[undertow-dev] Reading request body parsed/buffered by RequestBufferingHandler

[Stuart Douglas]

On Tue, Jul 3, 2018 at 8:15 PM Girish Sharma <scrapmachines at gmail.com>
wrote:

> Hi Stuart,
>
> Thanks for getting back to me. I have some comments below:
>
> You just read it as normal
>>
>  I am assuming that by normal, you mean the
>
> exchange.startBlocking() + (InputStream stream =
> exchange.getInputStream())
>
> approach to read the input stream? But then what benefit we get here as
> compared to not using the RequestBufferingHandler and directly using this
> approach? Is the following loop (typically used in reading input stream)
> going to be much more efficient?:
>

Say you have a slow mobile client that takes 2s to upload its request.
Without the request buffering handler the worker thread will be blocked for
2s. If you have lots of these slow clients you could exhaust the worker
thread pool, causing request to queue and generally decreasing performance.
If you use the request buffering handler the worker thread will not start
work until after the data has been read, so it does not block on IO.

Stuart



>
> while ((line = bufferedReader.readLine()) != null) {
>     stringBuffer.append(line);
> }
>
> Regards
>
>
> On Tue, Jul 3, 2018 at 6:34 AM Stuart Douglas <sdouglas at redhat.com> wrote:
>
>> You just read it as normal. The advantage is that if you are going to
>> dispatch to a worker thread then the dispatch does not happen until the
>> request has been read, thus reducing the amount of time a worker spends
>> processing the request. Essentially this allows you to take advantage of
>> non-blocking IO even for applications that use blocking IO, but at the
>> expense of memory for buffering.
>>
>> Stuart
>>
>> On Mon, Jul 2, 2018 at 8:55 PM Girish Sharma <scrapmachines at gmail.com>
>> wrote:
>>
>>> Hi,
>>>
>>> I tried searching around in github/stackexchange but could not find
>>> anything related to RequestBufferingHandler.
>>>
>>> I understand that RequestBufferingHandler would read the request body
>>> for me and then call the handler assigned as the next handler. But how does
>>> the next handler read the buffered request body?
>>>
>>> Looking around the code of RequestBufferingHandler, I see that it adds
>>> an attachment to the exchange, but the key for that attachment is protected
>>> to the undertow package.
>>>
>>> How can I read the value of that attachment? Or is there some other way
>>> to read the buffered request body?
>>>
>>> PS: I know the alternate approach of reading request body i.e
>>> startBlocking + getInputStream and getRequestReceiver().receiveFullString ,
>>> but I am interested in using the RequestBufferingHandler in particular.
>>>
>>> --
>>> Girish Sharma
>>> _______________________________________________
>>> undertow-dev mailing list
>>> undertow-dev at lists.jboss.org
>>> https://lists.jboss.org/mailman/listinfo/undertow-dev
>>
>>
>
> --
> Girish Sharma
> B.Tech(H), Civil Engineering,
> Indian Institute of Technology, Kharagpur
>
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