Best way to make user sign N number of transactions

Question

In a dApp, I want the users to be able to do N number of transactions.

Those N transactions will be batched in a batchAll call. If N exceeds the maximum benchmarked amount of transactions in one batch, let's say x, it will create multiple batchAll transactions for the user to sign.

I would like to know what's the correct way, if there is one, for the user to sign 1 transaction on the UI instead of N divided by x.

Answer 1

If your batch call must be split over multiple extrinsics, there is really not a way to avoid the user having to sign multiple calls unless you have the private key, and do a non-interactive message signing.

You can imagine that if a developer could force a user to sign multiple extrinsics at once, that would be really easy to attack the user.

I would suggest, as a part of your user experience, you notify the user how many transactions you are expecting them to sign before you start prompting them for signatures, and that could at least make them aware of what is happening.

Otherwise, you probably can create a local application which does this, but again, you would need to give direct access to the private key to do a non-interactive signing process.

Answer 2

You already have the solution: just sign the batchAll call.