Performance: Cache complete organizer index page, cache subevent list template fragment (#2125)

src/pretix/base/templatetags/cache_large.py

@@ -0,0 +1,35 @@
+from django.conf import settings
+from django.template import Library, Node, TemplateSyntaxError, Variable
+from django.templatetags.cache import CacheNode
+
+register = Library()
+
+
+class DummyNode(Node):
+    def __init__(self, nodelist, *args):
+        self.nodelist = nodelist
+
+    def render(self, context):
+        value = self.nodelist.render(context)
+        return value
+
+
+@register.tag('cache_large')
+def do_cache(parser, token):
+    nodelist = parser.parse(('endcache_large',))
+    parser.delete_first_token()
+    tokens = token.split_contents()
+    if len(tokens) < 3:
+        raise TemplateSyntaxError("'%r' tag requires at least 2 arguments." % tokens[0])
+
+    if not settings.CACHE_LARGE_VALUES_ALLOWED:
+        return DummyNode(
+            nodelist,
+        )
+
+    return CacheNode(
+        nodelist, parser.compile_filter(tokens[1]),
+        tokens[2],  # fragment_name can't be a variable.
+        [parser.compile_filter(t) for t in tokens[3:]],
+        Variable(repr(settings.CACHE_LARGE_VALUES_ALIAS)),
+    )