NAME
    ngx_http_referer_host_module - implements $referer_host variable 

SYNOPSIS
	http {

	    map $referer_host $valid {
		default          0;
		example.com      1;
		www.example.com  1;
	    }

	    map $referer_host $invalid {
		hostnames;
		default          1;
		.example.com     0;
	    }

	    ...

	    server {

		location / {
		    if ($invalid) {
			return 403;
		    }
		}

		...
	    }
	}

DESCRIPTION
    A very simple module that parses http referer header and exports 
    resulting hostname into $referer_host variable to use in nginx.conf.

    And just in case modifies referer header making its hostname part
    lower-cased.

    You can achieve something like this in nginx 0.9.6+ with map and pcre:

	map $http_referer $referer_host {
	    default "";
	    ~^https?://(?<H>[^:/]+) $H;
	}

INSTALLATION
    As usual for nginx modules:

	./configure --add-module=/path/to/ngx_http_referer_host_module ... 
	make
	make install

AUTHOR
    Alexandr Gomoliako <[email protected]>

LICENSE
    Copyright 2011 Alexandr Gomoliako. All rights reserved.

    This module is free software. It may be used, redistributed and/or 
    modified under the terms described in LICENSE file.