Retrieve signer from WalletConnect

[nicolapertosa]

Hello,

I try to make a fund transfer with the SDK and interacting with WalletConnect.
But to submit my transaction to the blockchain, I need to provide the signer.
My question is, how do I get this signer from WalletConnect ?
And I guess the signer is not the signed transaction hash...

const signedTx = ( await api.tx(txHex).signAsync(account, { nonce, **signer** }) ).toHex();

Thank you for your help.

[ipapandinas]

Hello @nicolapertosa,

WalletConnect and browser extensions like Polkadot Extension-dApp operate differently.

Browser extensions inject an account into the web page. You are right, the signer used by these extensions is typically a private key associated with the user's account, rather than a signed transaction hash.

WalletConnect is a protocol, you have to initialize a client instance and trigger a sign-transaction request, here is an example of helper:

const TERNOA_ALPHANET_CHAIN = "ternoa:18bcdb75a0bba577b084878db2dc2546";
// For mainnet => ternoa:6859c81ca95ef624c9dfe4dc6e3381c3

export const signWC = async (tx: string, nonce?: number): Promise<`0x${string}`> => {
  if (typeof client === 'undefined') {
    reset()
    throw new Error('WalletConnect is not initialized')
  }
  if (typeof session === 'undefined') {
    reset()
    throw new Error('Session is not connected')
  }
  if (account === undefined) {
    reset()
    throw new Error('Account is not connected')
  }
  const resPromise = await client.request({
    request: {
      method: 'sign_transaction',
      params: {
        pubKey: account.split(':')[2],
        request: {
          hash: tx,
          nonce: nonce,
          validity: undefined,
          submit: false,
        },
      },
    },
    topic: session.topic,
    chainId: TERNOA_ALPHANET_CHAIN,
  })
  const promises = [resPromise, sleepFunction(() => redirectToAppIfMobile(), 1000)]
  const values = await Promise.all(promises)
  return JSON.parse(values[0] as any).signedTxHash
}

A tutorial covering Wallet Connect full flow is available here: wallet-connect-integration/TUTORIAL.md