- Bi-directional communication in Real-time over TCP connection
- Unique connection to reduce latency issues from long-polling
- Both client and server can stream handshake messages independently and simultaneously over TCP
- A web socket handler keeps an open connection with active users
- Server responds with HTTP status
101 Switching protocols
- Header
Sec-web Socket-Accept with a processed string of client-key (given by the client)
- This helps ensure secure/authenticated key
Masking
- Masking helps distinguish web socket data from HTTP requests
- Helps stop caching from proxies
Fragmentation
- Fragmentation helps prevents exceeding of buffer limitations and stops overwhelming connections from large messages
- FIN( Final) bit tells us if the existing frame is the final fragment of the message
- Set to
0 for all but last frames of the message
- Set to ‘1’ for final frame to signal final fragment of message to receiver
HTTP Polling
- Makes it so the client keeps sending, requests
- Server sends a blank response when nothing to report
- Leads to a lot of requests being made
HTTP Long Polling
- A client needs to connect periodically, making long polling more resource-intensive
- Client waits with a hanging GET request to a server and waits until timeout
- If the request times out, the client will send another hanging GET request