nginx判断移动端还是pc端分别转发不同地址

server {

        listen   80;
        server_name xxx.cn;


	 location / { 
                root /data/web/pc;
                  
       if ( $http_user_agent ~ "(MIDP)|(WAP)|(UP.Browser)|(Smartphone)|(Obigo)|(Mobile)|(AU.Browser)|(wxd.Mms)|(
WxdB.Browser)|(CLDC)|(UP.Link)|(KM.Browser)|(UCWEB)|(SEMC-Browser)|(Mini)|(Symbian)|(Palm)|(Nokia)|(Panasonic)|(MOT-)|(Sony
Ericsson)|(NEC-)|(Alcatel)|(Ericsson)|(BENQ)|(BenQ)|(Amoisonic)|(Amoi-)|(Capitel)|(PHILIPS)|(SAMSUNG)|(Lenovo)|(Mitsu)|(Mot
orola)|(SHARP)|(WAPPER)|(LG-)|(LG/)|(EG900)|(CECT)|(Compal)|(kejian)|(Bird)|(BIRD)|(G900/V1.0)|(Arima)|(CTL)|(TDG)|(Daxian)
|(DAXIAN)|(DBTEL)|(Eastcom)|(EASTCOM)|(PANTECH)|(Dopod)|(Haier)|(HAIER)|(KONKA)|(KEJIAN)|(LENOVO)|(Soutec)|(SOUTEC)|(SAGEM)
|(SEC-)|(SED-)|(EMOL-)|(INNO55)|(ZTE)|(iPhone)|(Android)|(Windows CE)|(Wget)|(Java)|(curl)|(Opera)" )
       	 {       
       	         root /data/web/mobile;
       	 }
	}
	#Images
       location ~ .*\.(ico|gif|jpg|jpeg|png|bmp|swf|apk|exe)$ {
       access_log off;
       root /data/images;
       expires      5d;

        }
    }

	server {
		
		listen 80;
		server_name xxx.com;

		 location / {
			 proxy_set_header    Host $host;
       			 proxy_set_header    X-Real-IP $remote_addr;
        		proxy_set_header    X-Forwarded-For $proxy_add_x_forwarded_for;
    			proxy_pass  http://100.100.100.100:8081;
		}
	}
}