Hi.
I have now committed an incubating/beta feature to support websockets in a controller. It can change without notice so use at your own risk right now. To use this feature you will need the latest 6.4.0-SNAPSHOT (2015-02-04T14:00:00 or above). Only service-controllers has this feature so pages/parts cannot implement server-side websocket handling.
To use websocket support, firstly add lib-websocket to your build.
dependencies {
...
include 'com.enonic.xp:lib-websocket:6.4.0-SNAPSHOT'
...
}
Next, create a service controller and implement a get method. This method is called first when a websocket http-upgrade request is submitted.
exports.get = function(req) {
if (!req.webSocket) {
// Do something if this is not a web-socket request
}
// If web-socket request, then you will need to accept the web-socket.
return {
webSocket: {
subProtocols: ['text'],
data: {
myField: 'myValue'
}
}
};
}
Sub-protocols indicate what type of sub-protocols to accept. The data field is extra data that is passed to the web-socket session so it can be used later. It only supports simple key/value pairs since it’s serialized between calling threads.
Next is to create the actual web-socket event handling. To do this, implement and export a new method called webSocketEvent.
exports.webSocketEvent = function(event) {
if (event.type == 'open') {
// Do something on open
} else if (event.type == 'close') {
// Do something on close
} else if (event.type == 'error') {
// Do something on error
} else if (event.type == 'message') {
// Do something on message
}
}
The event object holds the following values:
- type - type of event (open, close, error and message)
- session - websocket session information.
- session.id - websocket session id.
- session.params - URL parameters from the request.
- session.path - Path for the websocket endpoint.
- data - Data that was passed from the
getfunction. - error - Error information if type = error.
- message - Message if type = message.
- closeReason - Close reason code if type = close.
To send messages to a single web-socket or a group of sockets, you can use lib-websocket. Here’s an example of a chat.
webSocketLib = requlre('/lib/xp/websocket');
exports.webSocketEvent = function(event) {
if (event.type == 'open') {
webSocketLib.addToGroup('chat', event.session.id);
webSocketLib.send(event.session.id, 'You have joined the chat.');
}
if (event.type == 'message') {
webSocketLib.sendToGroup('chat', event.message);
}
}
If you want to look at a similar example, go to https://github.com/enonic/app-features/tree/master/src/main/resources/site/services/chat. Also, look at the lib-websocket js-docs here: http://repo.enonic.com/public/com/enonic/xp/docs/6.4.0-SNAPSHOT/docs-6.4.0-SNAPSHOT-libdoc.zip!/index.html.
