oembed api

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

@@ -0,0 +1,72 @@
+defmodule PhilomenaWeb.Api.Json.OembedController do
+  use PhilomenaWeb, :controller
+
+  alias Philomena.Images.Image
+  alias Philomena.Repo
+  import Ecto.Query
+
+  @cdn_regex ~r/\/img\/.*\/(\d+)(\.|[\/_][_\w])/
+  @img_regex ~r/\/(\d+)/
+
+  def index(conn, %{"url" => url}) do
+    parsed = URI.parse(url)
+
+    try_oembed(conn, parsed)
+  end
+  def index(conn, _params), do: oembed_error(conn)
+
+  defp try_oembed(conn, %{path: path}) do
+    cdn = Regex.run(@cdn_regex, path, capture: :all_but_first)
+    img = Regex.run(@img_regex, path, capture: :all_but_first)
+
+    image_id =
+      cond do
+        cdn  -> hd(cdn)
+        img  -> hd(img)
+        true -> nil
+      end
+
+    load_image(image_id)
+    |> oembed_image(conn)
+  end
+
+  defp load_image(nil), do: nil
+  defp load_image(id) do
+    Image
+    |> where(id: ^id, hidden_from_users: false)
+    |> preload([:tags, :user])
+    |> Repo.one()
+  end
+
+  defp oembed_image(nil, conn), do: oembed_error(conn)
+  defp oembed_image(image, conn), do: json(conn, oembed_json(image, conn))
+
+  defp oembed_error(conn) do
+    conn
+    |> Plug.Conn.put_status(:not_found)
+    |> json(%{error: "couldn't find an image"})
+  end
+
+  defp oembed_json(image, conn) do
+    %{
+      version: "1.0",
+      type: "photo",
+      title: "##{image.id} - #{image.tag_list_cache} - Derpibooru",
+      author_url: image.source_url,
+      author_name: artist_tags(image.tags),
+      provider_name: "Derpibooru",
+      provider_url: Routes.image_url(conn, :show, image),
+      cache_age: 7200,
+      derpibooru_id: image.id,
+      derpibooru_score: image.score,
+      derpibooru_comments: image.comments_count,
+      derpibooru_tags: Enum.map(image.tags, & &1.name)
+    }
+  end
+
+  defp artist_tags(tags) do
+    tags
+    |> Enum.filter(& &1.namespace == "artist")
+    |> Enum.map_join(", ", & &1.name)
+  end
+end

lib/philomena_web/plugs/filter_id_plug.ex

@@ -9,7 +9,7 @@ defmodule PhilomenaWeb.FilterIdPlug do
     filter = load_filter(conn.params)
     user = conn.assigns.current_user
 
-    case Canada.Can.can?(user, :show, filter) do
+    case not is_nil(filter) and Canada.Can.can?(user, :show, filter) do
       true  -> Plug.Conn.assign(conn, :current_filter, filter)
       false -> conn
     end

lib/philomena_web/router.ex

@@ -80,6 +80,7 @@ defmodule PhilomenaWeb.Router do
       resources "/reverse", ReverseController, only: [:create]
     end
     resources "/search", SearchController, only: [:index]
+    resources "/oembed", OembedController, only: [:index]
   end
 
   scope "/", PhilomenaWeb do