feat: implement direct file upload functionality with S3 integration

apps/backend/src/lib/s3.ts

@@ -37,7 +37,7 @@ async function uploadToS3(fileName: string, mediaUrl: string, maxRetry = 3) {
       }
 
       const buffer = await response.arrayBuffer();
-      
+
       // 2. Bun S3 Client만 사용하여 쓰기
       // client.write는 내부적으로 효율적인 스트리밍/버퍼 처리를 수행합니다.
       await client.write(fileName, buffer, {
@@ -67,4 +67,11 @@ async function uploadToS3(fileName: string, mediaUrl: string, maxRetry = 3) {
   throw lastError;
 }
 
-export { makeS3FileName, uploadToS3, client as s3Client };
+async function writeToS3(fileName: string, data: ArrayBuffer | Blob, contentType: string) {
+  await warmupS3();
+  await client.write(fileName, data, {
+    type: contentType,
+  });
+}
+
+export { makeS3FileName, uploadToS3, writeToS3, client as s3Client };

apps/backend/src/routes/post.ts

@@ -9,7 +9,7 @@ import { normalizeQueryTags, normalizeTags } from "@/lib/tag";
 import { fetchTweetData } from "@/lib/tweet";
 import { fetchPixivData } from "@/lib/pixiv";
 import { checkExistingPostByUrl } from "@/lib/post";
-import { makeS3FileName, s3Client, uploadToS3 } from "@/lib/s3";
+import { makeS3FileName, s3Client, uploadToS3, writeToS3 } from "@/lib/s3";
 
 const inFlightUploads = new Set<string>();
 
@@ -685,6 +685,91 @@ export default new Elysia({ prefix: "/post" })
         })
     })
 
+    .post("/upload/direct", async ({ body, status, request }) => {
+        const requester = (request as any).requester;
+        if (!requester || (requester.role !== "admin" && requester.role !== "writer")) {
+            return status(401, uploadError("업로드 권한이 없습니다."));
+        }
+
+        const { files, author, tag } = body;
+        const fileList = Array.isArray(files) ? files : [files];
+
+        if (fileList.length === 0) {
+            return status(400, uploadError("업로드할 파일이 없습니다."));
+        }
+
+        let savedCount = 0;
+        let failedCount = 0;
+        const savedIds: string[] = [];
+        const normalizedTags = normalizeTags(tag || ["미분류"]);
+
+        for (const [index, file] of fileList.entries()) {
+            try {
+                const extension = file.name.split(".").pop();
+                const fileName = `direct/${crypto.randomUUID()}.${extension}`;
+                const mediaType = file.type.startsWith("video/") ? "video" : "image";
+
+                await writeToS3(fileName, file, file.type);
+
+                const post = await MediaUpload.create({
+                    type: "direct",
+                    mediaIndex: index,
+                    mediaUrl: `${config.s3.endpoint}/${config.s3.bucket}/${fileName}`,
+                    s3Key: fileName,
+                    mediaType,
+                    tags: normalizedTags,
+                    author: author || requester.username || "익명",
+                    uploadedBy: {
+                        userId: requester.userId,
+                        discordId: requester.discordId,
+                        username: requester.username,
+                        role: requester.role,
+                    },
+                });
+
+                if (post) {
+                    savedIds.push(post._id.toString());
+                    savedCount += 1;
+                }
+            } catch (error) {
+                failedCount += 1;
+                console.error(`[Direct upload failed] name=${file.name}`, error);
+            }
+        }
+
+        if (savedCount > 0) {
+            await saveTags(normalizedTags);
+            await createAuditLog({
+                actor: {
+                    userId: requester.userId,
+                    discordId: requester.discordId,
+                    username: requester.username,
+                    role: requester.role,
+                },
+                action: "post.upload.direct",
+                targetType: "post",
+                summary: `${requester.username} uploaded ${savedCount} files directly`,
+                detail: {
+                    savedCount,
+                    failedCount,
+                    ids: savedIds,
+                },
+            });
+        }
+
+        return uploadOk("업로드가 완료되었습니다.", {
+            savedCount,
+            failedCount,
+            ids: savedIds,
+        });
+    }, {
+        body: t.Object({
+            files: t.Files(),
+            author: t.Optional(t.String()),
+            tag: t.Optional(t.Array(t.String())),
+        })
+    })
+
     .post("/bulk-delete", async ({ body, status, jwt, cookie: { mizuki } }) => {
         const rawToken = mizuki.value;
         if (typeof rawToken !== "string" || rawToken.length === 0) {