chat-application | chat application for android | Chat library

I'm trying to make a real-time socket.io app in Angular and Node, exactly like what is explained here. I set up the server and the client connection, but the connection is never made.

Server Code:

I am beginner and trying to build a simple chat application with socket.io but when I am connecting socket.io-client with the backend it is reproducing the above mentioned error. I am unable to understand the meaning of the above error so please help me debug my code and understand the meaning and cause of error.

I have a react application and I would like to setup a websocket connection to my backend for some realtime updates. I was going to deploy an EC2 or ECS-cluster to host websocket connections. Then I stumbled into some articles showing how websocket connection can be setup in a serverless manner.

One example: https://medium.com/@likhita507/real-time-chat-application-using-webscockets-in-apigateway-e3ed759c4740

However, I can't seem to figure out how this works for a few reasons.

• Lambda has a max runtime of 15 min
• How does the backend establish a connection when no lambda is running and the backend wants to invoke a message to the frontend

Does this entail that I have to keep a lambda alive all the time, if so, it no longer feels like a good idea. In the above example, what I can't grasp is that when creating that chat application, can each chat room only exist for 15 min? And if a user disconnects from the room, how will that user be updated on new messages.

Does anyone have any experience with this kind of solution?

I'm currently writing a chat-application for my Website and storing all the Messages in one database, by referring to sender and receiver with a Foreign-key. Is this really the smartest Idea? I think the site could become slow when everybody is trying to access the same database or when the number of sent messages gets big. Would it be smarter/faster, to use one database per user, storing his/her messages there? If yes, am i right that this is not really possible to achieve this with Django?

Thanks for your Answer!

I have started to study SSE and I found an example with php chat application (http://www.developphp.com/video/JavaScript/Server-Sent-Events-Simple-Chat-Application-Example). The video shows that the messages are not delayed. But when I tried the example on my own server (WAMP) I have a very long delay to the point that it is no longer a real-time application as it claims. I found that if I changed the retry:15000 to a value much much smaller (for example 100 millisecond) only then getting near real-time. But this is not good. This is polling and not truly real-time application. It seems that after each message the connection to the server is lost and resets accordingly to retry. It doesn't seem like a very smart application because we have not avoided constant requests from client to server like plain Ajax polling. Thanks

I have seen this question, but it asks if it is okay to use http only and avoid websockets completely when building a chat app.

My situation is:

I have a simple chat app I am building. When sending a new message I am using an Http Post request(I am using Angular) to send the data to the server where it is persisted in the database, then is broadcasted via sockets to the appropriate clients. Are there any advantage or disadvantages of doing it like this? Instead of just using web sockets throughout?

According to this answer you should avoid using sockets where possible.

I'm building a multiple chatbox messaging like Facebook's popup messenger windows. At the moment, the user can call up a chatbox, close it, minimize it, etc.

When I click on multiple users, say 3, I'm supposed to have three chatboxes pop up corresponding to those three different users. Currently, only one chatbox appears.

This screenshot illustrates what I want to achieve. On each user's button click, it's own chatbox will popup.

Here is the demo and download link for a jQuery equivalent: link.

This is the full React code which shows just one chat box:

I've tried this tutorial on how to set up a localhost, and some code worked, some didn't. But currently I am receiving strange experience with it:

Below in the code at res.sendfile it's important to mention that the terminal comments this command as deprecated.

Using res.sendFile gives however the following error.

I've tried to use .sendFile with the absolute path, but it didn't work:

In this firestore official guide , it says that

Local writes in your app will invoke snapshot listeners immediately. This is because of an important feature called "latency compensation." When you perform a write, your listeners will be notified with the new data before the data is sent to the backend

1. So Firestore client (that posted this data) will not fetch this data via listeners from server ?
2. Will this still be charged as a Read Op (in case data is not fetched from server) ?
3. Is this concept true for Realtime Database as well ?

I tested it with a client writing new object to /chats/chatRoomId/ and same client having listeners for child_added on /chats/chatRoomId/. I turned off the internet, still the pushing new data was reported OK (due to offline ability i guess), and listeners also reported receiving new data (even without server access)

I want to structure my chat app's DB, such that i can cut cost on unnecessary reads (if there are any) in chat DB structure given here and here recommended by @FrankVanPuffelen from Firebase.

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