normano / dartzmq

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

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)
• 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))
• Asynchronous polling using ZPoller

Getting started

Currently Windows and Android are officially supported as platforms, but it depends on the used shared library of libzmq. I have tested this on Windows and Android, which 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.

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/)

Note that in order for this plugin to work you will need to either get 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)

Linux

Installing libzmq and running dart pub add dartzmq should be all that is required to use this package in your own application. To also run the example project, follow these steps:

1. Install libzmq
2. Install flutter (It may be easiest to install from source, otherwise you can follow the snap instructions)
3. Update .profile with PATH to /flutter/bin (e.g. export PATH=$PATH:~/src/flutter/bin)
4. Ensure ninja-build, clang, and libgtk-3-dev are installed (via apt or other package manager)
5. Run flutter
6. Run flutter config --enable-linux-desktop
7. Clone this repo and cd dartzmq/example
8. flutter create . to enable linux desktop for this project
9. flutter run
10. Click the "Send" button and the received message will be displayed as an array of ints [1,2,3,4,5]

Android

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

Usage

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]);

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
});

Destroy socket

socket.close();

Destroy context

context.stop();