haproxy(1.5) + ssl + websockets (see comments on how to create a .pem file)

haproxy.cfg

  defaults
  log     global
  mode    http
  option  httplog
  option  dontlognull
  retries 3
  option redispatch
  timeout connect 5s
  timeout client 50s
  timeout server 50s
  balance  roundrobin


frontend wss_frontend
  bind 0.0.0.0:443 ssl crt /etc/haproxy/server.pem
  timeout client 86400000
  default_backend bosh_backend
  acl is_websocket hdr(Upgrade) -i WebSocket
  acl is_websocket hdr_beg(Host) -i ws

#  use_backend bosh_backend if is_websocket

#frontend all 0.0.0.0:80
#  timeout client 86400000
#  default_backend bosh_backend
#  acl is_websocket hdr(Upgrade) -i WebSocket
#  acl is_websocket hdr_beg(Host) -i ws


backend bosh_backend
  balance roundrobin
  option forwardfor # This sets X-Forwarded-For
  timeout queue 5000
  timeout server 86400000
  timeout connect 5000
  server node-xmpp-bosh 127.0.0.1:5282


listen admin
       bind 127.0.0.1:9999
       mode http
       stats uri /

You have to generate a key and a certificate using openssl and concatenate them in a file, the certificate first, then the key.
$ cat server.crt server.key > server.pem