path: root/packages/kovan-faucets/src/ts/handler.ts

import * as express from 'express';
import * as _ from 'lodash';
import ProviderEngine = require('web3-provider-engine');
import HookedWalletSubprovider = require('web3-provider-engine/subproviders/hooked-wallet');
import NonceSubprovider = require('web3-provider-engine/subproviders/nonce-tracker');
import RpcSubprovider = require('web3-provider-engine/subproviders/rpc');

import { configs } from './configs';
import { EtherRequestQueue } from './ether_request_queue';
import { idManagement } from './id_management';
import { utils } from './utils';
import { ZRXRequestQueue } from './zrx_request_queue';

// HACK: web3 leaks XMLHttpRequest into the global scope and causes requests to hang
// because they are using the wrong XHR package.
// Filed issue: https://github.com/ethereum/web3.js/issues/844
// tslint:disable-next-line:ordered-imports
import * as Web3 from 'web3';

export class Handler {
    private _etherRequestQueue: EtherRequestQueue;
    private _zrxRequestQueue: ZRXRequestQueue;
    private _web3: Web3;
    constructor() {
        // Setup provider engine to talk with RPC node
        const providerObj = this._createProviderEngine(configs.RPC_URL);
        this._web3 = new Web3(providerObj);

        this._etherRequestQueue = new EtherRequestQueue(this._web3);
        this._zrxRequestQueue = new ZRXRequestQueue(this._web3);
    }
    public dispenseEther(req: express.Request, res: express.Response) {
        const recipientAddress = req.params.recipient;
        if (_.isUndefined(recipientAddress) || !this._isValidEthereumAddress(recipientAddress)) {
            res.status(400).send('INVALID_REQUEST');
            return;
        }
        const lowerCaseRecipientAddress = recipientAddress.toLowerCase();
        const didAddToQueue = this._etherRequestQueue.add(lowerCaseRecipientAddress);
        if (!didAddToQueue) {
            res.status(503).send('QUEUE_IS_FULL');
            return;
        }
        utils.consoleLog(`Added ${lowerCaseRecipientAddress} to the ETH queue`);
        res.status(200).end();
    }
    public dispenseZRX(req: express.Request, res: express.Response) {
        const recipientAddress = req.params.recipient;
        if (_.isUndefined(recipientAddress) || !this._isValidEthereumAddress(recipientAddress)) {
            res.status(400).send('INVALID_REQUEST');
            return;
        }
        const lowerCaseRecipientAddress = recipientAddress.toLowerCase();
        const didAddToQueue = this._zrxRequestQueue.add(lowerCaseRecipientAddress);
        if (!didAddToQueue) {
            res.status(503).send('QUEUE_IS_FULL');
            return;
        }
        utils.consoleLog(`Added ${lowerCaseRecipientAddress} to the ZRX queue`);
        res.status(200).end();
    }
    public getQueueInfo(req: express.Request, res: express.Response) {
        res.setHeader('Content-Type', 'application/json');
        const payload = JSON.stringify({
            ether: {
                full: this._etherRequestQueue.isFull(),
                size: this._etherRequestQueue.size(),
            },
            zrx: {
                full: this._zrxRequestQueue.isFull(),
                size: this._zrxRequestQueue.size(),
            },
        });
        res.status(200).send(payload);
    }
    // tslint:disable-next-line:prefer-function-over-method
    private _createProviderEngine(rpcUrl: string) {
        const engine = new ProviderEngine();
        engine.addProvider(new NonceSubprovider());
        engine.addProvider(new HookedWalletSubprovider(idManagement));
        engine.addProvider(
            new RpcSubprovider({
                rpcUrl,
            }),
        );
        engine.start();
        return engine;
    }
    private _isValidEthereumAddress(address: string): boolean {
        const lowercaseAddress = address.toLowerCase();
        return this._web3.isAddress(lowercaseAddress);
    }
}