isolate_contactor 0.0.1+2

An easy way to create a new isolate and comunicate with it and support sending values between main and child isolate multiple times.

Isolate Contactor

An easy way to create a new isolate and comunicate with it and support sending values between main and child isolate multiple times.

This package is different from the compute method, IsolateContactor allows the isolate to run, send, receive data data until you terminate it. It'll save a lot of starting time.

How to use it

There are multiple ways to use this package, the only thing to notice that the function have to be a static or top-level function to make it works.

Create IsolateContactor instance

IsolateContactor isolateContactor = await IsolateContactor.create(fibonacci);

Listen to the result of the isolate

Like the above example, the result will be passed into stream listener, so you need to make sure that the stream has been called before sending message to the isolate for computing.

isolateContactor.onMessage.listen((message) {
  print('Result from isolate: $message');
});

Send data to isolate for computing

isolateContactor.sendMessage(value);

This is the very basic example of the package

main() async {
    // Just for waiting until the results have arrived
    bool valueExit = false;

    // Create IsolateContactor instance
    IsolateContactor isolateContactor =
        await IsolateContactor.create(fibonacci);

    // Listen to the results
    isolateContactor.onMessage.listen((event) {
      print('isolate 1: $event');
      expect(event, 55);

      valueExit = true;
    });

    // Send 10 to fibonacci isolate function
    isolateContactor.sendMessage(10);

    // Only for waiting the result. Don't need to use in your real app
    while (!valueExit) {
      await Future.delayed(const Duration(milliseconds: 10));
    }

    // Dispose
    isolateContactor.dispose();
}

dynamic fibonacci(dynamic n) {
  if (n == 0) return 0;
  if (n == 1 || n == 2) return 1;

  return fibonacci(n - 2) + fibonacci(n - 1);
}

Easy build-in function

I have implemented a build-in static function to make you easier to create an isolate as fast as possible. You just need to create a function of this form:

dynamic function(dynamic param) {
  // do something
  return something; // <-- This result will be send back to your `onMessage` in main isolate.
}

The param can be anything even a List of variable like this (but its type must be dynamic):

dynamic subtract(dynamic n) => n[1] - n[0];

Add create the instance with IsolateContactor.create(function) or IsolateContactor.create(subtract).

This is an example test:

void main() {
  test('Create isolate with build-in function', () async {
    bool value1Exit = false;
    bool value2Exit = false;

    IsolateContactor isolateContactor1 = await IsolateContactor.create(fibonacci);
    IsolateContactor isolateContactor2 = await IsolateContactor.create(subtract);

    // Listen to f10
    isolateContactor1.onMessage.listen((event) {
      print('isolate 1: $event');
      expect(event, 55);

      value1Exit = true;
    });

    // Listen to f20
    isolateContactor2.onMessage.listen((event) {
      print('isolate 3: $event');

      expect(event, 10);

      value2Exit = true;
    });

    // Send 10 to [fibonacci]
    isolateContactor1.sendMessage(10);

    // Send 10 and 20 to [subtract]
    isolateContactor2.sendMessage([10, 20]);

    while (!value1Exit && !value2Exit) {
      await Future.delayed(const Duration(milliseconds: 10));
    }

    isolateContactor1.dispose();
    isolateContactor2.dispose();
  });
}

// single parameter
dynamic fibonacci(dynamic n) {
  if (n == 0) return 0;
  if (n == 1 || n == 2) return 1;

  return fibonacci(n - 2) + fibonacci(n - 1);
}

// multi parameters as an dynamic
dynamic subtract(dynamic n) => n[1] - n[0];

Create your own function

This is also not too complicated to use, you're completely control your isolate function with this method. You just need to create a function of this form:

void isolateFunction(List<dynamic> params) {
  final channel = IsolateChannel.connectSend(params.last);
  channel.stream.listen((rawMessage) {
    final message = IsolateContactor.getMessage(rawMessage);
    if (message != null) {
      // Do your stuff here
      final result = add(message[0], message[1]);

      // This method will send the results to the main isolate. Listen through `onMessage`.
      channel.sendResult(result);
    }
  });
}

And use IsolateContactor.createOwnIsolate(isolateFunction) and the package will do anything else for you. Please remember that you need to create exactly the same form to make it works. This is the example:

main() async {
  IsolateContactor isolateContactor = await IsolateContactor.createOwnIsolate(isolateFunction);

  // Listen to the results
  isolateContactor.onMessage.listen((event) {
    print('isolate 2: $event');

    expect(event, 30);
  });

  // Send 10 and 20 to [isolateFunction]
  isolateContactor.sendMessage([10, 20]);
}

// Create your own function here
void isolateFunction(List<dynamic> params) {
  final channel = IsolateChannel.connectSend(params.last);
  channel.stream.listen((rawMessage) {
    final message = IsolateContactor.getMessage(rawMessage);
    if (message != null) {
      // Do your stuff here
      final result = add(message[0], message[1]);

      // This method will send the results to the main isolate. Listen through `onMessage`.
      channel.sendResult(result);
    }
  });
}

// multi parameters as an dynamic
dynamic add(dynamic a, dynamic b) => a + b;

Notice

This package is still in the early stages of development.

Contributions

If you encounter any problems or feel the library is missing a feature, please feel free to open an issue. Pull request are also welcome.