portico: Provide isolated single-page versions of /terms and /privacy .

The `isolated_page` context flag we rely on was added in the
parent commit.

zerver/tests/test_docs.py

@@ -560,3 +560,18 @@ class PrivacyTermsTest(ZulipTestCase):
         with self.settings(PRIVACY_POLICY=abs_path):
             response = self.client_get('/privacy/')
         self.assert_in_success_response(['This is some <em>bold text</em>.'], response)
+
+    def test_no_nav(self) -> None:
+        # Test that our ?nav=0 feature of /privacy and /terms,
+        # designed to comply with the Apple App Store draconian
+        # policies that ToS/Privacy pages linked from an iOS app have
+        # no links to the rest of the site if there's pricing
+        # information for anything elsewhere on the site.
+        response = self.client_get("/terms/")
+        self.assert_in_success_response(["Plans"], response)
+
+        response = self.client_get("/terms/?nav=no")
+        self.assert_not_in_success_response(["Plans"], response)
+
+        response = self.client_get("/privacy/?nav=no")
+        self.assert_not_in_success_response(["Plans"], response)

zerver/views/portico.py

@@ -39,3 +39,15 @@ def team_view(request: HttpRequest) -> HttpResponse:
             'date': data['date'],
         },
     )
+
+def get_isolated_page(request: HttpRequest) -> bool:
+    '''Accept a GET param `?nav=no` to render an isolated, navless page.'''
+    return request.GET.get('nav') == 'no'
+
+def terms_view(request: HttpRequest) -> HttpResponse:
+    return render(request, 'zerver/terms.html',
+                  context={'isolated_page': get_isolated_page(request)})
+
+def privacy_view(request: HttpRequest) -> HttpResponse:
+    return render(request, 'zerver/privacy.html',
+                  context={'isolated_page': get_isolated_page(request)})

zproject/urls.py

@@ -563,8 +563,8 @@ i18n_urls = [
     url(r'^atlassian/$', TemplateView.as_view(template_name='zerver/atlassian.html')),
 
     # Terms of Service and privacy pages.
-    url(r'^terms/$', TemplateView.as_view(template_name='zerver/terms.html'), name='terms'),
-    url(r'^privacy/$', TemplateView.as_view(template_name='zerver/privacy.html'), name='privacy'),
+    url(r'^terms/$', zerver.views.portico.terms_view, name='terms'),
+    url(r'^privacy/$', zerver.views.portico.privacy_view, name='privacy'),
 
     url(r'^config-error/google$', TemplateView.as_view(
         template_name='zerver/config_error.html',),