm.write {
block(realm, obj)
}
}
catch {
errorHandler(error)
}
}
}
}
func asyncSaveArray<T: Object>(obj: [T]) {
for item in obj {
self.asyncWrite(obj: item) { (realm, itemToSave) in
guard let itemToSave = itemToSave else { return }
realm.add(itemToSave, update: .modified)
}
}
}
}

Answer 1

To pass in an array of objects, you might use a Realm extension:
extension Realm {
  func asyncWrite<T : ThreadConfined>(obj: T, errorHandler: #escaping ((_ error : Swift.Error) -> Void) = { _ in return }, block: #escaping ((Realm, T?) -> Void)) {
    let wrappedObj = ThreadSafeReference(to: obj)
    let config = self.configuration
    DispatchQueue.global(qos: .background).async {
      autoreleasepool {
        do {
          let realm = try Realm(configuration: config)
          let obj = realm.resolve(wrappedObj)
           
          try realm.write {
            block(realm, obj)
          }
        }
        catch {
          errorHandler(error)
        }
      }
    }
  }
   
  func asyncSaveArray<T: Object>(obj: [T]) {
     
    for item in obj {
      self.asyncWrite(obj: item) { (realm, itemToSave) in
        guard itemToSave != nil else { return }
        realm.add(itemToSave!, update: .modified)
      }
    }
  }
}
There might be two possible use cases.
One is to actually pass an array of Objects:
realm.asyncSaveArray(obj: yourObjectsArray)
The other one is instead of passing in the array of objects, you can use an instance of Results<Object> received somewhere in code previously:
var yourObjects = realm.objects(YourType.self)
self.asyncWrite(obj: yourObjects) { (realm, itemToSave) in
        guard itemToSave != nil else { return }
        realm.add(itemToSave!, update: .modified)
}