Crate mssql_codec 

mssql-codec

Async framing layer for TDS packet handling.

This crate transforms raw byte streams into high-level TDS packets, handling packet reassembly across TCP segment boundaries and packet continuation for large messages.

Features

• Packet reassembly across TCP segments
• Message reassembly from multiple packets
• IO splitting for cancellation safety (ADR-005)
• Integration with tokio-util’s codec framework

Architecture

The codec layer sits between raw TCP streams and the higher-level client:

TCP Stream → TdsCodec (packet framing) → MessageAssembler → Client

Cancellation Safety

Per ADR-005, the connection splits the TCP stream into read and write halves. This allows sending Attention packets for query cancellation even while blocked reading a large result set.

use mssql_codec::Connection;

let conn = Connection::new(tcp_stream);
let cancel = conn.cancel_handle();

// Cancel from another task
tokio::spawn(async move {
    cancel.cancel().await?;
});

Re-exports

pub use connection::CancelHandle;

pub use connection::Connection;

pub use error::CodecError;

pub use framed::PacketReader;

pub use framed::PacketStream;

pub use framed::PacketWriter;

pub use message::Message;

pub use message::MessageAssembler;

pub use packet_codec::Packet;

pub use packet_codec::TdsCodec;

Modules

connection

Split I/O connection for cancellation safety.

error

Codec error types.

framed

Framed packet stream for async I/O.

message

TDS message reassembly.

packet_codec

TDS packet codec implementation.