KeychainDataSource

KeychainDataSource<T> is a Swift key-value storage that implements GetDataSource, PutDataSource and DeleteDataSource storing values into the device Keychain. Type T is required to be Codable.

Usage

// Swift
let dataSource = KeychainDataSource<Double>(KeychainService())

dataSource.put(3.14159265359, forId: "pi")
dataSource.get("pi")
dataSource.delete("pi")

Note that the example above is using the extension methods of DataSoruce that encapsulate queries of type IdQuery<T>.

The KeychainService class is a wrapper on the iOS Keychain. For more details, read the class documentation.

Query Types

All queries must adopt the KeyQuery interface as the KeychainDataSource<T> is based on a key-value pattern.

Object Types

Even if KeychainDataSource<T> has a generic type, the Keychain can only store Data. However, the class has a built-in data conversion for any type T that is Codable.

Otherwise, a DataSourceMapper<In,Out> can be used to map any type T to Data.

Error Handling

Among the typicial errors CoreError.NotFound on GET methods, the KeychainDataSource<T> can return the error CoreError.OSStatusFailure in PUT and DELETE methods. This error is result of a failure in the manipulation of the Keychain. For more details, check the OSStatus value of the error.