The first example of Section 5.7 of Websocket Protocol RFC 6455 reads:
A single-frame unmasked text message
- 0x81 0x05 0x48 0x65 0x6c 0x6c 0x6f (contains "Hello")
What are the first two octets in this example and why are they there?
Looking up the UTF-8 codes for the last five octets I can see how those bytes would translate to Hello
.
The first two octets in this example contain metadata about the data frame and the payload it contains. The last five octets represent the payload or Hello
.
The first two octets 0x81 0x05
are hexadecimal representations of two bytes or 16 bits of data. In binary they translate to: 1000 0001 0000 0101
.
Using the Data Frame Diagram from the RFC you can see what these bits tell us about the data frame. To summarize: