New /filters/:id API endpoint (#48)

* New /filters/:id API endpoint

* Fix to use can? permissions

* Fixes requested

lib/philomena_web/controllers/api/json/filter_controller.ex

@@ -0,0 +1,28 @@
+defmodule PhilomenaWeb.Api.Json.FilterController do
+  use PhilomenaWeb, :controller
+
+  alias PhilomenaWeb.FilterJson
+  alias Philomena.Filters.Filter
+  alias Philomena.Repo
+  import Ecto.Query
+
+  def show(conn, %{"id" => id}) do
+    user = conn.assigns.current_user
+
+    filter =
+      Filter
+      |> where(id: ^id)
+      |> preload(:user)
+      |> Repo.one()
+
+    case Canada.Can.can?(user, :show, filter) do
+      true ->
+        json(conn, %{filter: FilterJson.as_json(filter)})
+
+      _ ->
+        conn
+        |> put_status(:not_found)
+        |> text("")
+    end
+  end
+end

lib/philomena_web/filter_json.ex

@@ -0,0 +1,17 @@
+defmodule PhilomenaWeb.FilterJson do
+  def as_json(filter) do
+    %{
+      id: filter.id,
+      name: filter.name,
+      description: filter.description,
+      public: filter.public,
+      system: filter.system,
+      user_count: filter.user_count,
+      user_id: filter.user_id,
+      hidden_tag_ids: filter.hidden_tag_ids,
+      spoilered_tag_ids: filter.spoilered_tag_ids,
+      hidden_complex: filter.hidden_complex_str,
+      spoilered_complex: filter.spoilered_complex_str
+    }
+  end
+end

lib/philomena_web/router.ex

@@ -119,6 +119,7 @@ defmodule PhilomenaWeb.Router do
     resources "/comments", CommentController, only: [:show]
     resources "/posts", PostController, only: [:show]
     resources "/profiles", ProfileController, only: [:show]
+    resources "/filters", FilterController, only: [:show]
 
     resources "/forums", ForumController, only: [:show, :index] do
       resources "/topics", Forum.TopicController, only: [:show, :index] do