Add keychain service

keychain-kit/Sources/Keychain.swift

@@ -0,0 +1,88 @@
+//
+//  Keychain.swift
+//  keychain-kit
+//
+//  Created by Aleksey Zgurskiy on 02.02.2020.
+//  Copyright © 2020 mr.noone. All rights reserved.
+//
+
+import Foundation
+
+public struct Keychain {
+  public enum Error: Swift.Error {
+    case noData
+    case unexpectedData
+    case unexpected(code: OSStatus)
+  }
+  
+  // MARK: - Inits
+  
+  public init() {}
+  
+  // MARK: - Public methods
+  
+  public func get(_ key: String) throws -> Data {
+    let query: [CFString : AnyObject] = [
+      kSecClass : kSecClassGenericPassword,
+      kSecAttrAccount : key as AnyObject,
+      kSecMatchLimit : kSecMatchLimitOne,
+      kSecReturnData : kCFBooleanTrue
+    ]
+    
+    var queryResult: AnyObject?
+    let status = withUnsafeMutablePointer(to: &queryResult) {
+      SecItemCopyMatching(query as CFDictionary, UnsafeMutablePointer($0))
+    }
+    
+    guard status != errSecItemNotFound else { throw Error.noData }
+    guard status == noErr else { throw Error.unexpected(code: status) }
+    
+    guard
+      let item = queryResult as? [CFString : AnyObject],
+      let data = item[kSecValueData] as? Data
+    else { throw Error.noData }
+    
+    return data
+  }
+  
+  public func get(_ key: String) throws -> String {
+    return String(data: try get(key), encoding: .utf8)!
+  }
+  
+  public func get<T>(_ key: String, decoder: JSONDecoder = JSONDecoder()) throws -> T where T: Decodable {
+    return try decoder.decode(T.self, from: get(key))
+  }
+  
+  public func set(_ data: Data, for key: String) throws {
+    try delete(key)
+    
+    let query: [CFString : AnyObject] = [
+      kSecClass : kSecClassGenericPassword,
+      kSecAttrAccount : key as AnyObject,
+      kSecValueData : data as AnyObject
+    ]
+    
+    let status = SecItemAdd(query as CFDictionary, nil)
+    guard status == noErr else { throw Error.unexpected(code: status) }
+  }
+  
+  public func set(_ value: String, for key: String) throws {
+    try set(value.data(using: .utf8)!, for: key)
+  }
+  
+  public func set<T>(_ value: T, for key: String, encoder: JSONEncoder = JSONEncoder()) throws where T: Encodable {
+    try set(encoder.encode(value), for: key)
+  }
+  
+  public func delete(_ key: String) throws {
+    let query: [CFString : AnyObject] = [
+      kSecClass : kSecClassGenericPassword,
+      kSecAttrAccount : key as AnyObject
+    ]
+    
+    let status = SecItemDelete(query as CFDictionary)
+    guard status == noErr  || status == errSecItemNotFound else {
+      throw Error.unexpected(code: status)
+    }
+  }
+}