Use promesa promises as lacinia ResolverResults.
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Use promesa promises as lacinia ResolverResults.
[com.github.hden/promecinia "0.1.0-SNAPSHOT"]
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"]}))
(core/attach
{: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)))
(core/attach
{:warning {:message "Try not. Do or do not. There is no try."}
:context {:episode episode}}))))
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 http://www.eclipse.org/legal/epl-2.0.
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 https://www.gnu.org/software/classpath/license.html.