examples/ex4-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 program is a very simple echo client. After connecting to
   7 ;;;; the server it reads a line from the console, echos it to the
   8 ;;;; server, reads the response back, then echos it to
   9 ;;;; *standard-output*. We handle common conditions. Type "quit" on a
  10 ;;;; line by itself to exit the client.
  11
  12 ;; ex-0b
  13 (defun run-ex4-client-helper (host port)
  14
  15   ;; Create a internet TCP socket under IPV4
  16   (with-open-socket
  17       (socket :connect :active
  18               :address-family :internet
  19               :type :stream
  20               :external-format '(:utf-8 :eol-style :crlf)
  21               :ipv6 nil)
  22
  23     ;; do a blocking connect to the daytime server on the port.
  24     (connect socket (lookup-hostname host) :port port :wait t)
  25
  26     (format t "Connected to server ~A:~A from my local connection at ~A:~A!~%"
  27             (remote-host socket) (remote-port socket)
  28             (local-host socket) (local-port socket))
  29
  30     (handler-case
  31         (ex4-str-cli socket)
  32
  33       (socket-connection-reset-error ()
  34         (format t "Got connection reset. Server went away!"))
  35
  36       (hangup ()
  37         (format t "Got hangup. Server closed connection on write!~%"))
  38
  39       (end-of-file ()
  40         (format t "Got end-of-file. Server closed connection on read!~%")))))
  41 ;; ex-0e
  42
  43 ;; ex-1b
  44 ;; read a line from stdin, write it to the server, read the response, write
  45 ;; it to stdout. If we read 'quit' then echo it to the server which will
  46 ;; echo it back to us and then close its connection to us.
  47 (defun ex4-str-cli (socket)
  48   (loop
  49      (let ((line (read-line)))
  50        ;; send it to the server, get the response.
  51        (format socket "~A~%" line)
  52        (finish-output socket)
  53        (format t "~A~%" (read-line socket)))))
  54 ;; ex-1e
  55
  56 ;; ex-2b
  57 ;; This is the entry point into this example
  58 (defun run-ex4-client (&key (host *host*) (port *port*))
  59   (unwind-protect
  60        (handler-case
  61
  62            (run-ex4-client-helper host port)
  63
  64          ;; handle a commonly signaled error...
  65          (socket-connection-refused-error ()
  66            (format t "Connection refused to ~A:~A. Maybe the server isn't running?~%"
  67                    (lookup-hostname host) port)))
  68
  69     ;; Cleanup form
  70     (format t "Client Exited.~%")))
  71 ;; ex-2e