Access plugin for pathom

access-plugin.clj

(defmulti check-access! (fn [_env [k v]] k))
(defmethod check-access! :decide.models.proposal/id
  [env input]
  ; Add code to check access and add input to access-cache
  false) 
(defmethod check-access! :default [_ _] true)

(defn has-access? [env input]
  (or
    (contains? @(:access-cache env) input)
    (check-access! env input)))

(def access-plugin
  {::p/wrap-parser
   (fn [parser]
     (fn [env tx]
       (parser (assoc env :access-cache (atom #{})) tx)))

   ::pc/wrap-resolve
   (fn [resolve]
     (fn [env input]
       (let [allowed?
             (if (seq? input)                               ; batched?
               (every? (fn [input] (every? #(has-access? env %) input)) input)
               (every? #(has-access? env %) input))]
         (when allowed?
           (resolve env input)))))})


;; To optimize access-checks resolvers can add access prematurely 

(defresolver resolve-proposals [{:keys [db access-cache] :as env} {::process/keys [slug]}]
  {::pc/output [{::process/proposals [::proposal/id]}]}
  (if-let [response (d/pull db [{::process/proposals [::proposal/id]}] [::process/slug slug])]
    (do
      (swap! access-cache (fn [state] (apply conj state (map #(find % ::proposal/id) (::process/proposals response)))))
      response)
    {::process/proposals []}))

I could generalize the plugin to make it reusable.

Generalized version:

https://github.com/hhucn/decide3/blob/master/src/main/decide/server_components/access_plugin.cljc