detect

Documentation

Overview

Package detect provides HTTP protocol detection from initial connection bytes.

Index

• Constants
• Variables
• func Detect(buf []byte) (engine.Protocol, error)

Constants

const MinPeekBytes = 4

MinPeekBytes is the minimum number of bytes needed to begin detection.

const PrefaceLen = len(frame.ClientPreface)

PrefaceLen is the full HTTP/2 client connection preface length.

Variables

var (
	// ErrInsufficientData indicates not enough bytes for detection.
	ErrInsufficientData = errors.New("insufficient data for protocol detection")
	// ErrUnknownProtocol indicates the data does not match any known protocol.
	ErrUnknownProtocol = errors.New("unknown protocol")
)

Functions

func Detect

func Detect(buf []byte) (engine.Protocol, error)

Detect examines the initial bytes of a connection and returns the detected protocol.

Detection logic:

1. If len(buf) < 4, return ErrInsufficientData.
2. If first 4 bytes are "PRI ", this may be HTTP/2. Need 24 bytes total. If we have 24 bytes and they match ClientPreface -> engine.H2C If we have < 24 bytes -> ErrInsufficientData (need more data) If 24 bytes don't match -> ErrUnknownProtocol
3. If first byte is a known HTTP method start character -> engine.HTTP1
4. Otherwise -> ErrUnknownProtocol