From e0673548c58ed2a4493cb286d76ea9a55a151ee2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jochen=20Wersd=C3=B6rfer?= <jochen@wersdoerfer.de>
Date: Thu, 7 Sep 2023 10:17:26 +0200
Subject: [PATCH] #105 add proper context manager for passing request to
 wagtail pages + test

---
 cast/api/views.py | 30 ++++++++++++++++++++++++++++--
 tests/api_test.py | 22 ++++++++++++++++++++++
 2 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/cast/api/views.py b/cast/api/views.py
index 8158a675..0c3c6360 100644
--- a/cast/api/views.py
+++ b/cast/api/views.py
@@ -1,10 +1,12 @@
 import logging
 from collections import OrderedDict
+from collections.abc import Iterator
+from contextlib import contextmanager
 from typing import Any, cast
 
 from django.contrib.auth.mixins import LoginRequiredMixin
 from django.db.models import QuerySet
-from django.http import JsonResponse
+from django.http import HttpRequest, JsonResponse
 from django.urls import reverse
 from django.views.generic import CreateView
 from rest_framework import generics, status
@@ -203,11 +205,35 @@ def get_filtered_queryset(self) -> QuerySet:
         return filterset.qs
 
     def get_queryset(self):
-        ProxyRequest.request = self.request
         if self.request.GET.dict().get("use_post_filter", "false") == "true":
             return self.get_filtered_queryset()
         return super().get_queryset()
 
+    def dispatch(self, request, *args, **kwargs):
+        """
+        Override dispatch to set request on ProxyRequest to be able to use
+        the real request in page models. This is needed for example to select
+        the correct template base directory (theme) from `request.session` which
+        would otherwise not be available.
+
+        Putting this into get_queryset() would not work because `ProxyRequest.request`
+        would be None again before it gets used in the `page.get_description` method.
+        """
+
+        @contextmanager
+        def tunneled_request(_request: HttpRequest) -> Iterator:
+            """
+            Set request on ProxyRequest for use in page models temporarily.
+            """
+            ProxyRequest.request = _request
+            try:
+                yield
+            finally:
+                ProxyRequest.request = None
+
+        with tunneled_request(request):
+            return super().dispatch(request, *args, **kwargs)
+
 
 # Wagtail API
 wagtail_api_router = WagtailAPIRouter("cast:api:wagtail")
diff --git a/tests/api_test.py b/tests/api_test.py
index d419172d..5a46bb57 100644
--- a/tests/api_test.py
+++ b/tests/api_test.py
@@ -320,3 +320,25 @@ def test_update_theme_invalid(api_client):
     print(result)
     assert result["error"] == "Theme slug is invalid"
     assert api_client.session.get("template_base_dir") is None
+
+
+@pytest.mark.django_db
+def test_render_html_with_theme_from_session(api_client, post):
+    # Given we have custom theme set in the session
+    r = api_client.post(
+        # FIXME there's some way to update the session more elegantly
+        # use this instead of the post request
+        reverse("cast:api:theme-update"),
+        {"theme_slug": "plain"},
+        format="json",
+    )
+    assert r.status_code == 200
+
+    # When we request the blog post via api
+    url = reverse("cast:api:wagtail:pages:detail", kwargs={"pk": post.pk})
+    r = api_client.get(url, format="json")
+    assert r.status_code == 200
+
+    # Then we expect the blog post to be rendered with the theme from the session
+    assert r.context.get("template_base_dir") == "plain"
+    assert all([t.name.startswith("cast/plain/") for t in r.templates])