78 lines
2.1 KiB
TypeScript
78 lines
2.1 KiB
TypeScript
import { useState, useEffect, useContext } from "react";
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import { RuntimeContext } from "./useRuntime";
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import { topic0URL } from "./url";
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export type Topic0Entry = {
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signatures: string[] | undefined;
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};
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const fullCache = new Map<string, Topic0Entry | null>();
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/**
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* Extract topic0 DB info
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*
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* @param rawTopic0 an hex string containing the keccak256 of event signature
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*/
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export const useTopic0 = (
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rawTopic0: string
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): Topic0Entry | null | undefined => {
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if (rawTopic0.length !== 66 || !rawTopic0.startsWith("0x")) {
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throw new Error(
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`rawTopic0 must contain a 32 bytes hex event signature starting with 0x; received value: "${rawTopic0}"`
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);
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}
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const runtime = useContext(RuntimeContext);
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const assetsURLPrefix = runtime.config?.assetsURLPrefix;
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const topic0 = rawTopic0.slice(2);
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const [entry, setEntry] = useState<Topic0Entry | null | undefined>(
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fullCache.get(topic0)
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);
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useEffect(() => {
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if (assetsURLPrefix === undefined) {
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return;
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}
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const signatureURL = topic0URL(assetsURLPrefix, topic0);
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fetch(signatureURL)
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.then(async (res) => {
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if (!res.ok) {
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console.error(`Signature does not exist in topic0 DB: ${topic0}`);
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fullCache.set(topic0, null);
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setEntry(null);
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return;
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}
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// Get only the first occurrence, for now ignore alternative param names
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const sig = await res.text();
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const sigs = sig.split(";");
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const entry: Topic0Entry = {
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signatures: sigs,
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};
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setEntry(entry);
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fullCache.set(topic0, entry);
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})
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.catch((err) => {
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console.error(`Couldn't fetch signature URL ${signatureURL}`, err);
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setEntry(null);
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fullCache.set(topic0, null);
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});
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}, [topic0, assetsURLPrefix]);
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if (assetsURLPrefix === undefined) {
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return undefined;
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}
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// Try to resolve topic0 name
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if (entry === null || entry === undefined) {
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return entry;
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}
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// Simulates LRU
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// TODO: implement LRU purging
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fullCache.delete(topic0);
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fullCache.set(topic0, entry);
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return entry;
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};
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