Override PHP server variables like `REQUEST_URI`

[mqudsi]

I've used nginx-unit for standalone php servers in the past with great success so I decided to try and move a rather large production configuration of nginx + php-fpm to nginx + nginx-unit (php) but ran into what seems to be a limitation in the design. It seems that while nginx-unit supports sitting behind nginx, it doesn't really cater for cases where nginx is performing redirects for the app because it expects that php's $_SERVER['REQUEST_URI'] will come from $request_uri.

In this case, because I am porting a php-fpm installation to nginx-unit, nginx has already rewritten "virtual urls" to the actual document url. I thought I could use proxy_set_header X-Request-Uri $request_uri; in nginx to make a variable $header_x_request_uri available to nginx-unit and then configure nginx-unit to tell php to use $header_x_request_uri as REQUEST_URI but this does not seem possible (the only options are script and index?).

In an nginx + php-fpm installation, the nginx fastcgi_param directive can be used to set the following variables:

fastcgi_param  QUERY_STRING       $query_string;
fastcgi_param  REQUEST_METHOD     $request_method;
fastcgi_param  CONTENT_TYPE       $content_type;
fastcgi_param  CONTENT_LENGTH     $content_length;

fastcgi_param  SCRIPT_NAME        $fastcgi_script_name;
fastcgi_param  REQUEST_URI        $request_uri;
fastcgi_param  DOCUMENT_URI       $document_uri;
fastcgi_param  DOCUMENT_ROOT      $document_root;
fastcgi_param  SERVER_PROTOCOL    $server_protocol;
fastcgi_param  REQUEST_SCHEME     $scheme;
fastcgi_param  HTTPS              $https if_not_empty;

fastcgi_param  GATEWAY_INTERFACE  CGI/1.1;
fastcgi_param  SERVER_SOFTWARE    nginx/$nginx_version;

fastcgi_param  REMOTE_ADDR        $remote_addr;
fastcgi_param  REMOTE_PORT        $remote_port;
fastcgi_param  SERVER_ADDR        $server_addr;
fastcgi_param  SERVER_PORT        $server_port;
fastcgi_param  SERVER_NAME        $server_name;

# PHP only, required if PHP was built with --enable-force-cgi-redirect
fastcgi_param  REDIRECT_STATUS    200;

but there doesn't seem to be any way to do the same in nginx-unit?