auto-resolving nginx magento development config with multi-domain and multi-storeview support.

auto-magento-config-for-nginx

server {
	listen 80 default_server;
	listen [::]:80 default_server ipv6only=on;

    # Automatic generation of the server-name.  
    # both subdomain.domain.tld and storeview.subdomain.domain.tld work. 
	server_name ~^(((?<storeview>.*)\.)?((?<subdomain>.*)\.)(?<domain>[^.]+)\.(?<tld>[^.]+))$; 

    # set root folder. both storeview.dev.magen.to and dev.magen.to resolve to /var/www/magen/htdocs 
	root /var/www/${subdomain}/htdocs;

    # set magento runcode. for example: mysite_nl.dev.magen.to resolves to mysite_nl, dev.magen.to results in default. 
	set $runcode "${storeview}";

    # sets the domainname for rewrites
	set $s1 $1;

    # optional: modified access_log
	access_log /var/log/nginx/dev.log dev;

	client_max_body_size 20M;

	rewrite_log on;

	location / {
		index index.php;
		try_files $uri $uri/ @handler;
		expires 180d; ## Assume all files are cachable
	}

	## Emulate robots.txt for all dev sites
	location /robots.txt {
		return 200 "User-agent: *\nDisallow: /";
	}

        ## These locations would be hidden by .htaccess normally
        location ^~ /app/                { deny all; }
        location ^~ /includes/           { deny all; }
        location ^~ /lib/                { deny all; }
        location ^~ /media/downloadable/ { deny all; }
        location ^~ /pkginfo/            { deny all; }
        location ^~ /report/config.xml   { deny all; }
        location ^~ /var/                { deny all; }

        location /var/export/ { ## Allow admins only to view export folder
                auth_basic              "Restricted"; ## Message in login window
                auth_basic_user_file    /var/www/.htpasswd;
                autoindex               on;
        }

        ## Disable .htaccess and other hidden files
        location ~ /\. {
                return 404;
        }

        location @handler { ## Magento front handler
                rewrite /  /index.php;
        }

        location ~ .php/ { ## Forward paths like /js/index.php/x.js to relevant handler
                rewrite ^(.*.php)/ $1 last;
        }

        location ~ \.php(/.*)? { ## Execute PHP Scripts
                if (!-e $request_filename) { rewrite / /index.php last; } ## Catch 404s that try_files misses

                expires         off; ## Do not cache dynamic content

		set $runtype store;

                fastcgi_pass    unix:/var/run/php5-fpm.sock;
                fastcgi_split_path_info ^(.*\.php)(/.*)?$;
                fastcgi_param   SCRIPT_FILENAME $document_root$fastcgi_script_name;
                fastcgi_param   MAGE_RUN_CODE $runcode;
                fastcgi_param   MAGE_RUN_TYPE $runtype;
                fastcgi_read_timeout 1800;
                include         fastcgi_params; ## See /etc/nginx/fastcgi_params
        }
}

create a wildcard DNS entry like:

  *.mydevelopmentdomain.tld A 127.0.0.1  

and point this to your development server at 127.0.0.1 or a "public" dev server, for instance at Digital Ocean.

examples:

site1.mydevelopmendomain.tld resolves to /var/www/site1
site2.mydevelopmentdomain.tld resolves to /var/www/site2
storeview_nl.site2.mydevelopmentdomain.tld resolves to /var/www/site2 and sets $runcode to storeview_nl
storeview_en.dev.otherdomain.tld resolves to /var/www/dev/ and sets $rundcode to storeview_en

Update 02/03/2015

Added automatic robots.txt emulation for all sites.