Re: [libmicrohttpd] upgrading connection

[Evgeny Grin]

-------- Forwarded Message --------
Subject: Re: [libmicrohttpd] upgrading connection
Date: Wed, 20 Apr 2016 19:48:53 +0300
From: Evgeny Grin <address@hidden>
To: address@hidden



On 20.04.2016 18:54, José Bollo wrote:
> Le mercredi 20 avril 2016 à 18:03 +0300, Evgeny Grin a écrit :

>> We are collecting ideas how to support "upgrade" in
>> the best way, you can see some preliminary drafts in disabled part of
>> microhttpd.h (look for "MHD_UpgradeAction").
> 
> Seen. Well... I don't fully understand the design at first look. In
> particular, the comment of MHD_UpgradeHandler write things about
> 'data_in/out' but I don't understand what it refers to.

Give us more ideas, we are open.

>> Not sure that MHD_suspend_connection()/MHD_resume_connection() are
>> designed to be used in such way. MHD keeps internal stage of connection
>> processing and it's not updated after MHD_resume_connection().
>> How did you obtain socket FD and when you are calling
>> MHD_resume_connection()?
> 
> I use on suspend (not resume)
> MHD_get_connection_info(connection,MHD_CONNECTION_INFO_CONNECTION_FD)->connect_fd

I suppose that you check return value for NULL and used this simplified
form only to illustrate idea. ;)
Anyway, if you are not using MHD_resume_connection(), you're leaking
resources. For every new connection MHD allocate new internal structure,
which are freed after connection is closed. If you never invoke
MHD_resume_connection() then connection-specific structure is kept
forever, even if you close socket in your application.

> I configure MHD to use EPOLL
> 
> The effect of suspending is that the fd is removed from the file set
> using  EPOLL_CTL_DEL. This works very well (with the patch) because the
> buffers are clean. I guess that is will always be the case but...
As I said, you have resources leak.
May be we will extend API to allow "detach" of connection FD, but
currently API frozen until may.

> Anyway the connection must be kept alive. No?
Right, handling of "connection: " header must be improved.

-- 
Best Wishes,
Evgeny Grin

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