Add support for generating a simple Web App Manifest file, which helps mobile browsers display the site smartly

wellknowns/urls.py

@@ -7,5 +7,6 @@ urlpatterns = [
     url(r'^keybase.txt$', views.keybase, name='keybase'),
     url(r'^host-meta$', views.host_meta_xml, name='host-meta'),
     url(r'^host-meta.json$', views.host_meta_json, name='host-meta.json'),
+    url(r'^manifest.json$', views.manifest, name='manifest'),
     url(r'^webfinger$', views.webfinger, name='webfinger'),
 ]

wellknowns/views/__init__.py

@@ -1,3 +1,4 @@
 from .static import keybase
 from .host_meta import host_meta_xml, host_meta_json
+from .manifest import manifest
 from .webfinger import webfinger

wellknowns/views/manifest.py

@@ -0,0 +1,28 @@
+from django.conf import settings
+from django.http import JsonResponse
+from favicon.models import FaviconImg
+from lemoncurry import utils
+from lemoncurry.theme import theme
+from urllib.parse import urljoin
+
+
+def manifest(request):
+    origin = utils.origin(request)
+    app = {
+        'name': settings.LEMONCURRY_SITE_NAME,
+        'background_color': '#' + theme['base00'],
+        'theme_color': '#' + theme['base02'],
+    }
+
+    rels = ('shortcut icon', 'apple-touch-icon')
+    icons = FaviconImg.objects.filter(
+        faviconFK__isFavicon=True,
+        rel__in=rels,
+    ).order_by('size')
+    app['icons'] = [{
+        'type': 'image/png',
+        'size': '{0}x{0}'.format(icon.size),
+        'src': urljoin(origin, icon.faviconImage.url),
+    } for icon in icons]
+
+    return JsonResponse(app, content_type='application/manifest+json')