How to define mySigner for umi's .use(signerIdentity(mySigner));

Question

I'm creating a n umi instance and can't find info on how to define the mySigner const to use in creating the instance. Here's what I got.

import { createUmi } from "@metaplex-foundation/umi-bundle-defaults";
import { mplCandyMachine } from "@metaplex-foundation/mpl-candy-machine";
import { publicKey, signerIdentity, KeypairSigner } from "@metaplex-foundation/umi";

const mySigner = ???;
// Use the RPC endpoint of your choice.
export const umi = createUmi(endpoint)
.use(signerIdentity(mySigner))
.use(mplCandyMachine());

thank you, in advanced. 

Answer 1

It depends on what you want to use. There are different options:

This results in a newly generated keypair:

const mySigner = generateSigner(umi);
umi.use(keypairIdentity(myKeypairSigner))

you can also import a keypair like this:

const myKeypair = umi.eddsa.createKeypairFromSecretKey(mySecretKey);
const myKeypairSigner = createSignerFromKeypair(umi, myKeypair);
umi.use(keypairIdentity(myKeypairSigner));

If you want to use a wallet (like phantom, backback, Solflare) you should use the normal wallet adapter:

import { walletAdapterIdentity } from "@metaplex-foundation/umi-signer-wallet-adapters";
import { useWallet } from "@solana/wallet-adapter-react";
const wallet = useWallet();
umi.use(walletAdapterIdentity(wallet))

while this creates a dummy Signer based on a public key. (Attention: it can not actually sign but is only a helper

const mySigner = createNoopSigner(myPublicKey);

You can find more info on the signer topic in the umi readme.