rlp

What is rlp?

The 'rlp' npm package is used for encoding and decoding data using the Recursive Length Prefix (RLP) encoding scheme, which is commonly used in Ethereum and other blockchain technologies. RLP is a method to encode arbitrarily nested arrays of binary data, and it is particularly useful for serializing data structures in a compact and efficient manner.

What are rlp's main functionalities?

Encoding Data

This feature allows you to encode an array of data into RLP format. In this example, the array ['cat', 'dog'] is encoded into its RLP representation.

const rlp = require('rlp');
const encoded = rlp.encode(['cat', 'dog']);
console.log(encoded);

Decoding Data

This feature allows you to decode RLP-encoded data back into its original form. In this example, the RLP-encoded buffer is decoded back into the array ['cat', 'dog'].

const rlp = require('rlp');
const encoded = Buffer.from('c88363617483646f67', 'hex');
const decoded = rlp.decode(encoded);
console.log(decoded);

Other packages similar to rlp

ethereumjs-util

The 'ethereumjs-util' package provides a variety of utility functions for Ethereum, including RLP encoding and decoding. It offers a broader range of functionalities compared to 'rlp', such as cryptographic functions, keccak hashing, and more. It is more comprehensive for Ethereum-specific tasks.

rlp-stream

The 'rlp-stream' package is designed for streaming RLP encoding and decoding. It is useful for handling large datasets or continuous streams of data that need to be processed in chunks. This package is more specialized for streaming use cases compared to 'rlp'.

README

rlp

Recursive Length Prefix encoding for Node.js and the browser.

INSTALL

npm install rlp

install with -g if you want to use the CLI.

USAGE

import assert from 'assert'
import RLP from 'rlp'

const nestedList = [[], [[]], [[], [[]]]]
const encoded = RLP.encode(nestedList)
const decoded = RLP.decode(encoded)
assert.deepEqual(nestedList, decoded)

API

RLP.encode(plain) - RLP encodes an Array, Uint8Array or String and returns a Uint8Array.

RLP.decode(encoded, [stream=false]) - Decodes an RLP encoded Uint8Array, Array or String and returns a Uint8Array or NestedUint8Array. If stream is enabled, it will just decode the first rlp sequence in the Uint8Array. By default, it would throw an error if there are more bytes in Uint8Array than used by the rlp sequence.

Buffer compatibility

If you would like to continue using Buffers like in rlp v2, you can use:

import assert from 'assert'
import { arrToBufArr, bufArrToArr } from 'ethereumjs-util'
import RLP from 'rlp'

const bufferList = [Buffer.from('123', 'hex'), Buffer.from('456', 'hex')]
const encoded = RLP.encode(bufArrToArr(bufferList))
const encodedAsBuffer = Buffer.from(encoded)
const decoded = RLP.decode(Uint8Array.from(encodedAsBuffer)) // or RLP.decode(encoded)
const decodedAsBuffers = arrToBufArr(decoded)
assert.deepEqual(bufferList, decodedAsBuffers)

CLI

rlp encode <JSON string>
rlp decode <0x-prefixed hex string>

Examples

• rlp encode '5' -> 0x05
• rlp encode '[5]' -> 0xc105
• rlp encode '["cat", "dog"]' -> 0xc88363617483646f67
• rlp decode 0xc88363617483646f67 -> ["cat","dog"]

TESTS

Tests use mocha.

To run tests and linting: npm test

To auto-fix linting problems run: npm run lint:fix

CODE COVERAGE

Install dev dependencies: npm install

Run coverage: npm run coverage

The results will be at: coverage/lcov-report/index.html

EthereumJS

See our organizational documentation for an introduction to EthereumJS as well as information on current standards and best practices.

If you want to join for work or do improvements on the libraries have a look at our contribution guidelines.