Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages


home | help
WS_ATTACH_SERVER(3)	   libdill Library Functions	   WS_ATTACH_SERVER(3)

       ws_attach_server	 - creates WebSocket protocol on the top of underlying

	      #include <libdill.h>

	      int ws_attach_server(
		  int s,
		  int flags,
		  char*	resource,
		  size_t resourcelen,
		  char*	host,
		  size_t hostlen,
		  int64_t deadline);

       WARNING:	This is	experimental functionality and the API may  change  in
       the future.

       WebSocket  is  a	message-based protocol defined in RFC 6455.  It	can be
       used as a bidirectional communication channel for communication with  a
       web server.

       This  function instantiates WebSocket protocol on top of	the underlying
       bytestream protocol.  WebSocket protocol	being asymmetric,  client  and
       server  sides  are intialized in	different ways.	 This particular func-
       tion initializes	the client side	of the connection.

       The socket can be either	text- (WS_TEXT	flag)  or  binary-  (WS_BINARY
       flag)  based.   Binary is the default.  When sending messages via msend
       or msendl these will be typed based on the socket type.	When receiving
       messages	 via mrecv or mrecvl encountering a message that doesn't match
       the socket type results in EPROTO error.

       If you want to combine text and binary messages you can do so by	 using
       functions such as ws_send and ws_recv.

       WS_NOHTTP  flag	can  be	 combined with socket type flags.  If set, the
       protocol	will skip the initial HTTP handshake.  In this	case  resource
       and host	arguments won't	be used	and can	be set to NULL.

       Skipping	 HTTP handshake	is useful when you want	to do the handshake on
       your own.  For example, if you want to implement	custom	WebSocket  ex-
       tensions	 or  if	 you  want to write a multi-protocol application where
       initial HTTP handshake can be followed by different kinds of  protocols
       (e.g.  HTML and WebSocket).

       s: Handle of the	underlying socket.  It must be a bytestream protocol.

       flags: Flags.  See above.

       resource: Out parameter.	 HTTP resource specified by the	client.

       resourcelen: Size of the	resource buffer.

       host: Out parameter.  Virtual host specified by the client.

       hostlen:	Size of	the host buffer.

       deadline:  A  point in time when	the operation should time out, in mil-
       liseconds.  Use the now function	to get your current point in time.   0
       means immediate timeout,	i.e., perform the operation if possible	or re-
       turn without blocking if	not.  -1 means no  deadline,  i.e.,  the  call
       will block forever if the operation cannot be performed.

       The socket can be cleanly shut down using ws_detach function.

       This  function  is  not	available  if  libdill is compiled with	--dis-
       able-sockets option.

       In case of success the function returns newly  created  socket  handle.
       In  case	of error it returns -1 and sets	errno to one of	the values be-

       o EBADF:	Invalid	handle.

       o ECANCELED: Current coroutine was canceled.

       o ECONNRESET: Broken connection.

       o EINVAL: Invalid argument.

       o EMFILE: The maximum number of file descriptors	in the process are al-
	 ready open.

       o ENFILE:  The maximum number of	file descriptors in the	system are al-
	 ready open.

       o ENOMEM: Not enough memory.

       o ENOTSUP: The handle does not support this operation.

       o EPROTO: Underlying socket is not a bytestream socket.

       o ETIMEDOUT: Deadline was reached.

	      int s = tcp_accept(listener, NULL, -1);
	      s	= tls_attach_server(s, -1);
	      bsend(s, "ABC", 3, -1);
	      char buf[3];
	      ssize_t sz = brecv(s, buf, sizeof(buf), -1);
	      s	= tls_detach(s,	-1);

       hclose(3)  mrecv(3)  mrecvl(3)	msend(3)   msendl(3)   now(3)	ws_at-
       tach_client(3)  ws_attach_client_mem(3)	ws_attach_server_mem(3)	ws_de-
       tach(3)	ws_done(3)  ws_recv(3)	ws_recvl(3)  ws_request_key(3)	ws_re-
       sponse_key(3) ws_send(3)	ws_sendl(3) ws_status(3)

libdill							   WS_ATTACH_SERVER(3)


Want to link to this manual page? Use this URL:

home | help