How to identify each user on the web app?

To identify each user in a simple web chat application, we can implement a user identification system that associates every message with its sender. First, each user should have a unique identifier (User ID) and a username. These can be assigned when the user registers, logs in, or joins the chat. Second, every message should include relevant information such as:

• User ID: Identifies the sender uniquely.
• Username: Displays the sender's name.
• Message: Contains the text sent by the user.
• Timestamp: Records when the message was sent.

For example:

const message = {
    userId: "user_123",
    username: "Vangelis",
    text: "Hello Migue!",
    timestamp: new Date().toISOString()
};

Third, the application should transmit this information to the server, which associates the message with the correct user. The server can then distribute the message to other connected users.

Finally, JavaScript can dynamically update the web page to display messages in the following format:

Vangelis (10:30 AM): Hello Migue!

Migue (10:31 AM): Hi Vange!

For security, the server should verify each user's identity instead of trusting usernames submitted directly by the browser. This helps prevent users from impersonating others.

This approach can be implemented using different technologies, including JavaScript, Python, PHP (although recently discovered security vulnerabilities could be an issue), Node.js, or Firebase, depending on the application's architecture.

The main principle is to associate every message with a unique and verified user identity, allowing everyone in the chat to know who sent each message.

References:

1. Mozilla Developer Network. WebSocket: message event.
   https://developer.mozilla.org/en-US/docs/Web/API/WebSocket/message_event

2. OWASP Foundation. Session Management Cheat Sheet.
   https://cheatsheetseries.owasp.org/cheatsheets/Session_Management_Cheat_Sheet.html