Liking cljdoc? Tell your friends :D


Clojars Project

Use promesa promises as lacinia ResolverResults.


[com.github.hden/promecinia "0.1.0-SNAPSHOT"]


Plain Usage

Just return a promise within a resolver.

(require '[promecinia.core :as core])
(require '[promesa.core :as p])

(defn get-hero [_ arguments _]
  (let [{:keys [episode]} arguments]
    (-> (p/future
          (Thread/sleep 100)
          (if (= episode :NEWHOPE)
            {:id 1000
             :name "Luke"
             :home_planet "Tatooine"
             :appears_in ["NEWHOPE" "EMPIRE" "JEDI"]}
            {:id 2000
             :name "Lando Calrissian"
             :home_planet "Socorro"
             :appears_in ["EMPIRE" "JEDI"]}))
        {:warning {:message "Try not. Do or do not. There is no try."}
         :context {:episode episode}}))))


Since Lacinia can now work directly with promises, there is no need to bridge functions under superlifter.lacinia namespace.

(require '[superlifter.api :as s]) ;; not superlifter.lacinia!

(s/def-superfetcher FetchHero [episode]
  (fn [coll {:keys [conn]}]
    (-> (p/future
         (let [episodes (map :episode coll)]
           (find-heros-by-episodes episodes)))
      (p/catch (fn [ex]
                 (map (constantly {:message "My error message."}) coll))))))

(defn get-hero-resolver [context arguments _]
  (let [{:keys [superlifter]} context
        {:keys [episode]} arguments]
    (-> (s/with-superlifter superlifter
          (s/enqueue! (fetch-hero episode)))
        {:warning {:message "Try not. Do or do not. There is no try."}
         :context {:episode episode}}))))

Error handling

By default, promecinia hides error messages as internal server errors. To customize GraphQL errors, use com.walmartlabs.lacinia.resolve/with-error.

(require '[com.walmartlabs.lacinia.resolve :as resolve])

(-> (p/future
      (throw some-internal-error))
  (p/catch (fn [ex]
             (resolve/with-error nil {:message "These aren’t the droids you’re looking for."}))))


Copyright © 2021 Haokang Den

This program and the accompanying materials are made available under the terms of the Eclipse Public License 2.0 which is available at

This Source Code may also be made available under the following Secondary Licenses when the conditions for such availability set forth in the Eclipse Public License, v. 2.0 are satisfied: GNU General Public License as published by the Free Software Foundation, either version 2 of the License, or (at your option) any later version, with the GNU Classpath Exception which is available at

Can you improve this documentation?Edit on GitHub

cljdoc is a website building & hosting documentation for Clojure/Script libraries

× close