core: add pre-hydrated relative URL (#13243)

Signed-off-by: Jens Langhammer <jens@goauthentik.io>

authentik/core/templates/base/header_js.html

@@ -11,6 +11,7 @@
         build: "{{ build }}",
         api: {
             base: "{{ base_url }}",
+            relBase: "{{ base_url_rel }}",
         },
     };
     window.addEventListener("DOMContentLoaded", function () {

authentik/core/views/interface.py

@@ -53,6 +53,7 @@ class InterfaceView(TemplateView):
         kwargs["build"] = get_build_hash()
         kwargs["url_kwargs"] = self.kwargs
         kwargs["base_url"] = self.request.build_absolute_uri(CONFIG.get("web.path", "/"))
+        kwargs["base_url_rel"] = CONFIG.get("web.path", "/")
         return super().get_context_data(**kwargs)