KCReadWithKeys.swift

func createQuery(for serivce: String) -> [String: Any] {
  let query: [String: Any] = [
    kSecClass as String: kSecClassGenericPassword,
    kSecAttrService as String: service,
    kSecReturnAttributes as String: true,
    kSecReturnData as String: true,
    kSecMatchLimit as String: kSecMatchLimitAll
  ]
  return query
}

func get(service: String, type: Int) throws -> [(account: String, password: Data)] {
  // 1. create the query to retrieve the type
  var query = createQuery(for: serive)
  query[kSecAttrType as String] = type

  // 2. retrieve the data
  var extractedData: AnyObject?
  let status = SecItemCopyMatching(query as CFDictionary, &extractedData)

  // 3. handle the result
  guard status == errSecItemNotFound || status == errSecSuccess else {
    throw Error.otherError(status)
  }

  guard status != errSecItemNotFound else {
    return []
  }

  let array = extractedData as! CFArray
  let dictionaries: [[String: Any]] = array.toSwiftArray()
  let pairs = dictionaries.compactMap { $0.accountPasswordPair }
  return pairs
}

func get(service: String, label: String) throws -> [(account: String, password: Data)] {
  var query = createQuery(for: serive)
  query[kSecAttrLabel as String] = label

  var extractedData: AnyObject?
  let status = SecItemCopyMatching(query as CFDictionary, &extractedData)

  guard status == errSecItemNotFound || status == errSecSuccess else {
    throw Error.otherError(status)
  }

  guard status != errSecItemNotFound else {
    return []
  }

  let array = extractedData as! CFArray
  let dictionaries: [[String: Any]] = array.toSwiftArray()
  let pairs = dictionaries.compactMap { $0.accountPasswordPair }
  return pairs
}

// MARK: - Helper extensions to extract data from CFArray and Dictionaries
extension CFArray {
  func toSwiftArray<T>() -> [T] {
    let array = Array<AnyObject>(_immutableCocoaArray: self)
    return array.compactMap { $0 as? T }
  }
}

extension Dictionary where Key == String, Value == Any {
  var accountPasswordPair: (account: String, password: Data)? {

    guard
      let account = self[kSecAttrAccount as String] as? String,
      let password = self[kSecValueData as String] as? Data
      else {
        return nil
    }
    return (account, password)
  }
}