index.html now gets resolved for any subfolder too (+tests)

application/lambda/lambda.go

@@ -194,6 +194,11 @@ func (local *localLambda) writeStaticFile(path string, out io.Writer) error {
 	if err != nil {
 		return err
 	}
+	dir, err := f.Readdir(1)
+	if len(dir) > 0 {
+		f.Close()
+		return local.writeStaticFile( path + "/index.html", out )
+	}
 	defer f.Close()
 	_, err = io.Copy(out, f)
 	return err

application/lambda/lambda_test.go

@@ -152,6 +152,7 @@ func TestStaticFile(t *testing.T) {
 	require.NoError(t, os.WriteFile(filepath.Join(d, "static", "foo", "foo"), []byte("foo page"), 0755))
 	require.NoError(t, os.Mkdir(filepath.Join(d, "static", "foo", "bar"), 0755))
 	require.NoError(t, os.WriteFile(filepath.Join(d, "static", "foo", "bar", "bar"), []byte("bar page"), 0755))
+	require.NoError(t, os.WriteFile(filepath.Join(d, "static", "foo","index.html"), []byte("sub index page"), 0755))
 
 	fn, err := DummyPublic(d, "cat", "-")
 	require.NoError(t, err)
@@ -189,6 +190,21 @@ func TestStaticFile(t *testing.T) {
 		require.NoError(t, err)
 		assert.Equal(t, "bar page", string(content))
 	})
+	t.Run("sub path with index.html served (no trailing slash)", func(t *testing.T) {
+		content, err := testRequest(fn, http.MethodGet, "/f/foo", nil)
+		require.NoError(t, err)
+		assert.Equal(t, "sub index page", string(content))
+	})
+	t.Run("sub path with index.html served (with trailing slash)", func(t *testing.T) {
+		content, err := testRequest(fn, http.MethodGet, "/f/foo/", nil)
+		require.NoError(t, err)
+		assert.Equal(t, "sub index page", string(content))
+	})
+	t.Run("sub path with index.html served (with trailing slash + index.html)", func(t *testing.T) {
+		content, err := testRequest(fn, http.MethodGet, "/f/foo/index.html", nil)
+		require.NoError(t, err)
+		assert.Equal(t, "sub index page", string(content))
+	})
 }
 
 func testRequest(fn application.Invokable, method string, path string, payload []byte) ([]byte, error) {