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peer.dart
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peer.dart
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// Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
import 'dart:async';
import 'package:stream_channel/stream_channel.dart';
import 'channel_manager.dart';
import 'client.dart';
import 'parameters.dart';
import 'server.dart';
import 'utils.dart';
/// A JSON-RPC 2.0 client *and* server.
///
/// This supports bidirectional peer-to-peer communication with another JSON-RPC
/// 2.0 endpoint. It sends both requests and responses across the same
/// communication channel and expects to connect to a peer that does the same.
class Peer implements Client, Server {
final ChannelManager _manager;
/// The underlying client that handles request-sending and response-receiving
/// logic.
Client _client;
/// The underlying server that handles request-receiving and response-sending
/// logic.
Server _server;
/// A stream controller that forwards incoming messages to [_server] if
/// they're requests.
final _serverIncomingForwarder = new StreamController(sync: true);
/// A stream controller that forwards incoming messages to [_client] if
/// they're responses.
final _clientIncomingForwarder = new StreamController(sync: true);
Future get done => _manager.done;
bool get isClosed => _manager.isClosed;
@override
ErrorCallback get onUnhandledError => _server?.onUnhandledError;
/// Creates a [Peer] that communicates over [channel].
///
/// Note that the peer won't begin listening to [channel] until [Peer.listen]
/// is called.
///
/// Unhandled exceptions in callbacks will be forwarded to [onUnhandledError].
/// If this is not provided, unhandled exceptions will be swallowed.
Peer(StreamChannel<String> channel, {ErrorCallback onUnhandledError})
: this.withoutJson(
jsonDocument.bind(channel).transform(respondToFormatExceptions),
onUnhandledError: onUnhandledError);
/// Creates a [Peer] that communicates using decoded messages over [channel].
///
/// Unlike [new Peer], this doesn't read or write JSON strings. Instead, it
/// reads and writes decoded maps or lists.
///
/// Note that the peer won't begin listening to [channel] until
/// [Peer.listen] is called.
///
/// Unhandled exceptions in callbacks will be forwarded to [onUnhandledError].
/// If this is not provided, unhandled exceptions will be swallowed.
Peer.withoutJson(StreamChannel channel, {ErrorCallback onUnhandledError})
: _manager = new ChannelManager("Peer", channel) {
_server = new Server.withoutJson(
new StreamChannel(_serverIncomingForwarder.stream, channel.sink),
onUnhandledError: onUnhandledError);
_client = new Client.withoutJson(
new StreamChannel(_clientIncomingForwarder.stream, channel.sink));
}
// Client methods.
Future sendRequest(String method, [parameters]) =>
_client.sendRequest(method, parameters);
void sendNotification(String method, [parameters]) =>
_client.sendNotification(method, parameters);
withBatch(callback()) => _client.withBatch(callback);
// Server methods.
void registerMethod(String name, Function callback) =>
_server.registerMethod(name, callback);
void registerFallback(callback(Parameters parameters)) =>
_server.registerFallback(callback);
// Shared methods.
Future listen() {
_client.listen();
_server.listen();
return _manager.listen((message) {
if (message is Map) {
if (message.containsKey('result') || message.containsKey('error')) {
_clientIncomingForwarder.add(message);
} else {
_serverIncomingForwarder.add(message);
}
} else if (message is List &&
message.isNotEmpty &&
message.first is Map) {
if (message.first.containsKey('result') ||
message.first.containsKey('error')) {
_clientIncomingForwarder.add(message);
} else {
_serverIncomingForwarder.add(message);
}
} else {
// Non-Map and -List messages are ill-formed, so we pass them to the
// server since it knows how to send error responses.
_serverIncomingForwarder.add(message);
}
});
}
Future close() =>
Future.wait([_client.close(), _server.close(), _manager.close()]);
}