Harden canonical and robots URLs to production host

mandelstudio/settings/env/prd.py

@@ -18,6 +18,7 @@ ALLOWED_HOSTS = [
     "www.mandelblog.com",
     "mandelblog.com",
 ]
+CANONICAL_BASE_URL = "https://www.mandelblog.com"
 if "salt_target" in globals():
     ALLOWED_HOSTS.append("mandelstudio.%s" % salt_target)  # pylint: disable=E0602
 # pylint: disable=E0602

mandelstudio/sitemaps.py

@@ -1,5 +1,6 @@
 from django.contrib.sitemaps.views import index as sitemap_index_view
 from django.contrib.sitemaps.views import sitemap as sitemap_section_view
+from django.conf import settings
 from django.http import HttpResponse
 
 from wagtail.models import Locale, Page
@@ -15,6 +16,13 @@ from ocyan.plugin.wagtail_oscar_integration.sitemap import (
 )
 
 
+def _absolute_sitemap_url(request, path: str) -> str:
+    canonical_base = getattr(settings, "CANONICAL_BASE_URL", "").rstrip("/")
+    if canonical_base:
+        return f"{canonical_base}{path}"
+    return request.build_absolute_uri(path)
+
+
 class WagtailSitemap(BaseWagtailSitemap):
     def items(self):
         page_ids = []
@@ -74,7 +82,7 @@ def sitemap_section(request, section=None):
 
 
 def robots_txt(request):
-    sitemap_url = request.build_absolute_uri("/sitemap.xml")
+    sitemap_url = _absolute_sitemap_url(request, "/sitemap.xml")
     content = "\n".join(
         [
             "User-agent: *",

mandelstudio/templatetags/localized_navigation.py

@@ -2,12 +2,41 @@ from __future__ import annotations
 
 from django import template
 from django.conf import settings
+from urllib.parse import urlsplit, urlunsplit
 
 from wagtail.models import Page
 
 register = template.Library()
 
 
+def _canonical_base_url() -> str:
+    return getattr(settings, "CANONICAL_BASE_URL", "").rstrip("/")
+
+
+def _with_canonical_host(url_or_path: str | None) -> str:
+    value = url_or_path or ""
+    base = _canonical_base_url()
+    if not base:
+        return value
+    if not value:
+        return f"{base}/"
+    if value.startswith("/"):
+        return f"{base}{value}"
+    parsed = urlsplit(value)
+    if parsed.scheme and parsed.netloc:
+        canonical = urlsplit(base)
+        return urlunsplit(
+            (
+                canonical.scheme,
+                canonical.netloc,
+                parsed.path,
+                parsed.query,
+                parsed.fragment,
+            )
+        )
+    return f"{base}/{value.lstrip('/')}"
+
+
 def _normalize_language_code(language_code: str | None) -> str:
     return (language_code or settings.LANGUAGE_CODE).split("-")[0]
 
@@ -41,10 +70,10 @@ def _translated_pages(page):
 
 def _build_absolute_url(request, path: str | None, page=None) -> str:
     if path and request is not None:
-        return request.build_absolute_uri(path)
+        return _with_canonical_host(request.build_absolute_uri(path))
     if page is not None:
-        return getattr(page, "full_url", "") or path or ""
-    return path or ""
+        return _with_canonical_host(getattr(page, "full_url", "") or path or "")
+    return _with_canonical_host(path or "")
 
 
 @register.simple_tag
@@ -89,7 +118,7 @@ def page_canonical_url(context):
     if page is not None and getattr(page, "url", None):
         return _build_absolute_url(request, page.url, page)
     if request is not None:
-        return request.build_absolute_uri()
+        return _with_canonical_host(request.build_absolute_uri())
     return ""