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	 <C653D29D.C07A3%Brian.Akins@turner.com>
Date: Wed, 10 Jun 2009 11:28:29 +1000
Message-ID: <88e286470906091828v3ee5abber1264af92ce048d4b@mail.gmail.com>
Subject: Re: Some ramblings on httpd config
From: Graham Dumpleton <graham.dumpleton@gmail.com>
To: dev@httpd.apache.org
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2009/6/9 Akins, Brian <Brian.Akins@turner.com>:
> On 6/5/09 11:31 PM, "Graham Dumpleton" <graham.dumpleton@gmail.com> wrote=
:
>
>> This last example wasn't even related to driving configuration. It was
>> in practice an actual handler hook implementation for request
>> processing, not configuration phases.
>
> The way I see it, we have artificially separated configuration from reque=
st
> processing.

Well, I believe that separation already exists. How you would do
things in each context would be different. See mod_perl for example:

  http://perl.apache.org/docs/2.0/api/Apache2/PerlSections.html

How you write its configuration stuff is quite different to an actual handl=
er.

> If you squint and tilt your head just right, you can see that
> virtualhosts today are really just syntactical sugar over the if/else log=
ic
> inside of core:

Except that for handler the calculation is more dynamic and not driven
through static defined data structures setup in configuration phase.

> Some pseudo request processing code to do same thing:
> =A0if listening_port =3D=3D 80 then
> =A0 =A0 if r.hostname =3D=3D 'www.foo.com' then
> =A0 =A0 =A0 =A0 ....
> =A0 =A0 elseif r.hostname =3D~ /www\d.bar.[org|net]/
> =A0 =A0 end
> =A0end
>
>
> Of course this could be further hidden from users with
> macros/functions/libraries/modules...
>
> Now, on the practical side, do we completely ditch the current config
> system. =A0Part of me says yes, but I know that will be -1'd to death. =
=A0So,
> I'd just like the ability to do something like this:
>
> LoadModule lua_module mod_lua.so
> Listen 80
> LuaRequestHandler /path/to/my/lua/handler.lua

Huh, are you sure you can't do that now somehow. The vhost module uses
translate name hook so if you use LuaHookTranslateName I would presume
it would be possible to do something equivalent in lua.

> (or it can be inline <Lua> but have found that to be somewhat cumbersome)
>
> Because I don't want to rewrite mod_proxy in lua, it'd be nice to have ju=
st
> a little bit of glue that would allow me to use it in a more "scripty" so=
rt
> of way:
>
> LoadModule proxy_module mod_proxy.so
> LoadModule proxy_http_module mod_proxy_http.so
> ....
> =A0require httpd.proxy -- provided by mod_proxy glue
>
> =A0p =3D httpd.proxy.get_url('http://blah')

Again, are you sure there aren't already ways of doing that with
mod_lua. Setting up proxying is simple enough to do in mod_python and
would be possible with mod_perl as well. For mod_python see example
in:

  http://issues.apache.org/jira/browse/MODPYTHON-141

If mod_lua provides equivalent wrappers for request object, would be
done in same way.

> (Of course, that example could be handled like we do in mod_rewrite)
>
> Currently, we can sorta do most request processing in lua. (FWIW, do the
> request phases make any sense in a world where the entire request process=
 is
> handled by a "script"??) =A0What is missing is the glue to the other, use=
ful
> parts of httpd - like cache, mod_dbd, proxy, etc.

Getting a bit confused here. You acknowledge you know about request
processing phases, but at the same time say you would like to see
stuff that I would have thought was already possible.

Do not I haven't used mod_lua/mod_wombat, so maybe it doesn't give you
level of programmability as modules such as mod_perl and mod_python.

> Sure, one of us could hack together some example glue here and there, but
> until we as a whole "get" why this is useful/important, it will be just
> another list of patches waiting to be reviewed.
>
> --
> Brian Akins
> Chief Operations Engineer
> Turner Digital Media Technologies
>
>