Meteor.bindEnvironment does not work outside of a Fiber

[speigg]

Meteor.bindEnvironment fails to wrap code in a Fiber when there is no current Fiber.

This is the error:

app/packages/meteor/dynamics_nodejs.js:54
    var boundValues = _.clone(Fiber.current._meteor_dynamics || []);
                                           ^
TypeError: Cannot read property '_meteor_dynamics' of undefined
    at Object.Meteor.bindEnvironment (app/packages/meteor/dynamics_nodejs.js:54:44)

Seems like boundValues should also be set to an empty array if Fiber.current is null.

[glasser]

In what context are you trying to call bindEnvironment outside of a fiber?

The idea of bindEnvironment is so that, when passing callbacks to non-Meteor code, you can keep them running in the current context. On the server that includes the current fiber. So if you're finding yourself outside of a Fiber on the server, you're probably not calling bindEnvironment enough!

[speigg]

Here is the context:

    Meteor.default_server.stream_server.register(function(socket) {
        var intervalID = setInterval(function() {
            if (socket.meteor_session) {

                var connection = {
                    connectionID: socket.meteor_session.id,
                    ...
                };

                socket.id = socket.meteor_session.id;

                var insertConnection = Meteor.bindEnvironment(function() { 
                    Ethereal.connections.insert(connection); 
                }, function (e) {
                    Meteor._debug("Exception from connection register callback:", e);
                }); insertConnection();

                clearInterval(intervalID);
            }
        }, 1000);

        socket.on('close', function () {

            var removeConnection = Meteor.bindEnvironment(function() { 
                Ethereal.connections.remove({connectionID: socket.id});
            }, function (e) {
                Meteor._debug("Exception from connection close callback:", e);
            }); removeConnection()

        });
    });

So what you are saying then, is that I need to wrap the function that I am passing to Meteor.default_server.stream_server.register with Meteor.bindEnvironment as well?

[heavyk]

try using Meteor.setInterval ?

[glasser]

Right, Meteor.setInterval takes care of wrapping its callback in a fiber for you.

(BTW, stream_server is an undocumented internal detail of Meteor.default_server, and is likely to be renamed to something more like _streamServer in a future release. We definitely need to provide some sort of disconnect hook sometime soon...)

[speigg]

Thanks, it seems like I had to wrap every layer of callbacks with Meteor.bindEnvironment, as well as using Meteor.setInterval. Unfortunately I ran into another problem (Issue #471), so I'm still not 100% sure if it is working correctly.

[speigg]

BTW, this is what I ended up doing.

Ethereal.connections = new Meteor.Collection("connections");

if (Meteor.isServer) {

    Ethereal.connections.remove({});    

    Meteor.default_server.stream_server.register( Meteor.bindEnvironment( function(socket) {
        var intervalID = Meteor.setInterval(function() {
            if (socket.meteor_session) {

                var connection = {
                    connectionID: socket.meteor_session.id,
                    connectionAddress: socket.address,
                    userID: socket.meteor_session.userId
                };

                socket.id = socket.meteor_session.id;

                Ethereal.connections.insert(connection); 

                Meteor.clearInterval(intervalID);
            }
        }, 1000);

        socket.on('close', Meteor.bindEnvironment(function () {
            Ethereal.connections.remove({connectionID: socket.id});
        }, function(e) {
            Meteor._debug("Exception from connection close callback:", e);
        }));


    }, function(e) {
        Meteor._debug("Exception from connection registration callback:", e);
    }));

}

[glasser]

Yes, that looks right to me (or as right as you can get before we provide a supported way of hooking into session/sockets like that).

[speigg]

Hah, glad to know this was useful for somebody :)

https://github.com/murilopolese/howmanypeoplearelooking/blob/master/server/main.js

[mizzao]

Additionally, Meteor.bindEnvironment fails without warning if the code is already in a Fiber. Just thought it would be useful to throw an error message of some sort :)