Palau - NSUserDefaults with Wings!

Introduction on Palau. A framework to simplify NSUserDefaults in Swift while adding some extra powers.

https://github.com/symentis/Palau

This presentation was held on Munich iOS Meetup 2016/05/18.
http://www.meetup.com/de-DE/The-Munich-iOS-Developers-Meetup/events/230640835/

Transcript

1. let palau = NSUserDefaults(for: .Swift) @elmkretzer
2. NSUserDefaults Optimized for storing user settings: NSUserDefaults is intended for relatively small amounts of data, queried very frequently, and modified occasionally. Using it in other ways may be slow or use more memory than solutions more suited to those uses. http://dscoder.com/defaults.html
3. What`s The Point? !
4. Missing TypeSafety extension NSUserDefaults { // life is too short subscript(key: String) -> AnyObject? { get { return NSUserDefaults.standardUserDefaults().objectForKey(key) } set { NSUserDefaults.standardUserDefaults().setObject(newValue, forKey: key) } } } typical usage - somewhere on GitHub
5. Verbose Workarounds class UserSettings { class var defaultCities: [String] { return ["Hamburg", "Berlin", "Munich"] } class var userCityKey: String { return "userCityKey" } class func getUserCities() -> [String] { let userCities = NSUserDefaults.standardUserDefaults() .arrayForKey(UserSettings.userCityKey) if userCities == nil { NSUserDefaults.standardUserDefaults() .setObject(UserSettings.defaultCities, forKey: UserSettings.userCityKey) NSUserDefaults.standardUserDefaults().synchronize() return UserSettings.defaultCities } else { return userCities as! [String] } } typical usage - somewhere on GitHub
6. Research
7. New Ideas? "
8. NSUserDefaults with Wings!
9. Goals Type-Safe / Concise Fallbacks / Rules / Observers Customizable
10. // set username PalauDefaults.username.value = "name" // get username let name = PalauDefaults.username.value
11. Simple import Palau // Define user defaults in an extension extension PalauDefaults { // getter and empty setter static var username: PalauDefaultsEntry<String> { get { return value("username") } set { } } }
12. // what if value is not yet set - any fallback? let cities = PalauDefaults.cities.value // -> ["Munich", "London"] // then change PalauDefaults.cities.value = ["Bielefeld"] // -> ["Bielefeld"]
13. Configurable extension PalauDefaults { // define individual nil fallbacks static var cities: PalauDefaultsEntry<[String]> { get { return value("cities").whenNil(use: ["Munich", "London"]) } set { } } }
14. // shorter please typealias Defaults = PalauDefaults // get initial value let secondsA = Defaults.alertTimeSeconds.value // -> 10 // set invalid value Defaults.alertTimeSeconds.value = 8 // get valid value let secondsB = Defaults.alertTimeSeconds.value // -> 10
15. Versatile // your everyday-Int-checker
 func lessThan(int: Int) -> Int? -> Bool { return { $0.map { $0 < int } ?? false } } extension PalauDefaults { // define custom rules static var alertTimeSeconds: PalauDefaultsEntry<Int> { get { return value("alertTimeSeconds") .whenNil(use: 10) .ensure(when: lessThan(10), use: 10) } set { } } }
16. PalauDefaults.loginDate.value = NSDate() // -> tell s.o. that it changed
 // - to: currentDate
 // - from: previousDate
17. Observable // simple listener closure receiving new and old value let listenChange = { print("changed to", $0, "from", $1) } extension PalauDefaults { // listen to changes static var loginDate: PalauDefaultsEntry<NSDate> { get { return value("loginDate").didSet(listenChange) } set { } } }
18. // You wanna have a dedicated model-like // struct storing a value on year base? var yearSettings = YearSettings(year: 2016) yearSettings.value = 100
19. Extendable /// create instance for subscript var palauDefaults = PalauDefaults() extension PalauDefaults { /// retroactive way of adding init init(){} /// dynamic defaults value, subscript can not be static subscript (valueInYear year: Int) -> PalauDefaultsEntry<Int> { get { return PalauDefaults.value("value-\(year)") } set { } } } // convenience struct model struct YearSettings { let year: Int var value: Int? { get { return palauDefaults[valueInYear: year].value } set { palauDefaults[valueInYear: year].value = newValue } } }
20. NSDeveloperRelaxed #$%
21. https://github.com/symentis/Palau • Most Standard Types Out-of-the-box • Also supports NSCoding and RawRepresentable • Also add your Custom Types (e.g. struct) • Per-property based chain-able Rules • DidSet Observation • 100% Unit Test Coverage
22. @elmkretzer / elm4ward.github.io happy-go-swift www.symentis.com