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

FreeBSD Manual Pages


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

       ws_attach_server_mem  - creates WebSocket protocol on the top of	under-
       lying socket

	      #include <libdill.h>

	      int ws_attach_server_mem(
		  int s,
		  int flags,
		  char*	resource,
		  size_t resourcelen,
		  char*	host,
		  size_t hostlen,
		  struct ws_storage* mem,
		  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).

       This  function allows to	avoid one dynamic memory allocation by storing
       the object in user-supplied memory.  Unless  you	 are  hyper-optimizing
       use ws_attach_server instead.

       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.

       mem:  The  structure to store the newly created object in.  It must not
       be deallocated before the object	is closed.

       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(3) ws_detach(3)
       ws_done(3)  ws_recv(3) ws_recvl(3) ws_request_key(3) ws_response_key(3)
       ws_send(3) ws_sendl(3) ws_status(3)

libdill						       WS_ATTACH_SERVER_MEM(3)


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

home | help