Sails.js Sockets - Best Practices 4/2014 - sails.js

Question

I believe the approach to Sockets within sails.js has changed over the last several months. A little confused on what the best practice should be.
socket.get('/comment/subscribe', function () {
socket.on('comment', function(obj) {
if (obj.verb == 'created') {
var data = obj.data;
if (data.project == 1) {
// This adds it to a visual list.
addComment("data.content");
}
}
});
});
I believe this approach is deprecated. What is the best syntax socket subscription?
Also - am I able to subscribe to a particular criteria of the model, in this case a particular comment or other attribute?

Answer 1

By default when you request a model, you will be subscribed to it. That is the default if you are using blueprints. There is no need to explicitly subscribe.
However, you if you are making your own controller methods. You will need to subscribe socket requests to record updates manually on the server side.
Assuming you have a User model...
To have a socket be notified of all created events call User.watch(req)
For updated and destroyed call User.subscribe(req, records)
Here is a copy of my User controller for a project, I have put comments on the lines that handle subscriptions. hope it helps....
UserController = {
find: (req, res) ->
User.watch(req) // Subscription
if req.params.all().id
query = User.findOne(id: req.params('id'))
else
query = User.find()
query.exec((err, records) =>
return res.send(500, err) if (err)
User.subscribe(req, records) // Subscription
return res.json(records)
)
create: (req, res) ->
User.create(req.body).exec((err, record) =>
return res.send(500, err) if (err)
User.publishCreate(record, record.toJSON()) // Subscription
return res.json(record.toJSON())
)
update: (req, res) ->
User.update(req.params('id'), req.body).exec((err, records) =>
return res.send(500, err) if (err)
return res.notFound() if _.isEmpty(records)
record = _.first(records)
User.publishUpdate(record.id, record.toJSON()) // Subscription
return res.json(record.toJSON())
)
destroy: (req, res) ->
User.destroy(req.params('id')).exec((err, records) =>
return res.send(500, err) if (err)
return res.notFound() if _.isEmpty(records)
record = _.first(records)
User.publishDestroy(record.id) // Subscription
return res.send(204, null)
)
me: (req, res) ->
User.findOne(
id: req.session.user_id
).done((err, user) =>
User.subscribe(req, user) // Subscription
return res.json(user)
)
}
module.exports = UserController

Answer 2

Assuming you want to get some data from the server via socket the code should look something like this on frontend
socket.get('/comment/subscribe', function serverResponse(data) {
// use data
})
on server side in commentController
subscribe: function(req, res) {
//some logic
res.json({
data: 'some random data'
});
}
it depends on what exactly you want to do but this is the basic structure. Also note that sails uses blueprints which is a way to make some basic CRUD routes available without coding them in the controller More info here: http://irlnathan.github.io/sailscasts/blog/2014/01/17/sailscasts-answers-ep8-how-do-blueprint-actions-and-blueprint-routes-work-in-sails/
Regarding the part of the code in your question that starts with socket.on this is an event listener on the client side listening for server to send some data. For example
socket.on('room', function messageReceived(message) {
switch (message.verb) {
case 'created':
addRoom(message.data);
break;
case 'addedTo':
postStatusMessage('room-messages-'+message.id, $('#user-'+message.addedId).text()+' has joined');
increaseRoomCount(message.id);
break;
case 'removedFrom':
postStatusMessage('room-messages-'+message.id, $('#user-'+message.removedId).text()+' has left');
decreaseRoomCount(message.id);
break;
case 'destroyed':
removeRoom(message.id);
break;
case 'messaged':
receiveRoomMessage(message.data);
default:
break;
}
});