add parameter recoder

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

@@ -3,6 +3,7 @@ defmodule PhilomenaWeb.Api.Json.TagController do
 
   alias Philomena.Tags.Tag
 
+  plug PhilomenaWeb.RecodeParameterPlug, [name: "id"] when action in [:show]
   plug :load_resource, model: Tag, id_field: "slug", persisted: true, preload: [:aliased_tag, :aliases, :implied_tags, :implied_by_tags, :dnp_entries]
 
   def show(conn, _params) do

lib/philomena_web/controllers/tag_controller.ex

@@ -8,6 +8,8 @@ defmodule PhilomenaWeb.TagController do
   alias Philomena.Repo
   import Ecto.Query
 
+  plug PhilomenaWeb.RecodeParameterPlug, [name: "id"] when action in [:show]
+
   def index(conn, params) do
     query_string = params["tq"] || "*"
 

lib/philomena_web/plugs/recode_parameter_plug.ex

@@ -0,0 +1,17 @@
+defmodule PhilomenaWeb.RecodeParameterPlug do
+  def init(opts), do: opts
+
+  def call(conn, [name: name]) do
+    fixed_value =
+      conn
+      |> Map.get(:params)
+      |> Map.get(name)
+      |> to_string()
+      |> URI.encode_www_form()
+      |> String.replace("%2B", "+")
+
+    params = Map.put(conn.params, name, fixed_value)
+
+    %{conn | params: params}
+  end
+end