rlp.cr

a native library implementing rlp purely for the crystal language. rlp is ethereum's recursive length prefix used to encode arbitray data structures.

this library allows for rlp-encoding of:

• binary data (assumed encoded)
• boolean values (true, false)
• scalars (positive integers)
• string literals and characters
• arrays containing any of the the above
• nested arrays containing any of the above

installation

add the rlp library to your shard.yml

dependencies:
  rlp:
    github: q9f/rlp.cr
    version: "~> 0.1"

usage

# import rlp
require "rlp"

this library exposes the following modules (in logical order):

• Rlp: core library exposing encode and decode logic
• Rlp::Util: a collection of utilities to ease the conversion between data types

this library is work in progress.

basic usage:

rlp = Rlp.encode("A cat with a short string.")
=> Bytes[154, 65, 32, 99, 97, 116, 32, 119, 105, 116, 104, 32, 97, 32, 115, 104, 111, 114, 116, 32, 115, 116, 114, 105, 110, 103, 46]

pp Rlp::Util.bin_to_hex rlp
=> "9a4120636174207769746820612073686f727420737472696e672e"

documentation

generate a local copy with:

crystal docs

testing

the library is entirely specified through tests in ./spec; run:

crystal spec --verbose

contribute

create a pull request, and make sure tests and linter passes.

this library with built with the help of the blog post by the mana team implementing rlp in elixir and coinmonks' annotated version of the rlp specification. ethereum classic's rlp article allows for some sweet test cases.

license: apache license v2.0

contributors: @q9f