headers_in_hash

[Maxim Dounin]

Hello!

On Fri, Feb 14, 2014 at 04:39:23PM -0500, atarob wrote:

> Creating a module, I want to read in from config desired http header fields.
> Then, during config still, I want to get the struct offset for the fields
> that have dedicated pointers in the header_in struct. It seems that when I
> access headers_in_hash from the main config,  it is uninitialized. I can see
> in the code that there is
> 
> ngx_http_init_headers_in_hash(ngx_conf_t *cf, ngx_http_core_main_conf_t
> *cmcf)
> 
> in ngx_http.c. It seems to be called when the main conf is being generated
> though I am not certain yet.
> 
> Where and when exactly is headers_in_hash initialized? If I wanted to read
> from it during ngx_http_X_merge_loc_conf(), what would I need to do?  Or am
> I supposed to do it at some point later?

The cmcf->headers_in_hash is expected to be initialized during 
runtime.  As of now, it will be initialized before  
postconfiguration hooks, but I wouldn't recommend relaying on 
this.

I also won't recommend using cmcf->headers_in_hash in your own 
module at all, unless you have good reasons to.  It's not really a 
part of the API, it's an internal entity which http core uses to 
do it's work.

-- 
Maxim Dounin
http://nginx.org/