Re: 回复： Re: How to bind variable with connection in a customized module?

[Liu Haifeng]

Thank you again. Last mail was sent from my mobile phone(android). Sorry for the trouble.

Proxied connection is not a big problem for me for now. But good note, I'll think about it in the future.

On Jan 22, 2013, at 10:16 PM, Maxim Dounin <mdounin at mdounin.ru> wrote:

> Hello!
> 
> (Just a side note: it looks like you mail client have problems 
> with proper mail encoding.  I have to recover message headers by 
> hand, as the Subject header was split across multiple 
> non-consecutive lines, breaking other headers as well.)
> 
> On Tue, Jan 22, 2013 at 05:33:31AM -0800, Haifeng Liu wrote:
> 
>> Thank you very much. And for your note, I know the connections 
>> are reusable, it's not a problem for me. To be sure, during a 
>> client is alive, the connection won't serve other clients, is it 
>> correct?
> 
> This depends on what do you mean by "client".  If next hop http 
> client - true, the connection is always with one client.  But on 
> the same connection request from different users might appear, 
> e.g. if requests are proxied via the same proxy server ("client" 
> from nginx point of view).
> 
> It might be helpfull to read this section of RFC2616 for better 
> understanding:
> 
> http://tools.ietf.org/html/rfc2616#section-1.4
> 
>> 
>> Maxim Dounin <mdounin at mdounin.ru>编写：
>> 
>> 
>> Hello!
>> 
>> On Tue, Jan 22, 2013 at 08:16:36PM +0800, Liu Haifeng wrote:
>> 
>>> hi all,
>>> 
>>> I want save state during a long connection (keep-alive) for 
>>> performance optimization in my own HTTP handler module, thus I 
>>> can peek up the saved state when handling requests, to speed up 
>>> response. Actually it's quite like session concept. I saw 
>>> request struct has a member ctx, but what I want is a ctx on the 
>>> connection. It seems no way to save any customized variable to 
>>> the ngx_connection_t structure. What's the suggested way to make 
>>> this if I don't want the client hold something like session_id?
>> 
>> This was recently discussed on nginx-devel@ mailing list, and 
>> probably the best way currently available is to install connection 
>> pool cleanup handler with custom data and then iterate over 
>> connection pool cleanup handlers to find your data.  It is 
>> relatively costly, but allows to keep memory footprint from 
>> keepalive connections low and still allows modules to keep their 
>> per-connection data in rare cases when they really need to.
>> 
>> See here:
>> http://mailman.nginx.org/pipermail/nginx-devel/2012-December/003049.html
>> 
>> Note well though, that HTTP is stateless protocol, and the fact 
>> that request came from the same connection means mostly nothing: 
>> it might be a request from a completely different user.
>> 
>> -- 
>> Maxim Dounin
>> http://nginx.com/support.html
>> 
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> 
> -- 
> Maxim Dounin
> http://nginx.com/support.html