import createAsyncMiddleware from 'json-rpc-engine/src/createAsyncMiddleware' import { ethErrors } from 'eth-json-rpc-errors' /** * Create middleware for handling certain methods and preprocessing permissions requests. */ export default function createMethodMiddleware ({ addDomainMetadata, getAccounts, getUnlockPromise, hasPermission, requestAccountsPermission, }) { let isProcessingRequestAccounts = false return createAsyncMiddleware(async (req, res, next) => { switch (req.method) { // Intercepting eth_accounts requests for backwards compatibility: // The getAccounts call below wraps the rpc-cap middleware, and returns // an empty array in case of errors (such as 4100:unauthorized) case 'eth_accounts': res.result = await getAccounts() return case 'eth_requestAccounts': if (isProcessingRequestAccounts) { res.error = ethErrors.rpc.resourceUnavailable( 'Already processing eth_requestAccounts. Please wait.' ) return } if (hasPermission('eth_accounts')) { isProcessingRequestAccounts = true await getUnlockPromise() isProcessingRequestAccounts = false } // first, just try to get accounts let accounts = await getAccounts() if (accounts.length > 0) { res.result = accounts return } // if no accounts, request the accounts permission try { await requestAccountsPermission() } catch (err) { res.error = err return } // get the accounts again accounts = await getAccounts() /* istanbul ignore else: too hard to induce, see below comment */ if (accounts.length > 0) { res.result = accounts } else { // this should never happen, because it should be caught in the // above catch clause res.error = ethErrors.rpc.internal( 'Accounts unexpectedly unavailable. Please report this bug.' ) } return // custom method for getting metadata from the requesting domain, // sent automatically by the inpage provider when it's initialized case 'wallet_sendDomainMetadata': if (typeof req.domainMetadata?.name === 'string') { addDomainMetadata(req.origin, req.domainMetadata) } res.result = true return default: break } next() }) }