I know it's kind of a huge task, but would it be theoretically possible to use ZeroMQ in Flutter without thinking about Android/Windows/iOS/Linux?

What steps would be necessary?

Would it be possible to distribute precompiled zeromq-Versions (.dll, .so etc) within this plugin?

Is it theoretically possible to transpile the ZeroMQ Code to Dart only?

We think this is an amazing plugin but we're really uncertain about the fact that you need to make sure that e.g. a precompiled .dll (windows) works on every machine (it does not).

Launching lib/main.dart on Linux in debug mode...
Building Linux application...
Debug service listening on ws://127.0.0.1:37089/w-K6VIMgRmg=/ws
Syncing files to device Linux...
[ERROR:flutter/lib/ui/ui_dart_state.cc(198)] Unhandled Exception: Exception: Could not load any zeromq library
#0      ZContext._initBindings (package:dartzmq/src/zeromq.dart:77:7)
#1      new ZContext (package:dartzmq/src/zeromq.dart:66:5)
#2      main (package:remote_volume_control/main.dart:6:28)
#3      _runMainZoned.<anonymous closure>.<anonymous closure> (dart:ui/hooks.dart:130:25)
#4      _rootRun (dart:async/zone.dart:1426:13)
#5      _CustomZone.run (dart:async/zone.dart:1328:19)
#6      _runZoned (dart:async/zone.dart:1861:10)
#7      runZonedGuarded (dart:async/zone.dart:1849:12)
#8      _runMainZoned.<anonymous closure> (dart:ui/hooks.dart:126:5)
#9      _delayEntrypointInvocation.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:297:19)
#10     _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:192:12)

[dartzmq] Failed to load library zmq:  Invalid argument(s): Failed to lookup symbol 'zmq_poller_new': /lib64/libzmq.so: undefined symbol: zmq_poller_new
[dartzmq] Failed to load library libzmq:  Invalid argument(s): Failed to load dynamic library 'liblibzmq.so': liblibzmq.so: cannot open shared object file: No such file or directory
[dartzmq] Failed to load library libzmq-v142-mt-4_3_5:  Invalid argument(s): Failed to load dynamic library 'liblibzmq-v142-mt-4_3_5.so': liblibzmq-v142-mt-4_3_5.so: cannot open shared object file: No such file or directory

--------------------------------------------------

sean@sean-fedora /lib64> ls | grep libzmq
libzmq.so
libzmq.so.5
libzmq.so.5.2.4

not entirely sure whats going on here the code is looking in the right place. any help would be appreciated

Hi, why socket.send() parameter is from List<int> type? does it get data as binary array? what if someone wants to send data non-binary?

and I have another question; how we can receive response from a req socket connection?

Question At the moment I try to use your library for a pub/sub setup. I try to get string messages of my python publisher. If I try to write a subscriber with your dart library I have problems to get out the message as string. I tried your provided example too. But there I have the same problem... I do not get the string message, instead of a string I get some ZFrame... Can you help me with my problem? (Look at "To Reproduce") Thank you!

Setup with python publisher and subscriber: Publisher:

import zmq
import random
import sys
import time

port = "6555"
if len(sys.argv) > 1:
    port = sys.argv[1]
    int(port)

context = zmq.Context()
socket = context.socket(zmq.PUB)
socket.bind("tcp://*:%s" % port)

while True:
    # Receives a string format message
    socket.send_string("ML hello")
    time.sleep(1)

Subscriber:

# simple_sub.py
import zmq

host = "127.0.0.1"
port = "6555"

# Creates a socket instance
context = zmq.Context()
socket = context.socket(zmq.SUB)

# Connects to a bound socket
socket.connect("tcp://{}:{}".format(host, port))

# Subscribes to all topics
socket.subscribe("ML")

while True:
    # Receives a string format message
    whole_message = socket.recv_string()
    topic, actual_message = whole_message.split(" ")
    print(actual_message)

Environment OS: Archlinux 6.0.12-arch1-1 Android x86 emulator: Pixel 5 API 30 flutter: 3.3.9 compileSdkVersion 33 ndkVersion flutter.ndkVersion

To Reproduce Subscriber with dart:

    // Tst
    final ZContext context = ZContext();
    final ZSocket socket = context.createSocket(SocketType.sub);
    late StreamSubscription _subscription;
    socket.connect("tcp://192.168.178.26:6555");
    socket.subscribe("ML");

    _subscription = socket.messages.listen((message) {
      print(message.toString());
    });

Output:

I/flutter (31175): ZMessage[ZFrame[[77, 76, 32, 104, 101, 108, 108, 111]]]

hi, did you find a problem? When subscribing to a topic under TCP protocol, big data will accept incompleteness, and I failed to set relevant properties.

Describe the Bug I try to use your library with the environment which I described below. If I call socket.connect and Socket.send if no Server is available there is no error message and no effect... so I can not detect, that something is not okay?

Environment OS: Archlinux 6.0.12-arch1-1 Android x86 emulator: Pixel 5 API 30 flutter: 3.3.9 compileSdkVersion 33 ndkVersion flutter.ndkVersion

To Reproduce

  // Send a test message
  // => via zmq
  testzmq() {
    // Tst
    final ZContext context = ZContext();
    final ZSocket socket = context.createSocket(SocketType.req);
    socket.connect("tcp://localhost:6555");
    //socket.sendString("Hello");
    socket.send([1, 2]);
    socket.close();
  }

Expected Behavior Error message if I can not connect to server / Get Stuck on server.connect

Reproducibility 100%

Hello,

I have been trying to use dartzmq on flutter to establish a connection to a remote server host, but I keep getting the error:

[dartzmq] Failed to load library zmq: Invalid argument(s): Failed to load dynamic library 'libzmq.so': dlopen failed: library "libzmq.so" not found [dartzmq] Failed to load library libzmq: Invalid argument(s): Failed to load dynamic library 'liblibzmq.so': dlopen failed: library "liblibzmq.so" not found [dartzmq] Failed to load library libzmq-v142-mt-4_3_5: Invalid argument(s): Failed to load dynamic library 'liblibzmq-v142-mt-4_3_5.so': dlopen failed: library "liblibzmq-v142-mt-4_3_5.so" not found

I have built the MacOS platform in my local dartzmq repo and linked it to my flutter app. I was wondering if anyone could help me debug this library issue? If someone has dealt with this problem before, a simple list of steps to fix it would be much appreciated. Thanks!

I don't know if the reason to this issue happens is the project is now still under development stage. but through observing the source code, I found that maybe one of the reason is the dartzmq doesn't provide the receive function, and the inner strategy is using loop to handle the receive data without sending data for reply. but whether I use reply mode or request mode, zmq doesn't allow no sending action within two receiving actions. so, it seemed the exception occurs. i want to know why the dartzmq has not provide receive funciton directly? or the dartzmq developer has had a solution to solove the problem? I am looking forward to the reply very eagerly. Thanks in advance.

I updated the example project to include an echo socket to have a more complete example. I also switched the sockets to a dealer/router pair as I was getting an occasional exception with the req/rep pair. Those can be fussy as they change states often, so that might be something to look into further.

Hello there,

I'm testing this feature on windows. When using a push/pull or pub/sub pattern there seems to be a one second delay on the pull/sub socket. Is it built into ZeroMQ or can i configure this behaviour?

Best regards