remove html extension and trailing slash with nginx

rewrite-nginx-server.conf

server {
  listen   80;
  server_name test.com *.test.com;

  rewrite ^(/.*)\.html(\?.*)?$ $1$2 permanent;
  rewrite ^/(.*)/$ /$1 permanent;

  root /path/to/project/root;
  index index.html;
  try_files $uri/index.html $uri.html $uri/ $uri =404;

  error_page 404 /404.html;
  error_page 500 502 503 504 /500.html;
}

use rewrite and try_files directives to achieve two goals, remove the html extension and the trailing slash.