Websocket Driver
This library provides WebSocket server & client implementation for Common Lisp.
Supported Servers
Usage
Server-side with Clack
WebSocket server implementation is designed to work with Clack, which is a abstraction layer for web servers.
(ql:quickload '(:websocket-driver-server :clack))
(use-package :websocket-driver)
(defvar *echo-server*
(lambda (env)
(let ((ws (make-server env)))
(on :message ws
(lambda (message)
(send ws message)))
(lambda (responder)
(declare (ignore responder))
(start-connection ws)))))
;; Start Wookie server
(clack:clackup *echo-server* :server :wookie :port 5000)The backend server can be changed by replacing :wookie by other servers.
Client-side
(ql:quickload :websocket-driver-client)
(defvar *client* (wsd:make-client "ws://localhost:5000/echo"))
(wsd:start-connection *client*)
(wsd:on :message *client*
(lambda (message)
(format t "~&Got: ~A~%" message)))
(wsd:send *client* "Hi")
(wsd:close-connection *client*)APIs
[Function] make-server (env &key max-length accept-protocols additional-headers)
Returns a new SERVER object. The ENV is a property list represents server information, which Clack provides.
The max-length is the maximum message size allowed. The default is #x3ffffff. If at any time it stays bigger than this, the connection will be closed with code 1009 (too-large).
The accept-protocols is a list of custom protocol names as strings. This will be used for checking Sec-WebSocket-Protocol header client sent. The default is an empty list.
The additional-headers is an association list which represents HTTP headers to use in WebSocket handshake response. The default is an empty list.
[Function] make-client (url &key max-length accept-protocols additional-headers)
Returns a new CLIENT object. The URL is a string to connect.
Additional keyword arguments max-length, accept-protocols and additional-headers are shared with make-server.
[Class] ws
The base class for server and client.
As this inherits event-emitter, its object can be attached event listerners by on.
[Event] :open
Called when the socket becomes open.
(on :open ws
(lambda ()
(format t "Connected.~%")))[Event] :message
Called when a message is received. The callback function takes a MESSAGE as an argument which is either a string in the case of a text message or an (UNSIGNED-BYTE 8) vector in the case of a binary message.
(on :message ws
(lambda (message)
(format t "Received: ~S~%" message)))[Event] :error
Called when a protocol error occurs due to the other peer sending an invalid byte sequence. The callback function takes a PROTOCOL-ERROR as an argument.
(on :error ws
(lambda (error)
(format t "Got an error: ~S~%" error)))[Event] :close
Called when the socket becomes closed. The CALLBACK function takes CODE and REASON as arguments.
(on :close ws
(lambda (&key code reason)
(format t "Closed because '~A' (Code=~A)~%" reason code)))[Class] server
The class for WebSocket (version 13) server implementation.
[Class] client
The class for WebSocket client implementation.
[Method] (start-connection ws)
Initiates the protocol by sending the handshake - either the response for a server-side driver or the request for a client-side one. This should be the first method you invoke. Returns T if a handshake was sent.
[Method] (send ws data &key start end type code callback)
Sends DATA over the socket.
[Function] (send-text ws message &key start end callback)
Sends a text message over the socket.
[Function] (send-binary ws usb8-vector &key start end callback)
Takes an (UNSIGNED-BYTE 8) vector and sends them as a binary message.
[Method] (send-ping ws &optional message callback)
Sends a ping frame over the socket, queueing it if necessary.
[Method] (close-connection ws)
Initiates the closing handshake if the socket is still open.
[Method] (version driver)
Returns the WebSocket version in use as a string (ex. "hybi-13").
[Method] (protocol driver)
Returns a string containing the selected subprotocol, if any was agreed upon using the Sec-WebSocket-Protocol mechanism.
[Method] (ready-state ws)
Returns the connection state as a keyword, which is one of :connecting, :open, :closing and :closed.
Author
- Eitaro Fukamachi (e.arrows@gmail.com)
Copyright
Copyright (c) 2014 Eitaro Fukamachi (e.arrows@gmail.com)
License
Licensed under the BSD 2-Clause License.