decodeHeader

Parses an 8-byte Qubic TCP frame header into its size, message type, and dejavu fields.

Signature

decodeHeader(bytes: Uint8Array): DecodedHeader

Purpose

Parses an 8-byte frame header. Use this when implementing custom TCP message flows that need to inspect incoming frame metadata before reading the payload.

import { decodeHeader } from "@qubic.org/tcp"

const { size, messageType, dejavu } = decodeHeader(headerBytes)

Parameters

Name	Type	Description
`bytes`	`Uint8Array`	Exactly 8 bytes — the raw frame header

Returns

DecodedHeader — { size: number, messageType: number, dejavu: number }

`DecodedHeader` type

interface DecodedHeader {
  size: number         // total message length (header + payload)
  messageType: number  // message type constant
  dejavu: number       // 32-bit nonce echoed from the request
}

Constants

import { HEADER_SIZE, DEFAULT_PORT } from "@qubic.org/tcp"

HEADER_SIZE   // 8  — byte length of every TCP frame header
DEFAULT_PORT  // 21841

HEADER_SIZE is useful when computing the payload length from a decoded header: payloadLength = header.size - HEADER_SIZE.