refactor: replace ReverseProxyPlug with RuntimeRewritePlug in asset and ingest rewrites

- Updated the asset and ingest rewrite plugs to delegate to a new RuntimeRewritePlug for dynamic upstream URL handling.
- Introduced RuntimeRewritePlug to manage requests based on runtime configuration, improving flexibility.

Author: zcesur

lib/algora_web/plugs/rewrite_assets_plug.ex

@@ -1,5 +1,7 @@
 defmodule AlgoraWeb.Plugs.RewriteAssetsPlug do
   @moduledoc false
-  defdelegate init(opts), to: ReverseProxyPlug
-  defdelegate call(conn, opts), to: ReverseProxyPlug
+  alias AlgoraWeb.Plugs.RuntimeRewritePlug
+
+  defdelegate init(opts), to: RuntimeRewritePlug
+  defdelegate call(conn, opts), to: RuntimeRewritePlug
 end

lib/algora_web/plugs/rewrite_ingest_plug.ex

@@ -1,5 +1,7 @@
 defmodule AlgoraWeb.Plugs.RewriteIngestPlug do
   @moduledoc false
-  defdelegate init(opts), to: ReverseProxyPlug
-  defdelegate call(conn, opts), to: ReverseProxyPlug
+  alias AlgoraWeb.Plugs.RuntimeRewritePlug
+
+  defdelegate init(opts), to: RuntimeRewritePlug
+  defdelegate call(conn, opts), to: RuntimeRewritePlug
 end

lib/algora_web/plugs/runtime_rewrite_plug.ex

@@ -0,0 +1,20 @@
+defmodule AlgoraWeb.Plugs.RuntimeRewritePlug do
+  @moduledoc """
+  A plug that forwards requests to a runtime-configured upstream URL.
+  """
+  import Plug.Conn
+
+  def init(opts), do: opts
+
+  def call(conn, opts) do
+    upstream = Application.get_env(:algora, Keyword.get(opts, :upstream))
+
+    if upstream do
+      ReverseProxyPlug.call(conn, ReverseProxyPlug.init(upstream: upstream))
+    else
+      conn
+      |> send_resp(500, "Upstream URL not configured")
+      |> halt()
+    end
+  end
+end

lib/algora_web/router.ex

@@ -7,6 +7,8 @@ defmodule AlgoraWeb.Router do
   import Oban.Web.Router
   import Phoenix.LiveDashboard.Router, only: [live_dashboard: 2]
 
+  alias AlgoraWeb.Plugs.RuntimeRewritePlug
+
   pipeline :browser do
     plug :accepts, ["html"]
     plug :fetch_session
@@ -30,13 +32,8 @@ defmodule AlgoraWeb.Router do
   end
 
   scope "/" do
-    forward "/asset", AlgoraWeb.Plugs.RewriteAssetsPlug,
-      upstream: "#{Application.compile_env(:algora, :assets_url)}",
-      response_mode: :buffer
-
-    forward "/ingest", AlgoraWeb.Plugs.RewriteIngestPlug,
-      upstream: "#{Application.compile_env(:algora, :ingest_url)}",
-      response_mode: :buffer
+    forward "/asset", AlgoraWeb.Plugs.RewriteAssetsPlug, upstream: :assets_url
+    forward "/ingest", AlgoraWeb.Plugs.RewriteIngestPlug, upstream: :ingest_url
 
     # forward "/docs", AlgoraWeb.Plugs.RewriteDocsPlug,
     #   upstream: "https://docs.algora.io",