Cache the remote files with Web Cache API

CHANGELOG.md

@@ -15,6 +15,7 @@ Any BREAKING CHANGE between minor versions will be documented here in upper case
 - New `site.searcher` property with a instance of `Searcher` class.
   It's used by plugins like `search`, `nav`, `sitemap` and `feed`.
   (Previouly, each plugin had it's own instance).
+- Cache the remote files using Web Cache API.
 
 ## [1.17.3] - 2023-05-10
 ### Fixed

core/utils.ts

@@ -444,7 +444,23 @@ export async function read(
     return isBinary ? Deno.readFile(path) : Deno.readTextFile(path);
   }
 
-  const response = await fetch(path);
+  const url = new URL(path);
+
+  if (url.protocol === "file:") {
+    return isBinary ? Deno.readFile(url) : Deno.readTextFile(url);
+  }
+
+  const cache = await caches.open("lume_remote_files");
+  const cached = await cache.match(url);
+
+  if (cached) {
+    return isBinary
+      ? new Uint8Array(await cached.arrayBuffer())
+      : cached.text();
+  }
+
+  const response = await fetch(url);
+  await cache.put(url, response.clone());
 
   return isBinary
     ? new Uint8Array(await response.arrayBuffer())