Forward flashes and automatically pass via props (#13)

CHANGELOG.md

@@ -5,6 +5,8 @@
 - Support for propagating errors via an `assign_errors` helper ([#10](https://github.com/svycal/inertia-phoenix/issues/10))
 - Preservation of assigned errors across redirects ([#10](https://github.com/svycal/inertia-phoenix/issues/10))
 - Setup external redirects properly for Inertia requests ([#11](https://github.com/svycal/inertia-phoenix/issues/11))
+- Forward flash contents across forced refreshes ([#13](https://github.com/svycal/inertia-phoenix/issues/13))
+- Automatically pass Phoenix flash data via the `flash` prop
 
 ## 0.4.0
 

lib/inertia/controller.ex

@@ -137,6 +137,7 @@ defmodule Inertia.Controller do
       shared
       |> Map.merge(props)
       |> resolve_props(only: only, except: except)
+      |> maybe_put_flash(conn)
 
     conn
     |> put_private(:inertia_page, %{component: component, props: props})
@@ -220,6 +221,11 @@ defmodule Inertia.Controller do
     end
   end
 
+  # Skip putting flash in the props if there's already `:flash` key assigned.
+  # Otherwise, put the flash in the props.
+  defp maybe_put_flash(%{flash: _} = props, _conn), do: props
+  defp maybe_put_flash(props, conn), do: Map.put(props, :flash, conn.assigns.flash)
+
   defp send_response(%{private: %{inertia_request: true}} = conn) do
     conn
     |> put_status(200)

lib/inertia/plug.ex

@@ -15,6 +15,7 @@ defmodule Inertia.Plug do
     |> assign(:inertia_head, [])
     |> put_private(:inertia_version, compute_version())
     |> put_private(:inertia_error_bag, get_error_bag(conn))
+    |> merge_forwarded_flash()
     |> fetch_inertia_errors()
     |> detect_inertia()
   end
@@ -152,10 +153,30 @@ defmodule Inertia.Plug do
     conn
     |> put_resp_header("x-inertia-location", request_url(conn))
     |> put_resp_content_type("text/html")
+    |> forward_flash()
     |> send_resp(:conflict, "")
     |> halt()
   end
 
+  defp forward_flash(%{assigns: %{flash: flash}} = conn)
+       when is_map(flash) and map_size(flash) > 0 do
+    put_session(conn, "inertia_flash", flash)
+  end
+
+  defp forward_flash(conn), do: conn
+
+  defp merge_forwarded_flash(conn) do
+    case get_session(conn, "inertia_flash") do
+      nil ->
+        conn
+
+      flash ->
+        conn
+        |> delete_session("inertia_flash")
+        |> assign(:flash, Map.merge(conn.assigns.flash, flash))
+    end
+  end
+
   defp static_paths do
     Application.get_env(:inertia, :static_paths, [])
   end

test/inertia_test.exs

@@ -21,7 +21,7 @@ defmodule InertiaTest do
 
     assert %{
              "component" => "Home",
-             "props" => %{"text" => "Hello World", "errors" => %{}},
+             "props" => %{"text" => "Hello World", "errors" => %{}, "flash" => %{}},
              "url" => "/",
              "version" => @current_version
            } = json_response(conn, 200)
@@ -38,7 +38,12 @@ defmodule InertiaTest do
 
     assert %{
              "component" => "Home",
-             "props" => %{"text" => "Hello World", "foo" => "bar", "errors" => %{}},
+             "props" => %{
+               "text" => "Hello World",
+               "foo" => "bar",
+               "errors" => %{},
+               "flash" => %{}
+             },
              "url" => "/shared",
              "version" => @current_version
            } = json_response(conn, 200)
@@ -178,7 +183,8 @@ defmodule InertiaTest do
                "lazy_1" => "lazy_1",
                "lazy_3" => "lazy_3",
                "nested" => %{"lazy_2" => "lazy_2"},
-               "errors" => %{}
+               "errors" => %{},
+               "flash" => %{}
              },
              "url" => "/lazy",
              "version" => @current_version
@@ -196,7 +202,11 @@ defmodule InertiaTest do
 
     assert json_response(conn, 200) == %{
              "component" => "Home",
-             "props" => %{"a" => %{"b" => %{"c" => "c", "e" => %{"f" => "f"}}}, "errors" => %{}},
+             "props" => %{
+               "a" => %{"b" => %{"c" => "c", "e" => %{"f" => "f"}}},
+               "errors" => %{},
+               "flash" => %{}
+             },
              "url" => "/nested",
              "version" => @current_version
            }
@@ -213,7 +223,7 @@ defmodule InertiaTest do
 
     assert json_response(conn, 200) == %{
              "component" => "Home",
-             "props" => %{"a" => %{"b" => %{"c" => "c"}}, "errors" => %{}},
+             "props" => %{"a" => %{"b" => %{"c" => "c"}}, "errors" => %{}, "flash" => %{}},
              "url" => "/nested",
              "version" => @current_version
            }
@@ -230,7 +240,7 @@ defmodule InertiaTest do
 
     assert json_response(conn, 200) == %{
              "component" => "Home",
-             "props" => %{"a" => "a", "important" => "stuff", "errors" => %{}},
+             "props" => %{"a" => "a", "important" => "stuff", "errors" => %{}, "flash" => %{}},
              "url" => "/always",
              "version" => @current_version
            }
@@ -249,7 +259,8 @@ defmodule InertiaTest do
              "component" => "Home",
              "props" => %{
                "a" => %{"b" => %{"c" => "c", "e" => %{"f" => "f", "g" => "g"}, "d" => "d"}},
-               "errors" => %{}
+               "errors" => %{},
+               "flash" => %{}
              },
              "url" => "/nested",
              "version" => @current_version
@@ -265,7 +276,7 @@ defmodule InertiaTest do
 
     assert json_response(conn, 200) == %{
              "component" => "Home",
-             "props" => %{"b" => "b", "errors" => %{}},
+             "props" => %{"b" => "b", "errors" => %{}, "flash" => %{}},
              "url" => "/tagged_lazy",
              "version" => @current_version
            }
@@ -282,7 +293,7 @@ defmodule InertiaTest do
 
     assert json_response(conn, 200) == %{
              "component" => "Home",
-             "props" => %{"a" => "a", "errors" => %{}},
+             "props" => %{"a" => "a", "errors" => %{}, "flash" => %{}},
              "url" => "/tagged_lazy",
              "version" => @current_version
            }
@@ -298,7 +309,8 @@ defmodule InertiaTest do
     assert json_response(conn, 200) == %{
              "component" => "Home",
              "props" => %{
-               "errors" => %{"settings.theme" => "can't be blank", "name" => "can't be blank"}
+               "errors" => %{"settings.theme" => "can't be blank", "name" => "can't be blank"},
+               "flash" => %{}
              },
              "url" => "/changeset_errors",
              "version" => @current_version
@@ -321,7 +333,8 @@ defmodule InertiaTest do
                    "settings.theme" => "can't be blank",
                    "name" => "can't be blank"
                  }
-               }
+               },
+               "flash" => %{}
              },
              "url" => "/changeset_errors",
              "version" => @current_version
@@ -365,6 +378,56 @@ defmodule InertiaTest do
     assert get_resp_header(conn, "x-inertia-location") == ["http://www.example.com/"]
   end
 
+  test "automatically includes flash in props", %{conn: conn} do
+    conn =
+      conn
+      |> patch(~p"/")
+
+    assert html_response(conn, 302)
+
+    conn =
+      conn
+      |> recycle()
+      |> get("/")
+
+    assert html_response(conn, 200) =~ ~s("flash":{"info":"Patched") |> html_escape()
+  end
+
+  test "does not clobber the flash prop if manually set", %{conn: conn} do
+    conn =
+      conn
+      |> get(~p"/overridden_flash")
+
+    assert html_response(conn, 200) =~ ~s("flash":{"foo":"bar") |> html_escape()
+  end
+
+  test "forwards flash across forced refreshes", %{conn: conn} do
+    conn =
+      conn
+      |> patch(~p"/")
+
+    assert html_response(conn, 302)
+
+    # The next redirect hop triggers a forced refresh...
+    conn =
+      conn
+      |> recycle()
+      |> put_req_header("x-inertia", "true")
+      |> put_req_header("x-inertia-version", "different")
+      |> get("/")
+
+    assert html_response(conn, 409)
+    assert get_resp_header(conn, "x-inertia-location") == ["http://www.example.com/"]
+
+    # After the hop, flash should be present in the props
+    conn =
+      conn
+      |> recycle()
+      |> get("/")
+
+    assert html_response(conn, 200) =~ ~s("flash":{"info":"Patched") |> html_escape()
+  end
+
   defp html_escape(content) do
     content
     |> Phoenix.HTML.html_escape()

test/support/my_app/lib/my_app_web/controllers/page_controller.ex

@@ -73,18 +73,28 @@ defmodule MyAppWeb.PageController do
     redirect(conn, external: "http://www.example.com/")
   end
 
+  def overridden_flash(conn, _params) do
+    conn
+    |> assign(:page_title, "Home")
+    |> assign_prop(:flash, %{foo: "bar"})
+    |> render_inertia("Home")
+  end
+
   def update(conn, _params) do
     conn
+    |> put_flash(:info, "Updated")
     |> redirect(to: "/")
   end
 
   def patch(conn, _params) do
     conn
+    |> put_flash(:info, "Patched")
     |> redirect(to: "/")
   end
 
   def delete(conn, _params) do
     conn
+    |> put_flash(:info, "Deleted")
     |> redirect(to: "/")
   end
 

test/support/my_app/lib/my_app_web/router.ex

@@ -24,6 +24,7 @@ defmodule MyAppWeb.Router do
     get "/redirect_on_error", PageController, :redirect_on_error
     get "/bad_error_map", PageController, :bad_error_map
     get "/external_redirect", PageController, :external_redirect
+    get "/overridden_flash", PageController, :overridden_flash
     put "/", PageController, :update
     patch "/", PageController, :patch
     delete "/", PageController, :delete