A property wrapper for Keychain storage

KeychainStorage.swift

import SwiftUI
import KeychainAccess

@propertyWrapper
struct KeychainStorage<T: Codable>: DynamicProperty {
  typealias Value = T
  let key: String
  @State private var value: Value?
  
  init(wrappedValue: Value? = nil, _ key: String) {
    self.key = key
    var initialValue = wrappedValue
    do {
      try Keychain().get(key) {
        attributes in
        if let attributes = attributes, let data = attributes.data {
          do {
            let decoded = try JSONDecoder().decode(Value.self, from: data)
            initialValue = decoded
          } catch let error {
            fatalError("\(error)")
          }
        }
      }
    }
    catch let error {
      fatalError("\(error)")
    }
    self._value = State<Value?>(initialValue: initialValue)
  }
  var wrappedValue: Value? {
    get  { value }
    
  nonmutating set {
    value = newValue
    do {
         if (value == nil) {
          Keychain()[key] = nil
        } else {
          let encoded = try JSONEncoder().encode(value)
          try Keychain().set(encoded, key: key)
        }
      } catch let error {
      fatalError("\(error)")
    }
  }
  var projectedValue: Binding<Value?> {
    Binding(get: { wrappedValue }, set: { wrappedValue = $0 })
  }
}

Instead of writing the code myself, which is pretty complicated, I’ve used a Swift package called KeychainAccess. Create a blank SwiftUI project in Xcode and go to File > Swift Packages > Add Package Dependency. Paste the KeychainAccess GitHub URL and click “Next” to import. Once the package has been added, you will be able to interact with the keychain by using the Keychain class.

Could you give us a example on how to use it on view ?

Also can you confirm , Does it notice the change and update the view ?