Revoke
======

**Example**: Here is an example workflow of `RevokeFile`.

Suppose user Alice owns "file" and shared the file with Bob.

.. code-block:: go

    u1, _ := GetUser("user_alice", "pw1")
    u2, _ := InitUser("user_bob", "pw2")
    accessToken, err := u1.ShareFile("file", "user_bob")
    u2.ReceiveFile("file_from_alice", "user_alice", accessToken)

Then Bob will have access to Alice’s file, under the filename “file_from_alice”.

Next, Alice revokes Bob’s permission to this file:

.. code-block:: go

    u1, _ := GetUser("user_alice", "pw1")
    u1.RevokeFile("file", "user_bob")

Now, Alice can still access "file", but Bob cannot.

.. code-block:: go

    file_data, _ := u1.LoadFile("file")

Alice can update the file:

.. code-block:: go

    u1, _ := GetUser("user_alice", "pw1")
    u1.StoreFile("file", new_file_data)

This file is no longer shared with Bob. You must ensure
that Bob does not have access to the new file content.