Tracking online user with GraphQL Apollo - node.js

Question

I need to handle events "user is now online" and "user is now offline" on GraphQL Apollo Node.js server. What's the best way to do it?
My investigation: I pretty sure that I don't need to implement any heartbeat logic, because subscriptions are working on WebSockets. But I didn't find any info in their docs how to handle WebSockets events like "connecting" and "disconnecting" from the subscription... Actually I can handle those events from the outside of actual subscription:
SubscriptionServer.create({
execute,
subscribe,
schema,
onConnect = (...args) => {
console.log('User connected')
},
onDisconnect = (...args) => {
console.log('User disconnected')
}
}, {
server: ws,
path: '/subscriptions'
})
But can't determine which user is connected via this socket.
My implementation: for now I made it work like that:
We have express middleware for all the calls, it is pushing user object from jsonwebtoken to req object. Here I can trigger "user is now online" logic.
I've created separate subscription, client subscribes on it on login and unsubscribes on logout. Since there is no unsubscribe handler, I manage to determine that filter function gets called on user disconnect without payload, so I did this approach:
userOnlineSubscription: {
subscribe: withFilter(
() => pubSub.asyncIterator('userOnlineSubscription'),
async (payload, variables) => {
if (!payload) {
// set user offline
}
return false
}
)
}
As for me, the solution above is ugly. Can someone recommend the better approach?

Answer 1

I used this approach
onConnect (connectionParams, webSocket) {
const userPromise = new Promise((resolve, reject) => {
if (connectionParams.jwt) {
jsonwebtoken.verify(
connectionParams.jwt,
JWT_SECRET,
(err, decoded) => {
if (err) {
reject(new Error('Invalid Token'))
}
resolve(
User.findOne({
where: { id: decoded.id }
})
)
}
)
} else {
reject(new Error('No Token'))
}
})
return userPromise.then(user => {
if (user) {
return { user: Promise.resolve(user) }
}
return Promise.reject(new Error('No User'))
})
}