Getting Started

Installation

Add the gem to your project:

$ bundle add protocol-hpack

Or install it yourself as:

$ gem install protocol-hpack

Core Concepts

The protocol-hpack gem provides a class Protocol::HPACK::Compressor and class Protocol::HPACK::Decompressor for HTTP 2 headers, HPACK, as defined by RFC7541.

HPACK is a compression format designed specifically for HTTP/2 to reduce header size and improve performance by minimizing overhead. It addresses the redundancy and repetitive nature of HTTP/1.x headers by employing a static table of common header fields and a dynamic table that evolves based on the headers seen in a particular connection. Headers are encoded into a more compact format, using Huffman coding for literal values and indexing to refer to previously transmitted headers. This approach significantly reduces the amount of data transmitted between client and server, especially in contexts where headers are similar or identical across multiple requests and responses. HPACK's design directly tackles the inefficiencies of HTTP/1.x headers, providing a more bandwidth-efficient and faster web experience by optimizing the way headers are transmitted in HTTP/2 connections.

Compressing Headers

require 'protocol/hpack'

buffer = String.new.b
compressor = Protocol::HPACK::Compressor.new(buffer)

compressor.encode([['content-length', '5']])
=> "\\\x015"

Decompressing Headers

Reusing buffer from above:

require 'protocol/hpack'

# Buffer from above...
buffer = "\\\x015"
decompressor = Protocol::HPACK::Decompressor.new(buffer)

decompressor.decode
=> [["content-length", "5"]]