Query page

lib/my_app_web/live/queries_live.ex

@@ -0,0 +1,70 @@
+defmodule MyAppWeb.QueriesLive do
+  use MyAppWeb, :live_view
+
+  alias MyApp.Repo
+
+  @impl true
+  def render(assigns) do
+    ~H"""
+    <div class="mx-auto max-w-2xl p-8">
+      <h1 class="text-3xl font-bold mb-8">Database Queries</h1>
+
+      <div class="space-y-8">
+        <div class="card bg-base-100 shadow-xl">
+          <div class="card-body">
+            <h2 class="card-title">now()</h2>
+            <p class="text-lg font-mono"><%= @now %></p>
+          </div>
+        </div>
+
+        <div class="card bg-base-100 shadow-xl">
+          <div class="card-body">
+            <h2 class="card-title">random()</h2>
+            <.async_result assign={@random}>
+              <div id="random_value" :if={rn = @random.ok? && @random.result}>{rn}</div>
+              <:loading>
+                <div class="loading loading-spinner loading-md"></div>
+              </:loading>
+              <:failed :let={reason}>
+                <p class="text-error">Failed to load: <%= reason %></p>
+              </:failed>
+            </.async_result>
+          </div>
+        </div>
+      </div>
+    </div>
+    """
+  end
+
+  @impl true
+  def mount(_params, _session, socket) do
+    {:ok, results} = Repo.query("SELECT now();")
+    [[now]] = results.rows
+
+    socket =
+      socket
+      |> assign(:now, now)
+      |> assign_async(:random, fn -> fetch_random_number() end)
+
+    {:ok, socket}
+  end
+
+
+  defp fetch_random_number() do
+    # Maybe pretend this is slow
+    Process.sleep(query_delay())
+    {:ok, results} = Repo.query("SELECT random();")
+    [[random]] = results.rows
+    {:ok, %{random: random}}
+  end
+
+  defp query_delay do
+    with delay_str <- System.get_env("QUERY_DELAY"),
+         true <- is_binary(delay_str),
+         {delay, ""} <- Integer.parse(delay_str) do
+      delay
+    else
+      _ -> 0
+    end
+  end
+end

lib/my_app_web/router.ex

@@ -25,6 +25,11 @@ defmodule MyAppWeb.Router do
     pipe_through :browser
 
     get "/", PageController, :home
+
+    live_session :default,
+      on_mount: @common_on_mount_hooks do
+      live "/queries", QueriesLive, :index
+    end
   end
 
   # Other scopes may use custom stacks.

test/features/register_test.exs

@@ -19,5 +19,7 @@ defmodule Features.RegisterTest do
     |> visit(~p"/users/settings")
     |> assert_has(".phx-connected")
     |> assert_has("h1", text: "Settings")
+    |> visit(~p"/queries")
+    |> assert_has("h1", text: "Database Queries")
   end
 end