Disabling Django CSRF for views that do not always have a response
I know you already got your answer, and indeed Ned's right;but in addition to that: not only Django really expects views to return a response, your client also! It's an HTTP error and likely a resource waste not to return something (and thus close the connection straight away)!
I would think that a 204 No Content or 304 Not modified (see: HTTP Status Codes) are the appropriate http codes to use in this situation; in django:
return HttpResponse(status=204)or
from django.http import HttpResponseNotModifiedreturn HttpResponseNotModified()
Django really expects view functions to return responses. Maybe you could return an empty response instead of None? Or return an HTTP error code?