@paystring/utils

A TypeScript library providing PayString utility functions.

Usage

This library was designed to solve various pain points when implementing a PayString client or server.

import * as utils from '@paystring/utils'

const payString = 'alice$example.com'

const payStringUrl = utils.convertPayStringToUrl(payString)

console.log(payStringUrl) // Logs 'example.com/alice'

parsePayString()

Given an arbitrary input, return a string typed as a PayString if it is a valid PayString, and throw an error otherwise.

parsePayStringUrl()

Given an arbitrary input, return a Node.js URL objet typed as a PayStringUrl if it is a valid PayString URL, and throw an error otherwise.

convertPayStringToUrl()

Given an arbitrary string, return a PayString URL if the string was a valid PayString, and throw an error otherwise.

convertUrlToPayString()

Given an arbitrary Node.js URL object or a string, return a PayString if the input was a valid PayString URL, and throw an error otherwise.

splitPayString()

Given an arbitrary string, return the tuple of [user, host] of the PayString string.

const payString = 'alice$example.com'

splitPayString(payString)
// Returns ['alice', 'example.com']

V.PayString

The V.PayString RFC defines a method for signing and verifying PayString address mappings using cryptographic keys. The utils library provides several functions related to V.PayString.

generateNewKey()

Generates a new elliptic curve key in JWK format.

sign(key, address, signingParameters)

Signs an address mapping using the provided key and signing parameters and returns a verified address object in JWS format.

verify(paymentInfo)

Verifies the signatures on verifiedAddresses in the provided `paymentInfo' object. Returns true if signatures are valid, false if any are invalid.

verifySignedAddress(payString, verifiedAddress)

Verifies that the signature on a specific verifiedAddress matches its PayString and embedded public key.

getJwkFromRecipient(signer)

Gets the public JWK from a JWS recipient/signer on a verified address.

V.PayString Example

The following shows a complete example of using the utils library to generate a key, sign an address mapping and construct a payment info object containing the verified/signed address, and lastly verifying the signature of a signed PayString address.

import * as utils from '@paystring/utils'

const payString = 'alice$payString.example'
const address = {
  environment: 'TESTNET',
  paymentNetwork: 'XRPL',
  addressDetailsType: {
    address: 'rP3t3JStqWPYd8H88WfBYh3v84qqYzbHQ6',
  },
}

// create a signing key
const key = await utils.generateNewKey()

const signingParameters = new utils.IdentityKeySigningParams(
  key,
  utils.getDefaultAlgorithm(key),
)

// generate a signed/verified address using the signing key
const verifiedAddress = utils.sign(payString, address, signingParameters)

// build a PaymentInfo containing a verified address
const paymentInfo = {
  payString,
  verifiedAddresses: [verifiedAddress],
}

// pretty print the JSON representation.
// this is what the PayString server should return for PayString lookups.
console.log(JSON.stringify(paymentInfo, null, 2))

// verify signatures on all the verifiedAddresses in a PaymentInfo object.
utils.verifyPayString(paymentInfo)

// verify a specific verifiedAddress
utils.verifySignedAddress(payString, paymentInfo.verifiedAddresses[0])

// inspect the PaymentInfo for detail information on signatures
const inspector = new utils.PaymentInformationInspector()
inspector.inspect(paymentInfo)

// extract the public key for the first signature of the first verified address
utils.getJwkFromRecipient(paymentInfo.verifiedAddresses[0].signatures[0])

Legal

By using, reproducing, or distributing this code, you agree to the terms and conditions for use (including the Limitation of Liability) in the Apache License 2.0. If you do not agree, you may not use, reproduce, or distribute the code. This code is not authorised for download in Australia. Any persons located in Australia are expressly prohibited from downloading, using, reproducing or distributing the code.