From 37cf309bb008af25c3811f982e219dfc1b0ee9ba Mon Sep 17 00:00:00 2001
From: Jake Howard <git@theorangeone.net>
Date: Thu, 17 Nov 2022 22:36:22 +0000
Subject: [PATCH] Add activitypub well-known forwarding

Disabled until needed
---
 requirements.txt            |  1 +
 website/settings.py         |  3 +++
 website/well_known/tests.py | 42 ++++++++++++++++++++++++++++++++++++-
 website/well_known/urls.py  | 15 +++++++++++++
 website/well_known/views.py | 17 +++++++++++++--
 5 files changed, 75 insertions(+), 3 deletions(-)

diff --git a/requirements.txt b/requirements.txt
index ef9b846..f312be8 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -29,6 +29,7 @@ django-cors-headers==3.13.0
 django-csp==3.7
 django-permissions-policy==4.13.0
 django-enforce-host==1.1.0
+django-proxy==1.2.1
 
 # DRF OpenAPI dependencies
 uritemplate
diff --git a/website/settings.py b/website/settings.py
index 2097543..81884a4 100644
--- a/website/settings.py
+++ b/website/settings.py
@@ -14,6 +14,7 @@ env = environ.Env(
     SENTRY_DSN=(str, ""),
     TEST=(bool, False),
     ALLOWED_HOSTS=(list, ["*"]),
+    ACTIVITYPUB_HOST=(str, ""),
 )
 
 # Read local secrets
@@ -305,6 +306,8 @@ WAGTAIL_MODERATION_ENABLED = False
 UNSPLASH_CLIENT_ID = env("UNSPLASH_CLIENT_ID")
 SPOTIFY_PROXY_HOST = env("SPOTIFY_PROXY_HOST")
 
+ACTIVITYPUB_HOST = env("ACTIVITYPUB_HOST")
+
 SEO_INDEX = env("SEO_INDEX")
 
 if DEBUG:
diff --git a/website/well_known/tests.py b/website/well_known/tests.py
index fe8a8f3..ed3b340 100644
--- a/website/well_known/tests.py
+++ b/website/well_known/tests.py
@@ -1,4 +1,7 @@
-from django.test import SimpleTestCase, TestCase
+from unittest.mock import patch
+
+from django.http.response import HttpResponse
+from django.test import SimpleTestCase, TestCase, override_settings
 from django.urls import reverse
 
 
@@ -36,3 +39,40 @@ class MatrixClientViewTestCase(SimpleTestCase):
         self.assertEqual(response.status_code, 200)
         self.assertEqual(response["Content-Type"], "application/json")
         self.assertTemplateUsed(response, "well-known/matrix-client.json")
+
+
+class ActivityPubProxyView(TestCase):
+    PROXIED_PATHS = [
+        reverse("well-known:webfinger"),
+        reverse("well-known:hostmeta"),
+        reverse("well-known:nodeinfo"),
+    ]
+
+    def setUp(self):
+        super().setUp()
+
+        proxy_view_patcher = patch("website.well_known.views.proxy_view")
+        self.proxy_view = proxy_view_patcher.start()
+        self.addCleanup(proxy_view_patcher.stop)
+
+        self.proxy_view.return_value = HttpResponse()
+
+    @override_settings(ACTIVITYPUB_HOST="activitypub.example.com")
+    def test_urls(self):
+        for path in self.PROXIED_PATHS:
+            with self.subTest(path):
+                response = self.client.get(path)
+                self.assertEqual(response.status_code, 200)
+                self.assertEqual(
+                    self.proxy_view.call_args[0][1],
+                    f"https://activitypub.example.com{path}",
+                )
+                self.assertEqual(response["Cache-Control"], "max-age=60")
+
+    @override_settings(ACTIVITYPUB_HOST="")
+    def test_unconfigured(self):
+        for path in self.PROXIED_PATHS:
+            with self.subTest(path):
+                response = self.client.get(path)
+                self.assertEqual(response.status_code, 404)
+                self.assertFalse(self.proxy_view.called)
diff --git a/website/well_known/urls.py b/website/well_known/urls.py
index c50ac29..9a915a6 100644
--- a/website/well_known/urls.py
+++ b/website/well_known/urls.py
@@ -20,4 +20,19 @@ urlpatterns = [
         views.MatrixClientView.as_view(),
         name="matrix-client",
     ),
+    path(
+        "webfinger",
+        views.activitypub_proxy,
+        name="webfinger",
+    ),
+    path(
+        "hostmeta",
+        views.activitypub_proxy,
+        name="hostmeta",
+    ),
+    path(
+        "nodeinfo",
+        views.activitypub_proxy,
+        name="nodeinfo",
+    ),
 ]
diff --git a/website/well_known/views.py b/website/well_known/views.py
index a573cfb..066e598 100644
--- a/website/well_known/views.py
+++ b/website/well_known/views.py
@@ -1,11 +1,13 @@
 from datetime import timedelta
 
+from django.conf import settings
 from django.http.request import HttpRequest
-from django.http.response import HttpResponse
+from django.http.response import Http404, HttpResponse
 from django.utils import timezone
 from django.utils.decorators import method_decorator
-from django.views.decorators.cache import cache_control
+from django.views.decorators.cache import cache_control, cache_page
 from django.views.generic import TemplateView
+from proxy.views import proxy_view
 
 from website.contact.models import ContactPage
 from website.contrib.singleton_page.utils import SingletonPageCache
@@ -46,3 +48,14 @@ class MatrixServerView(TemplateView):
 class MatrixClientView(TemplateView):
     template_name = "well-known/matrix-client.json"
     content_type = "application/json"
+
+
+@cache_page(60)
+def activitypub_proxy(request: HttpRequest) -> HttpResponse:
+    if not settings.ACTIVITYPUB_HOST:
+        raise Http404
+
+    return proxy_view(
+        request,
+        f"https://{settings.ACTIVITYPUB_HOST}{request.path}",
+    )