Fixing unescaped # in the URL with nginx

Question

A bad HTTP client isn't escaping hash signs and is sending them to nginx, like so:

GET /foo/escaped#stuff

Instead of:

GET /foo/escaped%23stuff

This breaks my nginx configuration, since nginx strips the text after the # in the proxy_pass directive. How do I escape the hash sign?

• Using return 200 "$request_uri"; does show me that nginx is reading it, so it seems like it's possible. Nginx, however, ignores it in location blocks, so I can't actually match it with anything.

• You can use the below code to send unescaped HTTP GET requests in Python:

  import socket
  
  def get(host, port, uri):
      sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
      sock.connect((host, port))
      sock.send('GET {} HTTP/1.0\r\nHost: {}\r\n\r\n'.format(uri, host))
  
      return sock.recv(1000)