MetaMask does not show signature request if open when 'eth_signTypedData' request is sent

[alex-ppg]

This is quite a crucial issue with user interaction as we cannot reasonably expect a user, after unlocking his account, to close and re-open the MetaMask plugin screen.

• Expected Behavior: Whilst the MetaMask plugin screen is open, either the page itself transitions to the signature request or the signature request pop-up shows.
• Actual Behavior: If MetaMask is open when the request is sent, the request does not show unless I close and re-open the MetaMask screen.
• Browser Used: Google Chrome although I believe this is irrelevant.
• Operating System Used: Windows 10 but likewise irrelevant.

Code Example (Ensure your account is locked):

const msgParams = [
    {
        type: 'string',
        name: 'Authorization Request',
        value: 'test'
    }
];
if (typeof window.web3 !== 'undefined' && typeof window.web3.currentProvider !== 'undefined') {
    let localWeb3 = new Web3(window.web3.currentProvider);
    window.web3.eth.getAccounts((err, accounts) => {
        if (!accounts[0]) {
            watchAccountUnlock();
        } else {
            localWeb3.eth.defaultAccount = accounts[0];
            requestSignature();
        }
    });
}

function watchAccountUnlock() {
    const toClear = setInterval(() => {
       window.web3.eth.getAccounts((err, accounts) => {
            if (accounts[0] !== localWeb3.eth.defaultAccount) {
                localWeb3.eth.defaultAccount = accounts[0];
                requestSignature();
                clearInterval(toClear);
            }
        });
    },500);
}

function requestSignature() {
    localWeb3.currentProvider.sendAsync({
      method: 'eth_signTypedData',
      params: [msgParams, localWeb3.eth.defaultAccount],
      from: localWeb3.eth.defaultAccount,
    }, (err, result) => {
      if (err) return console.error(err)
      if (result.error) {
        // User denied signature
      }
      const signature = result.result;
      alert(signature);
    });
}

[bdresser]

@alex-ppg a simple workaround might be to have the user click a UI element to prompt the signing request, rather than trying to fire it automatically on login.

curious what your usecase is – if you're trying to create a sort of log-in behavior, make sure you've checked out this web3 opt-in feature that we'll be rolling out shortly.

@danfinlay @bitpshr any other thoughts?

[alex-ppg]

@bdresser While what I am trying to do is create a sort of log-in behavior, it doesn't exactly work in the same way most DApps do.

We are creating a multi-currency front-end wallet that derives the various keys from a seed and in order to support MetaMask, we want the user to sign a randomly generated (once) and server-side stored string, using the resulting signature as the seed for the various currencies.

We are going to allow the user to use their Ethereum based wallet directly via MetaMask obviously but we need the signature for the rest of the currencies.

[danfinlay]

This does sound like a bug that we should fix.

Please be aware @alex-ppg that our current signTypedData implementation is not the final one, and we may need to break the current method definition (or add a new method name for the actual spec version) soon: #4803

[bdresser]

@bitpshr might have to do with the logic around the popup ID #4592

[joenhon]

Excuse me, how do you call MetaMask, is it convenient to call the code to give me a copy?

[alex-ppg]

Hey @joenhon, sorry for the late response I've been abroad. I recreated the problem in the following Gist: https://gist.github.com/alex-ppg/86ddf1bd997e016aef95f46b8497d7b7

I am developing the application using Angular but the problem seems to be related to the MetaMask plugin API rather than any of the technology stacks as showcased by the Gist which is a simple HTML webpage.

I have also tried delaying the signature request for a while but the issue is that the MetaMask pop-up is kept open after unlocking. If I close the MetaMask plugin page before the signature request occurs, the pop-up will show just fine.