utilize etags

src/index.ts

@@ -11,6 +11,22 @@ const development = env.NODE_ENV !== 'production';
 
 const faviconInit = { headers: new Headers({ 'Content-Type': 'image/png' }) };
 
+
+function getEtag(data: string) {
+  const sha = Bun.SHA256.hash(data);
+  return Buffer.from(sha.buffer).toString('base64url');
+}
+
+function etagResponse(etag: string, cacheControl?: string) {
+  const headers = new Headers();
+  headers.set('ETag', etag);
+  if (cacheControl) headers.set('Cache-Control', cacheControl);
+  return new Response('', { status: 304, headers });
+}
+
+let entriesETag = '';
+let entriesNotModified = false;
+
 Bun.serve({
   routes: {
     '/': homepage,
@@ -26,10 +42,21 @@ Bun.serve({
       async GET(req) {
         if (!isAuthenticated(req)) return unauthorizedResp();
 
-        const entries = await drizzleDB.select({ id: entry.id, name: entry.name, href: entry.href, finished: entry.finished, updated_at: entry.updatedAt }).from(entry).orderBy(desc(entry.updatedAt));
+        if (entriesNotModified && req.headers.get('if-none-match') === entriesETag) {
+          return etagResponse(entriesETag);
+        }
 
-        return new Response(JSON.stringify(entries), {
+        entriesNotModified = true;
-          headers: { 'Content-Type': 'application/json' }
+        const entries = await drizzleDB
+          .select({ id: entry.id, name: entry.name, href: entry.href, finished: entry.finished, updated_at: entry.updatedAt })
+          .from(entry)
+          .orderBy(desc(entry.updatedAt));
+
+        const body = JSON.stringify(entries);
+        entriesETag = getEtag(body);
+
+        return new Response(body, {
+          headers: { 'Content-Type': 'application/json', 'ETag': entriesETag }
         });
       },
       async PUT(req) {
@@ -52,6 +79,7 @@ Bun.serve({
           return new Response('Invalid data, multiple matches?', { status: 400 });
         }
 
+        entriesNotModified = false;
         return new Response(JSON.stringify({ created }), {
           headers: { 'Content-Type': 'application/json' }
         });
@@ -82,6 +110,8 @@ Bun.serve({
         await drizzleDB.update(entry).set(body).where(eq(entry.id, id)).execute();
 
         let created = false;
+
+        entriesNotModified = false;
         return new Response(JSON.stringify({ created: false }), {
           headers: { 'Content-Type': 'application/json' }
         });
@@ -94,6 +124,7 @@ Bun.serve({
 
         await drizzleDB.delete(entry).where(eq(entry.id, id)).execute();
 
+        entriesNotModified = false;
         return new Response('OK');
       },
     },
@@ -111,6 +142,7 @@ Bun.serve({
           .where(eq(entry.id, id))
           .execute();
 
+        entriesNotModified = false;
         return new Response('OK');
       },
     },