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dartzmq

A simple dart zeromq implementation/wrapper around the libzmq C++ library

Features

Currently supported:

  • Creating sockets (pair, pub, sub, req, rep, dealer, router, pull, push, xPub, xSub, stream)
    • Depending on the zeromq library also server, client, radio, dish, channel, peer, raw, scatter and gather
  • Sending messages (of type List<int>, String, ZFrame or ZMessage)
  • Bind (bind(String address))
  • Connect (connect(String address))
  • Curve (setCurvePublicKey(String key), setCurveSecretKey(String key) and setCurveServerKey(String key))
  • Socket options (setOption(int option, String value))
  • Receiving multipart messages (ZMessage)
  • Topic subscription for sub sockets (subscribe(String topic) and unsubscribe(String topic))
  • Monitoring socket states (ZMonitor and MonitoredZSocket)
  • Asynchronous (ZSocket) and Synchronous (ZSyncSocket) sockets

Getting started

Currently Windows and Android are officially supported as platforms. Basically there a no extra setup steps unless the provided zeromq binary does not work for your platform. I have tested this on Windows and Android, which both work. Other platforms have not been tested, but should work. If you have tested this plugin on another platform and got it to work, please share your steps and create an issue so I can add it to the list below.

Usage

Create context

final ZContext context = ZContext();

Create asynchronous socket

final ZSocket socket = context.createSocket(SocketType.req);

Create synchronous socket

final ZSyncSocket socket = context.createSocket(SocketType.req);

Connect socket

socket.connect("tcp://localhost:5566");

Send message

socket.send([1, 2, 3, 4, 5]);

socket.sendString('My Message');

socket.sendFrame(ZFrame([1, 2, 3, 4, 5]));

var message = ZMessage();
message.add(ZFrame([1, 2, 3, 4, 5]));
message.add(ZFrame([6, 7, 8, 9, 10]));
socket.sendMessage(message, flags: ZMQ_DONTWAIT);

Receive ZMessages

socket.messages.listen((message) {
    // Do something with message
});

Receive ZFrames

socket.frames.listen((frame) {
    // Do something with frame
});

Receive payloads (Uint8List)

socket.payloads.listen((payload) {
    // Do something with payload
});

NOTE: If you're trying to use req/rep pattern, consider using either a ZSyncSocket and call socket.recv() or a ZSocket of type SocketType.dealer instead. For the latter you need to add an empty ZFrame at the beginning of your ZMessage as identification.

Receive socket events

final MonitoredZSocket socket = context.createMonitoredSocket(SocketType.req);
socket.events.listen((event) {
    log('Received event ${event.event} with value ${event.value}');
});

final ZSocket socket = context.createSocket(SocketType.req);
final ZMonitor monitor = ZMonitor(
    context: context,
    socket: socket,
    event: ZMQ_EVENT_CONNECTED | ZMQ_EVENT_CLOSED, // Only listen for connected and closed events
);
monitor.events.listen((event) {
    log('Received event ${event.event} with value ${event.value}');
});

Destroy socket

socket.close();

Destroy monitor

monitor.close();

Destroy context

context.stop();

Using a custom libzmq binary

Windows

Place a shared library of libzmq next to your executable (for example place libzmq-v142-mt-4_3_5.dll in the folder yourproject/build/windows/runner/Debug/)

You can use a shared library of libzmq or compile it yourself. Especially when using this on windows you need to make sure that libzmq is compiled using MSVC-2019 if you are using clang it will not work (more info)

Android

Note that you need to use Android NDK version r21d. Newer versions are currently not supported (see https://github.com/zeromq/libzmq/issues/4276)

  1. Follow these steps to build a libzmq.so for different platforms
    • If you need curve support make sure to set the environment variable CURVE either to export CURVE=libsodium or export CURVE=tweetnacl before running the build command
  2. Include these in your project following these steps
  3. Include the compiled standard c++ library libc++_shared.so files located inside the Android NDK as in step 2 (reference)
    • You can find these inside the Android NDK for example under this path ndk\21.4.7075529\toolchains\llvm\prebuilt\windows-x86_64\sysroot\usr\lib

IOS

Note IOS arm64 architecture supported so it will run from iPhone5s to the latest Iphone, Ipads devices

  1. To make it Run on simulator you have to modify the podspec file in the ios directory of plugin
  2. modify this - s.pod_target_xcconfig = { "OTHER_LDFLAGS" => "$(inherited) -force_load $(PODS_TARGET_SRCROOT)/Frameworks/libzmq.a -lstdc++" }
  • From s.pod_target_xcconfig = { "OTHER_LDFLAGS" => "$(inherited) -force_load $(PODS_TARGET_SRCROOT)/Frameworks/libzmq.a -lstdc++" }
  • To s.pod_target_xcconfig = { "OTHER_LDFLAGS" => "$(inherited) -force_load $(PODS_TARGET_SRCROOT)/Frameworks/libzmq_simulator.a -lstdc++" }

Libraries

dartzmq