auth_request_set into variable and lua

[Maxim Dounin]

Hello!

On Tue, Dec 04, 2012 at 06:19:02PM -0800, agentzh wrote:

> Hello!
> 
> On Tue, Dec 4, 2012 at 2:18 PM, djczaski wrote:
> > Trying to get a header from an auth_request into a variable and use it from
> > Lua with no luck.  This was the simple example I tried.
> >
> 
> You're making several mistakes. See the discussion below:
> 
> >       location = /auth {
> >            add_header    X-Boo    "Hello World";
> 
> Mistake #1: The add_header directive from the standard ngx_headers
> module has no effect on subrequests while your location /auth here is
> accessed by a subrequest issued via the auth_request directive.
> 
> >            return 204;
> >         }
> >
> >         location /test {
> >             auth_request /auth;
> >             auth_request_set $test $upstream_http_x_boo;
> 
> Mistake #2: The $upstream_http_XXX variables are only meaningful when
> the *current* location is configured by one of those Nginx upstream
> modules like ngx_proxy, ngx_fastcgi, ngx_uwsgi, and etc. Here your
> current location, location /test, is not configured by any Nginx
> upstream modules (neither ngx_auth_request nor ngx_lua are upstream
> modules).
> 
> Mistake #3: The $upstream_http_XXX variables are only in effect for
> the current request. It won't inherit values from any other requests
> including subrequests.

The #2 and #3 are the reasons why the auth_request_set directive 
exists: it allows to store variables specific to auth subrequest, 
like $upstream_http_*, in variables of main request.

So the only valid problem in config is #1.

[...]

-- 
Maxim Dounin
http://nginx.com/support.html