Zane-HTTPParser

A minimal, safe, hand-written HTTP protocol family library for C++23. Supports HTTP/1.1, HTTP/2, and HTTP/3 framing.

Why not llhttp?

llhttp is generated by llparse through a multi-stage pipeline (llparse → TypeScript → C). This layered code generation makes the final C code hard to audit, debug, and maintain. Security guarantees are difficult to verify when the source of truth is buried behind two intermediate representations.

Zane-HTTPParser is written by hand in plain C++. Every byte of the parser is explicit, auditable, and free of generated machinery.

Features

HTTP/1.1 (http_parser.hpp)

• State-machine design: clear, predictable parsing phases (method → URL → headers → body)
• Bounds-checked: all reads verify against the input buffer length
• Content-Length support: body collected when Content-Length header is present
• Case-insensitive header normalization: field names stored in lowercase
• Zero external dependencies: only the C++23 standard library

HTTP/2 (http2.hpp)

• Binary frame layer: frame header (9-byte) parsing and construction for all frame types
• HPACK: full Huffman-coded header compression (RFC 7541), static + dynamic table
• Connection management: preface exchange, stream tracking, SETTINGS negotiation
• Build helpers: buildSettings, buildGoaway, buildResponse (HEADERS + DATA)

HTTP/3 (http3.hpp)

• QUIC varint encoding: variable-length integer encode/decode (RFC 9000)
• HTTP/3 frame layer: frame type and length decoding, payload extraction
• QPACK: header compression adapted for QUIC (RFC 9204), encoder/decoder streams
• Connection management: control stream, SETTINGS, GOAWAY, stream type detection
• QUIC transport abstraction: QUICTransport interface for attaching any QUIC backend

API

HTTP/1.1 — zane::http

zane::http::Request

Field	Type	Description
m_method	std::string	HTTP method (GET, POST, …)
m_url	std::string	Raw request target
m_pathname	std::string	URL path before ?
m_headers	std::map<std::string, std::string>	Lowercased header fields
m_body	std::vector<uint8_t>	Request body bytes

zane::http::Parser

Method	Returns	Description
execute(data, len)	int32_t	Feed raw bytes. Returns 0 on success, non-zero on error
isComplete()	bool	True when a full request has been parsed
hasError()	bool	True when a parse error occurred
errorMessage()	const std::string&	Human-readable error description
result()	const Request&	Parsed request (valid only when isComplete())
reset()	void	Re-initialize for a new request

zane::http::buildResponse()

std::string buildResponse(int32_t status, const std::string& status_text,
                          const std::map<std::string, std::string>& headers,
                          const uint8_t* body, size_t body_len);

Builds a raw HTTP/1.1 response string. Auto-adds Content-Length if neither it nor Transfer-Encoding is present.

HTTP/2 — zane::http2

Frame Types (zane::http2::FrameType)

DATA, HEADERS, PRIORITY, RST_STREAM, SETTINGS, PUSH_PROMISE, PING, GOAWAY, WINDOW_UPDATE, CONTINUATION

zane::http2::Connection

Method	Returns	Description
feed(data, size, on_frame, on_error)	int32_t	Feed raw bytes, process preface + frames
buildSettings(settings_map)	vector<uint8_t>	Build a SETTINGS frame
buildGoaway(last_stream_id, error)	vector<uint8_t>	Build a GOAWAY frame
buildResponse(stream_id, headers, body, end_stream)	vector<uint8_t>	Build HEADERS + DATA frames
reset()	void	Reset to initial state
prefaceReceived()	bool	True after client preface is received
clientPreface()	const uint8_t*	Client connection preface bytes
clientPrefaceLen()	size_t	Length of client preface

zane::http2::HPACK

Method	Returns	Description
encode(headers)	vector<uint8_t>	Encode headers into HPACK binary
decode(data, size, out)	int32_t	Decode HPACK binary into header pairs
setMaxTableSize(size)	void	Update dynamic table capacity from SETTINGS
maxTableSize()	uint32_t	Current max table size
reset()	void	Clear dynamic table

HTTP/3 — zane::http3

Frame Types (zane::http3::FrameType)

DATA, HEADERS, CANCEL_PUSH, SETTINGS, PUSH_PROMISE, GOAWAY, MAX_PUSH_ID, DUPLICATE_PUSH

zane::http3::Connection

Method	Returns	Description
init()	void	Initialize, send SETTINGS on control stream
feedStream(stream_id, data, size, fin, on_frame, on_error)	int32_t	Feed data on a QUIC stream
buildResponse(stream_id, headers, body, fin)	vector<uint8_t>	Build HEADERS + DATA for a stream
buildSettings(settings_map)	vector<uint8_t>	Build a SETTINGS frame
buildGoaway(last_stream_id)	vector<uint8_t>	Build a GOAWAY frame
reset()	void	Reset to initial state
initialized()	bool	True after init() completes

zane::http3::QPACK

Method	Returns	Description
encode(headers)	vector<uint8_t>	Encode headers into QPACK binary
decode(data, size, out)	int32_t	Decode QPACK binary into header pairs
feedEncoderStream(data, size)	int32_t	Process encoder stream instructions
buildDecoderStream(increment)	vector<uint8_t>	Generate decoder stream instruction
setMaxTableCapacity(cap)	void	Set max table capacity from SETTINGS
reset()	void	Clear dynamic table

zane::http3::QUICTransport (abstract)

Method	Description
sendStreamData(stream_id, data, size, fin)	Send data on a given stream
sendControlData(data, size)	Send data on the control stream
closeWithError(error_code, reason)	Close connection with error
isConnected()	Returns true if still active

File Structure

File	Protocol
http_parser.hpp/.cpp	HTTP/1.1 request parser
http2.hpp/.cpp	HTTP/2 framing, HPACK, connection
http3.hpp/.cpp	HTTP/3 framing, QPACK, connection

License

Same as Zane.

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Doug McIlroy: Make each program do one thing well. To do a new job, build afresh rather than complicate old programs by adding new "features".
We extracted this library for exactly that reason.