Peter Meier
78 lines
2.3 KiB
TypeScript
78 lines
2.3 KiB
TypeScript
/**
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* Cache für CMS-API-Responses (nur serverseitig, Node fs/crypto).
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* Wird ausschließlich per dynamic import aus cms.ts geladen – nie von Layout/Middleware,
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* damit es nicht ins Client-Bundle gelangt. Flag/State: cms-cache-state.ts.
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*/
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import { createHash } from "node:crypto";
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import { readFile, writeFile, mkdir } from "node:fs/promises";
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import { existsSync } from "node:fs";
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import { setCmsFromCacheUsed } from "./cms-cache-state";
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const CACHE_DIR = `${process.cwd()}/.cache/cms`;
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function cacheKeyFromUrl(url: string): string {
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return createHash("sha256").update(url).digest("hex");
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}
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async function ensureCacheDir(): Promise<void> {
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if (!existsSync(CACHE_DIR)) {
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await mkdir(CACHE_DIR, { recursive: true });
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}
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}
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interface CachedResponse {
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status: number;
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body: string;
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}
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async function getCached(key: string): Promise<CachedResponse | null> {
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try {
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const path = `${CACHE_DIR}/${key}.json`;
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if (!existsSync(path)) return null;
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const raw = await readFile(path, "utf-8");
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const data = JSON.parse(raw) as CachedResponse;
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return data?.body != null ? data : null;
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} catch {
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return null;
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}
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}
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async function setCached(key: string, data: CachedResponse): Promise<void> {
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try {
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await ensureCacheDir();
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const path = `${CACHE_DIR}/${key}.json`;
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await writeFile(path, JSON.stringify(data), "utf-8");
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} catch {
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// Cache schreiben optional
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}
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}
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/**
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* Fetch mit Cache: bei Erfolg wird die Response in .cache/cms gespeichert (überschreibt vorhanden).
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* Bei Fehler wird versucht, aus dem Cache zu lesen; wenn gefunden, wird usedCacheThisRequest gesetzt.
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*/
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export async function cachedFetch(url: string): Promise<Response> {
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const key = cacheKeyFromUrl(url);
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try {
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const res = await fetch(url);
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const body = await res.text();
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await setCached(key, { status: res.status, body });
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return new Response(body, {
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status: res.status,
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headers: res.headers,
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});
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} catch {
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const cached = await getCached(key);
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if (cached) {
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setCmsFromCacheUsed();
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return new Response(cached.body, {
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status: cached.status,
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headers: { "Content-Type": "application/json" },
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});
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}
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throw new Error(`CMS nicht erreichbar (${url}) und kein Cache für diese Anfrage.`);
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}
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}
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