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'.
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))
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.