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import { AbiDecoder } from '@0xproject/utils';
import { default as axios } from 'axios';
import { BlockParam, BlockParamLiteral, DecodedLogArgs, LogEntry, LogWithDecodedArgs } from 'ethereum-types';
import * as R from 'ramda';
import { artifacts } from './artifacts';
// const EXCHANGE_ADDRESS = '0x4f833a24e1f95d70f028921e27040ca56e09ab0b';
const ETHERSCAN_URL = 'https://api.etherscan.io/api';
// TOOD(albrow): Pass this in as a constructor argument instead of an env var.
const ETHERSCAN_API_KEY = process.env.ETHERSCAN_API_KEY;
// Raw response from etherescan.io
interface EventsResponse {
status: string;
message: string;
result: EventsResponseResult[];
}
// Events as represented in the response from etherscan.io
interface EventsResponseResult {
address: string;
topics: string[];
data: string;
blockNumber: string;
timeStamp: string;
gasPrice: string;
gasUsed: string;
logIndex: string;
transactionHash: string;
transactionIndex: string;
}
// Parses and abi-decodes the fill events response from etherscan.io.
const parseFillEventsResponse = R.pipe(R.map(convertResponseToLogEntry), R.map(tryToDecodeLogOrNoop));
function convertResponseToLogEntry(result: EventsResponseResult): LogEntry {
const radix = 10;
return {
logIndex: parseInt(result.logIndex, radix),
transactionIndex: parseInt(result.logIndex, radix),
transactionHash: result.transactionHash,
blockHash: '',
blockNumber: parseInt(result.blockNumber, radix),
address: result.address,
data: result.data,
topics: result.topics,
};
}
function tryToDecodeLogOrNoop(log: LogEntry): LogWithDecodedArgs<DecodedLogArgs> {
const abiDecoder = new AbiDecoder([artifacts.Exchange.compilerOutput.abi]);
const logWithDecodedArgs = abiDecoder.tryToDecodeLogOrNoop(log);
// tslint:disable-next-line:no-unnecessary-type-assertion
return logWithDecodedArgs as LogWithDecodedArgs<DecodedLogArgs>;
}
/**
* Gets the decoded events for a specific contract and block range.
* @param contractAddress The address of the contract to get the events for.
* @param fromBlock The start of the block range to get events for (inclusive).
* @param toBlock The end of the block range to get events for (inclusive).
* @returns A list of decoded events.
*/
export async function getContractEventsAsync(
contractAddress: string,
fromBlock: BlockParam = BlockParamLiteral.Earliest,
toBlock: BlockParam = BlockParamLiteral.Latest,
): Promise<Array<LogWithDecodedArgs<DecodedLogArgs>>> {
const fullURL = `${ETHERSCAN_URL}?module=logs&action=getLogs&address=${contractAddress}&fromBlock=${fromBlock}&toBlock=${toBlock}&apikey=${ETHERSCAN_API_KEY}`;
const resp = await axios.get<EventsResponse>(fullURL);
// TODO(albrow): Check response code.
const decodedEvents = parseFillEventsResponse(resp.data.result);
return decodedEvents;
}
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