import { HttpClient } from '@0xproject/connect';
import { APIOrder, OrderbookResponse } from '@0xproject/types';
import * as _ from 'lodash';
import {
AssetBuyerError,
OrderProvider,
OrderProviderRequest,
OrderProviderResponse,
SignedOrderWithRemainingFillableMakerAssetAmount,
} from '../types';
import { assert } from '../utils/assert';
import { orderUtils } from '../utils/order_utils';
export class StandardRelayerAPIOrderProvider implements OrderProvider {
public readonly apiUrl: string;
private readonly _sraClient: HttpClient;
/**
* Given an array of APIOrder objects from a standard relayer api, return an array
* of SignedOrderWithRemainingFillableMakerAssetAmounts
*/
private static _getSignedOrderWithRemainingFillableMakerAssetAmountFromApi(
apiOrders: APIOrder[],
): SignedOrderWithRemainingFillableMakerAssetAmount[] {
const result = _.map(apiOrders, apiOrder => {
const { order, metaData } = apiOrder;
// calculate remainingFillableMakerAssetAmount from api metadata, else assume order is completely fillable
const remainingFillableTakerAssetAmount = _.get(
metaData,
'remainingTakerAssetAmount',
order.takerAssetAmount,
);
const remainingFillableMakerAssetAmount = orderUtils.calculateRemainingMakerAssetAmount(
order,
remainingFillableTakerAssetAmount,
);
const newOrder = {
...order,
remainingFillableMakerAssetAmount,
};
return newOrder;
});
return result;
}
/**
* Instantiates a new StandardRelayerAPIOrderProvider instance
* @param apiUrl The standard relayer API base HTTP url you would like to source orders from.
* @return An instance of StandardRelayerAPIOrderProvider
*/
constructor(apiUrl: string) {
assert.isWebUri('apiUrl', apiUrl);
this.apiUrl = apiUrl;
this._sraClient = new HttpClient(apiUrl);
}
/**
* Given an object that conforms to OrderProviderRequest, return the corresponding OrderProviderResponse that satisfies the request.
* @param orderProviderRequest An instance of OrderProviderRequest. See type for more information.
* @return An instance of OrderProviderResponse. See type for more information.
*/
public async getOrdersAsync(orderProviderRequest: OrderProviderRequest): Promise<OrderProviderResponse> {
assert.isValidOrderProviderRequest('orderProviderRequest', orderProviderRequest);
const { makerAssetData, takerAssetData, networkId } = orderProviderRequest;
const orderbookRequest = { baseAssetData: makerAssetData, quoteAssetData: takerAssetData };
const requestOpts = { networkId };
let orderbook: OrderbookResponse;
try {
orderbook = await this._sraClient.getOrderbookAsync(orderbookRequest, requestOpts);
} catch (err) {
throw new Error(AssetBuyerError.StandardRelayerApiError);
}
const apiOrders = orderbook.asks.records;
const orders = StandardRelayerAPIOrderProvider._getSignedOrderWithRemainingFillableMakerAssetAmountFromApi(
apiOrders,
);
return {
orders,
};
}
}