Possible to overwrite a fastcgi_param "later", once a location block has already been closed?

Francis Daly francis at daoine.org
Tue Jul 9 21:47:55 UTC 2013

On Tue, Jul 09, 2013 at 04:48:27PM -0400, Ben Johnson wrote:

Hi there,

> I am working with a server configuration that is partly outside of my
> control,

I suspect that that's not the intended use case for nginx. Whoever writes
the config file has the opportunity to configure it not to start.

> and have a need to overwrite a fastcgi_param "after" the
> directives that are outside of my control have already been included.

That sentence is possible; but not the one in your Subject: line.

> location @php {
>     try_files $uri =404;
>     include /etc/nginx/fastcgi_params;
>     fastcgi_pass;
>     fastcgi_index index.php;
>     fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
>     fastcgi_intercept_errors on;
> }
> # At this point, the fastcgi_param values have already been defined.
> # This is the include file that I am able to modify.
> include my-include.conf

That line must be within the "location @php" block, in order for it to
do what you want.

(Otherwise, you could try completely hijacking the config by using
something like

  location ^~ / {
    location ~ php$ {
      # you control what goes here
    # and what goes here

in my-include.conf, but that would be a good way to lose config privileges
on the server.)

> Is it possible for me to overwrite the values that are defined on the
> line "include /etc/nginx/fastcgi_params;" from within the included file
> that I can modify, "my-include.conf"?

Current nginx sends all fastcgi_params that are defined, in order; so
if you set the same one multiple times in the same context, all are sent.

Your fastcgi server probably only pays attention to the first one
received, or maybe to the last one received. Test to find out.

When you know which it is, put your "include" line before or after the
other "include" line, and see how it works.

Future nginx may stop sending all repeated fastcgi_params. If you change
fastcgi server, the one it pays attention to may change. So your testing
should be repeated after every upgrade.

Francis Daly        francis at daoine.org

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