Add support for sitemap.xml

Author: tomkonidas

lib/plexus/apps.ex

@@ -32,6 +32,17 @@ defmodule Plexus.Apps do
     |> Repo.paginate(page_opts)
   end
 
+  @doc """
+  Fetches the most recently added app
+  """
+  @spec fetch_most_recently_added_app! :: App.t()
+  def fetch_most_recently_added_app! do
+    App
+    |> order_by(:inserted_at)
+    |> limit(1)
+    |> Repo.one!()
+  end
+
   @doc """
   Fetches an App.
 

lib/plexus_web.ex

@@ -41,7 +41,7 @@ defmodule PlexusWeb do
   def controller do
     quote do
       use Phoenix.Controller,
-        formats: [:html, :json],
+        formats: [:html, :json, :xml],
         layouts: [html: PlexusWeb.Layouts]
 
       import Plug.Conn

lib/plexus_web/controllers/sitemap_controller.ex

@@ -0,0 +1,67 @@
+defmodule PlexusWeb.SitemapController do
+  use PlexusWeb, :controller
+
+  def index(conn, _params) do
+    conn
+    |> put_resp_content_type("text/xml")
+    |> put_layout(false)
+    |> render("sitemap.xml", routes: routes())
+  end
+
+  defp routes do
+    base_url = PlexusWeb.Endpoint.url()
+
+    PlexusWeb.Router
+    |> Phoenix.Router.routes()
+    |> Enum.reduce([], fn
+      %{verb: :get, path: path}, acc ->
+        if String.starts_with?(path, "/admin") or
+             String.starts_with?(path, "/api") or
+             String.contains?(path, ":") or
+             String.ends_with?(path, ".xml") do
+          acc
+        else
+          [build_route(base_url, path) | acc]
+        end
+
+      _route, acc ->
+        acc
+    end)
+  end
+
+  defp build_route(base_url, path) do
+    %{
+      path: full_path(base_url, path),
+      priority: priority(path),
+      change_freq: change_freq(path),
+      last_mod: last_mod(path)
+    }
+  end
+
+  defp full_path(base_url, path) do
+    path =
+      case path do
+        "/" -> "/"
+        path -> path <> "/"
+      end
+
+    base_url
+    |> URI.new!()
+    |> URI.append_path(path)
+    |> URI.to_string()
+  end
+
+  defp priority("/"), do: 1.0
+  defp priority(_path), do: 0.5
+
+  defp change_freq("/swaggerui"), do: "yearly"
+  defp change_freq(_), do: "weekly"
+
+  defp last_mod("/") do
+    Plexus.Apps.fetch_most_recently_added_app!()
+    |> Map.fetch!(:inserted_at)
+    |> DateTime.to_date()
+  end
+
+  defp last_mod(_), do: false
+end

lib/plexus_web/controllers/sitemap_xml.ex

@@ -0,0 +1,4 @@
+defmodule PlexusWeb.SitemapXML do
+  use PlexusWeb, :html
+  embed_templates "sitemap_xml/*"
+end

lib/plexus_web/controllers/sitemap_xml/sitemap.xml.eex

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
+  <%= for route <- @routes do %>
+  <url>
+    <loc><%= route.path %></loc>
+    <%= if route.last_mod do %><lastmod><%= route.last_mod %></lastmod><% end %>
+    <changefreq><%= route.change_freq %></changefreq>
+    <priority><%= route.priority %></priority>
+  </url>
+  <% end %>
+</urlset>

lib/plexus_web/router.ex

@@ -23,6 +23,8 @@ defmodule PlexusWeb.Router do
     plug :auth
   end
 
+  get "/sitemap.xml", PlexusWeb.SitemapController, :index
+
   scope "/" do
     pipe_through :browser