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| -rw-r--r-- | demo/reqrep/README.adoc | 48 | ||||
| -rw-r--r-- | demo/reqrep/reqrep.c | 162 |
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diff --git a/demo/reqrep/README.adoc b/demo/reqrep/README.adoc new file mode 100644 index 00000000..b66d694c --- /dev/null +++ b/demo/reqrep/README.adoc @@ -0,0 +1,48 @@ += reqrep + +This is a very simple RPC service using the REQ/REP method. +It is derived in part from Tim Dysinger's +http://nanomsg.org/gettingstarted/[Getting Started With Nanomsg] +examples, but we have updated for _nng_, and converted to use binary +frames across the wire instead of string data. + +The protocol is simple: + +* Client will send a 64-bit command (network byte order, i.e. big endian). +* Server sends a 64-bit response (also network byte order.) + +The only command is "DATE", which has value 0x1. The value returned is +a UNIX timestamp (seconds since Jan 1, 1970.) + +(We used 64-bit values for simplicity, and to avoid the Y2038 bug when +compiled on 64-bit systems.) + +== Compiling + +The following is an example typical of UNIX and similar systems like +Linux and macOS: + +[source, bash] +---- +% export CPPFLAGS="-I /usr/local/include" +% export LDFLAGS="-L /usr/local/lib -lnng" +% export CC="cc" +% ${CC} ${CPPFLAGS} reqrep.c -o reqrep ${LDFLAGS} +---- + +== Running + +You can run either the client or the server, and use whatever legal +_nng_ URL you like: + +[source, bash] +---- +% ./reqrep server tcp://127.0.0.1:8899 & +% ./reqrep client tcp://127.0.0.1:8899 +CLIENT: SENDING DATE REQUEST +SERVER: RECEIVED DATE REQUEST +SERVER: SENDING DATE: Thu Feb 8 10:26:18 2018 +CLIENT: RECEIVED DATE: Thu Feb 8 10:26:18 2018 +---- + + diff --git a/demo/reqrep/reqrep.c b/demo/reqrep/reqrep.c new file mode 100644 index 00000000..b5891a83 --- /dev/null +++ b/demo/reqrep/reqrep.c @@ -0,0 +1,162 @@ +// +// Copyright 2018 Staysail Systems, Inc. <info@staysail.tech> +// Copyright 2018 Capitar IT Group BV <info@capitoar.com> +// +// This software is supplied under the terms of the MIT License, a +// copy of which should be located in the distribution where this +// file was obtained (LICENSE.txt). A copy of the license may also be +// found online at https://opensource.org/licenses/MIT. +// + +// +// This is just a simple REQ/REP demonstration application. It is derived +// from the legacy nanomsg demonstration program of the same name, written +// by Tim Dysinger, but updated for nng. I've also updated it to pass simpler +// binary data rather than strings over the network. +// +// The program implements a simple RPC style service, which just returns +// the date in UNIX time (seconds since 1970). +// +#include <stdlib.h> +#include <stdio.h> +#include <string.h> +#include <stdint.h> +#include <time.h> + +#include <nng/nng.h> +#include <nng/protocol/reqrep0/rep.h> +#include <nng/protocol/reqrep0/req.h> + +#define CLIENT "client" +#define SERVER "server" +#define DATECMD 1 + +#define PUT64(ptr, u) \ + do { \ + (ptr)[0] = (uint8_t)(((uint64_t)(u)) >> 56); \ + (ptr)[1] = (uint8_t)(((uint64_t)(u)) >> 48); \ + (ptr)[2] = (uint8_t)(((uint64_t)(u)) >> 40); \ + (ptr)[3] = (uint8_t)(((uint64_t)(u)) >> 32); \ + (ptr)[4] = (uint8_t)(((uint64_t)(u)) >> 24); \ + (ptr)[5] = (uint8_t)(((uint64_t)(u)) >> 16); \ + (ptr)[6] = (uint8_t)(((uint64_t)(u)) >> 8); \ + (ptr)[7] = (uint8_t)((uint64_t)(u)); \ + } while (0) + +#define GET64(ptr, v) \ + v = (((uint64_t)((uint8_t)(ptr)[0])) << 56) + \ + (((uint64_t)((uint8_t)(ptr)[1])) << 48) + \ + (((uint64_t)((uint8_t)(ptr)[2])) << 40) + \ + (((uint64_t)((uint8_t)(ptr)[3])) << 32) + \ + (((uint64_t)((uint8_t)(ptr)[4])) << 24) + \ + (((uint64_t)((uint8_t)(ptr)[5])) << 16) + \ + (((uint64_t)((uint8_t)(ptr)[6])) << 8) + \ + (((uint64_t)(uint8_t)(ptr)[7])) + + +void +fatal(const char *func, int rv) +{ + fprintf(stderr, "%s: %s\n", func, nng_strerror(rv)); + exit(1); +} + +void +showdate(time_t now) +{ + struct tm *info = localtime(&now); + printf("%s", asctime(info)); +} + +int +server(const char *url) +{ + nng_socket sock; + int rv; + + if ((rv = nng_rep0_open(&sock)) != 0) { + fatal("nng_rep0_open", rv); + } + if ((rv = nng_listen(sock, url, NULL, 0)) != 0) { + fatal("nng_listen", rv); + } + for (;;) { + char *buf = NULL; + size_t sz; + uint64_t val; + if ((rv = nng_recv(sock, &buf, &sz, NNG_FLAG_ALLOC)) != 0) { + fatal("nng_recv", rv); + } + if ((sz == sizeof (uint64_t)) && + ((GET64(buf, val)) == DATECMD)) { + time_t now; + printf("SERVER: RECEIVED DATE REQUEST\n"); + now = time(&now); + printf("SERVER: SENDING DATE: "); + showdate(now); + + // Reuse the buffer. We know it is big enough. + PUT64(buf, (uint64_t)now); + rv = nng_send(sock, buf, sz, NNG_FLAG_ALLOC); + if (rv != 0) { + fatal("nng_send", rv); + } + continue; + } + // Unrecognized command, so toss the buffer. + nng_free(buf, sz); + } +} + +int +client(const char *url) +{ + nng_socket sock; + int rv; + size_t sz; + char *buf = NULL; + uint8_t cmd[sizeof (uint64_t)]; + + PUT64(cmd, DATECMD); + + if ((rv = nng_req0_open(&sock)) != 0) { + fatal("nng_socket", rv); + } + if ((rv = nng_dial(sock, url, NULL, 0)) != 0) { + fatal("nng_dial", rv); + } + printf("CLIENT: SENDING DATE REQUEST\n"); + if ((rv = nng_send(sock, cmd, sizeof (cmd), 0)) != 0) { + fatal("nng_send", rv); + } + if ((rv = nng_recv(sock, &buf, &sz, NNG_FLAG_ALLOC)) != 0) { + fatal("nng_recv", rv); + } + + if (sz == sizeof (uint64_t)) { + uint64_t now; + GET64(buf, now); + printf("CLIENT: RECEIVED DATE: "); + showdate((time_t)now); + } else { + printf("CLIENT: GOT WRONG SIZE!\n"); + } + + // This assumes that buf is ASCIIZ (zero terminated). + nng_free(buf, sz); + nng_close(sock); + return (0); +} + +int +main(const int argc, const char **argv) +{ + if ((argc > 1) && (strcmp(CLIENT, argv[1]) == 0)) + return (client(argv[2])); + + if ((argc > 1) && (strcmp(SERVER, argv[1]) == 0)) + return (server(argv[2])); + + fprintf(stderr, "Usage: reqrep %s|%s <URL> ...\n", CLIENT, SERVER); + return (1); +} |