examples/ex3-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 similar to ex2-client.lisp, except we've added in
   7 ;;;; catching of various conditions which may be signaled during the
   8 ;;;; network communication.
   9
  10 ;; ex-0b
  11 (defun run-ex3-client-helper (host port)
  12
  13   ;; Create a internet TCP socket under IPV4
  14   (with-open-socket
  15       (socket :connect :active
  16               :address-family :internet
  17               :type :stream
  18               :external-format '(:utf-8 :eol-style :crlf)
  19               :ipv6 nil)
  20
  21     ;; do a blocking connect to the daytime server on the port.
  22     (connect socket (lookup-hostname host) :port port :wait t)
  23     (format t "Connected to server ~A:~A from my local connection at ~A:~A!~%"
  24             (remote-name socket) (remote-port socket)
  25             (local-name socket) (local-port socket))
  26
  27     (handler-case
  28         ;; read the one line of information I need from the daytime
  29         ;; server.  I can use read-line here because this is a TCP
  30         ;; socket. It will block until the whole line is read.
  31         (let ((line (read-line socket)))
  32           (format t "~A" line)
  33           t)
  34
  35       ;; However, let's notice the signaled condition if the server
  36       ;; went away prematurely...
  37       (end-of-file ()
  38         (format t "Got end-of-file. Server closed connection!")))))
  39 ;; ex-0e
  40
  41 ;; ex-1b
  42 ;; The main entry point into ex3-client
  43 (defun run-ex3-client (&key (host *host*) (port *port*))
  44   (handler-case
  45
  46       (run-ex3-client-helper host port)
  47
  48     ;; handle a commonly signaled error...
  49     (socket-connection-refused-error ()
  50       (format t "Connection refused to ~A:~A. Maybe the server isn't running?~%"
  51               (lookup-hostname host) port))))
  52 ;; ex-1e