reqrep

#! /usr/bin/env scheme-script
; -*- mode: scheme -*-

; Getting Started with 'nanomsg'
; Request/Reply (I ask, you answer)
; from https://github.com/dysinger/nanomsg-examples#requestreply

#!chezscheme

(import (nanomsg) (chezscheme))

(nanomsg-library-init)

(define node0-name "node0")
(define node1-name "node1")
(define date-name "DATE")

(define date date-and-time)

(define (node0 url)
  (define sock (nn-socket AF_SP NN_REP))
  (define eid (nn-bind sock url))
  (let loop ()
    (let ([buf (box #t)])
      (define bytes (nn-recv sock buf NN_MSG 0))
      (when (string=? date-name (utf8->string (unbox buf)))
	    (let* ([d (date)])
	      (printf "NODE0: RECEIVED DATE REQUEST~n")
	      (printf "NODE0: SENDING DATE ~d~n" d)
	      (nn-send sock (string->utf8 d) 0)))
      (loop)))
  (nn-shutdown sock eid))

(define (node1 url)
  (define sock (nn-socket AF_SP NN_REQ))
  (define eid (nn-connect sock url))
  (printf "NODE1: SENDING DATE REQUEST '~d'~n" date-name)
  (nn-send sock (string->utf8 date-name) 0)
  (let ([buf (box #t)])
    (nn-recv sock buf NN_MSG 0)
    (printf "NODE1: RECEIVED DATE ~d~n" (utf8->string (unbox buf))))
  (nn-shutdown sock eid))

(define argv (command-line-arguments))
(define argc (length argv))

(cond
 [(and (> argc 1) (string=? node0-name (car argv)))
  (node0 (cadr argv))]
 [(and (> argc 1) (string=? node1-name (car argv)))
  (node1 (cadr argv))]
 [else
  (printf "Usage: reqrep ~d|~d <URL> <ARG> ...'~n" node0-name node1-name)])


#!eof

./reqrep node0 ipc:///tmp/reqrep.ipc & node0=$! && sleep 1
./reqrep node1 ipc:///tmp/reqrep.ipc
kill $node0