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

Currently supported:

• Creating sockets (pair, pub, sub, req, rep, dealer, router, pull, push, xPub, xSub, stream)
• Sending messages (of type List<int>)
• 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) & unsubscribe(String topic))
• Monitoring socket states (ZMonitor & MonitoredZSocket)

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.

Create context

final ZContext context = ZContext();

Create socket

final ZSocket 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');

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
});

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();

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)

Note that you need to use Android NDK version r21d. Newer versions are currently not supported (see zeromq/libzmq#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