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July 17, 2019 00:21
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Proof-of-Concept - simpler blockchain Handler with no cache
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import { PaywallConfig, Locks, Lock, Transactions } from '../../unlockTypes' | |
import { EventEmitter } from 'events' | |
import linkKeysToLocks from './linkKeysToLocks' | |
import { POLLING_INTERVAL } from '../../constants' | |
type Web3ProviderType = string | Object | |
export interface WalletServiceType extends EventEmitter { | |
ready: boolean | |
connect: (provider: Web3ProviderType) => Promise<void> | |
getAccount: () => Promise<string | false> | |
purchaseKey: ( | |
lock: string, | |
owner: string, | |
keyPrice: string, | |
account: any, | |
data: any, | |
erc20Address: string | null | |
) => Promise<string> | |
} | |
export interface TransactionDefaults { | |
to: string | |
from: string | |
input: string | null | |
[key: string]: any | |
} | |
export interface KeyResult { | |
lock: string | |
owner: string | null | |
expiration: number | |
} | |
export type KeyResults = { [key: string]: KeyResult } | |
export interface Web3ServiceType extends EventEmitter { | |
refreshAccountBalance: (account: string) => Promise<string> | |
getTransaction: ( | |
transactionHash: string, | |
defaults?: TransactionDefaults | |
) => void | |
getLock: (address: string) => Promise<Lock> | |
getKeyByLockForOwner: (lock: string, owner: string) => Promise<KeyResult> | |
} | |
export type unlockNetworks = 1 | 4 | 1984 | |
export interface ConstantsType { | |
unlockAddress: string | |
blockTime: number | |
requiredConfirmations: number | |
locksmithHost: string | |
readOnlyProvider: string | |
defaultNetwork: unlockNetworks | |
} | |
export interface BlockchainData { | |
locks: Locks | |
account: string | null | |
balance: string | |
network: unlockNetworks | |
} | |
interface LocksmithTransactionsResult { | |
transactionHash: string | |
chain: unlockNetworks | |
recipient: string | |
data: string | null | |
sender: string | |
for: string | |
} | |
interface setupBlockchainHandlerParams { | |
walletService: WalletServiceType | |
web3Service: Web3ServiceType | |
constants: ConstantsType | |
configuration: PaywallConfig | |
emitChanges: (data: BlockchainData) => void | |
} | |
let config: PaywallConfig | |
let keys: KeyResults = {} | |
let locks: Locks = {} | |
let transactions: Transactions = {} | |
let account: string | null = null | |
let network: unlockNetworks | |
let balance: string = '0' | |
export function normalizeLockAddress(address: string) { | |
return address.toLowerCase() | |
} | |
export function normalizeAddressKeys(object: { [key: string]: any }) { | |
return Object.keys(object).reduce( | |
(newObject: { [key: string]: any }, key) => { | |
const value = object[key] | |
newObject[key.toLowerCase()] = value | |
return newObject | |
}, | |
{} | |
) | |
} | |
export function setKeys(newKeys: KeyResult[]) { | |
keys = newKeys.reduce((allKeys: KeyResults, key) => { | |
key.lock = normalizeLockAddress(key.lock) | |
allKeys[key.lock] = key | |
return allKeys | |
}, {}) | |
} | |
export function makeDefaultKeys( | |
lockAddresses: string[], | |
account: string | null | |
) { | |
return lockAddresses.reduce((allKeys: KeyResults, address: string) => { | |
allKeys[address] = { | |
lock: address, | |
owner: account, | |
expiration: 0, | |
} | |
return allKeys | |
}, {}) | |
} | |
// assumptions: | |
// 1. walletService has been "connected" to the Web3ProxyProvider | |
// 2. config has been validated already | |
// 3. emitChanges will pass along the updates to the main window | |
export default async function setupBlockchainHandler({ | |
walletService, | |
web3Service, | |
constants, | |
configuration, | |
emitChanges, | |
}: setupBlockchainHandlerParams) { | |
// take the paywall config, lower-case all the locks | |
config = configuration | |
const configLocks = normalizeAddressKeys(configuration.locks) | |
config.locks = configLocks | |
// this will be used to filter the keys and transactions we return | |
const lockAddresses = Object.keys(config.locks) | |
// first, retrieve the locks | |
lockAddresses.forEach(address => web3Service.getLock(address)) | |
// this is used to link keys/transactions/locks and send them up to the post office | |
const propagateChanges = async () => { | |
const fullLocks = await linkKeysToLocks({ | |
locks, | |
keys, | |
transactions, | |
requiredConfirmations: constants.requiredConfirmations, | |
}) | |
emitChanges({ | |
locks: fullLocks, | |
account, | |
balance, | |
network, | |
}) | |
} | |
// set up defaults | |
network = constants.defaultNetwork | |
// poll for account changes | |
setInterval(() => { | |
if (!walletService.ready) return | |
walletService.getAccount() | |
}, POLLING_INTERVAL) | |
// the event listeners propagate changes to the main window | |
// or fetch new data when network or account changes | |
walletService.on('account.changed', newAccount => { | |
if (newAccount !== account) { | |
keys = {} | |
transactions = {} | |
getNewData() | |
} | |
}) | |
walletService.on( | |
'account.updated', | |
(balanceForAccount, { balance: newBalance }) => { | |
if (balanceForAccount !== account) return | |
balance = newBalance | |
propagateChanges() | |
} | |
) | |
walletService.on('network.changed', networkId => { | |
if (networkId !== network) { | |
keys = {} | |
transactions = {} | |
getNewData() | |
} | |
}) | |
web3Service.on('key.updated', (_: any, key: KeyResult) => { | |
key.lock = normalizeLockAddress(key.lock) | |
keys[key.lock] = key | |
propagateChanges() | |
}) | |
web3Service.on('transaction.updated', (hash, update) => { | |
transactions[hash] = transactions[hash] || { | |
blockNumber: Number.MAX_SAFE_INTEGER, | |
hash, | |
} | |
transactions[hash] = { | |
...transactions[hash], | |
...update, | |
} | |
propagateChanges() | |
}) | |
web3Service.on('lock.updated', (lockAddress, update) => { | |
const address = normalizeLockAddress(lockAddress) | |
locks[address] = locks[address] || { address } | |
locks[address] = { | |
...locks[address], | |
...update, | |
} | |
propagateChanges() | |
}) | |
// this fetches keys/transactions in parallel | |
async function getNewData() { | |
// set up keys prior to retrieval | |
keys = makeDefaultKeys(lockAddresses, account) | |
if (!account) { | |
// no account, we only have fake keys and no transactions or balance | |
transactions = {} | |
balance = '0' | |
return | |
} | |
// first get keys | |
lockAddresses.map(address => { | |
return web3Service.getKeyByLockForOwner(address, account as string) | |
}) | |
// filter the transactions we request to only include the | |
// transactions relevant to locks. In most cases this will be | |
// key purchases | |
const filterLocks = lockAddresses | |
.map(lockAddress => `recipient[]=${encodeURIComponent(lockAddress)}`) | |
.join('&') | |
const url = `${ | |
constants.locksmithHost | |
}/transactions?for=${account.toLowerCase()}${ | |
filterLocks ? `&${filterLocks}` : '' | |
}` | |
const response = await window.fetch(url) | |
const result: { | |
transactions?: LocksmithTransactionsResult[] | |
} = await response.json() | |
if (result.transactions) { | |
Promise.all( | |
result.transactions | |
.map(t => ({ | |
hash: t.transactionHash, | |
network: t.chain, | |
to: t.recipient, | |
input: t.data, | |
from: t.sender, | |
for: t.for, | |
})) | |
.filter(transaction => transaction.network === network) | |
.map((transaction: TransactionDefaults) => { | |
// we pass the transaction as defaults if it has input set, so that we can | |
// parse out the transaction type and other details. If input is not set, | |
// we can't safely pass the transaction default | |
web3Service.getTransaction( | |
transaction.hash, | |
transaction.input ? transaction : undefined | |
) | |
}) | |
) | |
} | |
} | |
return getNewData | |
} |
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