Websocket and TCP - tcp

Question

According to my knowledge, Websocket is a message-based protocol and using TCP as the transport layer. But TCP itself is a stream-based protocol. Can someone explain
how websocket message in segmented in TCP?
what is framing in Websocket?
what's advantage of using message in Websocket? I saw from here asking that Why are WebSockets frame-based and not stream-based?
Correct me if I have any misconception.

Answer 1

To send a specific data format like a webSocket frame over TCP, you just have to define the data format so that the reader of the stream knows where the frame starts and ends based on the format. One typical way is to send a set of data that includes a fixed size (known in advance) header format that includes a length of the total frame and then you send the rest of the frame that is that length. The reader can then read the initial fixed size data, read the length out of that and then know how much more to read to get the whole frame.
what is framing in Websocket?
You can read about the whole webSocket frame here and here's a look at how a webSocket frame is structured.
Frame format:
​​
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-------+-+-------------+-------------------------------+
|F|R|R|R| opcode|M| Payload len | Extended payload length |
|I|S|S|S| (4) |A| (7) | (16/64) |
|N|V|V|V| |S| | (if payload len==126/127) |
| |1|2|3| |K| | |
+-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - +
| Extended payload length continued, if payload len == 127 |
+ - - - - - - - - - - - - - - - +-------------------------------+
| |Masking-key, if MASK set to 1 |
+-------------------------------+-------------------------------+
| Masking-key (continued) | Payload Data |
+-------------------------------- - - - - - - - - - - - - - - - +
: Payload Data continued ... :
+ - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
| Payload Data continued ... |
+---------------------------------------------------------------+
what's advantage of using message in Websocket?
It's unclear what you're asking with this. Reasons for using a webSocket connection include the following:
The ability to "push" data from server to the client at any time.
Very low overhead way to send data from either client to server or server to client at any time (much lower overhead for repeated packets than an http request).
Ability to have a persistent connection over which you can do many things without having to conform everything to the http request/response format.