On Tue, Jan 22, 2013 at 08:16:36PM +0800, Liu H. wrote:
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 [email protected] 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.
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.