https://github.com/hden/promecinia

Use promesa promises as lacinia ResolverResults.
https://github.com/hden/promecinia

Last synced: 3 months ago
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Use promesa promises as lacinia ResolverResults.

• Host: GitHub
• URL: https://github.com/hden/promecinia
• Owner: hden
• License: other
• Created: 2021-10-11T11:41:46.000Z (about 3 years ago)
• Default Branch: main
• Last Pushed: 2024-09-06T01:06:38.000Z (4 months ago)
• Last Synced: 2024-10-03T12:16:39.547Z (3 months ago)
• Language: Clojure
• Size: 118 KB
• Stars: 0
• Watchers: 2
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# promecinia

[![Clojars Project](https://img.shields.io/clojars/v/com.github.hden/promecinia.svg)](https://clojars.org/com.github.hden/promecinia)

Use [promesa promises](https://github.com/funcool/promesa) as lacinia ResolverResults.

## Installation

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

## Usage

### Plain Usage

Just return a promise within a resolver.

```clj

(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}}))))

```

### Superlifter

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

```clj

(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}}))))

```

### Error handling

By default, promecinia hides error messages as internal server errors.

To customize GraphQL errors, use `com.walmartlabs.lacinia.resolve/with-error`.

```clj

(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."}))))

```

## License

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.