server code for interacting with client is done, not tested. Working on

server broadcast function

1 files changed, 54 insertions, 96 deletions

diff --git a/server.rkt b/server.rkt
index 57874a8..c5bb6f3 100644
--- a/server.rkt
+++ b/server.rkt
@@ -6,11 +6,24 @@
 ;; might need to access it
 (define connections '())  ;; maintains a list of open ports
 ;; ((in1, out1), (in2, out2), (in3, out3), (in4, out4) ...)
+(define connections-s (make-semaphore 1)) ;; control access to connections
 
+;; every 5 seconds run to broadcast top message in list
+;; and remove it from list
+(define messages-s (make-semaphore 1))  ;; control access to messages
+(define messages '())  ;; stores a list of messages(strings) from currents
+
+(define threads-s (make-semaphore 1))  ;; control access to threads
 ;; lets keep thread descriptor values
-;
+(define threads '())  ;; stores a list of client serving threads as thread descriptor values
 
-(define fair (make-semaphore 1)) ;; managing connections above
+;; define a broadcast function
+(define broadcast
+  (lambda ()
+    (semaphore-wait messages-s)
+    (semaphore-wait threads-s)
+    (map (lambda (thread-descriptor)
+           ()))))
 
 (define can-i-broadcast (make-semaphore 1))
 
@@ -40,116 +53,61 @@
   (define cust (make-custodian))
   (parameterize ([current-custodian cust])
     (define-values (in out) (tcp-accept listener))
-    (semaphore-wait fair)
+    (semaphore-wait connections-s)
     ;; keep track of open ports
     (append connections (list (list in out)))
-    (semaphore-wait fiar)
+    (semaphore-wait connections-s)
 
-    ; thread will communicate to all clients at once in a broadcast
-    ; manner
-    (thread (lambda ()
+    ; start a thread to deal with specific client and add descriptor value to the list of threads
+    (append threads (list (thread (lambda ()
               (handle in out) ;; this handles connection with that specific client
               (close-input-port in)
-              (close-output-port out)))
-    )
+              (close-output-port out))))
+            )
   ;; Watcher thread:
   ;; kills current thread for waiting too long for connection from
   ;; clients
   (thread (lambda ()
             (sleep 120)
-            (custodian-shutdown-all cust))))
+            (custodian-shutdown-all cust)))))
 
 ; (define (handle connections)
 ;   ())
 ;; each thread needs 2 new threads
 (define (handle in out) 
-  ; define function to deal with in
+  ; define function to deal with incoming messages from client
   (define (something-to-say in)
-    (sync/timeout 4 (read-line-evt in 'linefeed)))
+    (define evt-t0 (sync/timeout 120  (read-line-evt in 'linefeed)))
+    (cond [(not evt-t0)
+           (displayln "Nothing received from " (current-thread) "exiting")]
+          [(string? evt-t0)
+           (semaphore-wait messages-s)
+           ; append the message to list of messages
+           (append messages (list evt-t0))
+           (semaphore-post messages-s)]))
+
+
   ; define function to deal with out
+  (define (something-to-send out)
+    (define evt-t1 (sync/timeout 120 (thread-receive-evt)))
+    ;; send message to client
+    (fprintf out "~a~n" (thread-receive))
+    (flush-output out)
+    )
   ; thread them each
+
+  ;; i could bind to values, and call wait on them
+  ;; thread that deals with incoming messages for that particular thread
+  (thread (lambda ()
+            (let loop []
+              (something-to-say in)
+              (loop))))
+
+  (thread (lambda ()
+            (let loop []
+              (something-to-say out)
+              (loop))))
   ; (server-loop in out)
-  (sleep 5) ;; wait 5 seconds to guarantee client has already send message
-  (define echo (read-line in)) ;; bind message to echo
-  (displayln (string-append echo "\n"))
-  ; echo back the message, appending echo
-  ; could regex match the input to extract the name
-  (writeln  "Admin: Hello there" out) ;; append "echo " to echo and send back
-  (flush-output out)
-)
-;; This is a single server communicating directly to the client
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-
-
-;; author: Ibrahim Mkusa
-;; about: print and read concurrently
-;; notes: output may need to be aligned and formatted nicely
-;; look into
-;; https://docs.racket-lang.org/gui/text-field_.html#%28meth._%28%28%28lib._mred%2Fmain..rkt%29._text-field~25%29._get-editor%29%29
-
-;; create custodian for managing all resources
-;; so we can shutdown everything at once
-;(define guard (make-custodian (current-custodian)))
-;(current-custodian guard)
-;; reads values continously from stdin and redisplays them
-(define (read-loop)
-  (display (read-line))
-  (display "\n")
-  (read-loop)
-  )
-
-(define input-prompt "input: ")
-(define output-prompt "output: ")
-
-;; prompt for username and bind to a variable username
-(display "What's your name?\n")
-(define username (read-line))
-(define usernamei (string-append username ": ")) ;; make username appear nicer in a prompt
-
-;; intelligent read, quits when user types in "quit"
-(define (read-loop-i)
-  
-  
-  ;(semaphore-wait fair)
-  (display usernamei)
-  (define input (read-line))
-  ;; do something over here with input maybe send it out
-  
-  ;; Tests input if its a quit then kills all threads
-  ;; An if would be better here tbh
-  (cond ((string=? input "quit") (begin (kill-thread a)
-                                        (kill-thread t))))
-  (display (string-append output-prompt input "\n"))
-  ;(semaphore-post fair)
-  (read-loop-i)
-  )
-
-
-;; print hello world continously
-;; "(hello-world)" can be executed as part of background thread
-;; that prints in the event there is something in the input port
-(define (hello-world)
-  (sleep (random-integer 0 15)) ;; sleep between 0 and 15 seconds to simulate coms
-                                ;; with server
-  ;(semaphore-wait fair)
-  ;; we will retrieve the line printed below from the server
-  ;; at this time we simulate the input from different users
-  (define what-to-print (random-integer 0 2))
-  (if (= what-to-print 0)
-      (display "Doug: What's up, up?\n")
-      (display "Fred: Looking good, good!\n"))
-  ;(semaphore-post fair)
-  (hello-world))
-
-(define t (thread (lambda ()
-                    (read-loop-i))))
-(define a (thread (lambda ()
-                    (hello-world))))
-
-(thread-wait t) ;; returns prompt back to drracket
-;; below doesn't execute
-; (sleep 10)
-; (kill-thread t)
-; (define a (thread (display "hello world!\n")))
-; (display "John: hello soso\n")
-; (display "Emmanuel: cumbaya!!!!\n")
+  ; (sleep 5) ;; wait 5 seconds to guarantee client has already send message
+  'ok
+ )