Behavior for checking user email preferences.

This behavior allows apps to implement their own preference checking logic, from simple field-based preferences to complex multi-tenant scenarios.

Simple Implementation

For straightforward preference systems (like Magasin):

defmodule MyApp.PreferenceProvider do
  @behaviour AshDispatch.Behaviours.PreferenceProvider

  def get_preferences(user_id) do
    MyApp.Accounts.get_user_email_preferences(user_id, authorize?: false)
  end

  def preference_enabled?(preferences, category) when is_atom(category) do
    Map.get(preferences, category, true)
  end
end

Complex Implementation

For advanced scenarios with dynamic preferences:

defmodule MyApp.AdvancedPreferenceProvider do
  @behaviour AshDispatch.Behaviours.PreferenceProvider

  def get_preferences(user_id) do
    # Load preferences from multiple sources
    # Apply tenant-specific rules
    # Handle preference hierarchies
    {:ok, combined_preferences}
  end

  def preference_enabled?(preferences, category) do
    # Complex logic considering:
    # - User tier
    # - Regulatory requirements
    # - Business rules
    MyApp.PreferenceEngine.check(preferences, category)
  end
end

Configuration

Configure the preference provider in your app's config:

config :ash_dispatch,
  preference_provider: MyApp.PreferenceProvider