68 lines
2.3 KiB
Racket
68 lines
2.3 KiB
Racket
#lang racket
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(require math/base) ;; for random number generation
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;; TODO clean up string message output and alignment
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;; author: Ibrahim Mkusa
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;; about: print and read concurrently
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;; notes: output may need to be aligned and formatted nicely
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; custodian for client connections
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(define main-client-cust (make-custodian))
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; make connection to server
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(define (client port-no)
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(parameterize ([current-custodian main-client-cust])
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;; connect to server at port 8080
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(define-values (in out) (tcp-connect "localhost" port-no)) ;; define values
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(display in)
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(displayln out)
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;; binds to multiple values akin to unpacking tuples in python
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(displayln "What's your name?")
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(define username (read-line))
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(define a (thread
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(lambda ()
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(displayln "Starting receiver thread.")
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(let loop []
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(receive-messages in)
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(sleep 1)
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(loop)))))
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(define t (thread
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(lambda ()
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(displayln "Starting sender thread.")
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(let loop []
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(send-messages username out)
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(sleep 1)
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(loop)))))
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(displayln "Now waiting for sender thread.")
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(thread-wait t) ;; returns prompt back to drracket
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(displayln "Closing client ports.")
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(close-input-port in)
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(close-output-port out))
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(custodian-shutdown-all main-client-cust))
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;; sends a message to the server
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(define (send-messages username out)
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;; intelligent read, quits when user types in "quit"
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(define input (read-line))
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(cond ((string=? input "quit") (exit)))
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(displayln (string-append username ": " input) out)
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(flush-output out))
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; receives input from server and displays it to stdout
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(define (receive-messages in)
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; retrieve a message from server
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(define evt (sync/timeout 60 (read-line-evt in)))
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(cond [(eof-object? evt)
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(displayln "Server connection closed.")
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(custodian-shutdown-all main-client-cust)
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;(exit)
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]
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[(string? evt)
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(displayln evt)] ; could time stamp here or to send message
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[else
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(displayln (string-append "Nothing received from server for 2 minutes."))]))
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(displayln "Starting client.")
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(define stop (client 4321))
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