Posted about 6 years ago. Visible to the public.

State machines [3d]


Movies in MovieDB should have one of the following workflow states:

  • draft
  • pending
  • accepted
  • rejected

A movie always begins as a draft and then transitions through the states as it's getting reviewed. This could be a typical state flow for a movie:

draft => pending => rejected => pending => accepted

Change the visibility rules (Consul powers) so:

  • All users can see accepted movies of other users.
  • All users can see the movies they created themselves, regardless of their state.
  • An admin can see movies from other users that are accepted, pending or rejected.

We will now add some additional controls to transition a movie between states:

  • When a user views one of her draft or rejected movies, she sees a button Submit on the movie's show view. This changes the movie's state to pending.
  • When an admin opens a pending movie by any user, she sees two buttons Accept and Reject.
  • Before the admin may reject a movie, she is required to enter a rejection reason. The rejection reason should be entered in a form like the other forms in your app, with the same form round trip and controller handling. Consider whether you want to implement this inside an existing :movies resource or in a new one just for the rejection form.
  • In addition, when an admin edits a movie by any user, she can choose any state from a select box, regardless of the movie's current state. Note that any transition constraints and callbacks will not be enforced when the #state is set directly. We only do this to allow admins to correct user errors.


Make two implementations of the requirements above:

Make sure that you have tests for all the changes you make.

Owner of this card:

Henning Koch
Last edit:
about 1 year ago
by Henning Koch
Posted by Henning Koch to makandra Curriculum
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