platform/lib/server.dart
2016-12-23 15:57:46 -05:00

257 lines
8.2 KiB
Dart

/// Server-side support for WebSockets.
library angel_websocket.server;
import 'dart:async';
import 'dart:convert';
import 'dart:io';
import 'dart:mirrors';
import 'package:angel_framework/angel_framework.dart';
import 'package:json_god/json_god.dart' as god;
import 'package:merge_map/merge_map.dart';
import 'angel_websocket.dart';
export 'angel_websocket.dart';
part 'websocket_context.dart';
part 'websocket_controller.dart';
/// Broadcasts events from [HookedService]s, and handles incoming [WebSocketAction]s.
class AngelWebSocket extends AngelPlugin {
Angel _app;
List<WebSocket> _clients = [];
final List<String> _servicesAlreadyWired = [];
final StreamController<WebSocketAction> _onAction =
new StreamController<WebSocketAction>();
final StreamController _onData = new StreamController();
final StreamController<WebSocketContext> _onConnection =
new StreamController<WebSocketContext>.broadcast();
final StreamController<WebSocketContext> _onDisconnect =
new StreamController<WebSocketContext>.broadcast();
/// Include debug information, and send error information across WebSockets.
final bool debug;
/// A list of clients currently connected to this server via WebSockets.
List<WebSocket> get clients => new List.unmodifiable(_clients);
/// Services that have already been hooked to fire socket events.
List<String> get servicesAlreadyWired =>
new List.unmodifiable(_servicesAlreadyWired);
/// The endpoint that users should connect a WebSocket to.
final String endpoint;
/// Fired on any [WebSocketAction].
Stream<WebSocketAction> get onAction => _onAction.stream;
/// Fired whenever a WebSocket sends data.
Stream get onData => _onData.stream;
/// Fired on incoming connections.
Stream<WebSocketContext> get onConnection => _onConnection.stream;
/// Fired when a user disconnects.
Stream<WebSocketContext> get onDisconnection => _onDisconnect.stream;
AngelWebSocket({this.endpoint: '/ws', this.debug: false});
_batchEvent(String path) {
return (HookedServiceEvent e) async {
var event = await transformEvent(e);
event.eventName = "$path::${event.eventName}";
await batchEvent(event);
};
}
/// Slates an event to be dispatched.
Future batchEvent(WebSocketEvent event) async {
// Default implementation will just immediately fire events
_clients.forEach((client) {
client.add(god.serialize(event));
});
}
/// Returns a list of events yet to be sent.
Future<List<WebSocketEvent>> getBatchedEvents() async => [];
/// Responds to an incoming action on a WebSocket.
Future handleAction(WebSocketAction action, WebSocketContext socket) async {
var split = action.eventName.split("::");
if (split.length < 2)
return socket.sendError(new AngelHttpException.BadRequest());
var service = _app.service(split[0]);
if (service == null)
return socket.sendError(new AngelHttpException.NotFound(
message: "No service \"${split[0]}\" exists."));
var actionName = split[1];
var params = mergeMap([
god.deserializeDatum(action.params),
{"provider": Providers.WEBSOCKET}
]);
try {
if (actionName == ACTION_INDEX) {
return socket.send(
"${split[0]}::" + EVENT_INDEXED, await service.index(params));
} else if (actionName == ACTION_READ) {
return socket.send("${split[0]}::" + EVENT_READ,
await service.read(action.id, params));
} else if (actionName == ACTION_CREATE) {
return new WebSocketEvent(
eventName: "${split[0]}::" + EVENT_CREATED,
data: await service.create(action.data, params));
} else if (actionName == ACTION_MODIFY) {
return new WebSocketEvent(
eventName: "${split[0]}::" + EVENT_MODIFIED,
data: await service.modify(action.id, action.data, params));
} else if (actionName == ACTION_UPDATE) {
return new WebSocketEvent(
eventName: "${split[0]}::" + EVENT_UPDATED,
data: await service.update(action.id, action.data, params));
} else if (actionName == ACTION_REMOVE) {
return new WebSocketEvent(
eventName: "${split[0]}::" + EVENT_REMOVED,
data: await service.remove(action.id, params));
} else {
return socket.sendError(new AngelHttpException.MethodNotAllowed(
message: "Method Not Allowed: \"$actionName\""));
}
} catch (e, st) {
if (e is AngelHttpException)
return socket.sendError(e);
else if (debug == true)
socket.sendError(new AngelHttpException(e,
message: e.toString(), stackTrace: st, errors: [st.toString()]));
else
socket.sendError(new AngelHttpException(e));
}
}
/// Hooks a service up to have its events broadcasted.
hookupService(Pattern _path, HookedService service) {
String path = _path.toString();
var batch = _batchEvent(path);
service
..afterCreated.listen(batch)
..afterModified.listen(batch)
..afterUpdated.listen(batch)
..afterRemoved.listen(batch);
_servicesAlreadyWired.add(path);
}
/// Runs before firing [onConnection].
Future handleConnect(WebSocketContext socket) async {}
/// Handles incoming data from a WebSocket.
handleData(WebSocketContext socket, data) async {
try {
socket._onData.add(data);
var fromJson = JSON.decode(data);
var action = new WebSocketAction.fromJson(fromJson);
_onAction.add(action);
if (action.eventName == null ||
action.eventName is! String ||
action.eventName.isEmpty) {
throw new AngelHttpException.BadRequest();
}
if (fromJson is Map && fromJson.containsKey("eventName")) {
socket._onAction.add(new WebSocketAction.fromJson(fromJson));
socket.on
._getStreamForEvent(fromJson["eventName"].toString())
.add(fromJson["data"]);
}
if (action.eventName.contains("::")) {
var split = action.eventName.split("::");
if (split.length >= 2) {
if (ACTIONS.contains(split[1])) {
var event = handleAction(action, socket);
if (event is Future) event = await event;
if (event is WebSocketEvent) {
batchEvent(event);
}
}
}
}
} catch (e, st) {
// Send an error
if (e is AngelHttpException)
socket.sendError(e);
else if (debug == true)
socket.sendError(new AngelHttpException(e,
message: e.toString(), stackTrace: st, errors: [st.toString()]));
else
socket.sendError(new AngelHttpException(e));
}
}
/// Transforms a [HookedServiceEvent], so that it can be broadcasted.
Future<WebSocketEvent> transformEvent(HookedServiceEvent event) async {
return new WebSocketEvent(eventName: event.eventName, data: event.result);
}
/// Hooks any [HookedService]s that are not being broadcasted yet.
wireAllServices(Angel app) {
for (Pattern key in app.services.keys.where((x) {
return !_servicesAlreadyWired.contains(x) &&
app.services[x] is HookedService;
})) {
hookupService(key, app.services[key]);
}
}
@override
Future call(Angel app) async {
_app = app..container.singleton(this);
if (runtimeType != AngelWebSocket)
app.container.singleton(this, as: AngelWebSocket);
// Set up services
wireAllServices(app);
app.onService.listen((_) {
wireAllServices(app);
});
app.get(endpoint, (RequestContext req, ResponseContext res) async {
if (!WebSocketTransformer.isUpgradeRequest(req.io))
throw new AngelHttpException.BadRequest();
res
..willCloseItself = true
..end();
var ws = await WebSocketTransformer.upgrade(req.io);
_clients.add(ws);
var socket = new WebSocketContext(ws, req, res);
await handleConnect(socket);
_onConnection.add(socket);
req.properties['socket'] = socket;
ws.listen((data) {
_onData.add(data);
handleData(socket, data);
}, onDone: () {
_onDisconnect.add(socket);
_clients.remove(ws);
}, onError: (e) {
_onDisconnect.add(socket);
_clients.remove(ws);
}, cancelOnError: true);
});
}
}