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import {
assetDataUtils,
BigNumber,
ContractWrappers,
generatePseudoRandomSalt,
Order,
orderHashUtils,
Provider,
RPCSubprovider,
signatureUtils,
SignedOrder,
SignerType,
Web3ProviderEngine,
} from '0x.js';
import { NonceTrackerSubprovider, PrivateKeyWalletSubprovider } from '@0xproject/subproviders';
import { logUtils } from '@0xproject/utils';
import { Web3Wrapper } from '@0xproject/web3-wrapper';
import * as express from 'express';
import * as _ from 'lodash';
import { configs } from './configs';
import { constants } from './constants';
import { DispatchQueue } from './dispatch_queue';
import { dispenseAssetTasks } from './dispense_asset_tasks';
import { rpcUrls } from './rpc_urls';
import { TOKENS_BY_NETWORK } from './tokens';
interface NetworkConfig {
dispatchQueue: DispatchQueue;
web3Wrapper: Web3Wrapper;
contractWrappers: ContractWrappers;
networkId: number;
}
interface ItemByNetworkId<T> {
[networkId: string]: T;
}
enum RequestedAssetType {
ETH = 'ETH',
WETH = 'WETH',
ZRX = 'ZRX',
}
const FIVE_DAYS_IN_MS = 4.32e8; // TODO: make this configurable
const NULL_ADDRESS = '0x0000000000000000000000000000000000000000';
const ZERO = new BigNumber(0);
const ASSET_AMOUNT = new BigNumber(0.1);
export class Handler {
private readonly _networkConfigByNetworkId: ItemByNetworkId<NetworkConfig> = {};
private static _createProviderEngine(rpcUrl: string): Provider {
if (_.isUndefined(configs.DISPENSER_PRIVATE_KEY)) {
throw new Error('Dispenser Private key not found');
}
const engine = new Web3ProviderEngine();
engine.addProvider(new NonceTrackerSubprovider());
engine.addProvider(new PrivateKeyWalletSubprovider(configs.DISPENSER_PRIVATE_KEY));
engine.addProvider(new RPCSubprovider(rpcUrl));
engine.start();
return engine;
}
constructor() {
_.forIn(rpcUrls, (rpcUrl: string, networkIdString: string) => {
const providerObj = Handler._createProviderEngine(rpcUrl);
const web3Wrapper = new Web3Wrapper(providerObj);
// tslint:disable-next-line:custom-no-magic-numbers
const networkId = parseInt(networkIdString, 10);
const contractWrappers = new ContractWrappers(providerObj, { networkId });
const dispatchQueue = new DispatchQueue();
this._networkConfigByNetworkId[networkId] = {
dispatchQueue,
web3Wrapper,
contractWrappers,
networkId,
};
});
}
public getQueueInfo(_req: express.Request, res: express.Response): void {
res.setHeader('Content-Type', 'application/json');
const queueInfo = _.mapValues(rpcUrls, (_rpcUrl: string, networkId: string) => {
const dispatchQueue = this._networkConfigByNetworkId[networkId].dispatchQueue;
return {
full: dispatchQueue.isFull(),
size: dispatchQueue.size(),
};
});
const payload = JSON.stringify(queueInfo);
res.status(constants.SUCCESS_STATUS).send(payload);
}
public dispenseEther(req: express.Request, res: express.Response): void {
this._dispenseAsset(req, res, RequestedAssetType.ETH);
}
public dispenseZRX(req: express.Request, res: express.Response): void {
this._dispenseAsset(req, res, RequestedAssetType.ZRX);
}
public async dispenseWETHOrderAsync(req: express.Request, res: express.Response): Promise<void> {
await this._dispenseOrderAsync(req, res, RequestedAssetType.WETH);
}
public async dispenseZRXOrderAsync(
req: express.Request,
res: express.Response,
_next: express.NextFunction,
): Promise<void> {
await this._dispenseOrderAsync(req, res, RequestedAssetType.ZRX);
}
private _dispenseAsset(req: express.Request, res: express.Response, requestedAssetType: RequestedAssetType): void {
const networkId = req.params.networkId;
const recipient = req.params.recipient;
const networkConfig = this._networkConfigByNetworkId[networkId];
let dispenserTask;
switch (requestedAssetType) {
case RequestedAssetType.ETH:
dispenserTask = dispenseAssetTasks.dispenseEtherTask(recipient, networkConfig.web3Wrapper);
break;
case RequestedAssetType.WETH:
case RequestedAssetType.ZRX:
dispenserTask = dispenseAssetTasks.dispenseTokenTask(
recipient,
requestedAssetType,
networkConfig.networkId,
networkConfig.contractWrappers.erc20Token,
);
break;
default:
throw new Error(`Unsupported asset type: ${requestedAssetType}`);
}
const didAddToQueue = networkConfig.dispatchQueue.add(dispenserTask);
if (!didAddToQueue) {
res.status(constants.SERVICE_UNAVAILABLE_STATUS).send('QUEUE_IS_FULL');
return;
}
logUtils.log(`Added ${recipient} to queue: ${requestedAssetType} networkId: ${networkId}`);
res.status(constants.SUCCESS_STATUS).end();
}
private async _dispenseOrderAsync(
req: express.Request,
res: express.Response,
requestedAssetType: RequestedAssetType,
): Promise<void> {
const networkConfig = _.get(this._networkConfigByNetworkId, req.params.networkId);
if (_.isUndefined(networkConfig)) {
res.status(constants.BAD_REQUEST_STATUS).send('UNSUPPORTED_NETWORK_ID');
return;
}
res.setHeader('Content-Type', 'application/json');
const makerToken = TOKENS_BY_NETWORK[networkConfig.networkId][requestedAssetType];
if (_.isUndefined(makerToken)) {
throw new Error(`Unsupported asset type: ${requestedAssetType}`);
}
const takerTokenSymbol =
requestedAssetType === RequestedAssetType.WETH ? RequestedAssetType.ZRX : RequestedAssetType.WETH;
const takerToken = TOKENS_BY_NETWORK[networkConfig.networkId][takerTokenSymbol];
if (_.isUndefined(takerToken)) {
throw new Error(`Unsupported asset type: ${requestedAssetType}`);
}
const makerAssetAmount = Web3Wrapper.toBaseUnitAmount(ASSET_AMOUNT, makerToken.decimals);
const takerAssetAmount = Web3Wrapper.toBaseUnitAmount(ASSET_AMOUNT, takerToken.decimals);
const makerAssetData = assetDataUtils.encodeERC20AssetData(makerToken.address);
const takerAssetData = assetDataUtils.encodeERC20AssetData(takerToken.address);
const order: Order = {
makerAddress: configs.DISPENSER_ADDRESS,
takerAddress: req.params.recipient as string,
makerFee: ZERO,
takerFee: ZERO,
makerAssetAmount,
takerAssetAmount,
makerAssetData,
takerAssetData,
salt: generatePseudoRandomSalt(),
exchangeAddress: networkConfig.contractWrappers.exchange.getContractAddress(),
feeRecipientAddress: NULL_ADDRESS,
senderAddress: NULL_ADDRESS,
// tslint:disable-next-line:custom-no-magic-numbers
expirationTimeSeconds: new BigNumber(Date.now() + FIVE_DAYS_IN_MS).div(1000),
};
const orderHash = orderHashUtils.getOrderHashHex(order);
const signature = await signatureUtils.ecSignOrderHashAsync(
networkConfig.web3Wrapper.getProvider(),
orderHash,
configs.DISPENSER_ADDRESS,
SignerType.Default,
);
const signedOrder: SignedOrder = {
...order,
signature,
};
const payload = JSON.stringify(signedOrder);
logUtils.log(`Dispensed signed order: ${payload}`);
res.status(constants.SUCCESS_STATUS).send(payload);
}
}
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