I am developing Social network type of application in node.js and MongoDB.
I want to add a functionality such as -
If user A has followed user B then when user B post something it should automatically come to user A on his wall!
Approach 1- This is what I have research till now
Create a channel of user B and all the other user subscribe to that channel and when user B post something then emit that with socket.io on all the subscribers.
so for this approach, we are thinking to create a channel when the new user signup every time.
But the problem is -
is this feasible approach as for how do I know which channel is which user or is there a way to store the channel in MongoDB.
if I create too many channels will that crash my server?
Approach 2 -
Another Approach that I have got is
Look up the followers of the source user in your database.
And emit feeds to all the followers using socket.io
How to scale this if I have got 100 followers of each user and when everytime user post, will searching in a Database creates an overhead.
Using Redis caching would be better to store followers?
And instead of checking the followers-
find that from Redis and emit the msg using socket.io
Approach 3 -
I have heard the name of Redis pub/sub but not able to find how it will work in my application.
Please suggest some best standards for creating something like this!
And if above approaches are fine can you pls suggest me the flow for that or how do I create a code for that!
I would be great if you provide me an example.
I think you can use Approach 2, but you must create a queue (redis queue or rabbitMQ) to do that.
I mean when you create a post, it must push to queue to push message to 100, 1000 follower in your DB.
Related
currently i'am developing a react app where user can post and comment and like a post.
so i did everything but there is one more thing that i want to do which is getting notification after user
Post or maybe comment and so on..
so let say i have a table called 'posts' in the database (PostgreSQL) and when user called "A" create post ,that post inserted into the database and then i want to receive a notification which Said that the user "A" created a post with the ID of that post and i think the main idea here is to watch the table of posts and whenever a new raw inserted a notification fire.
i searched many sources and find that i can use Pusher ,web-socket but to be honest i can't make a decision without figuring out the best way to achieve that.
So How i can get notified hence a new row inserted into the table "posts" ?
Thank you in advance.
Postgres has LISTEN/NOTIFY that you could use in conjunction with an on-insert trigger on the posts table.
Some process can then be listening for those notifications and figure out whom to send the notification to (via whichever transport you choose).
However, I think you might be better off adding a concrete table for notifications, so the user can see notifications that occurred when they weren't connected to the notification transport.
I'm doing chat app and I want to do it real time. Chat will be for now between two users. When user access to chat it finds all messages between them and displays messages. I think I need to create room with two users and then store room id in database. But I'm new to socket.io and I need advice how to do it.
Try to take some already pretty wide used chat, like Slack, as example. Usually you need pretty same set of things, workplaces, channels, private messages (like room but for two users only), and have users sending text messages with some formatting or images or just any files. Just take it easy, plan and make it step by step.
Also take note, that for both parties have their chat view updated with new messages you need not only save message one user send to db, but also broadcast that message to everyone, involved in conversation.
I am building a buy and sell website that is built on MEAN stack. Im planning to use socket.io. So here's how my website will work
User will register and login
They can post an item either buy/sell
Other users can offer to the post (i'll use socket.io on this so that the user who posted the item will have a notification)
The poster will have an option to view the current offers, then they will choose who'll they accept.
Once they accept the offer, both the Poster and the User who offered will have a communication both of them (Chat room)
So when the poster accepted the offer of the customer, it will open a chat for them to communicate. So here's my question, i will use socket io rooms. Once the poster accepts the offer, both of them will join the room (so i'll generate a room for them and automatically join them) then this room will be saved to the MongoDB, then every message they'll send, it will be saved to the database. So that they can see the history of their message even though they logout.
Is this the best method?
Create a room for both of them (saved to DB)
Saved to database everytime they send a message to each other
Query the database when they login for list of the rooms the user has joined so that they could see the messages they have
That would probably be the best way to do it. Here is a similar question is there a good way to save socket.io message history it shows how to save the message history.
You do not have to save the messages, but if you would like to be able to see messages later, you should save every message to a database. If you do not save every message to a database, when you reload the page all previous messages will disappear.
If you want a free database, mongoLab will host small mongoose databases for free. Here is a good tutorial showing how to use mongoLab, it does not use socket.io, but it will probably be very easy to implement it.
Hope this helps! Feel free to ask any questions below.
I have running on NodeJs/MongoDB and Android/HTML client where people are able to follow posts, I store their ids in an array of followers in the post's document.
I want to implement a notification feature when a new comment comes I want to notify all the followers.
So, I have looked across the web but I couldn't get one tutorial where I understood exactly how things work.
I have seen many recommend the Redis Pub/Sub, but from what I have read Redis is a in-memory database, so I was thinking, I could create a channel in Redis with the post's Id, when the user follows that post I would subscribe him to the channel, then when a new comment comes i just publish to the channel. Is this how it works?? If so, then how about when the user goes off then comes back in later, And how about when there are many posts, won't Redis clear the channel then I wouldn't be able to send the notification to all the followers?
I think I'm understanding it all wrong,I'd appreciate your help. How exactly can I be able to send a notification to all followers?
I'm building a chat application and I'd like to get a list of which of the people I'm following are online and what chat rooms they are in.
According to the pusher docs, the presence channels are per channel and
This is not the same as jabber style “which of my friends are online” presence.
Pusher doesn’t offer anything out of the box for that use case right now.
https://pusher.com/docs/client_api_guide/client_presence_channels
So if I were to create this feature on pusher, should I just create a global channel and have everyone connect to that silently in the background to get a global presence - if so there is a 100 person limit to that so it wouldn't be feasible. Or should I just create a single channel per user and then let users subscribe to a channel per each person they are friends with (though that seems a bit inefficient)? Note that this is a one way people I am following relationship and not a 2-way friend relationship.
As you pointed out Presence channels are more for rooms of up to 100 users.
Note: The thinking behind that is that a room with more than that isn't really a chat session. Hopefully this restriction will change in the future and it will increase the use case for presence channels.
To get a count of the number of the users you follow who are online you'll need to ensure each user is subscribed to a user-specific channel (e.g. myUserId-channel or private-myUserId-channel if auth is required) and then query the Pusher HTTP API and check to see if a user-specific channel is occupied. If it is then that user is subscribed to the channel and thus online. See Querying Application Channels.
For a more detailed description see Using presence for large groups of users.