How to whitelist file extensions in Nginx

gistfile1.pl

## This should be the first location in yout config.
location ~* \.(?:gif|html|jpe?g|png|ico|js|css|flv|swf|pdf|xml)$ {
   (...)
   # serve static files
}

# Put all other locations below 
location / {
  (...) # more stuff
}