The behaviour and macro for Dialup layout modules.

A layout wraps one or more pages with shared chrome (navigation, footer, etc.). Layouts are discovered automatically based on the directory hierarchy:

app/
├── layout.ex          # wraps all pages under app/
└── blog/
    ├── layout.ex      # wraps all pages under app/blog/ (nested)
    └── [slug]/
        └── page.ex

Usage

defmodule MyApp.App.Layout do
  use Dialup.Layout

  # Called once when the WebSocket connection is established.
  # Use it to set session-scoped data (e.g. the current user).
  def mount(session) do
    user = Repo.get(User, session[:user_id])
    {:ok, Map.put(session, :current_user, user)}
  end

  def render(assigns) do
    ~H"""
    <nav>{@current_user.name}</nav>
    <main>{raw(@inner_content)}</main>
    """
  end
end

Callbacks

• mount/1 — optional; called once when the WebSocket connection is established. Receives the current session map (empty %{} for the root layout, or whatever the parent layout returned). Return {:ok, new_session}.
• render/1 — renders the layout HTML using HEEx. Use {raw(@inner_content)} to inject the child content.

Colocation CSS

Place a layout.css file in the same directory as layout.ex. The styles are automatically scoped and applied to all pages under that directory at compile time.

Nesting

Layout mount/1 calls are chained from outermost to innermost. Each layout receives the session returned by its parent and may enrich it further.

Navigation actions

A layout may declare navigation links with <.dialup_action navigate="/path">, exactly like a page. These render the shared chrome links for humans and are merged into the MCP tool catalog of every page wrapped by the layout, so an attached agent gets the same site-wide navigation a human sees in the nav bar. Layouts support navigation actions only; event-handling actions (<.dialup_action> with desc/params) belong on a page that implements handle_event/3.