56 lines
1.6 KiB
TypeScript
56 lines
1.6 KiB
TypeScript
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import { ethers } from "ethers";
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import { EvmLog, EvmTopicFilter } from "../entities";
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/**
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* Handling means mapping and forward to a given target.
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* As of today, only one type of event can be handled per each instance.
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*/
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export class HandleEvmLogs<T> {
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cfg: HandleEvmLogsConfig;
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mapper: (log: EvmLog, parsedArgs: ReadonlyArray<any>) => T;
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target: (parsed: T[]) => Promise<void>;
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constructor(
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cfg: HandleEvmLogsConfig,
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mapper: (log: EvmLog, args: ReadonlyArray<any>) => T,
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target: (parsed: T[]) => Promise<void>
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) {
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this.cfg = this.normalizeCfg(cfg);
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this.mapper = mapper;
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this.target = target;
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}
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public async handle(logs: EvmLog[]): Promise<T[]> {
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const mappedItems = logs
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.filter(
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(log) =>
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this.cfg.filter.addresses.includes(log.address.toLowerCase()) &&
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this.cfg.filter.topics.includes(log.topics[0].toLowerCase())
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)
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.map((log) => {
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const iface = new ethers.utils.Interface([this.cfg.abi]);
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const parsedLog = iface.parseLog(log);
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return this.mapper(log, parsedLog.args);
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});
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await this.target(mappedItems);
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// TODO: return a result specifying failures if any
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return mappedItems;
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}
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private normalizeCfg(cfg: HandleEvmLogsConfig): HandleEvmLogsConfig {
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return {
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filter: {
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addresses: cfg.filter.addresses.map((addr) => addr.toLowerCase()),
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topics: cfg.filter.topics.map((topic) => topic.toLowerCase()),
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},
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abi: cfg.abi,
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};
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}
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}
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export type HandleEvmLogsConfig = {
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filter: EvmTopicFilter;
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abi: string;
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};
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