Expecting render function when using embed_templates in Live View 0.18.3

Phoenix Forum Questions / Help
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1

The error

Raised when navigating to http://localhost:4000/foo/bar

MainWeb.App.Root.render/2 is undefined or private

MainWeb.App.Root being the module passed to plug :put_root_layout in router.ex.

Not sure if this is a bug or I am missing something. Any help in figuring it out would be much appreciated.

Versions

  • Live View 0.18.3
  • Phoenix 1.6.15

The code

lib/main_web/router.ex

defmodule MainWeb.Router do
  use MainWeb, :router
  import Phoenix.LiveDashboard.Router

  pipeline :browser do
    plug :accepts, ["html"]
    plug :fetch_session
    plug :fetch_live_flash
    plug :put_root_layout, {MainWeb.App.Root, :root}
    # other plugs...
  end

  scope "/foo" do
    pipe_through :browser
    live_session :foo do
      live "/bar", MainWeb.Foo.BarLive, :index
    end
  end
end

lib/main_web/app/root.ex

defmodule MainWeb.App.Root do
  use MainWeb, :html
  embed_templates "*"
end

lib/main_web/app/root.html.heex

<!DOCTYPE html>
<html lang="pt">
   <!-- other headers... -->
    <meta name="csrf-token" content={csrf_token_value()}>
    <.live_title suffix=" · Baz"><%= assigns[:page_title] %></.live_title>
    <link phx-track-static rel="stylesheet" href={Routes.static_path(@conn, "/assets/app.css")}/>
    <script defer phx-track-static type="text/javascript" src={Routes.static_path(@conn, "/assets/app.js")}></script>
  <body>
    <%= @inner_content %>
  </body>
</html>

lib/main_web.ex

defmodule MainWeb do
  def html do
    quote do
      use Phoenix.HTML
      use Phoenix.Component
      alias MainWeb.Router.Helpers, as: Routes
      import Phoenix.HTML.Tag,
        only: [csrf_token_value: 0]
      import Phoenix.Controller,
        only: [get_flash: 1, get_flash: 2, view_module: 1, view_template: 1]   end
  end

  def live_view(opts \\ []) do
    quote do
      use Phoenix.LiveView, unquote(opts)

      unquote(html())
    end
  end

  #defmacro __using__ , etc...
end

lib/main_web/foo/bar_live.ex

defmodule MainWeb.Foo.BarLive do
  use MainWeb, :live_view

  def render(assigns) do
    ~H"""
    <span>live!</span>
    """
  end
end
2

Main.App.Root, needs to be a view, meaning it has to use Phoenix.View which implements the missing render function.

Can you show us the code for that module?

3

Then code is in my original post, but here it goes:

And use MainWeb, :html uses Phoenix.Component.

The docs say Phoenix.View is to be replaced by Phoenix.Compoent, which does not require a render() implementation:
https://hexdocs.pm/phoenix_view/Phoenix.View.html#module-replaced-by-phoenix-component

So, this would be except for :put_root_layout? In that case I think either the docs need to be updated to clarify that, and/or the plug needs to be changed.

4

Your answer made pay more attention to the error stack trace. The call to render is coming from:

Phoenix.View.render_to_iodata (phoenix_view.ex:525)
Phoenix.Controller.render_and_send (controller.ex:772)
Phoenix.Router.__call__ (router.ex:354)

So it really looks like the template cannot be implemented as in Phoenix.Component — Phoenix LiveView v0.18.3. Which is what I was trying to do.

5

It sounds like you are on an older Phoenix. You need to be on Phoenix 1.6.15 for rendering function components from the controller stack. mix deps.update phoenix

6

errr, ignore me. We only support this on upcoming Phoenix 1.7 :slight_smile:

7

Oh, ok. Now it all makes sense Thanks!

Maybe it is worth mentioning this in Phoenix.View — phoenix_view v2.0.0.

Cheers!