fix: etag caching HTTP headers

denoland · Jun 25, 2024 · d292dc2 · d292dc2
1 parent 4983907
commit d292dc2
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Showing 2 changed files with 16 additions and 10 deletions.
diff --git a/src/middlewares/static_files.ts b/src/middlewares/static_files.ts
@@ -67,10 +67,12 @@ export function staticFiles<T>(): MiddlewareFn<T> {
     } else {
       const ifNoneMatch = req.headers.get("If-None-Match");
       if (
-        etag !== null &&
-        (ifNoneMatch === etag || ifNoneMatch === "W/" + etag)
+        ifNoneMatch !== null &&
+        (ifNoneMatch === etag || ifNoneMatch === `W/"${etag}"`)
       ) {
         return new Response(null, { status: 304, headers });
+      } else if (etag !== null) {
+        headers.set("Etag", `W/"${etag}"`);
       }
     }
 

diff --git a/src/middlewares/static_files_test.ts b/src/middlewares/static_files_test.ts
@@ -79,18 +79,22 @@ Deno.test("static files - etag", async () => {
     { buildCache },
   );
 
-  const headers = new Headers();
-  headers.append("If-None-Match", "123");
   const cacheUrl = `/foo.css?${ASSET_CACHE_BUST_KEY}=${BUILD_ID}`;
-  const res = await server.get(cacheUrl, { headers });
+  let res = await server.get(cacheUrl);
+  await res.body?.cancel();
+  expect(res.headers.get("Etag")).toEqual('W/"123"');
+
+  let headers = new Headers();
+  headers.append("If-None-Match", "123");
+  res = await server.get(cacheUrl, { headers });
   await res.body?.cancel();
   expect(res.status).toEqual(304);
 
-  const headers2 = new Headers();
-  headers2.append("If-None-Match", "W/123");
-  const res2 = await server.get(cacheUrl, { headers });
-  await res2.body?.cancel();
-  expect(res2.status).toEqual(304);
+  headers = new Headers();
+  headers.append("If-None-Match", 'W/"123"');
+  res = await server.get(cacheUrl, { headers });
+  await res.body?.cancel();
+  expect(res.status).toEqual(304);
 });
 
 Deno.test("static files - 404 on missing favicon.ico", async () => {