How to stream an HttpResponse with Django
I'm trying to get the 'hello world' of streaming responses working for Django (1.2). I figured out how to use a generator and the yield function. But the response still not streaming. I suspect there's a middleware that's mucking with it -- maybe ETAG calculator? But I'm not sure how to disable it. Can somebody please help?
Here's the "hello world" of streaming that I have so far:
def stream_response(request):
resp = HttpResponse( stream_response_generator())
return resp
def stream_response_generator():
for x in range(1,11):
yield "%s\n" % x # Returns a chunk of the response to the browser
time.sleep(1)
Answer
You can disable the ETAG middleware using the condition decorator. That will get your response to stream back over HTTP. You can confirm this with a command-line tool like curl. But it probably won't be enough to get your browser to show the response as it streams. To encourage the browser to show the response as it streams, you can push a bunch of whitespace down the pipe to force its buffers to fill. Example follows:
from django.views.decorators.http import condition
@condition(etag_func=None)
def stream_response(request):
resp = HttpResponse( stream_response_generator(), content_type='text/html')
return resp
def stream_response_generator():
yield "<html><body>\n"
for x in range(1,11):
yield "<div>%s</div>\n" % x
yield " " * 1024 # Encourage browser to render incrementally
time.sleep(1)
yield "</body></html>\n"