component-pedestal

A Component implementation of Pedestal whose goal is to streamline the wiring of system dependencies to interceptors and handlers.

Usage

Components provide service capabilities by exposing routes. To do this they implement the RouteProvider protocol. The Pedestal component is configured in the system map to depend on route providers and builds the service's routes from them.

Components which provide routes may attach themselves to the context and request through the com.ddeaguiar.component.pedestal/attach fn. This provides downstream interceptors and handlers access to the component.

(require '[io.pedestal.http :as http])
(require '[io.pedestal.http.body-params :as body-params])
(require '[com.ddeaguiar.component.pedestal :as component-pedestal])
(require '[com.stuartsierra.component :as component])
(require '[ring-resp/response :as ring-resp])

(defprotocol UserStore
  (find-user [this id]))

(defn user-handler
  [req]
  (let [user-store (::component-pedestal/component req)
        id         (get-in req [:path-params :id])
        user-name  (or (find-user user-store id) "not found")]
    (ring-resp/response (str "User name is: " user-name))))


(defrecord Users [db]
  component-pedestal/RouteProvider
  (routes [this]
    #{["/user/:id" :get (conj [(body-params/body-params)
                               http/html-body
                               (component-pedestal/attach this)]
                              `user-handler) :route-name ::user]})

  UserStore
  (find-user [_ id]
    (get db id)))

(def system (component/system-map
             :db {"dan"  "Daniel De Aguiar"
                  "yogi" "Yogi Bear"}
             :user-store (component/using
                          (map->Users {})
                          [:db])
             :pedestal (component/using
                        (component-pedestal/with-automatic-port (component-pedestal/component-pedestal))
                        [:user-store])))

Copyright and License

MIT License

Copyright (c) 2017 Daniel De Aguiar

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.