In my iOS app, I get the following exception:
'Linking objects notifications are only supported on managed objects.'
when I try to add an observer block:
y.xxx.observe { ... }
to a property that is defined as such:
class Y: Object {
...
let xxx = LinkingObjects(fromType: X.self, property: "y")
...
}
I believe this means that y.xxx does not have a Realm, and indeed I can see in the debugger that y.xxx.realm is nil. However, y.realm is NOT nil.
How can the linking objects not have a Realm if the object I am linking to does have one?
For completeness, this is how Class X is defined:
class X: Object {
...
#Persisted var y: Y?
...
}
Realm version 10.11.0, RealmDatabase version 11.1.1.
Context: I am in the last phase of migrating an app that was originally written in ObjC to be purely in Swift. This means switching to the Swift version of Realm. I have not encountered this problem in the previous version of the app that is largely the same code base except that it uses a very old version of the Realm framework and the Realm objects are defined in ObjC.
You can add an observer to a linking objects property as long as the objects are managed. Let me set this up starting with the PersonClass who has a List property of DogClass objects
class PersonClass: Object {
#objc dynamic var _id = ObjectId.generate()
#objc dynamic var name = "Jay"
let dogList = List<DogClass>()
override static func primaryKey() -> String? {
return "_id"
}
}
and then our DogClass has an inverse relationship to the PersonClass objects
class DogClass: Object {
#objc dynamic var _id = ObjectId.generate()
#objc dynamic var name = ""
let linkingOwners = LinkingObjects(fromType: PersonClass.self, property: "dogList")
override static func primaryKey() -> String? {
return "_id"
}
}
Then suppose we want to observe Spot's linkingOwners - both Jay and Cindy had Spot added to their dogList previously
let spot = realm.objects(DogClass.self).filter("name == 'Spot'").first!
self.peopleToken = spot.linkingOwners.observe { changes in
switch changes {
case .initial(let dogs):
print(" spots owners have been loaded")
case .update(_, let deletions, let insertions, let modifications ):
print(" something changed in spots owners")
case .error(let error):
print(error.localizedDescription)
}
}
Running this section of code outputs this to console and adds the observer the linkingObjects
spots owners have been loaded
Then, lets make a change to one of the owners properties
let jay = realm.objects(PersonClass.self).filter("name == 'Jay'").first!
try! realm.write {
jay.name = "Jay, Spots owner"
}
that last piece of code will output this to the console
something changed in spots owners
The above code creates a PersonClass object and a DogClass object object with a inverse relationship. The code then adds an observer the linkingObjects (PersonClass) and fires when one of them changes.
Turns out the linking objects now have to be declared like so:
class Y: Object {
...
#Persisted(originProperty: "y") var xxx: LinkingObjects<X>
...
}
I am not sure if the declaration style I used in my question is still supposed to be valid and if this is a bug, but using the new style gets rid of the exception.
Related
I met a problem in realm-cocoa 2.8.0(in 2.7.0 it works good) which is when I want to save an object into the realm file, I saw an empty object with default value is saved into the realm rather than the object I created(even the primary key is different.)
Eg.
class XXXRealmObject: RLMObject {
#objc dynamic var id: String = UUID().uuidString.lowercased()
#objc dynamic var name: String = ""
#objc init(name: String) {
self.name = name
super.init()
}
#objc override init() {
super.init()
}
override class func primaryKey() -> String {
return "id"
}
}
let obj = XXXRealmObject(name: "jojo")
let realm = try! RLMRealm(configuration: .default())
try? realm.transaction {
*breakpoint*
realm.addOrUpdate(object)
}
I add a before realm.addOrUpdate(object) and print the object, it show correct object, but after realm.addOrUpdate(object) get executed, in realm file, I can only see an object
{
id: 169e6bc2-9b34-44ae-8ac3-70e6b9145adc,
name: ""
}
and the id is also different from what I saw in break point. It looks like Realm create an object rather use the object I passed in. I am asking for some help here.
So what will cause realm create an empty object(maybe default value?) rather than save the object I passed. I just want to get some possible reasons here.
I think I got it, in my project, we have a category for NSObject which include a method called objectForKey, and in Realm's src, when we read value from RLMObject, we check if it can response to objectForKey, normally it should return false and keep executing following code to get the real value, but in my project, the code will return nil because it's not a dictionary.
So will close this
OK, first, I know that there is no such thing as AnyRealmObject.
But I have a need to have something the behaves just like a Realm List, with the exception that any kind of Realm Object can be added to the list -- they don't all have to be the same type.
Currently, I have something like this:
enter code here
class Family: Object {
var pets: List<Pet>
}
class Pet: Object {
var dog: Dog?
var cat: Cat?
var rabbit: Rabbit?
}
Currently, if I wanted to add in, say, Bird, I'd have to modify the Pet object. I don't want to keep modifying that class.
What I really want to do is this:
class Family: Object {
var pets: List<Object>
}
Or, maybe, define a Pet protocol, that must be an Object, and have var pets: List<Pet>
The point is, I want a databag that can contain any Realm Object that I pass into it. The only requirement for the databag is that the objects must be Realm Objects.
Now, since Realm doesn't allow for this, how could I do this, anyway? I was thinking of creating something like a Realm ObjectReference class:
class ObjectReference: Object {
var className: String
var primaryKeyValue: String
public init(with object: Object) {
className = ???
primaryKeyValue = ???
}
public func object() -> Object? {
guard let realm = realm else { return nil }
var type = ???
var primaryKey: AnyObject = ???
return realm.object(ofType: type, forPrimaryKey: primaryKey)(
}
}
The stuff with the ??? is what I'm asking about. If there's a better way of doing this I'm all ears. I think my approach is ok, I just don't know how to fill in the blanks, here.
(I'm assuming that you are writing an application, and that the context of the code samples and problem you provided is in terms of application code, not creating a library.)
Your approach seems to be a decent one given Realm's current limitations; I can't think of anything better off the top of my head. You can use NSClassFromString() to turn your className string into a Swift metaclass object you can use with the object(ofType:...) API:
public func object() -> Object? {
let applicationName = // (application name goes here)
guard let realm = realm else { return nil }
guard let type = NSClassFromString("\(applicationName).\(className)") as? Object.Type else {
print("Error: \(className) isn't the name of a Realm class.")
return nil
}
var primaryKey: String = primaryKeyValue
return realm.object(ofType: type, forPrimaryKey: primaryKey)(
}
My recommendation is that you keep things simple and use strings exclusively as primary keys. If you really need to be able to use arbitrary types as primary keys you can take a look at our dynamic API for ideas as to how to extract the primary key value for a given object. (Note that although this API is technically a public API we don't generally offer support for it nor do we encourage its use except when the typed APIs are inadequate.)
In the future, we hope to offer enhanced support for subclassing and polymorphism. Depending on how this feature is designed, it might allow us to introduce APIs to allow subclasses of a parent object type to be inserted into a list (although that poses its own problems).
This may not be a complete answer but could provide some direction. If I am reading the question correctly (with comments) the objective is to have a more generic object that can be the base class for other objects.
While that's not directly doable - i.e. An NSObject is the base for NSView, NSString etc, how about this...
Let's define some Realm objects
class BookClass: Object {
#objc dynamic var author = ""
}
class CardClass: Object {
#objc dynamic var team = ""
}
class MugClass: Object {
#objc dynamic var liters = ""
}
and then a base realm object called Inventory Item Class that will represent them
class InvItemClass: Object {
#objc dynamic var name = ""
#objc dynamic var image = ""
#objc dynamic var itemType = ""
#objc dynamic var book: BookClass?
#objc dynamic var mug: MugClass?
#objc dynamic var card: CardClass?
}
then assume we want to store some books along with our mugs and cards (from the comments)
let book2001 = BookClass()
book2001.author = "Clarke"
let bookIRobot = BookClass()
bookIRobot.author = "Asimov"
let item0 = InvItemClass()
item0.name = "2001: A Space Odyssey"
item0.image = "Pic of Hal"
item0.itemType = "Book"
item0.book = book2001
let item1 = InvItemClass()
item1.name = "I, Robot"
item1.image = "Robot image"
item1.itemType = "Book"
item1.book = bookIRobot
do {
let realm = try Realm()
try! realm.write {
realm.add(item0)
realm.add(item1)
}
} catch let error as NSError {
print(error.localizedDescription)
}
From here, we can load all of the Inventory Item Objects as one set of objects (per the question) and take action depending on their type; for example, if want to load all items and print out just the ones that are books.
do {
let realm = try Realm()
let items = realm.objects(InvItemClass.self)
for item in items {
switch item.itemType {
case "Book":
let book = item.book
print(book?.author as! String)
case "Mug":
return
default:
return
}
}
} catch let error as NSError {
print(error.localizedDescription)
}
As it stands there isn't a generic 'one realm object fits all' solution, but this answer provides some level of generic-ness where a lot of different object types could be accessed via one main base object.
I have a Models class defined like this:
class BaseModel: Object {
var data: JSON = JSON.null
convenience init(_ data: JSON) {
self.init()
self.data = data
}
override static func ignoredProperties() -> [String] {
return ["data"]
}
}
class RecipeModel: BaseModel {
dynamic var title: String {
get { return data["fields"]["title"].stringValue }
set { self.title = newValue }
}
... more vars ...
var ingredients: List<IngredientsModel> {
get {
let ingredients = List<IngredientsModel>()
for item in data["fields"]["ingredients"] {
ingredients.append(IngredientsModel(item.1))
}
return ingredients
}
set { self.ingredients = newValue }
}
}
class IngredientsModel: BaseModel {
dynamic var text: String {
get { return data["text"].stringValue }
set { self.text = newValue }
}
... more vars ...
}
And I would like to use it something like this:
Api.shared.fetchAllEntries().call(onSuccess: {response in
print(response.json)
let realm = try! Realm()
try! realm.write {
realm.deleteAll()
}
for item in response.json["items"].arrayValue {
let recipe = RecipeModel(item)
try! realm.write {
realm.add(recipe)
}
}
}, onError: {
print("error")
})
So basically the idea is to just pass the whole JSON to the initial RecipeModel class, and it should parse it out and create the objects I need in the Realm database. It works quite well except for the nested list of IngredientsModel. They do not get added to the realm database.
What I see as a potential problem is that I call self.init() before I call self.data in the convenience init, but I do not see any way to work around this. Do you guys please know how I could achieve that also the IngredientsModel would have its contents set up properly and I would have a list of ingredients in the RecipeModel?
Your current implementation doesn't work, because you are not calling the getter/setter of ingredients in the init method of RecipeModel and hence the IngredientsModel instances are never persisted in Realm.
Moreover, using a computed property as a one-to-many relationship (Realm List) is a really bad idea, especially if you are parsing the results inside the getter for this property. Every time you call the getter of ingredients, you create new model objects instead of just accessing the existing ones that are already stored in Realm, but you are never deleting the old ones. If you were actually saving the IngredientsModel instances to Realm (which you don't do at the moment as mentioned above) you would see that your database is full of duplicate entries.
Your whole approach seems really suboptimal. You shouldn't store the unparsed data object in your model class and use computed properties to parse it. You should parse it when initializing your models and shouldn't store the unparsed data at all. You can use the ObjectMapper library for creating Realm objects straight away from the JSON response.
I'm new in Realm and I tried to add an Array as I did with strings and I ended up with some errors. So after a little search I found out a solution:
class Sensors : Object {
dynamic var name = ""
dynamic var message = ""
var topic: [String] {
get {
return _backingNickNames.map { $0.stringValue }
}
set {
_backingNickNames.removeAll()
_backingNickNames.append(objectsIn: newValue.map({ RealmString(value: [$0]) }))
}
}
let _backingNickNames = List<RealmString>()
override static func ignoredProperties() -> [String] {
return ["topic"]
}
}
class RealmString: Object {
dynamic var stringValue = ""
}
This is working very good, now I want to add another array inside this class.
If someone knows any other ways to add arrays with realm please share it.
Thanks in advance
As a general rule it's way more efficient to use the one-to-many relationships provided by Realm instead of trying to emulate them by using arrays (Realm's collections are lazy, the objects contained are instantiated only when needed as opposed to plain Swift arrays).
In your case, if I understand correctly what you're trying to do, you want to add [RealmString] Swift arrays to the _backingNickNames list.
Why not use the append(objectsIn:) method of Realm's List class (see here), like this:
// Dog model
class Dog: Object {
dynamic var name = ""
dynamic var owner: Person?
}
// Person model
class Person: Object {
dynamic var name = ""
dynamic var birthdate = NSDate(timeIntervalSince1970: 1)
let dogs = List<Dog>()
}
let jim = Person()
let dog1 = Dog()
let dog2 = Dog()
// here is where the magic happens
jim.dogs.append(objectsIn: [dog1, dog2])
If you want to do the opposite (convert from a List to an Array) just do :
let dogsArray = Array(jim.dogs)
• • • • • • • •
Back to your own posted solution, you could easily refactor the model to accommodate this. Each Sensor object could have several Topic and several Message objects attached.
Just ditch the message and topic computed properties and rename topicV and messageV to topics and messages respectively. Also rename RealmString to Topic and RealmString1 to Message.
Now, you could easily iterate through the, say, topics attached to a sensor like this :
for topic in sensor1.topics { ... }
Or if you want to attach a message to a sensor you could do something like this (don't forget to properly add the newly created object to the DB first):
let message1 = Message()
message1.stringValue = "Some text"
sensor2.messages.append(message1)
So, no need to use intermediary Swift Arrays.
After testing I managed to add another array like that:
class Sensors : Object {
dynamic var type = ""
dynamic var name = ""
dynamic var badge = 0
var topic: [String] {
get {
return topicV.map { $0.stringValue }
}
set {
topicV.removeAll()
topicV.append(objectsIn: newValue.map({ RealmString(value: [$0]) }))
}
}
var message: [String] {
get {
return messageV.map { $0.stringValue1 }
}
set {
messageV.removeAll()
messageV.append(objectsIn: newValue.map({ RealmString1(value: [$0]) }))
}
}
let topicV = List<RealmString>()
let messageV = List<RealmString1>()
override static func ignoredProperties() -> [String] {
return ["topic", "message"]
}
}
class RealmString: Object {
dynamic var stringValue = ""
}
class RealmString1: Object {
dynamic var stringValue1 = ""
}
What bogdanf has said, and the way you've implemented it are both correct.
Basic value types aside, Realm can only store references to singular Realm Object objects, as well as arrays of Objects using the List type. As such, if you want to save an array of types, it's necessary to encapsulate any basic types you want to save (like a String here) in a convenience Realm Object.
Like bogdanf said, it's not recommended to convert Realm Lists to standard Swift arrays and back again, since you lose the advantages of Realm's lazy-loading features (which can cause both performance and memory issues), but memory issues can at least be mitigated by enclosing the code copying data out of Realm in an #autoreleasepool block.
class MyObject: Object {
dynamic var childObject: MyObject?
let objectList = List<MyObject>()
}
So in review, it's best practice to work directly with Realm List objects whenever possible, and to use #autoreleasepool any time you do actually want to loop through every child object in a Realm. :)
I'm trying to create a bundle realm for my application. I thought it should be quite simple. Since I already have all needed records in Parse, I just have to:
create realm models and objects
load parse records to realm objects
save the realm
So, I created two realm models:
class RealmContainer : Object {
dynamic var rContainerId: String! //should be equal objectId from Parse
dynamic var rContainerName: String! //should be equal "name" field from Parse
...
var messages = List<RealmMessage>()
override static func primaryKey() -> String? {
return "rContainerId"
}
}
and
class RealmMessage : Object {
dynamic var rMessageId: String!
...
dynamic var rParentContainer: RealmContainer!
}
Getting results from Parse seems to be working. Also my realm objects are also good
var allUserContainers: [RealmContainer] = []
I was able to populate this array with values from Parse. But when I'm trying to save this realm, I'm getting a) nothing or b) error message
My code (this one'll get nothing):
let realm = try! Realm()
try! realm.write {
realm.add(self.allUserContainers[0])
print(Realm().path)
print(realm.path)
}
My code (this one'll get nothing too):
let realm = try! Realm()
try! realm.write {
realm.create(RealmContainer.self, value: self.allUserContainers[0], update: true)
print(Realm().path)
print(realm.path)
}
My code 3 (this will get me an error message "Terminating app due to uncaught exception 'RLMException', reason: 'Illegal recursive call of +[RLMSchema sharedSchema]. Note: Properties of Swift Object classes must not be prepopulated with queried results from a Realm"):
//from firstViewController, realm is a global variable
let realm = try! Realm()
//another swift module
try! realm.write {
realm.create(RealmContainer.self, value: self.allUserContainers[0], update: true)
print(Realm().path)
print(realm.path)
}
Obviously I don't properly understand how it should work, but I tried several swift/realm tutorials and they were actually straightforward. So, what did I do wrong?
Update
So, I updated my code to make it as much simple/readable as possible. I have a Dog class, and I am trying to get Dogs from Parse and put them to Realm.
AppDelegate.swift
let realm = try! Realm() //global
Dog.swift
class Dog : Object {
dynamic var name = ""
dynamic var age = 0
}
User.swift (getDogs and putDogs functions)
class User {
var newDogs:[Dog] = []
...
func getDogs() {
self.newDogs = []
let dogsQuery = PFQuery(className: "Dogs")
dogsQuery.limit = 100
dogsQuery.findObjectsInBackgroundWithBlock { (currentModes, error) -> Void in
if error == nil {
let tempModes:[PFObject] = currentModes as [PFObject]!
for var i = 0; i < tempModes.count; i++ {
let temp = Dog()
temp.name = currentModes![i]["dogName"] as! String
self.newDogs.append(temp)
}
} else {
print("something happened")
}
}
}
...
func putDogs() {
print(self.newDogs.count)
try! realm.write({ () -> Void in
for var i = 0; i < newDogs.count; i++ {
realm.add(newDogs[i])
}
})
try! realm.commitWrite() //doesn't change anything
}
error message still the same:
Terminating app due to uncaught exception 'RLMException', reason:
'Illegal recursive call of +[RLMSchema sharedSchema]. Note: Properties
of Swift Object classes must not be prepopulated with queried
results from a Realm
I believe I just have some global misunderstanding about how Realm is working because it is extremely simple configuration.
About your RealmSwift code : You have implemented it right.
When you declare a class of realm in swift, it's a subclass of Object class. Similarly for the parse it's subclass of PFObject.
You custom class have to have only one base class. So can't use functionalities of both the libraries Parse as well as Realm.
If you have to have use both Parse and Realm, you need to declare two different classes like RealmMessage and ParseMessage.
Retrieve data for ParseMessage from parse and copy properties to RealmMessage.
Why you want to use both Parse and Realm ?
parse also provides local data store by just writing Parse.enableLocalDatastore() in appDelegate before
Parse.setApplicationId("key",
clientKey: "key")
Your Realm Swift code seems fine. Realm is very flexible when creating objects using (_:value:update:), in being able to take in any type of object that supports subscripts. So you could even directly insert PFObject if the schemas matched.
The problem seems to be how you're populating the allUserContainers array. As the error says, you cannot fetch a Realm Object from Realm and then try and re-add it that way. If you're trying to update an object already in Realm, as long as the primary key properties match, you don't need to supply the whole object back again.
Can you please revisit the logic of how your allUserContainers variable is being populated, and if you can't fix it, post the code into your question?
Sidenote: You probably don't need to define your Realm properties as implicitly unwrapped as well. This is the recommended pattern:
class RealmContainer : Object {
dynamic var rContainerId = ""
dynamic var rContainerName = ""
}
Actually I found what was wrong: as i suspected it was a stupid mistake, some property in my class was UIImage type, and Realm just can't work with this type (even if I'm not trying to put objects of this class into realm). So, my bad. I am slightly embarassed by it, but will not delete my question because error messages from Realm were not very understandable in this case