#| 

SOCKETTHREADS.LISP

Simple examples of sockets and threads in ABCL Common LISP.

Clark Elliott 2019-05-19

See how to run, and example output at the bottom of the file.

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(setf GameAddr 8894)
(defvar GameStream nil)
(defvar GameSocket nil)

(defun Connect2Game ()
  (let ((GameSocket (make-socket "localhost" GameAddr)))
    (setf GameStream (get-socket-stream GameSocket))))

(defun CloseGame ()
  (close GameStream)
  (socket-close GameSocket)
  (server-socket-close GameServerSocket))

(defun Gameclient ()
  (let ((s nil))
    (format t "Type in what you want to send to the Game:~%~%")
    (dotimes (n 5)
      (setf s (read-line))
      (format GameStream "~s~%" s))
    (format t "From the server:~%~s~%" (read-line GameStream))
    ))

;;; This Server works
(defun GameServer ()
  (let ((s (make-server-socket GameAddr)) (val nil) (n 0) (b nil))
    (setq GameServerSocket s) ; so I can close it later if crash
    (setq GameSocket (socket-accept s))
    (setf GameStream (get-socket-stream GameSocket))
    (setf ww GameStream)
    (format t "About to read a line~%")
    (setf val (read-line GameStream)) ; Block waiting
    (format t "~a~%" val)
    (loop while (< (incf n) 5)
       do
	 (setf val (read-line GameStream))
	 (format t "Got: ~a~%" val))
    (format GameStream "THANK YOU FOR YOUR COMMENTS~%")
    (server-socket-close s)))


;;; This closure works as well, but be careful about standard output, esp. with SLIME.
(let
    ((closure-game nil))
  (defun make-it ()
    (setf closure-game
	  (threads:make-thread
	   #'(lambda ()
	       (let ((s (make-server-socket GameAddr)) (val nil) (n 0) (b nil))
		 (format t "I am alive!~%")
		 (setq GameServerSocket s) ; so I can close it later if crash
		 (setq GameSocket (socket-accept s))
		 (setf GameStream (get-socket-stream GameSocket))
		 (setf ww GameStream)
		 (format *standard-output* "About to read a line~%")
		 (setf val (read-line GameStream)) ; Block waiting
		 (format t "~a~%" val)
		 (loop while (< (incf n) 5)
		    do
		      (setf val (read-line GameStream))
		      (format t "Got: ~a~%" val))
		 (format GameStream "THANK YOU FOR YOUR COMMENTS~%")
		 (server-socket-close s)
		 (format *standard-output* "Goodbye Cruel World~%"))))))
  
  
  ;; Works, but takes a while:
  (defun kill-it () (threads:destroy-thread closure-game))
  
  (defun alivep () (THREADS:THREAD-ALIVE-P closure-game))
)
  
(defun close-em ()
  (close ww)
  (socket-close ax)
  (server-socket-close nn))

(setf my-val 1)

;;; Output to *standard-output* for Inferior Lisp, so careful with SLIME:
(defun make-a-thread ()
  (setf q
	(threads:make-thread
	 #'(lambda ()
	     (format t "I am alive!~%")
	     (sleep 15)
	     (format t "Goodbye Cruel World~%")
       (setf my-val (1+ my-val))))))


;;; Works, but takes a while:
(defun kill-it () (threads:destroy-thread q))

(defun alivep () (THREADS:THREAD-ALIVE-P q))

#|

Example of running the simple game conversation between client and server, run in two separate command windows:

On the SERVER:

CL-USER(2): (gameserver)
About to read a line
"one"
Got: "two"
Got: "three"
Got: "four"
Got: "five"
T
CL-USER(3): 

On the CLIENT:

CL-USER(2): (connect2game)
#<TWO-WAY-STREAM {2A938AE3}>
CL-USER(3): (gameclient)
Type in what you want to send to the Game:

one
two
three
four
five
From the server:
"THANK YOU FOR YOUR COMMENTS"
NIL
CL-USER(4): 
-----------------------------------------------

The background server:

CL-USER(4): (make-it)
#<THREAD {22667EC4}>
CL-USER(5): I am alive!
About to read a line
"This is line one to the background server"
Got: "two"
Got: "three"
Got: "four"
Got: "five"
Goodbye Cruel World

-----------------------------------------------

The client for the background server (same as before):

CL-USER(6): (connect2game)
#<TWO-WAY-STREAM {5A37AC0}>

CL-USER(7): (gameclient)
Type in what you want to send to the Game:

This is line one to the background server
two
three
four
five
From the server:
"THANK YOU FOR YOUR COMMENTS"
NIL
CL-USER(8): 

-----------------------------------------------

The sample thread running in the background:

my-val
2
CL-USER(8): (make-a-thread)
#<THREAD {7D99476F}>
CL-USER(9): I am alive!
Goodbye Cruel World
my-val
3
CL-USER(10): 

Sample output:

CL-USER(12): (make-a-thread)
#<THREAD {44F16433}>
CL-USER(13): I am alive!
(kill-it)
T
CL-USER(14): (alivep)
NIL
CL-USER(15): (make-a-thread)
#<THREAD {12748547}>
CL-USER(16): I am alive!
(alivep)
T
CL-USER(17): Goodbye Cruel World
(alivep)
NIL
CL-USER(18): 

CL-USER(18): (make-a-thread)
#<THREAD {5A434AED}>
CL-USER(19): I am alive!
(alivep)
T
CL-USER(20): (kill-it)
T
CL-USER(21): (alivep)
NIL
CL-USER(22): 
---------------------------

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