examples/ex2-client.lisp

   1 (in-package :iolib.examples)
   2
   3 ;;;; This file was originally written by Peter Keller (psilord@cs.wisc.edu)
   4 ;;;; and this code is released under the same license as IOLib.
   5
   6 ;;;; This example is almost the same as ex1-client.lisp, except we move it
   7 ;;;; closer to a Common Lisp style.
   8
   9 ;; ex-0b
  10 (defun run-ex2-client (&key (host *host*) (port *port*))
  11
  12   ;; We introduce with-open-socket here as a means to easily wrap
  13   ;; usually synchronous and blocking communication with a form that
  14   ;; ensures the socket is closed no matter how we exit it.
  15   (with-open-socket
  16       (socket :connect :active
  17               :address-family :internet
  18               :type :stream
  19               :external-format '(:utf-8 :eol-style :crlf)
  20               :ipv6 nil)
  21
  22     ;; Do a blocking connect to the daytime server on the port.  We
  23     ;; also introduce lookup-hostname, which converts a hostname to an
  24     ;; 4 values, but in our case we only want the first, which is an
  25     ;; address.
  26     (connect socket (lookup-hostname host) :port port :wait t)
  27     (format t "Connected to server ~A:~A from my local connection at ~A:~A!~%"
  28             (remote-name socket) (remote-port socket)
  29             (local-name socket) (local-port socket))
  30
  31     ;; read the one line of information I need from the daytime
  32     ;; server.  I can use read-line here because this is a TCP
  33     ;; socket. It will block until the whole line is read.
  34     (let ((line (read-line socket)))
  35       (format t "~A" line)
  36       t)))
  37 ;; ex-0e