From cb381871d518077649be6272af823dabec2fcd28 Mon Sep 17 00:00:00 2001
From: Ibrahim Mkusa <ibrahimmkusa@gmail.com>
Date: Sun, 9 Apr 2017 22:37:50 -0400
Subject: reorganized repo a bit better

---
 tests/tcpevents/README.md      |   1 +
 tests/tcpevents/crpovertcp.rkt | 155 +++++++++++++++++++++++++++++++++++++++++
 tests/tcpevents/server.rkt     |  39 +++++++++++
 3 files changed, 195 insertions(+)
 create mode 100644 tests/tcpevents/README.md
 create mode 100644 tests/tcpevents/crpovertcp.rkt
 create mode 100644 tests/tcpevents/server.rkt

(limited to 'tests/tcpevents')

diff --git a/tests/tcpevents/README.md b/tests/tcpevents/README.md
new file mode 100644
index 0000000..7c3ec21
--- /dev/null
+++ b/tests/tcpevents/README.md
@@ -0,0 +1 @@
+TCP communication racket concepts of events. For more see the racket guide.
diff --git a/tests/tcpevents/crpovertcp.rkt b/tests/tcpevents/crpovertcp.rkt
new file mode 100644
index 0000000..57874a8
--- /dev/null
+++ b/tests/tcpevents/crpovertcp.rkt
@@ -0,0 +1,155 @@
+#lang racket
+(require math/base) ;; for random number generation
+
+;; globals
+;; must control access via semaphore as listener thread or broadcast thread
+;; might need to access it
+(define connections '())  ;; maintains a list of open ports
+;; ((in1, out1), (in2, out2), (in3, out3), (in4, out4) ...)
+
+;; lets keep thread descriptor values
+;
+
+(define fair (make-semaphore 1)) ;; managing connections above
+
+(define can-i-broadcast (make-semaphore 1))
+
+
+;;
+
+;; This is a relay server making two clients communicate
+;; Both `server' and `accept-and-handle' change
+;; to use a custodian.
+;; To start server
+;; (define stop (serve 8080))
+;; (stop) to close the server
+
+(define (serve port-no)
+  (define main-cust (make-custodian))
+  (parameterize ([current-custodian main-cust])
+    (define listener (tcp-listen port-no 5 #t))
+    (define (loop)
+      (accept-and-handle listener)
+      (loop))
+    (thread loop))
+  (lambda ()
+    (displayln "\nGoodbye, shutting down all services\n")
+    (custodian-shutdown-all main-cust)))
+
+(define (accept-and-handle listener)
+  (define cust (make-custodian))
+  (parameterize ([current-custodian cust])
+    (define-values (in out) (tcp-accept listener))
+    (semaphore-wait fair)
+    ;; keep track of open ports
+    (append connections (list (list in out)))
+    (semaphore-wait fiar)
+
+    ; thread will communicate to all clients at once in a broadcast
+    ; manner
+    (thread (lambda ()
+              (handle in out) ;; this handles connection with that specific client
+              (close-input-port in)
+              (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))))
+
+; (define (handle connections)
+;   ())
+;; each thread needs 2 new threads
+(define (handle in out) 
+  ; define function to deal with in
+  (define (something-to-say in)
+    (sync/timeout 4 (read-line-evt in 'linefeed)))
+  ; define function to deal with out
+  ; thread them each
+  ; (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")
diff --git a/tests/tcpevents/server.rkt b/tests/tcpevents/server.rkt
new file mode 100644
index 0000000..4313bda
--- /dev/null
+++ b/tests/tcpevents/server.rkt
@@ -0,0 +1,39 @@
+#lang racket
+
+(define (serve in-port out-port)
+  (let loop []
+    (define evt (sync/timeout 2
+                              (read-line-evt in-port 'any)
+                              (thread-receive-evt)))
+    (cond
+      [(not evt)
+       (displayln "Timed out, exiting")
+       (tcp-abandon-port in-port)
+       (tcp-abandon-port out-port)]
+      [(string? evt)
+       (fprintf out-port "~a~n" evt)
+       (flush-output out-port)
+       (loop)]
+      [else
+        (printf "Received a message in mailbox: ~a~n"
+                (thread-receive))
+        (loop)])))
+
+(define port-num 4321)
+(define (start-server)
+  (define listener (tcp-listen port-num))
+  (thread
+    (lambda ()
+      (define-values [in-port out-port] (tcp-accept listener))
+      (serve in-port out-port))))
+
+(start-server)
+
+(define client-thread
+  (thread
+    (lambda ()
+      (define-values [in-port out-port] (tcp-connect "localhost" port-num))
+      (display "first\nsecond\nthird\n" out-port)
+      (flush-output out-port)
+      ; copy-port will block until EOF is read from in-port
+      (copy-port in-port (current-output-port)))))
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