class Permissify::PredicateFactSource

Optional adapter: source a family of facts from a Predicate entity through the FactSource port, without a load-time dependency on the ‘predicate` gem.

Predicate ALWAYS memoizes, so this belongs to STABLE domain-validity facts —“is this article complete?”, “does this lot have media?” — never to volatile authorization facts like roles or ownership, which must stay fresh as inline facts. Predicate is a domain layer beneath authorization; Permissify reads its result as a plain boolean and still owns the decision.

source = Permissify::PredicateFactSource.new(
  entity: Predicate.for(:article),          # responds to call(name, state) -> bool
  facts:  [:content_complete],              # the facts this source owns
  state:  ->(ctx) { { title: ctx.resource.title, body: ctx.resource.body,
                       media_ids: ctx.resource.media_ids } }
)

Permissify.decide(actor:, action:, resource:, resource_key:, fact_source: source)

The entity is injected (never looked up here), so the adapter is fully testable with a stub and works whether or not Predicate is installed.

Public Class Methods

new(entity:, facts:, state:) click to toggle source

entity: any object responding to +call(fact_name, state_hash) -> boolean+ (exactly +Predicate.for(:x)+).
facts: the fact names this source owns. A name outside this set returns FactSource::Missing so inline facts and other sources still win.
state: a callable +(context) -> Hash+ building the Predicate state from the DecisionContext (reads context.resource, context.actor, …).

# File lib/permissify/predicate.rb, line 33
def initialize(entity:, facts:, state:)
  @entity = entity
  @facts  = Array(facts).map(&:to_sym)
  @state  = state
end

Public Instance Methods

fetch(name, context) click to toggle source

Return the boolean for an owned fact, or FactSource::Missing for anything else. An error raised by the entity for an owned fact propagates — the decision pipeline converts it into a default-deny with reason :fact_error.

# File lib/permissify/predicate.rb, line 42
def fetch(name, context)
  key = name.to_sym
  return FactSource::Missing unless @facts.include?(key)

  @entity.call(key, @state.call(context)) ? true : false
end