Create response-storage.ts

src/response-storage.ts

@@ -0,0 +1,72 @@
+import path from "node:path";
+import { URL } from "node:url";
+import { getCache, setCache } from "./filesystem-cache";
+
+/**
+ * Determines if the URL is metadata eligible for storage (e.g., GitHub API).
+ */
+function isMetadata(url: string): boolean {
+  const urlObj = new URL(url);
+  const { pathname } = urlObj;
+  const pathObj = path.parse(pathname);
+
+  const isSecure = "https:" === urlObj.protocol;
+  const isGitHub = "github.com" === urlObj.hostname;
+  const isGitHubApi = "api.github.com" === urlObj.hostname;
+
+  let extension = pathObj.ext;
+  if (".asc" === extension) {
+    extension = path.parse(pathObj.name).ext;
+  }
+
+  const secureApi = isSecure && isGitHubApi;
+  const smallish = isSecure && isGitHub && ".txt" === extension;
+
+  return secureApi || smallish;
+}
+
+/**
+ * Retrieves a stored Response from the filesystem if available.
+ */
+export function getStoredResponse(url: string): Response | undefined {
+  if (!isMetadata(url)) {
+    return undefined;
+  }
+
+  const data = getCache(url);
+  if (null !== data) {
+    const host = new URL(url).hostname;
+    const contentType =
+      "api.github.com" === host
+        ? "application/json"
+        : "text/plain; charset=utf-8";
+    return new Response(data, {
+      status: 200,
+      headers: {
+        "Content-Type": contentType,
+        "X-Storage-Hit": "true",
+      },
+    });
+  }
+  return undefined;
+}
+
+/**
+ * Clones the response and persists its body to storage.
+ */
+export async function setStoredResponse(
+  url: string,
+  res: Response,
+): Promise<void> {
+  if (!isMetadata(url) || !res.ok) {
+    return;
+  }
+
+  try {
+    // We clone so the original stream remains readable by the caller
+    const body = await res.clone().text();
+    setCache(url, body);
+  } catch {
+    // Fail silently to avoid breaking the main execution flow
+  }
+}