I have an app which is inconsistently returning 'nil' when using FileHandle to open a file for Read. I'm on OSX (10.13.4), XCode 9.4, Swift 4.1
This OSX app uses the NSOpenPanel() to get a list of files selected by the user. My 'model' class code opens these files to build a collection of data structures The code which does this starts out like this and successfully gets a FileHandle EVERY TIME for any file and is able to read data from the file.
private func getFITHeader(filename: String) {
let file: FileHandle? = FileHandle(forReadingAtPath: filename)
if file == nil {
print("FITFile >>> File open failed for file \(filename)")
}
else {
var databuffer: Data
databuffer = (file?.readData(ofLength: 80))!
:
:
}
The files also contain a block of binary data which I process in another part of the app. While I develop the code for this I'm temporarily hard coding one of the same filenames as works above for test purposes. BUT this code (below) ALWAYS throws an exception 'Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value' when it gets to fileHandle?.seek() - for some reason the attempt to create a FileHandle is always returning 'nil' despite the code being functionally identical to tha above.
#IBAction func btnProcFile(_ sender: Any) {
var data: Data
let filename = "/Users/johncneal/Dropbox/JN Astronomy/Astronomy/Spectroscopy/RSpec_Analyses/Gamma_Cas/20161203/Gamma Cas_065.fit"
let fileHandle: FileHandle? = FileHandle(forReadingAtPath: filename)
fileHandle?.seek(toFileOffset: 2880) //skip past the headers
let dataLenToRead = 1391 * 1039 * 2
data = (fileHandle?.readData(ofLength: dataLenToRead))!
:
:
}
The code in the second function works fine in a Playground (not attaching too much meaning to that) and, wierdly, has also worked when temporarily added to a different project. Probably also worth mentioning the length of the file path doesn't seem to matter - it behaves the same on short paths.
So the question is - why is this behaviour of FileHandle reliably inconsistent?
print()'ing the filenames presented to FileHandle() showed they were identical in each case (see below). So I'm stumped and frustrated by this - any perspectives or workarounds would be appreciated.
/Users/johncneal/Dropbox/JN Astronomy/Astronomy/Spectroscopy/RSpec_Analyses/Gamma_Cas/20161203/Gamma Cas_065.fit
/Users/johncneal/Dropbox/JN Astronomy/Astronomy/Spectroscopy/RSpec_Analyses/Gamma_Cas/20161203/Gamma Cas_065.fit
Found the answer - Sandboxing !!
Darren - coincidentally I did look at the URL based route and discovering it 'throws' put some proper error reporting in the catches. Low and behold they reported I didn't have permissions on the file (which initially surprised me since I'm obviously admin on my Mac's and all the files ar local and under my username.
I bit more research turned up. this article - https://forums.developer.apple.com/thread/96062 which quickly revealed its a sandboxing problem :-) Looks like recent versions of XCode have it turned on in 'Entitlements'. The post also points out that the NSOpenPanel FileOpen dialog returns 'Security scoped urls'. At first I thought this explained why the code in the first function worked but I'm not totally convinced because I was only feeding the url.path property to FileHandle.
However, turning off Sandbox in Entitlements makes everything work just fine. Yes, I know thats not the right thing to do longer term (or if I want this to go to the App Store) so I'll be checking out the right way to do this. At least I can get on now - thanks for the input.
The FileHandle initializers are not well named.
You should use FileHandle(forReadingFrom:URL) instead of FileHandle(forReadingAtPath:String). The former is newer API that throws an error instead of returning nil. You can use the thrown error to see why it is failing, and your variables are guaranteed to be non-nil.
For example:
#IBAction func btnProcFile(_ sender: Any) {
do {
let fileUrl = URL(fileURLWithPath:"/Users/johncneal/Dropbox/JN Astronomy/Astronomy/Spectroscopy/RSpec_Analyses/Gamma_Cas/20161203/Gamma Cas_065.fit")
let fileHandle = try FileHandle(forReadingFrom: fileUrl)
fileHandle.seek(toFileOffset: 2880) //skip past the headers
let dataLenToRead = 1391 * 1039 * 2
let data: Data = fileHandle.readData(ofLength: dataLenToRead)
// etc...
} catch let error as NSError {
print("FITFile >>> File open failed: \(error)")
NSApp.presentError(error)
}
}
I am testing a sync conflict when I save a record that contains a CKAsset (simply a JPG image) using CKModifyRecordsOperation with a save policy of .IfServerRecordUnchanged. I am getting the error CKErrorCode.ServerRecordChanged. This CKError returns me useful information for conflict resolution, including the CKRecord I tried to save, and the current server version of the record. The first is in error.userInfo[CKRecordChangedErrorClientRecordKey] the second is in error.userInfo[CKRecordChangedErrorServerRecordKey].
My problem is I am trying to access the server record's CKAsset with this code:
if let photoAsset = rec["myPhoto"] as? CKAsset {
print("PhotoAsset.fileURL: \(photoAsset.fileURL)") // BAD_ACCESS ERROR HERE
self.myPartner.photo = NSData(contentsOfURL: photoAsset.fileURL)
}
I don't get how this is possible. But after further investigating, I print out the client and server CKRecords and the server one is missing the 'path' property.
client CKAsset...myPhoto (modified) -> CKAsset: 0x7b960d90; path=~/tmp/BF185B2C-7A39-4730-9530-9797E843243Aphoto, size=373959, uploadRank=0, uploadReceipt=A92Eg1qoyPG7yrg3, UUID=3C2D5DC8-4FF5-4A81-853B-395FC1C59862, referenceSignature=<012fd149 200fc600 617e3907 88763e3e 5002abbf 5b>, flags=uploaded, wrappedEncryptionKey=, signature=<0134a297 38d52f5f 9275bfba fce5b1a8 3d6b9692 d3>
server CKAsset...myPhoto = CKAsset: 0x7be700d0; referenceSignature=<015337bd 84409893 7c014f46 36248d27 ce911dc3 7a>, size=373959, uploadRank=0, UUID=DF5D2EB4-033C-49A2-AF52-6055B5A44106, wrappedEncryptionKey=<767e7cfd d1e62110 32119ee9 f6f026b3 5bcf0cc3 8053a4de>, signature=<0134a297 38d52f5f 9275bfba fce5b1a8 3d6b9692 d3>
Notice how path=~/tmp/C706423B-A3E8-4051-A9B3-483C718BFBF5photo is missing from the server one? Can anyone explain this? To fix it I try to avoid touching the CKAsset from the server record. I would like to at least be able to check for nil. I wanted to put this out there in case it helps anyone else.
Due to the crash on accessing fileURL, this is most likely a framework bug. Probably an oversight on account of the CKRecord being buried in a dictionary. I just follow it up with a regular fetch(withRecordID:).
I'm experiencing this issue as well on iOS 11.2.1 when accessing CKAsset from serverRecord property in CKRecord. It's a little bit frustrating. A workaround is fetching the object once again via func fetch(withRecordID... and then access fileURL.
This seems like the correct behavior, not a bug.
CloudKit informed you that your write operation failed because you weren't working from the latest CKRecord and gave you a non-hydrated version of the server's current CKRecord so you could determine which fields were different from your starting point. The rest is up to you.
If CloudKit returned the fully hydrated server record in the error response for a write operation, it would potentially waste enormous amounts of bandwidth/resources.
That is why CKAssets exist: to separate the size-constrained key-value fields associated with a CKRecord from the unlimited-size binary assets that can be attached to them.
I get the following error when i try to unarchive a custom object
'cannot decode object of class (PhotoList) for key (root); the class may be defined in source code or a library that is not linked'
I currently have a version on the app store (v1.0, have issued an update via version TestFlight (v2.0) and this is where the error happens. The error doesn't happen on the same version builds via Xcode. Nothing has changed (that I can see!) that would have caused this.
Here is the code I have for archiving the object
let data = NSKeyedArchiver.archivedDataWithRootObject(VehicleList.instance)
NSUserDefaults.standardUserDefaults().setObject(data, forKey: "archiveName")
And here is the code I have for unarchiving the object
if let data = NSUserDefaults.standardUserDefaults().objectForKey("archiveName") as? NSData {
let photoList : PhotoList = NSKeyedUnarchiver.unarchiveObjectWithData(data) as! PhotoList
}
It turns out the issue was related to multiple targets. It seems when I duplicated targets, I swapped over the original target with another, so it was in fact a different target that couldn't unarchive the data.
So be careful when you create targets and make sure you don't mix them up! Hope this saves someone the amount of time it took me to figure this out!
I am writing a program in Swift that uses Just to fetch a webpage. I am new to Swift and know very little about it. My code is simple:
let r = Just.get("https://www.google.com/")
print(r.statusCode!)
print(r.text)
I would expect to see the contents of the downloaded web page, however, the output is:
200
nil
How can I retrieve the text contents of the response?
The problem is in your URL. If you'll try this, your response won't be nil:
let r = Just.get("https://medium.com/")
print(r.text!)
}
I had a project that was working fine. It had "Core Data" checked, and had the data model all set up. I only started adding a couple entities and properties tonight. When I try to run my app now, it won't even load. It just crashes on me.
Here's the error:
'NSInvalidArgumentException', reason: 'executeFetchRequest:error: A fetch request must have an entity.'
I'm really scared because I don't have a backup of this and if I can't get it working I don't know what I'll do. :)
Thanks in advance!
EDIT:
I got fed up with my data, so I just copied a new blank xcdatamodel to my project and I'm going to start fresh. Thanks for the help!
My issue is I didn't use the same name for Entity and Class. Trivial solution to fix it is by giving them the same name.
If you are using MagicalRecored with Swift:
Make sure you use #objc directive in the Swift NSManagedObject subclass to make the class accessible to Objective-C code from the MagicalRecord library
#objc(MyEntity)
class MyEntity: NSManagedObject {
#NSManaged var myAttribute: Int16
}
After searching all over for a solution, what fixed it for me was doing a Clean/Build in Xcode.
Product->Clean, Product->Build, then try running it.
It seemed as if my data got corrupted, so I deleted my data model and the database in the iPhone simulator, and started fresh.
I had the same error.
For me, it is because I have added a new Model Version, but I did not set it as "Current Version". Careless me! To fix, select the xcdatamodel, click Design > Data Model > Set Current Version. The xcdatamodel file will then have a green tick.
Hopes that helps.
Also, make sure that your .xcdatamodeld file is in the "Copy Bundle Resources" phase of your Build Phases.
Here's what fixed it for me:
As I was converting to Swift 3, Xcode was giving me an error when declaring a new NSFetchRequest, saying that it needed a type. After adding the type, I did what anyone else would have assumed; if the request is typed, why specify an entity name? So, I removed it.
It actually was my mistake.
Swift 2.2:
let request = NSFetchRequest(entityName: "MyEntity")
When I first converted to Swift 3:
let request = NSFetchRequest<MyEntity>()
That was giving me an error. I ended up with this:
let request = NSFetchRequest<MyEntity>(entityName: "MyEntity")
And everything works fine. Personally, I'm not sure why it needs to have an entity name specified, if you're typing the request. Maybe they'll update that at some point (I hope)
i found this solution in the apple develper forum and it was exactly my problem!
the solutions is that the context must be defined inside the struct App.
not in the environment parameter
import SwiftUI
#main
struct CoreDataDemoApp: App {
private let context = CoreDataStack.context.
var body: some Scene {
WindowGroup {
ContentView()
.environment(\.managedObjectContext, context)
}
}
}
Check if,
the entity is present in the xcdatamodel file.
entity name used are same.
If you are using Swift 3 and Core Data's new stack syntax:
var persistentContainer: NSPersistentContainer = {
let container = NSPersistentContainer(name: "MyAppModel")
container.loadPersistentStores(completionHandler: {
(storeDescription, error) in
if let error = error as NSError? {
fatalError("Unresolved error \(error), \(error.userInfo)")
} else {
print(storeDescription)
}
})
return container
}()
Then you should be using this fetch syntax:
let request: NSFetchRequest<Client> = Client.fetchRequest()
I had this error on the first fetch after app launches when using different variations:
let request: NSFetchRequest<NSFetchRequestResult> = Client.fetchRequest()
let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Client")
I did stumble across the same precise error upon taking my first steps into Core Data (and iOS 11 and Swift 4). I started off a book (sixth edition meant to target Swift 4 but presumably including some legacy stuff).
As suggested in the book my code was:
let fetchRequest = NSFetchRequest<ReminderData>()
let entity = ReminderData.entity()
fetchRequest.entity = entity
do {
let rows = try managedObjectContext.fetch(fetchRequest)
} catch {
fatalError("Unresolved error")
}
It turned out that all I got from ReminderData.entity() is nil. Not sure if I did something wrong when setting up the data model or ... Apple's docs say that NSManagedObject.entity() must not be overwritten?
Long story short, the Codegen file ReminderData+CoreDataProperties.swift did include the solution:
#nonobjc public class func fetchRequest() -> NSFetchRequest<ReminderData> {
return NSFetchRequest<ReminderData>(entityName: "ReminderDB")
}
which was all I had to use to end-up with a proper NSFetchRequest, no fiddling with the NSEntityDescription, problem gone!
let fetchRequest = NSFetchRequest<ReminderData>(entityName: "ReminderDB")
do {
let rows = try managedObjectContext.fetch(fetchRequest)
} catch {
fatalError("Unresolved error")
}
I built clean, and that didn't fix it. Then I deleted the app, and that didn't fix it. Then I built clean and deleted the app AT THE SAME TIME, and that fixed it.
Just add the same problem. I copied all my entities. Deleted the data model, recreated an empty one and pasted the entities back into the new data model. Solved my issue.
First I downloaded the app's data through the Organizer (to see what was happening) and noticed that it offered me to save it under a previous project name. This puzzled me. So I exited XCode 4.6.1, deleted the app (and its data) from my iPhone, and came back.
This time I got an error saying Cannot create an NSPersistentStoreCoordinator with a nil model. So I looked into the AppDelegate.m file and changed the URLForResource in the - (NSPersistentStoreCoordinator *) persistentStoreCoodinator method. It was set to the name of my app, and I changed it to 'Model' so as to match the name of my Model.xcdatamodeld.
It's working now.
This happened to me when I was fetching from the wrong database. My application has 3 sqlite databases, and of course 3 ManagedObjectContext instances. Well I was submitting the wrong ManagedObjectContext to a method asking it to query a table that didn't exist in the ManagedObjectContext I submitted. After using the correct ManagedObjectContext, all was good.
I think the original question/problem, and also the issue that most of these answers fixes (just in different ways) is just a real simple one:
Anytime you modify your core data (like adding an entity as you mention), you either have to delete all existing data (if you haven't published your app yet), or add a new version to your model.
Just thought I would post this answer, even though this is an older question, because this answer seems pretty obvious and so far hasn't been discussed in any of the questions or comments I read above.
You can also use setter method from CoraData ... Just do something like this...
On your CustomCoreDataManager.m
import "ObjectiveRecord.h"
call init method like this
(instancetype)init {
self = [super init];
if (self) {
[[CoreDataManager sharedManager] setModelName:#"YourModelName"];
}
return self; }
Hope this helps to someone...
Maybe you are trying to load a Database from a different/the wrong bundle?
For instance from or within a Framework?
I had this issue and solved it by loading the DB from the bundle of the related Framework. And then it all worked fine!!
Swift 4 + MagicalRecord:
let frameworkBundle = Bundle(for: AClassFromTheFramework.self)
let managedObjectModel = NSManagedObjectModel.mergedModel(from: [frameworkBundle])
MagicalRecord.setShouldAutoCreateManagedObjectModel(false)
NSManagedObjectModel.mr_setDefaultManagedObjectModel(managedObjectModel)
MagicalRecord.setupCoreDataStack(withAutoMigratingSqliteStoreNamed: "db.sqlite")
And voila !
I faced same issue, actually i was calling MyEnty instead of MyEntity so please re-check what names you have given to your entities and call the same and also check whether you are calling same attributes that you have defined like name
In my case, it was because this dropdown was not set to "Current Product Module" in the Data Model Inspector in Xcode (13.4.1):
Once I set that, it stopped crashing.
Hope this helps!