action_channel

Description:

action channel

Action Channel #
Communication channel, that bundles a sink and a stream. Wrapper with convenient functionalities.
Essentially it is a wrapper that acts as a sink and a stream, with additional logic.
Features #

Allows the input/sink type to be different from the output/stream type, simplifying the entry point.
Handling of "replies", allowing it to be used as a request-response channel.
Run actions when receiving certain data.

Getting Started #
dart pub add action_channel
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And import the package:
import 'package:action_channel/action_channel.dart';
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Usage #
Create a channel using a sink and a stream.
You may specify an action to be executed using the data returned in the .on() method.
final channel = Channel(
sink, stream,
action: (String data) => print('Action using "$data"')
);
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Listening for data #
Listen to the channel with .on(), this will enable you to run an action with the returning data, like a "reply".
final subscription = channel.on((data) {
print('Data received "$data"');
return 'New action using "$data"';
});

subscription.cancel();
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You can also use .once() to listen to the channel only once.

Note:
The channel can be used just like a stream, with .listen().

Channel Controller #
Create a channel using ChannelController, creating a channel that handles the sink and stream, by itself.
Abstracting the sink and stream creation.
A controller needs a function that transforms the input/sink data type into the output/stream data type.
It's recommended to use the Channel.controller() factory, which automatically creates a ChannelController.
final channel = Channel<int, String, void>.controller(
(int id) => User(id),
);
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In addition, it offers callbacks and the ability to append and prepend them.
final channel = Channel<int, String, void>.controller(
(int id) => User(id),

onAdded: (int id) => print('User $id added'),
onData: (User user) => print('User with id "${ user.id }" received'),
onListen: (subscription) => print('Channel listened'),
onClose: () => print('Channel closed'),
);
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Example #

User Channel (/example/main.dart)
import 'package:action_channel/action_channel.dart';

final users = <User>{
User(1, 'John'),
User(2, 'Tom', muted: true),
User(3, 'Alex'),
};

void main() {
final channel = Channel<int, User, String>.controller(
(id) => users.firstWhere((user) => user.id == id),
action: (message, user, channel) => user.say(message),
);

channel.where((user) => !user.muted).on((user) => 'Hello!');

channel.once((data) {
print('First user: ${ data.name }');
return null;
});

channel.add(1);
channel.add(2);
channel.add(3);
}

/* -= Models =- */

class User {
final int id;
final String name;
final bool muted;

User(this.id, this.name, { this.muted = false });

void say(String message) => print('User $id says "$message"');
}
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Contributing #
Contributions are welcome! Please open an issue or pull request if you find a bug or have a feature request.