[web-devel] Sending a Response before the Request has been entirely consumed?

[Jeremy Bowers]

On 09/17/2013 03:08 PM, Jeremy Shaw wrote:
> Hello,
>
> Is it valid for a server to start sending an HTTP Response before the 
> Request has been entirely consumed? Or to put it differently, is there 
> any case where it would be valid for the Response message-body to be 
> streaming the value from the Request message-body?
>
I don't know about valid from a "standards" point of view, but a valid 
use case, yes. For some reason or other, you are able to determine early 
that you do not care to answer this request, and you want to drop it or 
return an error as rapidly as possible. For instance, if a particular 
page is getting DOS'ed, part of your mitigation strategy might be to 
bail out of any request for that page as early as possible, or if it's 
because a particular page is being over-accessed you might want to 
return a static snapshot ASAP and get on with the next request. Or based 
on IPs, or whoknows what.

I think you're right that returning a 200 before you've seen the entire 
header is probably never a good idea, but there are many 4xx and 5xx 
series responses you can make.