update discord patterns

lib/zoeyscomputer_web/plugs/discord_handler.ex

@@ -6,23 +6,44 @@ defmodule ZoeyscomputerWeb.DiscordHandler do
 
   def init(opts), do: opts
 
-  def call(%{path_info: ["images", _id]} = conn, _opts) do
-    user_agent = get_req_header(conn, "user-agent")
-    Logger.info("user-agent: #{user_agent}")
+  @discord_patterns [
+    ~r/^Mozilla\/5\.0 \(compatible; Discordbot\//,
+    # Pattern for common Discord web client
+    ~r/^Mozilla\/5\.0.*Firefox\/.*$/
+  ]
 
-    case user_agent do
-      ["Mozilla/5.0 (compatible; Discordbot/" <> _rest] -> handle_discord(conn)
-      _ -> conn
+  def call(%{path_info: ["images", _id | _]} = conn, _opts) do
+    user_agent = List.first(get_req_header(conn, "user-agent"))
+    request_id = Logger.metadata()[:request_id]
+
+    Logger.info("Processing image request",
+      user_agent: user_agent,
+      request_id: request_id
+    )
+
+    cond do
+      is_discord_request?(user_agent) -> handle_discord(conn)
+      true -> conn
     end
   end
 
   def call(conn, _opts), do: conn
 
+  defp is_discord_request?(nil), do: false
+
+  defp is_discord_request?(user_agent) do
+    Enum.any?(@discord_patterns, fn pattern ->
+      Regex.match?(pattern, user_agent)
+    end)
+  end
+
   defp handle_discord(%{path_info: ["images", id]} = conn) do
     case download_from_s3("imgs", id) do
       {:ok, image_binary, content_type} ->
         conn
         |> put_resp_content_type(content_type)
+        # Optional: Add caching
+        |> put_resp_header("cache-control", "public, max-age=86400")
         |> send_resp(200, image_binary)
         |> halt()