feat: add cache control headers and implement random post retrieval endpoint

apps/backend/src/routes/post.ts

@@ -122,6 +122,12 @@ export default new Elysia({ prefix: "/post" })
             secret: config.auth.jwt_secret,
         }),
     )
+    .onAfterHandle(({ set }) => {
+        set.headers["Cache-Control"] = "no-store, no-cache, must-revalidate, proxy-revalidate, max-age=0, s-maxage=0";
+        set.headers["Pragma"] = "no-cache";
+        set.headers["Expires"] = "0";
+        set.headers["Surrogate-Control"] = "no-store";
+    })
     .get("/total", async ({ query }) => {
         const filterTags = normalizeQueryTags(query.tags);
         const filter = filterTags.length > 0
@@ -339,15 +345,6 @@ export default new Elysia({ prefix: "/post" })
                     return status(400, "No media found in the Pixiv artwork.");
                 }
 
-                // const normalizedTags = normalizeTags(
-                //     body.tag
-                //         ?? (Array.isArray(pixivData.tags)
-                //             ? pixivData.tags
-                //                 .filter((tag: unknown): tag is string => typeof tag === "string")
-                //                 .map((tag: string) => tag.replace(/^#/, ""))
-                //             : ["미분류"]),
-                // );
-
                 const normalizedTags = normalizeTags(body.tag ?? ["미분류"]);
 
                 let savedCount = 0;
@@ -475,7 +472,6 @@ export default new Elysia({ prefix: "/post" })
                     const media = tweetData.tweet.media.photos || [];
                     if (media.length > 0) {
                         const mediaUrls = media.map((m: any) => m.url);
-                        // Upload to S3
                         const hasExplicitSelection = body.selected.length > 0;
                         for (const [index, url] of mediaUrls.entries()) {
                             const isSelected = hasExplicitSelection
@@ -633,3 +629,21 @@ export default new Elysia({ prefix: "/post" })
             ids: t.Array(t.String({ minLength: 1 }), { minItems: 1 }),
         }),
     })
+
+    .get("/random", async ({ status }) => {
+        const count = await MediaUpload.countDocuments();
+        console.log(`Total posts count: ${count}`);
+        if (count === 0) {
+            return status(404, "포스트를 찾을 수 없습니다.");
+        }
+
+        const randomIndex = Math.floor(Math.random() * count);
+        console.log(`Random index: ${randomIndex}`);
+        const randomPost = await MediaUpload.findOne().skip(randomIndex);
+        console.log(`Random post: ${randomPost?._id}`);
+        if (!randomPost) {
+            return status(404, "포스트를 찾을 수 없습니다.");
+        }
+
+        return fetch(randomPost.mediaUrl, { cache: "no-store" });
+    });