Explain the concept of web sockets and how they can be used to create real-time applications.

You: WebSockets are a communication protocol that provides full-duplex communication channels over a single TCP connection. Unlike HTTP, which follows a request-response model (where the client initiates a request and the server responds), WebSockets enable persistent, bidirectional communication between a client and a server. This makes WebSockets ideal for real-time applications where low latency and continuous data exchange are required.

Key Concepts:

1. Persistent Connection:

- WebSockets establish a persistent connection between the client and the server, which remains open for as long as needed.
- This eliminates the overhead of repeatedly establishing and tearing down connections for each message, as is the case with HTTP.

2. Full-Duplex Communication:

- WebSockets support full-duplex communication, meaning that both the client and the server can send data to each other simultaneously.
- This allows for real-time updates and interactions without the need for constant polling or long polling.

3. Low Latency:

- WebSockets have low latency due to the persistent connection and bidirectional communication.
- This makes them well-suited for applications where real-time updates are critical.

4. Protocol Upgrade:

- WebSockets use an HTTP upgrade mechanism to establish the WebSocket connection.
- The client sends an HTTP request with an `Upgrade` header, requesting the server to switch to the WebSocket protocol.
- If the server supports WebSockets, it responds with a 101 Switching Protocols response, indicating that the connection has been upgraded.

5. Frames:

- Once the WebSocket connection is established, data is transmitted in frames.
- Frames can contain text or binary data.

How WebSockets Work:

1. WebSocket Handshake:

- The client initiates the WebSocket connection by sending an HTTP request with the following headers:
```
GET /chat HTTP/1.1
Host: example.com
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
Sec-WebSocket-Version: 13
```
- The server responds with a 101 Switching Protocols response:
```
HTTP/1.1 101 Switching Protocols
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Accept: s3pPLMBiHLiPS6ee