Handle trailing slashes in static content

TODO.md

@@ -1,15 +1,19 @@
 # To-do
 
+* split the template/content files out from `conservancy/static` into their own
+  `content` directory (avoid mixing static and non-static content)
 * ask Denver about why so many license files
 * serve a 400 in Apache for a hostname we don't explicitly support
-* use `<detail>` elements for supporter page hidden sections, rather than complex jQuery - or consider Alpine.js
+* use `<detail>` elements for supporter page hidden sections, rather than
+  complex jQuery - or consider Alpine.js
 * replace `internalNavigate` with inline flexbox layout
 * add tests for main pages returning 200
 
 
 # Done
 
-* remove `ForceCanonicalHostnameMiddleware` by ensuring canonical redirect and HTTPS redirect is done by Apache
+* remove `ForceCanonicalHostnameMiddleware` by ensuring canonical redirect and
+  HTTPS redirect is done by Apache
 * standardise settings to replace `settings.py` and `djangocommonsettings.py`
   with `settings/prod.py` and move `SECRET_KEY` to an environment variable
 * migrate to Django 4.2 LTS

conservancy/urls.py

@@ -45,7 +45,7 @@ urlpatterns = [
     re_path(r'^learn/', static_views.index),
     re_path(r'^press/', static_views.index),
     re_path(r'^projects/', static_views.index),
-    re_path(r'^GiveUpGitHub', static_views.index),
+    re_path(r'^GiveUpGitHub/', static_views.index),
     re_path(r'^npoacct/', static_views.index, {'fundraiser_sought': 'npoacct'}),
     path('contractpatch/', include('conservancy.contractpatch.urls')),
     re_path(r'^overview/', static_views.index),

conservancy/views.py

@@ -1,8 +1,7 @@
 import mimetypes
 
 from django.conf import settings
-from django.http import Http404
-from django.http import FileResponse
+from django.http import FileResponse, Http404, HttpResponseRedirect
 from django.template.response import TemplateResponse
 
 from .local_context_processors import fundgoal_lookup
@@ -35,7 +34,10 @@ def index(request, *args, **kwargs):
         path += 'index.html'
     full_path = (base_path / path).resolve()
     safe_from_path_traversal = full_path.is_relative_to(base_path)
-    if not full_path.exists() or not safe_from_path_traversal:
+    if full_path.is_dir():
+        # Should have been accessed with a trailing slash.
+        return HttpResponseRedirect(request.path + '/')
+    elif not full_path.exists() or not safe_from_path_traversal:
         raise Http404()
     is_template = mimetypes.guess_type(full_path)[0] == 'text/html'
     if not is_template: