Re: [boost] [GSoC 2014] Http Server Proposal

Subject: Re: [boost] [GSoC 2014] Http Server Proposal
From: Niall Douglas (s_sourceforge_at_[hidden])
Date: 2014-03-07 12:46:49

On 7 Mar 2014 at 4:25, Vinícius dos Santos Oliveira wrote:

> I'm sorry for taking so long to present my proposal, but some
> unpredictable events delayed the available time I had to work on the
> proposal and the large number of mentions you guys made turned my work
> into a task more difficult.

Firstly, this is a not bad initial design given your unfamiliarity 
with Boost. Its biggest problem is vagueness in some key areas, but 
as a review of the existing approaches it's not bad.

I'll just make some observations:

* ASIO can use futures or callbacks. It can use threads or 
coroutines. Error handling can be an error code or exceptions. In 
short: ASIO is very flexible. The N3964 paper simply seeks to 
standardise ASIO's already existing design, so all those facilities 
are already there and available.

* AFIO is probably not hugely useful except for doing async file i/o 
which ASIO can't do, despite what ASIO claims in its docs. In other 
words you'd bring in AFIO for the static content backend where for 
example you can enumerate directories asynchronously, otherwise AFIO 
is overkill.

* I would very seriously reduce the scope of your present proposal. 
Just to write a semi-decent fully asynchronous static content HTTP 
1.1 server is more than enough to consider right now. I'd forget 
about any CGI or anything else like that for now. I'd *even* suggest 
restricting scope to HTTP 1.0 support as your first milestone, and 
then slowly extend out into HTTP 1.1.

* You mentioned "The implementation of a HTTP server isn't very 
challenging". Algorithmically you're right, but the fact people keep 
reinventing HTTP servers shows how hard implementing a *good* HTTP 
server is. HTTP servers are a good example of why a compsci whiz or 
an algorithms whiz can make lousy "real world" programmers. The hard 
part of a decent HTTP server is getting to a 100% asynchronous 
internal engine which is exception safe and linear scalable to load. 
I would *not* underestimate how hard one of these is: I would 
personally estimate about 1000 hours for me to implement just a fully 
async HTTP 1.0 static content server with validation and test suite 
and Boost quality documentation. If you think that proposed 
Boost.AFIO - which is just 1000 active LOC by the way - has consumed 
about 600 hours, and it's a fraction of the complexity of a HTTP 1.0 
server, you'll see what I mean.

Good luck!

Niall

-- 
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Work Portfolio: http://careers.stackoverflow.com/nialldouglas/