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SIWS

SiwsMessage

The SiwsMessage class helps you construct a human-readable message, and provides some useful methods.

// example usage
const siwsMessage = new SiwsMessage({
  nonce,
  domain: "localhost",
  uri: "https://localhost:3000",
  statement: "Welcome to SIWS! Sign in to see how it works.",
  address: address.toSs58(0),
  chainName: "Polkadot",
})

const humanReadableMessage = siwsMessage.prepareMessage()

SiwsMessage Properties

  • domain: RFC 4501 dns authority that is requesting the signing.
  • address: Substrate address signing the message.
  • uri: RFC 3986 URI referring to the resource that is the subject of the signing.
  • nonce: Randomized token used to prevent replay attacks.
  • statement (optional): Human-readable ASCII assertion that the user will sign, and it must not contain \n.
  • chainName (Optional): Will appear as sign in with your {{chainName}} account:
  • chainId (Optional): Identifier for chain-specific applications
  • expirationTime (Optional): Timestamp that indicates when the signed authentication message is no longer valid.
  • issuedAt (Optional): Timestamp of the current time.

SiwsMessage Methods

get asJson

A getter that returns all properties as an object without the methods. This is useful if you need to, for example, store the payload somewhere. Example usage:

const processed = processData(siwsMessage.asJson)

sign(injectedExtension)

Signs the message in one line and returns both the signature and message. Requires the injector that you can obtain with polkadot api.

// import web3FromSource
import { web3FromSource } from "@polkadot/extension-dapp"

// get the injector of your account to create a Signature prompt
const injectedExtension = await web3FromSource(selectedAccount.meta.source)
const { message, signature } = siwsMessage.sign(injectedExtension)

prepareMessage()

Prepares a signable message in human-readable format. This is useful if you want to build your own custom signing logics instead of using the siwsMessage.sign(injector) method.

const message = siwsMessage.prepareMessage()
const signature = injector.signer.signRaw({
  address,
  data: message,
  type: "payload",
})

prepareJson()

Sometimes you may want to show the message that users sign as JSON (e.g. if you building a dev focused application). SiwsMessage comes with a convenient prepareJson() method that prepares the message in a human readable JSON format.

const message = siwsMessage.prepareJson()
const signature = injector.signer.signRaw({
  address,
  data: message,
  type: "payload",
})