server now logs all received conversations and events to files

Hermes/TODO

@@ -12,3 +12,5 @@ e
 14. bye message prompt for clients
 15. Session stickiness for clients
 16. plain tcp -> ssl based 
+17. fix breaks for improper disconnects from clients
+18. Add topics after project completion

Hermes/client.rkt

@@ -6,6 +6,7 @@
 ;; notes: output may need to be aligned and formatted nicely
 (define host "10.0.0.160") ; internal home
 (define host2 "67.186.191.81")
+(define host3 "localhost")
 (define port-num 4321)
 
 
@@ -15,7 +16,7 @@
 (define (client port-no)
   (parameterize ([current-custodian main-client-cust])
     ;; connect to server at port 8080
-    (define-values (in out) (tcp-connect host2 port-no)) ;; define values
+    (define-values (in out) (tcp-connect host3 port-no)) ;; define values
     (display in)
     (displayln out)
     ;; binds to multiple values akin to unpacking tuples in python

Hermes/server.rkt

@@ -3,6 +3,8 @@
 
 ;; globals
 (define welcome-message "Welcome to Hermes coms. Type your message below")
+(define successful-connection-m "Successfully connected to a client. Sending client a welcome message.")
+
 ; track number of connections with closure
 (define (make-count no-count)
   (define (increment)
@@ -71,16 +73,32 @@
 (define messages-s (make-semaphore 1))  ;; control access to messages
 
 ;; Several threads may want to print to stdout, so  lets make things civil
+; constant always available
 (define stdout (make-semaphore 1))
 
+; TODO refactor to take a port. defaults to current-output port in this context
 ; Takes a string and a semaphore to print safely to stdout
 (define displayln-safe
-  (lambda (a-string a-semaphore)
+  (lambda (a-string [a-semaphore stdout] [a-output-port (current-output-port)])
-    (semaphore-wait a-semaphore)
+    (cond [(not (and (eq? a-semaphore stdout) (eq? a-output-port (current-output-port))))
-    (displayln a-string)
+           (semaphore-wait a-semaphore)
-    (semaphore-post a-semaphore)))
+           (semaphore-wait stdout)
-
+           (displayln a-string a-output-port)
+           (flush-output a-output-port)
+           (displayln a-string)
+           (semaphore-post stdout)
+           (semaphore-post a-semaphore)]
+          [else
+            (semaphore-wait stdout)
+            (displayln a-string)
+            (semaphore-post stdout)])))
 
+; two files to store error messages, and channel conversations
+(define error-out (open-output-file "/home/pcuser/Hermes/Hermes/error.txt" #:exists 'append))
+(define convs-out (open-output-file "/home/pcuser/Hermes/Hermes/conversations.txt" #:exists 'append))
+(define error-out-s (make-semaphore 1))
+(define convs-out-s (make-semaphore 1))
+; TODO finish logging all error related messages to 
 (define (serve port-no)
   (define main-cust (make-custodian))
   (parameterize ([current-custodian main-cust])
@@ -88,17 +106,24 @@
     (define (loop)
       (accept-and-handle listener)
       (loop))
-    (displayln "threading the listener")
+    (displayln-safe "Starting up the listener." error-out-s error-out)
     (thread loop)
+    (displayln-safe "Listener successfully started." error-out-s error-out)
     ;; Create a thread whose job is to simply call broadcast iteratively
     (thread (lambda ()
-              (displayln-safe "Broadcast thread started!\n" stdout)
+              (displayln-safe "Broadcast thread started!\n")
               (let loopb []
                 (sleep 0.5)  ;; wait 0.5 secs before beginning to broadcast
                 (broadcast)
                 (loopb)))))
   (lambda ()
-    (displayln "\nGoodbye, shutting down all services\n")
+    (displayln-safe "Goodbye, shutting down all services" error-out-s error-out)
+    (semaphore-wait error-out-s)
+    (semaphore-wait convs-out-s)
+    (close-output-port error-out)
+    (close-output-port convs-out)
+    (semaphore-post error-out-s)
+    (semaphore-post convs-out-s)
     (custodian-shutdown-all main-cust)))
 
 (define (accept-and-handle listener)
@@ -110,16 +135,13 @@
     ((c-count 'increment))
     (semaphore-post c-count-s)
 
-    (displayln-safe (string-append
+    (displayln-safe successful-connection-m)
-                      "Successfully connected to a client. "
-                      "Sending client a welcome message.")
-                    stdout)
     (displayln welcome-message out)
     ;; print to server log and client
     (define print-no-users (string-append "Number of users in chat: "
                                           (number->string ((c-count 'current-count)))))
     (displayln print-no-users out)
-    (displayln-safe print-no-users stdout)
+    (displayln-safe print-no-users convs-out-s convs-out)
     (flush-output out)
     (semaphore-wait connections-s)
     ((c-connections 'add) in out)
@@ -134,7 +156,7 @@
     (thread (lambda ()
               (displayln-safe (string-append
                                 "Started a thread to kill hanging "
-                                "connecting threads") stdout)
+                                "connecting threads"))
               (sleep 1360)
               (custodian-shutdown-all cust)))))
 
@@ -143,13 +165,11 @@
   (define (something-to-say in)
     (define evt-t0 (sync/timeout 60  (read-line-evt in 'linefeed)))
     (cond [(eof-object? evt-t0)
-           ; TODO remove pair of ports associated with client
            (semaphore-wait connections-s)
            ((c-connections 'remove-ports) in out)
            (semaphore-post connections-s)
-
+           ; TODO some form of identification for this client
-           (displayln-safe "Connection closed. EOF received"
+           (displayln-safe "Connection closed. EOF received" error-out-s error-out)
-                           stdout)
            (semaphore-wait c-count-s)
            ((c-count 'decrement))
            (semaphore-post c-count-s)
@@ -157,12 +177,12 @@
            (kill-thread (current-thread))]
           [(string? evt-t0)
            (semaphore-wait messages-s)
-           ; append the message to list of messages
+           ; append the message to list of messages NO NEED done during broadcast
-           (display (string-append evt-t0 "\n"))
+           ; (displayln-safe evt-t0 convs-out-s convs-out)
            ((c-messages 'add) evt-t0)
            (semaphore-post messages-s)]
           [else
-           (displayln-safe "Timeout waiting. Nothing received from client" stdout)]))
+           (displayln-safe "Timeout waiting. Nothing received from client")]))
 
   ; Executes methods above in another thread
   (thread (lambda ()
@@ -180,6 +200,8 @@
   (car ports))
 
 ; broadcasts received message from clients periodically
+; TODO before broadcasting the message make sure the ports is still open
+; no EOF if it is remove client from connections
 (define broadcast
   (lambda ()
     (semaphore-wait messages-s)
@@ -189,6 +211,7 @@
                   (displayln (first ((c-messages 'mes-list))) (get-output-port ports))
                   (flush-output (get-output-port ports)))
                 ((c-connections 'cons-list)))
+               (displayln-safe (first ((c-messages 'mes-list))) convs-out-s convs-out)
                ;; remove top message
                ((c-messages 'remove-top))
                (displayln "Message broadcasted"))])
@@ -196,4 +219,4 @@
 
 ; TODO move to its own file
 (define stop (serve 4321)) ;; start server then close with stop
-(display "Server process started\n")
+(displayln-safe "Server process started\n" error-out-s error-out)