Single-User File Storage
========================

Here is an example code snippet to help you understand some of the functionality
detailed in the :doc:`../design_requirements`.

.. code-block:: go

    f1 := []byte("content")
    f2 := []byte("different content")

    // Alice and Bob each start a users session by authenticating to the client.
    alice_session_1, _ := InitUser("user_alice", "password1")
    bob_session_1, _ := InitUser("user_bob", "password2")

    // Alice stores byte slice f1 with name "filename" and Bob stores byte slice
    // f2 also with name "filename".
    alice_session_1.StoreFile("filename", f1)
    bob_session_1.StoreFile("filename", f2)

    // Alice and Bob each confirm that they can load the file they previously
    // stored and that the file contents is the same.
    
    f1_loaded, _ := alice_session_1.LoadFile("filename")
    f2_loaded, _ := bob_session_1.LoadFile("filename")

    if f1 != f1_loaded {
        panic("file contents are different.")
    }
    if f2 != f2_loaded {
        panic("file contents are different.")
    }
    
    // Alice gets an error when trying to load a file that does not exist in her
    // namespace.
    _, err := alice_session_1.LoadFile("nonexistent")
    if err != nil {
        panic("downloaded a nonexistent file.")
    }

    // Bob creates a second user session by authenticating to the client again.
    bob_session_2, _ := GetUser("user_bob", "password2")
    
    // Bob stores byte slice f2 with name "newfile" using his second user
    // session.
    bob_session_2.StoreFile("newfile", f2)

    // Bob loads "newfile" using his first user session. Notice that Bob does
    // not need to reauthenticate. File changes must be available to all active
    // sessions for a given user.

    f2_newfile := bob_session_1.LoadFile("newfile")

    if f2 != f2_newfile {
        panic("file contents are different.")
    }