title: Setting content dispose based on url / nginx
body: <p>Having nginx serving static files with url like <code>http://foobar.tld/&lt;random_dir&gt;/&lt;file_md5sum_as_filename&gt;</code> and I would like if I specify at the end of url <code>?f="filename.filetype"</code> - nginx parse that query string at the end (if is specified) and prepares new content dispose matching specified arguments and without any dynamic backend that's like impossible. </p>
  
  <p>or instance <code>http://foobar.tld/&lt;random_dir&gt;/&lt;file_md5sum_as_filename&gt;?f="foobar.pdf"</code></p>
  
  <p>Can something like this be done with nginx/lua module? Does any one have any useful example or has done anything similar? </p>