Part 7: Simple PersistenceController

AppShared/JustOneThingApp.swift

@@ -9,6 +9,7 @@ import SwiftUI
 
 @main
 struct JustOneThingApp: App {
+    let persistenceController = PersistenceController.shared
     var body: some Scene {
         WindowGroup {
             ContentView()

JustOneThing.xcodeproj/project.pbxproj

@@ -39,6 +39,16 @@
 		5493A81B2A471E37001EBA08 /* JustOneThingProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5493A81A2A471E36001EBA08 /* JustOneThingProvider.swift */; };
 		5493A81C2A471E37001EBA08 /* JustOneThingProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5493A81A2A471E36001EBA08 /* JustOneThingProvider.swift */; };
 		5493A81D2A471E37001EBA08 /* JustOneThingProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5493A81A2A471E36001EBA08 /* JustOneThingProvider.swift */; };
+		54AE28412A5823D900719A56 /* JustOneThingCloudModel.xcdatamodeld in Sources */ = {isa = PBXBuildFile; fileRef = 54AE283F2A5823D900719A56 /* JustOneThingCloudModel.xcdatamodeld */; };
+		54AE28422A5823D900719A56 /* JustOneThingCloudModel.xcdatamodeld in Sources */ = {isa = PBXBuildFile; fileRef = 54AE283F2A5823D900719A56 /* JustOneThingCloudModel.xcdatamodeld */; };
+		54AE28432A5823D900719A56 /* JustOneThingCloudModel.xcdatamodeld in Sources */ = {isa = PBXBuildFile; fileRef = 54AE283F2A5823D900719A56 /* JustOneThingCloudModel.xcdatamodeld */; };
+		54AE28442A5823D900719A56 /* JustOneThingCloudModel.xcdatamodeld in Sources */ = {isa = PBXBuildFile; fileRef = 54AE283F2A5823D900719A56 /* JustOneThingCloudModel.xcdatamodeld */; };
+		54AE28452A5823D900719A56 /* JustOneThingCloudModel.xcdatamodeld in Sources */ = {isa = PBXBuildFile; fileRef = 54AE283F2A5823D900719A56 /* JustOneThingCloudModel.xcdatamodeld */; };
+		54AE28472A58245700719A56 /* PersistenceController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54AE28462A58245700719A56 /* PersistenceController.swift */; };
+		54AE28482A58245700719A56 /* PersistenceController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54AE28462A58245700719A56 /* PersistenceController.swift */; };
+		54AE28492A58245700719A56 /* PersistenceController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54AE28462A58245700719A56 /* PersistenceController.swift */; };
+		54AE284A2A58245700719A56 /* PersistenceController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54AE28462A58245700719A56 /* PersistenceController.swift */; };
+		54AE284B2A58245700719A56 /* PersistenceController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54AE28462A58245700719A56 /* PersistenceController.swift */; };
 		54BD36092A5700480022D6BE /* ThingView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54BD36082A5700480022D6BE /* ThingView.swift */; };
 		54BD360A2A5700480022D6BE /* ThingView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54BD36082A5700480022D6BE /* ThingView.swift */; };
 		54BD360B2A5700480022D6BE /* ThingView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 54BD36082A5700480022D6BE /* ThingView.swift */; };
@@ -144,6 +154,8 @@
 		54928C462A35F8CB00095445 /* WatchWidgetExtension.appex */ = {isa = PBXFileReference; explicitFileType = "wrapper.app-extension"; includeInIndex = 0; path = WatchWidgetExtension.appex; sourceTree = BUILT_PRODUCTS_DIR; };
 		54928C4A2A35F8CB00095445 /* SystemWidget.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SystemWidget.swift; sourceTree = "<group>"; };
 		5493A81A2A471E36001EBA08 /* JustOneThingProvider.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = JustOneThingProvider.swift; sourceTree = "<group>"; };
+		54AE28402A5823D900719A56 /* JustOneThingCloudModel.xcdatamodel */ = {isa = PBXFileReference; lastKnownFileType = wrapper.xcdatamodel; path = JustOneThingCloudModel.xcdatamodel; sourceTree = "<group>"; };
+		54AE28462A58245700719A56 /* PersistenceController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PersistenceController.swift; sourceTree = "<group>"; };
 		54BD36082A5700480022D6BE /* ThingView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ThingView.swift; sourceTree = "<group>"; };
 		54BD360C2A57020E0022D6BE /* WidgetBundle.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WidgetBundle.swift; sourceTree = "<group>"; };
 		54BD36102A57021E0022D6BE /* AccessoryWidget.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AccessoryWidget.swift; sourceTree = "<group>"; };
@@ -234,13 +246,9 @@
 		5483902E2A2A773900BF5624 = {
 			isa = PBXGroup;
 			children = (
-				5407E5012A2A8A5100EF00B8 /* AppShared */,
+				54AE283E2A58230400719A56 /* Model */,
-				548390392A2A773900BF5624 /* JustOneThing */,
+				54AE283C2A5822C600719A56 /* Apps */,
-				5431ED6E2A2A77C900515680 /* JustOneThingWatch */,
+				54AE283D2A5822D400719A56 /* Widgets */,
-				5472018B2A3655E4005B2FCC /* WidgetShared */,
-				54928C192A35F89900095445 /* MacWidget */,
-				54928C312A35F8B800095445 /* PhoneWidget */,
-				54928C492A35F8CB00095445 /* WatchWidget */,
 				54928C142A35F89900095445 /* Frameworks */,
 				548390382A2A773900BF5624 /* Products */,
 			);
@@ -300,6 +308,36 @@
 			path = WatchWidget;
 			sourceTree = "<group>";
 		};
+		54AE283C2A5822C600719A56 /* Apps */ = {
+			isa = PBXGroup;
+			children = (
+				5407E5012A2A8A5100EF00B8 /* AppShared */,
+				548390392A2A773900BF5624 /* JustOneThing */,
+				5431ED6E2A2A77C900515680 /* JustOneThingWatch */,
+			);
+			name = Apps;
+			sourceTree = "<group>";
+		};
+		54AE283D2A5822D400719A56 /* Widgets */ = {
+			isa = PBXGroup;
+			children = (
+				5472018B2A3655E4005B2FCC /* WidgetShared */,
+				54928C192A35F89900095445 /* MacWidget */,
+				54928C312A35F8B800095445 /* PhoneWidget */,
+				54928C492A35F8CB00095445 /* WatchWidget */,
+			);
+			name = Widgets;
+			sourceTree = "<group>";
+		};
+		54AE283E2A58230400719A56 /* Model */ = {
+			isa = PBXGroup;
+			children = (
+				54AE283F2A5823D900719A56 /* JustOneThingCloudModel.xcdatamodeld */,
+				54AE28462A58245700719A56 /* PersistenceController.swift */,
+			);
+			path = Model;
+			sourceTree = "<group>";
+		};
 /* End PBXGroup section */
 
 /* Begin PBXNativeTarget section */
@@ -493,8 +531,10 @@
 			buildActionMask = 2147483647;
 			files = (
 				5407E5032A2A8AE700EF00B8 /* ContentView.swift in Sources */,
+				54AE28422A5823D900719A56 /* JustOneThingCloudModel.xcdatamodeld in Sources */,
 				5407E5022A2A8AE200EF00B8 /* JustOneThingApp.swift in Sources */,
 				547201932A365868005B2FCC /* Widget.intentdefinition in Sources */,
+				54AE28482A58245700719A56 /* PersistenceController.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -503,8 +543,10 @@
 			buildActionMask = 2147483647;
 			files = (
 				5483903D2A2A773900BF5624 /* ContentView.swift in Sources */,
+				54AE28412A5823D900719A56 /* JustOneThingCloudModel.xcdatamodeld in Sources */,
 				5483903B2A2A773900BF5624 /* JustOneThingApp.swift in Sources */,
 				54928C222A35F89A00095445 /* Widget.intentdefinition in Sources */,
+				54AE28472A58245700719A56 /* PersistenceController.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -512,11 +554,13 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				54AE28492A58245700719A56 /* PersistenceController.swift in Sources */,
 				54EB3C1F2A5434A30082B059 /* Thing.swift in Sources */,
 				54928C212A35F89A00095445 /* Widget.intentdefinition in Sources */,
 				5493A81B2A471E37001EBA08 /* JustOneThingProvider.swift in Sources */,
 				54BD36092A5700480022D6BE /* ThingView.swift in Sources */,
 				54BD360D2A57020E0022D6BE /* WidgetBundle.swift in Sources */,
+				54AE28432A5823D900719A56 /* JustOneThingCloudModel.xcdatamodeld in Sources */,
 				5416C7382A56A867002196EE /* InterfaceExtensions.swift in Sources */,
 				547201972A461DBE005B2FCC /* SystemWidget.swift in Sources */,
 			);
@@ -527,6 +571,7 @@
 			buildActionMask = 2147483647;
 			files = (
 				54BD36122A57021E0022D6BE /* AccessoryWidget.swift in Sources */,
+				54AE28442A5823D900719A56 /* JustOneThingCloudModel.xcdatamodeld in Sources */,
 				54EB3C202A5434A30082B059 /* Thing.swift in Sources */,
 				547201962A461DBE005B2FCC /* SystemWidget.swift in Sources */,
 				5493A81C2A471E37001EBA08 /* JustOneThingProvider.swift in Sources */,
@@ -534,6 +579,7 @@
 				54BD360E2A57020E0022D6BE /* WidgetBundle.swift in Sources */,
 				5416C7392A56A867002196EE /* InterfaceExtensions.swift in Sources */,
 				5472018E2A36563B005B2FCC /* Widget.intentdefinition in Sources */,
+				54AE284A2A58245700719A56 /* PersistenceController.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -541,11 +587,13 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				54AE284B2A58245700719A56 /* PersistenceController.swift in Sources */,
 				54BD36132A57021E0022D6BE /* AccessoryWidget.swift in Sources */,
 				54EB3C212A5434A30082B059 /* Thing.swift in Sources */,
 				547201902A36563C005B2FCC /* Widget.intentdefinition in Sources */,
 				5493A81D2A471E37001EBA08 /* JustOneThingProvider.swift in Sources */,
 				54BD360B2A5700480022D6BE /* ThingView.swift in Sources */,
+				54AE28452A5823D900719A56 /* JustOneThingCloudModel.xcdatamodeld in Sources */,
 				54BD360F2A57020E0022D6BE /* WidgetBundle.swift in Sources */,
 				5416C73A2A56A867002196EE /* InterfaceExtensions.swift in Sources */,
 			);
@@ -1088,6 +1136,19 @@
 			defaultConfigurationName = Release;
 		};
 /* End XCConfigurationList section */
+
+/* Begin XCVersionGroup section */
+		54AE283F2A5823D900719A56 /* JustOneThingCloudModel.xcdatamodeld */ = {
+			isa = XCVersionGroup;
+			children = (
+				54AE28402A5823D900719A56 /* JustOneThingCloudModel.xcdatamodel */,
+			);
+			currentVersion = 54AE28402A5823D900719A56 /* JustOneThingCloudModel.xcdatamodel */;
+			path = JustOneThingCloudModel.xcdatamodeld;
+			sourceTree = "<group>";
+			versionGroupType = wrapper.xcdatamodel;
+		};
+/* End XCVersionGroup section */
 	};
 	rootObject = 5483902F2A2A773900BF5624 /* Project object */;
 }

Model/JustOneThingCloudModel.xcdatamodeld/JustOneThingCloudModel.xcdatamodel/contents

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<model type="com.apple.IDECoreDataModeler.DataModel" documentVersion="1.0" lastSavedToolsVersion="21754" systemVersion="22F82" minimumToolsVersion="Automatic" sourceLanguage="Swift" userDefinedModelVersionIdentifier="">
+    <entity name="PersistentThing" representedClassName="PersistentThing" syncable="YES" codeGenerationType="class">
+        <attribute name="createdAt" optional="YES" attributeType="Date" usesScalarValueType="NO"/>
+        <attribute name="text" optional="YES" attributeType="String"/>
+        <attribute name="uuid" optional="YES" attributeType="UUID" usesScalarValueType="NO"/>
+    </entity>
+</model>

Model/PersistenceController.swift

@@ -0,0 +1,87 @@
+//
+//  PersistenceController.swift
+//  JustOneThing
+//
+//  Created by Alan Francis on 07/07/2023.
+//
+
+import CoreData
+
+//MARK: - URL Extension
+// https://developer.apple.com/forums/thread/78120
+// There's an issue with tvOS and the path to the local DB.
+// This little extension encapsulates that
+public extension URL {
+    /// Returns a URL for the given app group and database pointing to the sqlite database.
+    static func storeURL(for appGroup: String, databaseName: String) -> URL {
+        var containerUrl:URL
+        
+        guard let initialContainer = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: appGroup) else {
+            fatalError("Shared file container could not be created.")
+        }
+
+        #if os(tvOS)
+           containerUrl = initialContainer.appendingPathComponent("Library/Caches")
+        #else
+            containerUrl = initialContainer
+        #endif
+    
+        return containerUrl.appendingPathComponent("\(databaseName).sqlite")
+    }
+}
+
+//MARK: - PeristenceController
+struct PersistenceController {
+    let container: NSPersistentCloudKitContainer
+
+    init(inMemory: Bool = false) {
+        container = NSPersistentCloudKitContainer(name: "JustOneThingCloudModel")
+
+        if inMemory {
+            container.persistentStoreDescriptions.first!.url = URL(fileURLWithPath: "/dev/null")
+        } else {
+            let url = URL.storeURL(for: "group.com.alancfrancis.apps.JustOneThing", databaseName: "JustOneThingCloudModel")
+            container.persistentStoreDescriptions.first!.url = url
+        }
+        
+        container.loadPersistentStores(completionHandler: { (storeDescription, error) in
+            if let error = error as NSError? {
+                Self.processError(error:error)
+            }
+        })
+
+        container.viewContext.automaticallyMergesChangesFromParent = true
+    }
+}
+
+//MARK: - static convenience
+extension PersistenceController {
+    static let shared = PersistenceController()
+    
+    var viewContext:NSManagedObjectContext {
+        get {
+            container.viewContext
+        }
+    }
+}
+
+//MARK: - error handling
+extension PersistenceController {
+    static func processError(error:NSError) {
+        // Replace this implementation with code to handle the error appropriately.
+        // fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
+
+        /*
+         Typical reasons for an error here include:
+         * The parent directory does not exist, cannot be created, or disallows writing.
+         * The persistent store is not accessible, due to permissions or data protection when the device is locked.
+         * The device is out of space.
+         * The store could not be migrated to the current model version.
+         Check the error message to determine what the actual problem was.
+         */
+        fatalError("Unresolved error \(error), \(error.userInfo)")
+    }
+}
+
+
+

WidgetShared/AccessoryWidget.swift

@@ -11,7 +11,8 @@ import Intents
 
 struct JustOneThingAccessoryWidget: Widget {
     let kind: String = "JustOneThingAccessoryWidget"
-    
+    let persistenceController = PersistenceController.shared
+
     var body: some WidgetConfiguration {
         IntentConfiguration(kind: kind,
                             intent: ConfigurationIntent.self,

WidgetShared/SystemWidget.swift

@@ -11,6 +11,7 @@ import Intents
 
 struct JustOneThingSystemWidget: Widget {
     let kind: String = "JustOneThingSystemWidget"
+    let persistenceController = PersistenceController.shared
 
     var body: some WidgetConfiguration {
         IntentConfiguration(kind: kind,