init

lib/forum/public_site.ex

@@ -0,0 +1,182 @@
+defmodule Forum.PublicSite do
+  @moduledoc """
+  A per-network process for serving public static websites on separate ports.
+  """
+  use GenServer
+
+  def child_spec(opts) do
+    network = opts |> Keyword.fetch!(:network) |> normalize_network()
+
+    %{
+      id: {:public_site, network},
+      start: {__MODULE__, :start_link, [[network: network]]},
+      restart: :permanent,
+      shutdown: 5_000,
+      type: :worker
+    }
+  end
+
+  def start_link(opts) do
+    network = Keyword.fetch!(opts, :network)
+    GenServer.start_link(__MODULE__, network, name: via(network))
+  end
+
+  def normalize_network(network) when is_binary(network) do
+    network
+    |> String.downcase()
+    |> String.split(":", parts: 2)
+    |> hd()
+  end
+
+  def serve(pid, request) do
+    GenServer.call(pid, {:serve, request})
+  end
+
+  @impl true
+  def init(network) do
+    {:ok, %{network: normalize_network(network), started_at: DateTime.utc_now()}}
+  end
+
+  @impl true
+  def handle_call({:serve, request}, _from, state) do
+    response = do_serve(state, request)
+    {:reply, response, state}
+  end
+
+  defp do_serve(%{network: network}, request) do
+    roots = public_roots(network)
+
+    case roots do
+      [] ->
+        %{
+          status: 404,
+          content_type: "text/plain",
+          body: "No public website configured for #{network}"
+        }
+
+      [primary | fallbacks] ->
+        static_response(primary, request.path, fallbacks)
+    end
+  end
+
+  defp static_response(root, path, fallback_roots \\ []) do
+    file_path = resolve_path(root, path)
+
+    cond do
+      file_path == :invalid ->
+        %{status: 403, content_type: "text/plain", body: "Forbidden"}
+
+      File.dir?(file_path) and File.regular?(Path.join(file_path, "index.html")) ->
+        send_file(Path.join(file_path, "index.html"))
+
+      File.regular?(file_path) ->
+        send_file(file_path)
+
+      versioned = find_versioned_file([root | fallback_roots], path) ->
+        send_file(versioned)
+
+      fallback = find_fallback_file(fallback_roots, path) ->
+        send_file(fallback)
+
+      true ->
+        %{status: 404, content_type: "text/plain", body: "Not found"}
+    end
+  end
+
+  defp find_versioned_file(roots, path) do
+    case path |> String.trim_leading("/") |> Path.split() do
+      [_version | rest] when rest != [] ->
+        stripped_path = "/" <> Path.join(rest)
+        find_fallback_file(roots, stripped_path)
+
+      _ ->
+        nil
+    end
+  end
+
+  defp find_fallback_file(roots, path) do
+    Enum.find_value(roots, fn root ->
+      file_path = resolve_path(root, path)
+
+      cond do
+        file_path == :invalid ->
+          nil
+
+        File.dir?(file_path) and File.regular?(Path.join(file_path, "index.html")) ->
+          Path.join(file_path, "index.html")
+
+        File.regular?(file_path) ->
+          file_path
+
+        true ->
+          nil
+      end
+    end)
+  end
+
+  defp resolve_path(root, path) do
+    relative =
+      path
+      |> String.trim_leading("/")
+      |> URI.decode()
+
+    candidate = Path.expand(relative, root)
+    rel_to_root = Path.relative_to(candidate, Path.expand(root))
+
+    if rel_to_root == ".." or String.starts_with?(rel_to_root, "../") do
+      :invalid
+    else
+      candidate
+    end
+  end
+
+  defp send_file(path) do
+    %{status: 200, content_type: content_type(path), body: File.read!(path)}
+  end
+
+  defp content_type(path) do
+    case Path.extname(path) do
+      ".html" -> "text/html"
+      ".css" -> "text/css"
+      ".js" -> "application/javascript"
+      ".json" -> "application/json"
+      ".svg" -> "image/svg+xml"
+      ".png" -> "image/png"
+      ".jpg" -> "image/jpeg"
+      ".jpeg" -> "image/jpeg"
+      ".webp" -> "image/webp"
+      ".gif" -> "image/gif"
+      ".ico" -> "image/x-icon"
+      ".txt" -> "text/plain"
+      _ -> "application/octet-stream"
+    end
+  end
+
+  defp public_roots("cs") do
+    ["networks/cs/website"]
+    |> Enum.map(&Forum.Assets.path/1)
+    |> Enum.filter(&File.dir?/1)
+  end
+
+  defp public_roots("comalyr") do
+    [
+      "networks/comalyr/comalyr.com/ui/desktop",
+      "networks/comalyr/comalyr.com/ui"
+    ]
+    |> Enum.map(&Forum.Assets.path/1)
+    |> Enum.filter(&File.dir?/1)
+  end
+
+  defp public_roots(network) do
+    [
+      Path.join(["networks", network, "website"]),
+      Path.join(["networks", network, "public"]),
+      Path.join(["networks", network, "www"])
+    ]
+    |> Enum.map(&Forum.Assets.path/1)
+    |> Enum.filter(&File.dir?/1)
+  end
+
+  defp via(network),
+    do: {:via, Registry, {Forum.ProcessRegistry, {:public_site, normalize_network(network)}}}
+end