GSP
Quick Navigator

Search Site

Unix VPS
A - Starter
B - Basic
C - Preferred
D - Commercial
MPS - Dedicated
Previous VPSs
* Sign Up! *

Support
Contact Us
Online Help
Handbooks
Domain Status
Man Pages

FAQ
Virtual Servers
Pricing
Billing
Technical

Network
Facilities
Connectivity
Topology Map

Miscellaneous
Server Agreement
Year 2038
Credits
 

USA Flag

 

 

Man Pages


Manual Reference Pages  -  ZBEACON (3)

.ds Aq ’

NAME

zbeacon - LAN discovery and presence

CONTENTS

SYNOPSIS

//  Create new zbeacon actor instance:
//
//      zactor_t *beacon = zactor_new (zbeacon, NULL);
//
//  Destroy zbeacon instance:
//
//      zactor_destroy (&beacon);
//
//  Enable verbose logging of commands and activity:
//
//      zstr_send (beacon, "VERBOSE");
//
//  Configure beacon to run on specified UDP port, and return the name of
//  the host, which can be used as endpoint for incoming connections. To
//  force the beacon to operate on a given interface, set the environment
//  variable ZSYS_INTERFACE, or call zsys_set_interface() before creating
//  the beacon. If the system does not support UDP broadcasts (lacking a
//  workable interface), returns an empty hostname:
//
//      //  Pictures: s = C string, i = int
//      zsock_send (beacon, "si", "CONFIGURE", port_number);
//      char *hostname = zstr_recv (beacon);
//
//  Start broadcasting a beacon at a specified interval in msec. The beacon
//  data can be at most UDP_FRAME_MAX bytes; this constant is defined in
//  zsys.h to be 255:
//
//      //  Pictures: b = byte * data + size_t size
//      zsock_send (beacon, "sbi", "PUBLISH", data, size, interval);
//
//  Stop broadcasting the beacon:
//
//      zstr_sendx (beacon, "SILENCE", NULL);
//
//  Start listening to beacons from peers. The filter is used to do a prefix
//  match on received beacons, to remove junk. Note that any received data
//  that is identical to our broadcast beacon_data is discarded in any case.
//  If the filter size is zero, we get all peer beacons:
//
//      zsock_send (beacon, "sb", "SUBSCRIBE", filter_data, filter_size);
//
//  Stop listening to other peers
//
//      zstr_sendx (beacon, "UNSUBSCRIBE", NULL);
//
//  Receive next beacon from a peer. Received beacons are always a 2-frame
//  message containing the ipaddress of the sender, and then the binary
//  beacon data as published by the sender:
//
//      zmsg_t *msg = zmsg_recv (beacon);
//
//  This is the zbeacon constructor as a zactor_fn:
CZMQ_EXPORT void
    zbeacon (zsock_t *pipe, void *unused);

// Self test of this class CZMQ_EXPORT void zbeacon_test (bool verbose);

DESCRIPTION

The zbeacon class implements a peer-to-peer discovery service for local networks. A beacon can broadcast and/or capture service announcements using UDP messages on the local area network. This implementation uses IPv4 UDP broadcasts. You can define the format of your outgoing beacons, and set a filter that validates incoming beacons. Beacons are sent and received asynchronously in the background.

This class replaces zbeacon_v2, and is meant for applications that use the CZMQ v3 API (meaning, zsock).

EXAMPLE

From zbeacon_test method.

//  Test 1 - two beacons, one speaking, one listening
//  Create speaker beacon to broadcast our service
zactor_t *speaker = zactor_new (zbeacon, NULL);
assert (speaker);
if (verbose)
    zstr_sendx (speaker, "VERBOSE", NULL);

zsock_send (speaker, "si", "CONFIGURE", 9999); char *hostname = zstr_recv (speaker); if (!*hostname) { printf ("OK (skipping test, no UDP broadcasting)\n"); zactor_destroy (&speaker); free (hostname); return; } free (hostname);

// Create listener beacon on port 9999 to lookup service zactor_t *listener = zactor_new (zbeacon, NULL); assert (listener); if (verbose) zstr_sendx (listener, "VERBOSE", NULL); zsock_send (listener, "si", "CONFIGURE", 9999); hostname = zstr_recv (listener); assert (*hostname); free (hostname);

// We will broadcast the magic value 0xCAFE byte announcement [2] = { 0xCA, 0xFE }; zsock_send (speaker, "sbi", "PUBLISH", announcement, 2, 100); // We will listen to anything (empty subscription) zsock_send (listener, "sb", "SUBSCRIBE", "", 0);

// Wait for at most 1/2 second if theres no broadcasting zsock_set_rcvtimeo (listener, 500); char *ipaddress = zstr_recv (listener); if (ipaddress) { zframe_t *content = zframe_recv (listener); assert (zframe_size (content) == 2); assert (zframe_data (content) [0] == 0xCA); assert (zframe_data (content) [1] == 0xFE); zframe_destroy (&content); zstr_free (&ipaddress); zstr_sendx (speaker, "SILENCE", NULL); } zactor_destroy (&listener); zactor_destroy (&speaker);

// Test subscription filter using a 3-node setup zactor_t *node1 = zactor_new (zbeacon, NULL); assert (node1); zsock_send (node1, "si", "CONFIGURE", 5670); hostname = zstr_recv (node1); assert (*hostname); free (hostname);

zactor_t *node2 = zactor_new (zbeacon, NULL); assert (node2); zsock_send (node2, "si", "CONFIGURE", 5670); hostname = zstr_recv (node2); assert (*hostname); free (hostname);

zactor_t *node3 = zactor_new (zbeacon, NULL); assert (node3); zsock_send (node3, "si", "CONFIGURE", 5670); hostname = zstr_recv (node3); assert (*hostname); free (hostname);

zsock_send (node1, "sbi", "PUBLISH", "NODE/1", 6, 250); zsock_send (node2, "sbi", "PUBLISH", "NODE/2", 6, 250); zsock_send (node3, "sbi", "PUBLISH", "RANDOM", 6, 250); zsock_send (node1, "sb", "SUBSCRIBE", "NODE", 4);

// Poll on three API sockets at once zpoller_t *poller = zpoller_new (node1, node2, node3, NULL); assert (poller); int64_t stop_at = zclock_mono () + 1000; while (zclock_mono () < stop_at) { long timeout = (long) (stop_at - zclock_mono ()); if (timeout < 0) timeout = 0; void *which = zpoller_wait (poller, timeout * ZMQ_POLL_MSEC); if (which) { assert (which == node1); char *ipaddress, *received; zstr_recvx (node1, &ipaddress, &received, NULL); assert (streq (received, "NODE/2")); zstr_free (&ipaddress); zstr_free (&received); } } zpoller_destroy (&poller);

// Stop listening zstr_sendx (node1, "UNSUBSCRIBE", NULL);

// Stop all node broadcasts zstr_sendx (node1, "SILENCE", NULL); zstr_sendx (node2, "SILENCE", NULL); zstr_sendx (node3, "SILENCE", NULL);

// Destroy the test nodes zactor_destroy (&node1); zactor_destroy (&node2); zactor_destroy (&node3);

AUTHORS

The czmq manual was written by the authors in the AUTHORS file.

RESOURCES

Main web site: \m[blue] \m[]

Report bugs to the email <\m[blue]zeromq-dev@lists.zeromq.org\m[][1]>

COPYRIGHT

Copyright (c) 1991-2012 iMatix Corporation -- http://www.imatix.com Copyright other contributors as noted in the AUTHORS file. This file is part of CZMQ, the high-level C binding for 0MQ: http://czmq.zeromq.org This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0. If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/. LICENSE included with the czmq distribution.

NOTES

1. zeromq-dev@lists.zeromq.org  mailto:zeromq-dev@lists.zeromq.org
Search for    or go to Top of page |  Section 3 |  Main Index


CZMQ 3&.0&.1 ZBEACON (3) 06/01/2015

Powered by GSP Visit the GSP FreeBSD Man Page Interface.
Output converted with manServer 1.07.