Nginx Redirect if useragent is android or iphone

gistfile1.txt

# 1
location / {
        set $mobile 0;
        if ($http_user_agent ~* "iphone|android") {
            set $mobile 1;
            }
            if ($mobile = 1) {
              # return or rewrite to somewhere
            }
}


# 2
location / {
        try_files $uri @mobile;
}

 location @mobile {
        set $mobile 0;
        if ($http_user_agent ~* "iphone|android") {
            set $mobile 1;
            }
            if ($mobile = 1) {
              # return or rewrite to somewhere
            }
}