[SOLVED] Django return http early flush (chunked response)

Django return http early flush (chunked response)

I have an algorithm which waits for almost 5 seconds to generate response and I want to send an ack (http 200) to user as soon as he sends request to tell him that his request has been received and wait for 5 seconds.

Generator function:

def chunked_res():
    yield "Chunk 1"

    stop = time.time() + 5    # wait for 5 seconds
    while time.time() < stop:
        pass

    yield "Chunk 2"

And in some view:

response = HttpResponse ( chunked_res() )
response['Connection'] = 'close'
response['Transfer-Encoding'] = 'chunked'
response['status'] = 200
return response

Response in browser:

"Transfer-Encoding: chunked\nstatus: 200\nConnection: close\nContent-Type: text/html; charset=utf-8\n\nChunk 1Chunk 2"

Problem: I am getting required response(Chunk 1, Chunk 2) but after 5 seconds. I want to send "Chunk 1" first and then "Chunk 2" after 5 seconds(update respose). Are there any particular settings/changes to implement this?

Update:

Django = 1.4 python = 2.7

Solution

Actually the solution was to make first chunk size of at least 1024 character for browser to show incrementally.

How to stream an HttpResponse with Django

def chunked_res():
    yield "Chunk 1"
    yield " " * 1024  # Encourage browser to render incrementally (either 1024 or 1024-7{length of "chunk 1"} = 1017)

    time.sleep(5)  # wait for 5 seconds

    yield "Chunk 2"


def myview(request):
    g = chunked_res()
    return HttpResponse(g)

If you are using nginx then you have to set proxy_buffering=off, for server to flush response as 1024 data chunk ready. http://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_buffer_size

Works with: HTTP/1.0 and HTTP/1.1