I’m having some trouble understanding how to inplement presence channels in a real-time laravel application.
From what i’ve read in the documentation and a lot of other online resources about this, i only need to broadcast on a Presence channel and have clients listen on that particular channel. By the way, I'm using laravel 5.6 and on the front end I use Larvel Echo.
So, my problem is that channel name I need to broadcast to. If it’s something generic like “chat”, ALL the users in my application will broadcast to this channel and users who have no ideea who that user is (not a friend) receive this notification and they have to process this new information. Ofcourse I can choose not to update the UI or just do nothing if the user is not in their friends list but this just seems like a lot of useless procesaing of notifications on the client side. Doesn’t seem like a good ideea in my opinion.
Second option would be to broadcast presence to a unique channel name like “chat-[unique]” where “[unique]” would be something like the logged user’s id/hash but this just means that every client that loggs in the application has to listen for ALL friends notifications, so he has to connect to chat-5426, chat-9482, chat-4847 and so on, for all his friends. Again, this does not seem efficient. But that’s not all. The friends list is paginated so a user, after is logged in, only sees his first 20 friends (unless he scrolls down) and I have no limit on how many friend a user can have - I can implement a limit but still, it would be in the thousands so I don’t think I can get all the users from the DB in one query. I had the ideea of using this last method, to listen to each user's channel on the front end just as they are, paginated. Then, when scrolling and navigation arround, if a new user is visible in the viewport, add it to my friends object (no UI change) and start listening on his presence channel. I can see this method failing pretty easy though.
However I think about this, it always seems like online presence is verry resource consuming and almost not worth it for a small startup, I don't know. I have no ideea what a good way would be to implement it as I`ve never done it before. I would greatly appreciate any help with this because all online resources I've found on the subject implement the first method I asked about, all users connectiong to a generic channel but this always works in tutorials because they only have like 2-3 users in the DB and none mantion a user having friends. I can't see this working in the real world, but I may be wrong.
Thanks in advance
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I have a task to display a list of online users present on the site. I've been said that I should use web-sockets for this.
I don't know how to implement this. I've already installed Pusher and Laravel Echo. Could you help me by pointing in right direction? I guess I should listen for the moment when user socket connects.
Reading all the comments I've imagined two possible solutions:
Broadcast when a user logs in / out
This is the very simple solution. You can use laravel notifications that allows you to implement a specific broadcast logic:
During the login / logout phase create a UserLogged[In|Out] notification and broadcast it to a specific channel
Using Laravel Echo and a "few lines" of javascript, update your onlineUsers list (for example in VueJs you may want to update the Vuex store)
But this may require a more complex logic and you may have to write a lot of code to keep the online users list updated... I think it's better to move to solution #2...
Use presence channels
I think this is the best way, since it doesn't require nothing else that a good Laravel-echo configuration. For the example I'm using Pusher (since you asked for), but this solution can be implemented with all the Laravel broadcast drivers.
When a user logs in, simply subscribe him / her to a presence channel (here the Laravel documentation)
Using Laravel Echo, subscribe the user to that channel
var chatRoom = Echo.join('my.chat.room.id');
Once subscribed use themembers.count method to keep an updated list of the channel users.
Using a setTimeout() function you can have a realtime update of the users list.
Notes
I've never implemented this solutions in a production environment, but just wrote some code to see how it works. so I think that if other people have diffent point of view or have a better way to explain this process I will be happy to update my answer.
I want to create something in Slack that sends a message (starting by calling someone with '#') to a channel when specific users login. I've checked ifttt and zapier. I also checked the slack api to create something myself, but I couldn't really find anything usefull.
Anyone has any ideas?
Slack does not track user login or logoff in a traditional sense. Instead, users are always always "logged in" and available to receive messages once they have joined a team / channel.
There also is the concept of "presence", which is related, but not the same thing. User presence can change multiple times during a few minutes, e.g. if the user is on a mobile. I am guessing you would not want to send the user your message that often.
Still you can poll the presence information of a user with the API users.getPresence , which could be used to implement a script that polls this information on a regular basis and send your message. You also want to filter out presence changes below a certain duration threshold.
Keep in mind though that the rate limit for API methods is 1 per second. So depending on how many users you have in your workspace there will be a significant delay between the user becoming "present" and your script being able to send the message.
There is a workaround for that to have a google sheet as a database for the users and you can trigger by day once and timestamp it.
So the best trigger is a private message or public and you can use filter when mentioning or signin or signout it depends on the trigger word then you pass the filter since zapier won't count your zaps if you used fiter as a second step.
I'm trying to figure out how Websockets works. I read some articles, tutorials, etc and I have a pretty basic understanding of how it works, but there is one element that I can't understand how to implement.
My idea is the following : One user will load a "customer" page containing all informations of that customer + a discussion thread. If an other user load that same page, they will be able to discuss in real time and if one user update the data of the customer, the second one will see the update.
The thing that is bugging me, is how can I allow users to access a customer data, but by checking that they can access it (for example, users can access the customer of their group, not all customers)
How can I be sure that the current user will access a customer he has the right (in the websocket)?
Thank you for your help!
Think of the websocket connection itself as a separate thing. A socket used by a client can subscribe to many different events.
What you're describing is topics. When the websocket connection is established, you send a message using whatever socket framework you're using to subscribe to a topic. For example, it could be a topic called customer-123. (A analogy for a topic, is a chat room)
Your application logic (server side) will verify that the currently logged in user has permission to access customer 123, and if so, permits them to join this topic. If you don't do this, it would be trivial for users to listen to any messages relating to any data.
Whenever a user updates any data that is relevant to customer 123, a message is posted to that topic. And thus, any user who is in that topic will receive the message.
An socket might subscribe to many many topics for each customer they open in your app. And topics can be combined and managed in groups depending on how you want to send messages.
In a typical large app, it's common to have a websocket subscribe to topics like user-123, team-456 by default so the server can send messages to them individually or to the entire team to which they are a member of.
For example, if a user updates customer-123, I might send a full data object to the customer-123 topic, and if customer 123 belongs to team-456, I would also send a small notification object like 'User 789 has updated customer 123' to the entire team (which is what powers Facebooks feed like system).
As your app grows, you'll use services like notification hubs to manage the fact that there could be thousands of topics each with thousands of subscribers.
The best thing to do is share a session ID and set up authentication token policies between your web application and your socket session. You could set up your own policy middleware to check the session ID.
You aren't really clear about how you're trying to accomplish this. If you're using express/socket.io, you can use this module: https://www.npmjs.com/package/express-socket.io-session
Hope this helps!
Like any other production application, you need authentication (who is allowed to use the app) and authorization (what functionality can a authenticated user perform). Authorization (ie, access control - ACL) is probably more precisely what you are looking for. Your app has to consult an authorization subsystem to see if the current user has access permission to edit/view another user's information.
This is not a trivial concern for many applications; security and privacy are important aspects of any web-based (distributed) application.
I have a problem and i think its have to do with sessions. (at least i want it to be related to sessions because i need to use sessions),
Suppose i have a list of names of people logged in, on my site .
I want that once i press someone's name, that he and I will get a game board. (No confirmation at the moment ..).
Now how do i get the game board , it's obvious. but, how to make that the other user will get one .. ?(the user that i chose from the list).
The other user, he is like a passive user, he suddenly getting a game board.
someone understands?
Thanks in advance .
Seems like you need some COMET/push technology. You may take a look at SignalR which would allow you to push contents to specified clients. Basically all clients will subscribe to notifications from the server and when a particular request comes from an administrator you could then send notification to the selected clients.
I'm wondering how it's implemented in Gmail, that every time you receive e-mail, the list of mails is automatically refreshed. It looks like the server is sending some kind of event to the browser, but how is it possible? Or maybe it’s simle: the browser ask the server for new messages every let’s say 2 seconds? But it would probably kill the performance…
Anyone have some ideas?
EDIT: OK, so if it's the simple answer, how do they manage performance? When I send an email from an other account to the gmail account the view is "refreshed" almost instantly. You were saying about a simple function that returns true / false, but it must have some logic (db connection or reads some files). How they manage it?
See also: How is GMail Chat able to make AJAX requests without client interaction?
Dont know exactly which technoloy Gmail uses, but the concept is to open a channel - using reverse AJAX, comet or sprocket based techniques.
Think of it as the client requesting the server for data, but the server does not return for one minute unless it has new mail. Using this technique, the client can almost show the results in a real time manner and it does not have to poll every 2 secs. Makes sense?
gmail is, in fact, polling the server for updates. Not as often as every two seconds, though. That would be madness. A bit of testing with Tamper Data makes it look like maybe every 20 seconds, though there seem to be multiple events going through that confuse it a bit.
Regarding your edit, I imagine they might have a last-activity timestamp on the account tracking in their database, with the client polling query retrieving that via Ajax and comparing with its last sync to determine whether it needs to do a full update.
You have right with simple answer. Google Mail checking new messages on server via AJAX.
It must be some kind of ajax listener that get informations every X seconds.
I already set something like that for one of my projects. What I was doing is calling a function that was returning true or false. True if the page needed to be refreshed, false otherwise. Then if you have an update, you do another call to get the actual update. This way you don't have to refresh everything every time... but it's still intense on the server if you have a lot of users.
In other words and like chaos said, it's polling the server.