Error rendering view, implementing the many function

hector97rch

Hi I’m new to elixir and I have a problem when i render one view using many, all of this happens when I call get_users the error its this:

# Could not render "usuario.json" for UsuariosWeb.UserView, please define a matching clause for render/2 or define a template at "lib/usuarios_web/templates/user/*". No templates were compiled for this module. Assigns:

my view its this:

defmodule UsuariosWeb.UserView do

  use UsuariosWeb, :view

  def render("usuarios.json", %{usuarios: usuarios}) do

    %{usuarios: render_many(usuarios, UsuariosWeb.UserView, "usuario.json")}

  end

  def render("usuario.json", %{usuario: usuario}) do

      %{

          id: usuario.id,

          name: usuario.name,

          email: usuario.email,

          estado: usuario.estado

      }

  end

end

and my contoller its this:

def show_usuarios(conn, _params) do

    usuarios = Usuarios.User.buscar_usuarios()

    case usuarios != [] do

        true ->

          conn

            |>put_status(200)

            |> put_resp_content_type("application/json")

            |>render("usuarios.json", %{usuarios: usuarios})

        false ->

          {:error, "no hay usuarios"}

    end

  end

  def show_usuario(conn, %{"id" => id}) do

      case Usuarios.User.buscar_usuario(id) do

        nil->

          {:error, "usuario no encontrado!"}

        usuario->

          conn

            |> put_status(200)

            |> render("usuario.json", %{usuario: usuario})

      end

  end

3 comments

/phoenix #views #render

0 1397 3

2021-12-10 19:08:11 UTC

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stefanchrobot

Try this:

%{usuarios: render_many(usuarios, UsuariosWeb.UserView, "usuario.json", as: :usuario)}

From the docs:

The underlying user is passed to the view and template as :user , which is inferred from the view name.

which means that

%{usuarios: render_many(usuarios, UsuariosWeb.UserView, "usuario.json")}

is equivalent to:

Enum.map(usuarios, fn user ->
  render(UserView, "usuario.json", user: user)
end)

because your view is named UserView.

As a side not, I think you can just use if in your controllers:

if usuario = Usuarios.User.buscar_usuario(id) do
  # conn ...
else
  {:error, "usuario no encontrado!"}
end

Post #1

hector97rch

I also tried it that way and I get the same error.

%{usuarios: render_many(usuarios, UsuariosWeb.UserView, "usuario.json", as: :usuario)}
[/quote]

Post #2

stefanchrobot

Here’s a full working example. Can you please check against your code? You can run this with elixir server.ex:

Application.put_env(:phoenix, :json_library, Jason)
Application.put_env(:sample, UsuariosWeb.Endpoint, [
  http: [ip: {127, 0, 0, 1}, port: 5001],
  server: true,
  secret_key_base: String.duplicate("a", 64),
  render_errors: [view: UsuariosWeb.ErrorView, accepts: ~w(html json), layout: false],
])

Mix.install([
  {:plug_cowboy, "~> 2.5"},
  {:jason, "~> 1.0"},
  {:phoenix, "~> 1.6"},
  {:phoenix_html, "~> 3.1"},
])

defmodule UsuariosWeb.UserView do
  use Phoenix.View, root: ""
  import Phoenix.View

  def render("usuarios.json", %{usuarios: usuarios}) do
    %{usuarios: render_many(usuarios, UsuariosWeb.UserView, "usuario.json", as: :usuario)}
  end

  def render("usuario.json", %{usuario: _usuario}) do
    %{
      ok: true
    }
  end
end

defmodule UsuariosWeb.UserController do
  use Phoenix.Controller

  def show_usuarios(conn, _params) do
    usuarios = [1, 2, 3]

    case usuarios != [] do
        true ->
          conn
            |> put_status(200)
            |> put_resp_content_type("application/json")
            |> render("usuarios.json", %{usuarios: usuarios})
        false ->
          {:error, "no hay usuarios"}
    end
  end
end

defmodule UsuariosWeb.ErrorView do
  use Phoenix.View, root: ""

  # By default, Phoenix returns the status message from
  # the template name. For example, "404.html" becomes
  # "Not Found".
  def template_not_found(template, _assigns) do
    Phoenix.Controller.status_message_from_template(template)
  end

end

defmodule Router do
  use Phoenix.Router

  pipeline :browser do
    plug :accepts, ["html"]
  end

  scope "/", UsuariosWeb do
    pipe_through :browser

    get "/usuarios", UserController, :show_usuarios

    # Prevent a horrible error because ErrorView is missing
    get "/favicon.ico", UserController, :show_usuarios
  end
end

defmodule UsuariosWeb.Endpoint do
  use Phoenix.Endpoint, otp_app: :sample
  plug Router
end

{:ok, _} = Supervisor.start_link([UsuariosWeb.Endpoint], strategy: :one_for_one)
Process.sleep(:infinity)

Post #3

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