404 Error Handling Inside Plug?

Mistake from my side only, this code works now

 conn = conn
            |>  Phoenix.Controller.render(XXXX.Api.V1.ErrorView, :"404error")
            |>  halt()

when i am trying to pass halt in pipes like follow

conn
|> Phoenix.Controller.render(XXXX.Api.V1.ErrorView, :“404error”)
|> halt()

it continues to call another plug, why doesn’t it work, ?

this is the right answer

def call(conn, _) do
  case logics(...) do
    :ok -> conn  
    :error ->
      conn
      |> Phoenix.Controller.render(MyApp.Web.ErrorView, :"404")
      |> halt()
  end
end

Passing an atom to Phoenix.Controller.render will handle the content negation and render the html/json/etc template.

You could write a controller test that looks something like the following

test "this thing halts", %{conn: conn} do
  conn = get(conn, some_path(conn, :index)
  assert conn.halted
end

How can i check its halted or not , currently inside the call/2 i am doing like follow

    body = "oops not found"
    conn
    |> put_resp_content_type("application/json")
    |> send_resp(404, body)
    |> halt

Easiest way is to call the error view render function with whatever code you want then halt() the pipeline.

Probably more correct ways, but that would work.