Property Encoder #swift #data #binary #plist

PropertyEncoder.swift

// Returns the URL for the plist file that stores the drink data.
    private func getDataURL() throws -> URL {
        // Get the URL for the app's document directory.
        let fileManager = FileManager.default
        let documentDirectory = try fileManager.url(for: .documentDirectory,
                                                    in: .userDomainMask,
                                                    appropriateFor: nil,
                                                    create: false)
        
        // Append the file name to the directory.
        return documentDirectory.appendingPathComponent("CoffeeTracker.plist")
    }



private func save() {
        // Save as a binary plist file.
        let encoder = PropertyListEncoder()
        encoder.outputFormat = .binary
        
        let data: Data
        
        do {
            // Encode the currentDrinks array.
            data = try encoder.encode(currentDrinks)
        } catch {
            print("*** An error occurred while encoding the data: \(error.localizedDescription) ***")
            return
        }
        
        // Save the data on a background queue.
        background.async { [unowned self] in
            do {
                try data.write(to: self.getDataURL(), options: [.atomic])
            } catch {
                print("*** An error occurred while saving the data: \(error.localizedDescription) ***")
            }
        }
    }


// Begin loading the data from disk.
    private func load() {
        // Read the data from a background queue.
        background.async { [unowned self] in
            let drinks: [Drink]
            
            do {
                // Load the drink data.
                let data = try Data(contentsOf: self.getDataURL())
                
                // Decode the data.
                let decoder = PropertyListDecoder()
                drinks = try decoder.decode([Drink].self, from: data)
            } catch CocoaError.fileReadNoSuchFile {
                print("*** No file found--creating an empty drink list. ***")
                drinks = []
            } catch {
                fatalError("*** An unexpected error occurred while loading the drink list: \(error.localizedDescription) ***")
            }
            
            // Update the entires on the main queue
            DispatchQueue.main.async { [unowned self] in
                // Filter the drinks.
                self.currentDrinks = filterDrinks(drinks: drinks)
                
                // Load new data from HealthKit
                self.healthKitController.requestAuthorization { (success) in
                    guard success else {
                        print("*** Unable to authorize HealthKit. ***")
                        return
                    }
                    
                    self.healthKitController.loadNewDataFromHealthKit()
                }
            }
        }
    }