Real Time Chat Application Project.(BACKEND)

Tech Stack used: Node.js, MongoDB, html, css , js.

Steps to start the application:

• Installing nessasary dependancies : npm install
• This Applications runs on 2 servers: 1. authentication server. 2. DataManagement server.
• Both the server connects to Database.

1. authentication server maintains authentication and authorization to access different content using jwt tokens.
2. Starting the server : npm run devStart2
3. server started on port 4000.
4. Connection to MongoDB: used mongoose to connect with mongodb.
5. Api's in authServer server:
   • /users - signup page for entering details to email and password and these stored in mongodb database Mongodb schema designed in model/user.js. api request : https://localhost:4000/users body : { gmail : "ram@gmail.com" , password : "user123"} -password will convert to hashed password. using bcrypt.
   • /users/login - login page authenticating user creating jwt token.
   • jwt contains header, payload , secret key : userid , name, access-token-key.
   • response from this route will provide us jwt token. api request: https://localhost:4000/users/login body { gmail : "ram@gmail.com", password: "user123"} This will authenticate user from database. If user signup data present in data base it will generate a jwt token. jwt token will be stored in client side.
   • You can user AuthencateToken middleware to authenticate before redirecting to access any data.
6. Another Server is running on port 3000:
7. run server 2: npm run devStart
   • To know better understanding for user and messages interaction run index.html after ran above command.
   • Now add another user to server opening index.html on another tab and start sending messages.
   • This server handles messages between users: Tech used : socket.io, MongoDB connection
   • Implemented socket functionalities : 4 scenarios :
     • New-user connected to server :this message will broadcast to other users.
     • Sending chat message : message entered by user will broadcast to other users connected on the server.(name and message).
     • When user disconnected from server : message ("user disconnected") will broadcasted to other users.
     • if user set status busy : open ai api will assist the user with messages.
   • Message will be stored into database in form of json format.
   • { "socketID" : { username : name , socketID : socket.id }
   • MongoDB schema is designed in /models/content.js. 8. Integrated OpenAI apis in aimodel.js : javascript function - generateChatCompletion() for the required query.