How else can I return the items in the array? I'm having trouble with the returning items as it's saying that I have used it before initializing it.
class func fetchEntities(className:NSString, withPredicate predicate:NSPredicate?, managedObjectContext:NSManagedObjectContext)->NSArray {
let fetchRequest: NSFetchRequest = NSFetchRequest()
let entetyDescription: NSEntityDescription = NSEntityDescription.entityForName(className as String, inManagedObjectContext: managedObjectContext)!
fetchRequest.entity = entetyDescription
if (predicate != nil) {
fetchRequest.predicate = predicate!
}
fetchRequest.returnsObjectsAsFaults = false
let items:NSArray
do {
items = try managedObjectContext.executeFetchRequest(fetchRequest)
}
catch(let error as NSError) {
NSLog(error.localizedDescription)
}
return items
}
You can define array of type ManagedObject and store result in it as below. I have declared an array named users which is of type ManagedObject User
// Declare users array which stores objects of `User` class only.
var users = [<User>]()
// Execute request and store result into array
users = try managedObjectContext.executeFetchRequest(fetchRequest)
// return stored array
return users
i hope this helps you.
You should be returning NSArray? (i.e. nullable) as it can be nul if an exception is thrown:
do {
items = try managedObjectContext.executeFetchRequest(fetchRequest)
}
catch(let error as NSError) {
NSLog(error.localizedDescription) // HERE!!!
}
return items
Related
I have a contact CKRecord with many location CKRecords ( 1 to many relationship)
Both contact CKRecord and Location CKRecord are created in public Database. I add CKReference fro contact to locaiotn via a field named owningContact on location.
ckRecord["owningContact"] = CKReference(record: contactRecord!, action: .deleteSelf)
I go to cloudKit dashboard and verify both the records exist. The location CKRecord has field owningContact that has the recordName of the contact CKRecord. I defined a function to get locations like this:
private func iCloudFetchLocations(withContactCKRecord: CKRecord, completionHandler: #escaping ([CKRecord]?, Error?) -> Void) {
var records = [CKRecord]()
let recordToMatch = CKReference(recordID: withContactCKRecord.recordID, action: .deleteSelf)
let predicate = NSPredicate(format: "owningContact == %#", recordToMatch)
// Create the query object.
let query = CKQuery(recordType: "location", predicate: predicate)
let queryOp = CKQueryOperation(query: query)
queryOp.resultsLimit = 1
queryOp.qualityOfService = .userInteractive
queryOp.recordFetchedBlock = {
records.append($0)
print($0)
}
queryOp.queryCompletionBlock = { (cursor, error) in
guard error == nil else {
if let ckerror = error as? CKError {
self.aErrorHandler.handleCkError(ckerror: ckerror)
}
return
}
if (cursor != nil) {
let newOperation = CKQueryOperation(cursor: cursor!)
newOperation.resultsLimit = queryOp.resultsLimit
newOperation.recordFetchedBlock = queryOp.recordFetchedBlock
newOperation.queryCompletionBlock = queryOp.queryCompletionBlock
self.publicDB?.add(newOperation)
}
completionHandler(records, error)
}
self.publicDB?.add(queryOp)
}
Then I call the code to fetch location CKRecord based on contact CKRecord like this:
let predicate = NSPredicate(format: "TRUEPREDICATE")
let query = CKQuery(recordType: Cloud.Entity.Contact, predicate: predicate)
publicDB?.perform(query, inZoneWith: nil, completionHandler: { (records, error) in
guard error == nil else {
if let ckerror = error as? CKError {
self.aErrorHandler.handleCkError(ckerror: ckerror)
}
return
completion(false)
}
if let contactRecords = records {
for aContactRecord in contactRecords {
// fetch Location Data
self.iCloudFetchLocations(withContactCKRecord: aContactRecord, completionHandler: { records, error in
guard error == nil else {
if let ckerror = error as? CKError {
self.aErrorHandler.handleCkError(ckerror: ckerror)
}
return
completion(false)
}
if let locationRecords = records {
}
})
}
}
})
I have two contacts the first one has been CKReferenc'ed to the location, where as the second contact is still not yet CKReferenc'ed to the location.
I think here is the problem: First time in the loop contact CKRecord information is sent by calling iCloudFetchLocations which returns immediately without waiting for cloud response, and the for loop sends the second contact and calls iCloudFetchLocations again. Since the second contact has no CKReference to the location, the call fails and I can never get to the first contact's location since it hasn't returned yet.
How to fix this?
I found that I had not set the CKReference field: owningContact as Queryable. The way I found out is printing error like this:
if let ckerror = error as? CKError {
print(ckerror.userInfo)
print(ckerror.errorUserInfo)
self.aErrorHandler.handleCkError(ckerror: ckerror)
}
As soon as I did that it started working, Since I was in a for loop it was timing out on previous fetch I think.
I am following an outdated tutorial from the Ray Wenderlich team that walks through the repopulation of a Core Data-backed application by using a Command Line Tool application.
I have successfully prepopulated the intended entities, verified by performing an NSFetchRequest.
Now, I want to use the same prepopulated data in my unit tests to verify that my interactions with CoreData are happening correctly. I tried setting up my mocked CoreDataStack subclass to use an in-memory store, but when I attempt to verify that I have the prepopulated data for use in my unit tests, I am getting a count of 0.
The class responsible for interacting with CoreData in my application's target, named CoreDataStack, follows:
/// The object that is responsible for managing interactions with Core Data.
internal class CoreDataStack {
// MARK: - Properties
/// The name of the `NSManagedObjectModel` object used for storing information with Core Data.
private let modelName: String
/// The `NSManagedObjectContext` object that is associated with the main queue.
internal lazy var mainContext: NSManagedObjectContext = {
return self.storeContainer.viewContext
}()
/// The `NSPersistentContainer` object that encapsulates the application's Core Data stack.
internal lazy var storeContainer: NSPersistentContainer = {
let container = NSPersistentContainer(name: self.modelName)
let directory = NSPersistentContainer.defaultDirectoryURL()
let storeURL = directory.appendingPathComponent("\(self.modelName).sqlite")
if !FileManager.default.fileExists(atPath: (storeURL.path)) {
guard let populatedURL = Bundle.main.url(forResource: self.modelName, withExtension: "sqlite") else {
fatalError("Invalid populated .sqlite file URL")
}
do {
try FileManager.default.copyItem(at: populatedURL, to: storeURL)
} catch {
fatalError("Error: \(error)")
}
}
let description = NSPersistentStoreDescription()
description.url = storeURL
container.persistentStoreDescriptions = [description]
container.loadPersistentStores(completionHandler: { (storeDescription, error) in
if let error = error as NSError? {
fatalError("Error: \(error)")
}
})
return container
}()
// MARK: - Initialization
/// Returns an instance of `CoreDataStack`.
/// - parameter modelName: The name of the `NSManagedObjectModel` object used for storing information with Core Data.
internal init(modelName: String) {
self.modelName = modelName
}
/// Attempts to save items to Core Data by committing changes to `NSManagedObject`s in a `NSManagedObjectContext`.
/// - parameter context: The `NSManagedObjectContext` of which changes should be committed.
internal func saveContext(_ context: NSManagedObjectContext) {
context.perform {
do {
try context.save()
} catch let error as NSError {
fatalError("Unresolved error \(error), \(error.userInfo)")
}
}
}
}
The subclass of CoreDataStack, MockCoreDataStack, used for testing follows:
internal class MockCoreDataStack: CoreDataStack {
// MARK: - Initialization
convenience init() {
self.init(modelName: "Currency")
}
override init(modelName: String) {
super.init(modelName: modelName)
let container = NSPersistentContainer(name: modelName)
let directory = NSPersistentContainer.defaultDirectoryURL()
let storeURL = directory.appendingPathComponent("\(modelName).sqlite")
if !FileManager.default.fileExists(atPath: (storeURL.path)) {
guard let populatedURL = Bundle(for: type(of: self)).url(forResource: modelName, withExtension: "sqlite") else {
fatalError("Invalid populated .sqlite file URL")
}
do {
try FileManager.default.copyItem(at: populatedURL, to: storeURL)
} catch {
fatalError("Error: \(error)")
}
}
let description = NSPersistentStoreDescription()
description.url = storeURL
description.type = NSInMemoryStoreType
container.persistentStoreDescriptions = [description]
container.loadPersistentStores { (storeDescription, error) in
if let error = error as NSError? {
fatalError("Unresolved error \(error), \(error.userInfo)")
}
}
self.storeContainer = container
}
}
The resulting count of my fetch request is 0 in my unit tests target. I expect to return a count consisting of the number of prepopulated objects, just as I get when I return the count in my application's target.
What am I doing incorrectly that is causing me to not return the expected result?
The in memory store doesn't use the store URL. It just creates an empty store in memory.
As an alternative to the in memory store, you could possibly create a parent NSManagedObjectContext between the persistent store and the contexts you actually use. (I'm not sure how that would play with NSPersistentContainer, however.)
Then you can just rollback() the parent context when you want to reset back to your initial state.
I'm in my first steps of using Realm Mobile Database, and I would like to know if there is a way of handling the error caused by trying to add an object with the same primaryKey as one previously inserted, causing the following Can't create object with existing primary key value.
Here are my snippets:
class CategoryRLM: Object {
dynamic var name: String = ""
dynamic var desc: String = ""
override static func primaryKey() -> String? {
return "name"
}
}
static func addCategory(category: CategoryRLM) -> Bool {
let realm = try! Realm()
do {
try realm.write {
realm.add(category)
}
return true
}
catch let error {
print(error)
return false
}
}
Using the previous function:
if !CategoryRLM.addCategory(category: newCategory) {
// There was an error while adding the object
}
The thing is that the error doesn't get handled by the do-catch.
Attempting to add an object with a primary key that already exists is classed as programmer error (that is, misuse of the API), and as such it is not possible to handle this error at runtime.
In your case you should instead check if an object exists with that primary key prior to attempting to add the category to the Realm:
static func addCategory(category: CategoryRLM) -> Bool {
let realm = try! Realm()
if let existingCategory = realm.object(ofType: CategoryRLM.self, forPrimaryKey: category.name) {
return false
}
try realm.write! {
realm.add(category)
}
return true
}
The glass mapper will return null object or (no items) for SitecoreQuery and SitecoreChildren attribute that are placed on the GlassModels. These attributes don't take any such parameter where I can specify them to return items if they don't exist in the the context lanaguge. The items e.g. exist in EN but don't exist in en-ES. I need to put a lot of null check in my views to avoid Null exception and makes the views or controller very messy. It is lot of boiler plate code that one has to write to make it work.
In Page Editor the SitecoreChildren returns item and content authors can create items in that langauge version by editing any field on the item. This automatically creates the item in that langauge. However the same code will fail in Preview mode as SitecoreChidren will return null and you see null pointer exception.
SitecoreQuery doesn't return any items in page editor and then Content Authors wont be able to create items in Page editor.
To make the experience good if we can pass a parameter to SiteocreQuery attribute so it disable VsersionCount and returns the items if they dont exist in that langauge.
This is actually not possible. There is an issue on GitHub which would make it easy to create a custom attribute to handle this very easy. Currently you need to create a new type mapper and copy all the code from the SitecoreQueryMapper. I have written a blog post here about how you can create a custom type mapper. You need to create the following classes (example for the SitecoreQuery).
New configuration:
public class SitecoreSharedQueryConfiguration : SitecoreQueryConfiguration
{
}
New attribute:
public class SitecoreSharedQueryAttribute : SitecoreQueryAttribute
{
public SitecoreSharedQueryAttribute(string query) : base(query)
{
}
public override AbstractPropertyConfiguration Configure(PropertyInfo propertyInfo)
{
var config = new SitecoreSharedQueryConfiguration();
this.Configure(propertyInfo, config);
return config;
}
}
New type mapper:
public class SitecoreSharedQueryTypeMapper : SitecoreQueryMapper
{
public SitecoreSharedQueryTypeMapper(IEnumerable<ISitecoreQueryParameter> parameters)
: base(parameters)
{
}
public override object MapToProperty(AbstractDataMappingContext mappingContext)
{
var scConfig = Configuration as SitecoreQueryConfiguration;
var scContext = mappingContext as SitecoreDataMappingContext;
using (new VersionCountDisabler())
{
if (scConfig != null && scContext != null)
{
string query = this.ParseQuery(scConfig.Query, scContext.Item);
if (scConfig.PropertyInfo.PropertyType.IsGenericType)
{
Type outerType = Glass.Mapper.Sc.Utilities.GetGenericOuter(scConfig.PropertyInfo.PropertyType);
if (typeof(IEnumerable<>) == outerType)
{
Type genericType = Utilities.GetGenericArgument(scConfig.PropertyInfo.PropertyType);
Func<IEnumerable<Item>> getItems;
if (scConfig.IsRelative)
{
getItems = () =>
{
try
{
return scContext.Item.Axes.SelectItems(query);
}
catch (Exception ex)
{
throw new MapperException("Failed to perform query {0}".Formatted(query), ex);
}
};
}
else
{
getItems = () =>
{
if (scConfig.UseQueryContext)
{
var conQuery = new Query(query);
var queryContext = new QueryContext(scContext.Item.Database.DataManager);
object obj = conQuery.Execute(queryContext);
var contextArray = obj as QueryContext[];
var context = obj as QueryContext;
if (contextArray == null)
contextArray = new[] { context };
return contextArray.Select(x => scContext.Item.Database.GetItem(x.ID));
}
return scContext.Item.Database.SelectItems(query);
};
}
return Glass.Mapper.Sc.Utilities.CreateGenericType(typeof(ItemEnumerable<>), new[] { genericType }, getItems, scConfig.IsLazy, scConfig.InferType, scContext.Service);
}
throw new NotSupportedException("Generic type not supported {0}. Must be IEnumerable<>.".Formatted(outerType.FullName));
}
{
Item result;
if (scConfig.IsRelative)
{
result = scContext.Item.Axes.SelectSingleItem(query);
}
else
{
result = scContext.Item.Database.SelectSingleItem(query);
}
return scContext.Service.CreateType(scConfig.PropertyInfo.PropertyType, result, scConfig.IsLazy, scConfig.InferType, null);
}
}
}
return null;
}
public override bool CanHandle(AbstractPropertyConfiguration configuration, Context context)
{
return configuration is SitecoreSharedQueryConfiguration;
}
}
And configure the new type mapper in your glass config (mapper and parameters for the constructor):
container.Register(Component.For<AbstractDataMapper>().ImplementedBy<SitecoreSharedQueryTypeMapper>().LifeStyle.Transient);
container.Register(Component.For<IEnumerable<ISitecoreQueryParameter>>().ImplementedBy<List<ItemPathParameter>>().LifeStyle.Transient);
container.Register(Component.For<IEnumerable<ISitecoreQueryParameter>>().ImplementedBy<List<ItemIdParameter>>().LifeStyle.Transient);
container.Register(Component.For<IEnumerable<ISitecoreQueryParameter>>().ImplementedBy<List<ItemIdNoBracketsParameter>>().LifeStyle.Transient);
container.Register(Component.For<IEnumerable<ISitecoreQueryParameter>>().ImplementedBy<List<ItemEscapedPathParameter>>().LifeStyle.Transient);
container.Register(Component.For<IEnumerable<ISitecoreQueryParameter>>().ImplementedBy<List<ItemDateNowParameter>>().LifeStyle.Transient);
You can then simply change the SitecoreQuery attribute on your model to SitecoreSharedQuery:
[SitecoreSharedQuery("./*")]
public virtual IEnumerable<YourModel> YourItems { get; set; }
For the children you could either use the shared query mapper and querying the children or create the same classes for a new SitecoreSharedChildren query.
Edit: Added bindings for IEnumerable<ISitecoreQueryParameter> as they are missing and therefor it threw an error.
Problem: I can't assign a string array (typed as 'AnyObject') to an empty array.
Steps:
1. Get a dictionary containing strings & arrays.
2. Grab an array from this dictionary via the key 'photos'.
Note: Xcode's warning suggest that I give the explicit type 'AnyObject'.
3. Create an empty array.
4. Attempt to assign it (failed).
let responseDictionary = responseDict as [String : AnyObject]
let ricPhotos:AnyObject = responseDictionary["photos"]!
var thePhotos:Array<AnyObject>?
thePhotos = ricPhotos <--- fails
Compiler Error:
...'AnyObject' is not convertible to 'Array<AnyObject>'
Question: How do I assign 'ricPhotos' to the empty array 'thePhotos' and preferably cast 'AnyObject' to 'String'?
Revision
let responseDictionary = responseDict as [String : AnyObject]
var anyObject: AnyObject? = responseDictionary["photos"]
Okay, 'anyObject' appears to be a Dictionary, and inside it is 'photo' which is an array; as seen in the data.
Here's some of the data(anyObject):
{
page = 1;
pages = 1334;
perpage = 100;
photo = (
{
farm = 3;
"height_m" = 336;
"height_s" = 161;
"height_sq" = 75;
"height_t" = 67;
id = 15166756998;
isfamily = 0;
isfriend = 0;
ispublic = 1;
owner = "127012961#N08";
secret = 053032f300;
server = 2941;
title = "You #NYPL";
"url_m" = "https://farm3.staticflickr.com/2941/15166756998_053032f300.jpg";
"url_s" = "https://farm3.staticflickr.com/2941/15166756998_053032f300_m.jpg";
"url_sq" = "https://farm3.staticflickr.com/2941/15166756998_053032f300_s.jpg";
"url_t" = "https://farm3.staticflickr.com/2941/15166756998_053032f300_t.jpg";
"width_m" = 500;
"width_s" = 240;
"width_sq" = 75;
"width_t" = 100;
},
...etc.
I want to grab the 'photo' array. But I can't downcast 'anyObject' to 'Dictionary' so that I can subscript it. I tried:
var anyObject:Dictionary = responseDictionary["photos"]
But I got:
'(String, AnyObject)' is not convertible to '[String : AnyObject]'
So I'm stuck with:
var anyObject: AnyObject? = responseDictionary["photos"]
So with anyObject, I tried to access 'photos':
let RicPhotos = anyObject["Photo"] as [String : AnyObject]
...I also tried:
let RicPhotos = anyObject["Photo"] as Array<Dictionary<String,String>>
But I got:
'AnyObject?' does not have a member named 'subscript'
I can see the data, but I can't extract into an empty variable.
I attempted to downcast to a specific type (Dictionary) but the compiler refuses.
There must be a strait forward way of getting an embedded array from a dictionary whilst casting to its respective cast (without the 'anyObject').Any ideas?
Edited my answer to fit your edit...
let responseDictionary = [:] as [String : AnyObject]
var photosDic: AnyObject? = responseDictionary["photos"]
if let photosDic = photosDic as? Dictionary<String, AnyObject> {
var photosArray: AnyObject? = photosDic["photo"]
if let photosArray = photosArray as? Array<Dictionary<String, AnyObject>> {
//There you go
}
}