packages/pipeline/src/data-sources/etherscan/index.ts


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import { default as axios } from 'axios';
import { BlockParam, BlockParamLiteral, DecodedLogArgs, LogWithDecodedArgs } from 'ethereum-types';

import { EventsResponse, parseRawEventsResponse } from './events';

const ETHERSCAN_URL = 'https://api.etherscan.io/api';

export class Etherscan {
    private readonly _apiKey: string;
    constructor(apiKey: string) {
        this._apiKey = apiKey;
    }

    /**
     * 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.
     */
    public async 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=${
            this._apiKey
        }`;
        const resp = await axios.get<EventsResponse>(fullURL);
        // TODO(albrow): Check response code.
        const decodedEvents = parseRawEventsResponse(resp.data.result);
        return decodedEvents;
    }
}