Phoenix Thinking

Mental shifts for Phoenix applications. These insights challenge typical web framework patterns.

Where to Load Data: mount vs handle_params

Default: load data in mount/3.

def mount(_params, _session, socket) do
  posts = Blog.list_posts(socket.assigns.current_scope)
  {:ok, assign(socket, posts: posts)}
end

Yes, mount runs twice on initial load (HTTP dead render + WebSocket connect). So does handle_params/3. That's the LiveView lifecycle, not a bug to route around. Moving queries from mount to handle_params does not dedupe them.

Use handle_params/3 for data that changes on live navigation (push_patch / <.link patch={...}>). mount does not re-run on patches, handle_params does.