Struct VersionCodec

pub struct VersionCodec;

Codec for detecting MQTT protocol version from initial handshake

This codec is specifically designed to handle the initial CONNECT packet and determine the protocol version before switching to version-specific codecs

Trait Implementations

impl Debug for VersionCodec

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Decoder for VersionCodec

fn decode( &mut self, src: &mut BytesMut, ) -> Result<Option<Self::Item>, Self::Error>

Decodes the protocol version from the initial CONNECT packet

Process

1. Checks for minimum packet length
2. Verifies CONNECT packet type
3. Reads variable length header
4. Validates protocol name (MQTT/MQIsdp)
5. Extracts protocol level byte

type Item = ProtocolVersion

The type of decoded frames.

type Error = DecodeError

The type of unrecoverable frame decoding errors.

fn decode_eof( &mut self, buf: &mut BytesMut, ) -> Result<Option<Self::Item>, Self::Error>

A default method available to be called when there are no more bytes available to be read from the underlying I/O.

fn framed<T>(self, io: T) -> Framed<T, Self>

where T: AsyncRead + AsyncWrite, Self: Sized,

Provides a Stream and Sink interface for reading and writing to this Io object, using Decode and Encode to read and write the raw data.

impl Encoder<ProtocolVersion> for VersionCodec

fn encode( &mut self, _: ProtocolVersion, _: &mut BytesMut, ) -> Result<(), Self::Error>

Encoding not supported for version detection codec

This codec is only used for initial protocol detection, actual packet encoding should be handled by version-specific codecs

type Error = EncodeError

The type of encoding errors.