Refactor FullUrlMixin get_domain to handle django.contrib.sites not i…

…n INSTALLED_APPS (#194)

changes/192.bugfix

@@ -0,0 +1 @@
+Refactor FullUrlMixin get_domain to handle django.contrib.sites not in INSTALLED_APPS

meta/views.py

@@ -2,6 +2,7 @@
 import warnings
 from datetime import date
 
+from django.apps import apps
 from django.core.exceptions import ImproperlyConfigured
 
 from .settings import get_setting
@@ -30,17 +31,20 @@ def get_domain(self):
 
         :return: domain URL
         """
-        from django.contrib.sites.models import Site
-
         try:
-            if self.use_sites:
-                return Site.objects.get_current(self.request).domain
+            use_site = self.use_sites
         except AttributeError:
-            if get_setting("USE_SITES"):
+            use_site = get_setting("USE_SITES")
+
+        if use_site:
+            try:
+                Site = apps.get_model("sites.Site")
                 try:
                     return Site.objects.get_current(self.request).domain
                 except AttributeError:
                     return Site.objects.get_current().domain
+            except LookupError:
+                raise ImproperlyConfigured("Add django.contrib.sites to INSTALLED_APPS because META_USE_SITES is True")
         if not get_setting("SITE_DOMAIN"):
             raise ImproperlyConfigured("META_SITE_DOMAIN is not set")
         return get_setting("SITE_DOMAIN")

tests/test_meta.py

@@ -3,7 +3,7 @@
 
 from django.contrib.sites.models import Site
 from django.core.exceptions import ImproperlyConfigured
-from django.test import RequestFactory, TestCase, override_settings
+from django.test import RequestFactory, TestCase, modify_settings, override_settings
 
 from meta.views import Meta
 
@@ -266,3 +266,20 @@ def test_as_json_ld(self):
             m.as_json_ld(),
             json.dumps(data),
         )
+
+    @override_settings(META_SITE_DOMAIN="example-no-sites.com", META_SITE_PROTOCOL="http")
+    @modify_settings(INSTALLED_APPS={"remove": "django.contrib.sites"})
+    def test_get_full_url_without_sites(self):
+        m = Meta()
+        self.assertEqual(m.get_full_url("foo/bar"), "http://example-no-sites.com/foo/bar")
+
+    @override_settings(
+        META_SITE_DOMAIN="example-no-sites.com",
+        META_SITE_PROTOCOL="http",
+        META_USE_SITES=True,
+    )
+    @modify_settings(INSTALLED_APPS={"remove": "django.contrib.sites"})
+    def test_get_full_url_without_sites_wrong_setting(self):
+        m = Meta()
+        with self.assertRaises(ImproperlyConfigured):
+            self.assertEqual(m.get_full_url("foo/bar"), "http://example-no-sites.com/foo/bar")