Rewrite handling order

[Fasih]

I see, thanks for the explanation.


On Tue, Jan 14, 2014 at 8:27 PM, Ruslan Ermilov <ru at nginx.com> wrote:

> On Tue, Jan 14, 2014 at 06:54:44PM +0530, Fasih wrote:
> > Thanks! Could you please explain why this is done?
>
> Modules register their handlers (at different phases
> of request processing) one by one, by adding an element
> into the corresponding array of handlers.  The order
> in which modules do this is somewhat important.
>
> For example, let's take a look at three standard "index"
> modules: autoindex, index, and random_index.  They are
> listed in auto/modules in the above mentioned sequence,
> and thus register their handlers in this sequence too.
> Their handlers are called in a reverse sequence, so it's
> either random index, or an index file, or an automatically
> generated directory listing, in this order.
>
> There are also 3rd party modules that are added to the
> list of modules at the end, and consequently register
> their handlers after the standard modules.  Now imagine
> you wrote a custom my_index module.  By processing
> handlers in a reverse order we give better chance for
> the 3rd party module to run.  If we did the opposite,
> then nginx would check the "index.html" file existence
> (the index module) before even calling your handler.
>
> > On Tue, Jan 14, 2014 at 4:41 PM, Maxim Dounin <mdounin at mdounin.ru>
> wrote:
> >
> > > Hello!
> > >
> > > On Tue, Jan 14, 2014 at 04:15:32PM +0530, Fasih wrote:
> > >
> > > > Hi
> > > >
> > > > I have a custom plugin that handles rewrite (NGX_HTTP_REWRITE_PHASE).
> > > There
> > > > is another plugin compiled before my plugin that also handles rewrite
> > > > (HttpLuaModule). I was expecting to see that my module would rewrite
> > > after
> > > > lua is done, however that is not the case. Some debugging showed that
> > > > whereas my module pushed into the
> > > > cmcf->phases[NGX_HTTP_REWRITE_PHASE].handlers after lua, the
> > > > cmcf.phase_engine.handlers had lua *after* my module. The culprit
> seems
> > > to
> > > > be the following:
> > > >
> > > > static ngx_int_t
> > > > ngx_http_init_phase_handlers(ngx_conf_t *cf,
> ngx_http_core_main_conf_t
> > > > *cmcf)
> > > > {
> > > > ..
> > > >         ph = cmcf->phase_engine.handlers;
> > > > ..
> > > >         n += cmcf->phases[i].handlers.nelts;
> > > >
> > > >         for (j = cmcf->phases[i].handlers.nelts - 1; j >=0; j--) {
> > > >             ph->checker = checker;
> > > >             ph->handler = h[j];
> > > >             ph->next = n;
> > > >             ph++;
> > > >         }
> > > > }
> > > >
> > > > The order is inverted here (h[j] before h[j-1]). Is this intentional
> or a
> > > > bug?
> > >
> > > It's intentional.
> > >
> > > --
> > > Maxim Dounin
> > > http://nginx.org/
> > >
> > > _______________________________________________
> > > nginx-devel mailing list
> > > nginx-devel at nginx.org
> > > http://mailman.nginx.org/mailman/listinfo/nginx-devel
> > >
>
>
> --
> Ruslan Ermilov
>
> _______________________________________________
> nginx-devel mailing list
> nginx-devel at nginx.org
> http://mailman.nginx.org/mailman/listinfo/nginx-devel
>
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