feat: implement direct file upload functionality with S3 integration

apps/backend/src/lib/s3.ts

@@ -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) {

apps/frontend/src/app/add/page.tsx

@@ -1,15 +1,16 @@
 "use client";
 
-import { FormEvent, useEffect, useMemo, useState } from "react";
+import { FormEvent, useEffect, useMemo, useRef, useState } from "react";
 import Link from "next/link";
 import { useRouter } from "next/navigation";
 import Header from "../../components/header";
 
-type SourceType = "twitter" | "pixiv";
+type SourceType = "twitter" | "pixiv" | "direct";
 
 type PreviewItem = {
     url: string;
     type?: "image" | "video";
+    file?: File;
 };
 
 type TweetApiResponse = {
@@ -88,6 +89,8 @@ export default function AddPage() {
     const [viewerRole, setViewerRole] = useState<Me["role"] | "guest">("guest");
     const [loadingRole, setLoadingRole] = useState(true);
     const [existingDetailId, setExistingDetailId] = useState<string | null>(null);
+    const [uploadMode, setUploadMode] = useState<"url" | "direct">("url");
+    const fileInputRef = useRef<HTMLInputElement>(null);
 
     const selectedCount = useMemo(
         () => selected.filter(Boolean).length,
@@ -133,6 +136,9 @@ export default function AddPage() {
     }, []);
 
     function resetPreview() {
+        previewItems.forEach((item) => {
+            if (item.file) URL.revokeObjectURL(item.url);
+        });
         setPreviewItems([]);
         setSelected([]);
         setSourceType(null);
@@ -140,6 +146,7 @@ export default function AddPage() {
         setError(null);
         setSuccess(null);
         setExistingDetailId(null);
+        if (fileInputRef.current) fileInputRef.current.value = "";
     }
 
     async function fetchPreview(targetUrl?: string) {
@@ -243,6 +250,21 @@ export default function AddPage() {
         }
     }
 
+    function handleFileChange(e: React.ChangeEvent<HTMLInputElement>) {
+        const files = Array.from(e.target.files || []);
+        if (files.length === 0) return;
+
+        setSourceType("direct");
+        const newItems: PreviewItem[] = files.map((file) => ({
+            url: URL.createObjectURL(file),
+            type: file.type.startsWith("video/") ? "video" : "image",
+            file,
+        }));
+
+        setPreviewItems((prev) => [...prev, ...newItems]);
+        setSelected((prev) => [...prev, ...newItems.map(() => true)]);
+    }
+
     useEffect(() => {
         if (loadingPreview) {
             return;
@@ -292,7 +314,24 @@ export default function AddPage() {
         setSubmitting(true);
         try {
             const tags = splitTags(tagsText);
-            const response = await fetch("/api/post/upload", {
+            let response: Response;
+
+            if (uploadMode === "direct") {
+                const formData = new FormData();
+                previewItems.forEach((item, index) => {
+                    if (selected[index] && item.file) {
+                        formData.append("files", item.file);
+                    }
+                });
+                if (author.trim()) formData.append("author", author.trim());
+                tags.forEach((t) => formData.append("tag", t));
+
+                response = await fetch("/api/post/upload/direct", {
+                    method: "POST",
+                    body: formData,
+                });
+            } else {
+                response = await fetch("/api/post/upload", {
                     method: "POST",
                     headers: {
                         "Content-Type": "application/json",
@@ -304,6 +343,7 @@ export default function AddPage() {
                         selected,
                     }),
                 });
+            }
 
             let data: UploadApiResponse | null = null;
             try {
@@ -359,13 +399,37 @@ export default function AddPage() {
                         </div>
                     </div>
 
-                    <form className="mt-5 space-y-4" onSubmit={submit}>
+                    <form className="mt-5 space-y-6" onSubmit={submit}>
                         {!loadingRole && !canManagePost ? (
                             <div className="border border-red-200 bg-red-50 px-3 py-2 text-sm text-red-700">
                                 업로드 권한이 없습니다. writer 또는 admin 권한이 필요합니다.
                             </div>
                         ) : null}
 
+                        <div className="flex gap-6 border-b border-border/40">
+                            <button
+                                type="button"
+                                onClick={() => {
+                                    setUploadMode("url");
+                                    resetPreview();
+                                }}
+                                className={`pb-2 text-sm font-medium transition ${uploadMode === "url" ? "border-b-2 border-foreground text-foreground" : "text-foreground/40 hover:text-foreground/60"}`}
+                            >
+                                URL 가져오기
+                            </button>
+                            <button
+                                type="button"
+                                onClick={() => {
+                                    setUploadMode("direct");
+                                    resetPreview();
+                                }}
+                                className={`pb-2 text-sm font-medium transition ${uploadMode === "direct" ? "border-b-2 border-foreground text-foreground" : "text-foreground/40 hover:text-foreground/60"}`}
+                            >
+                                직접 업로드
+                            </button>
+                        </div>
+
+                        {uploadMode === "url" ? (
                             <div className="space-y-2">
                                 <label className="block text-sm text-foreground/80" htmlFor="url">URL</label>
                                 <div className="flex flex-col gap-2 sm:flex-row">
@@ -383,11 +447,36 @@ export default function AddPage() {
                                         placeholder="https://x.com/... or https://www.pixiv.net/artworks/..."
                                         className="w-full border-b border-border bg-transparent px-2 py-2 text-sm outline-none ring-0 transition focus:border-foreground/40"
                                         disabled={loadingPreview}
-                                    required
+                                        required={uploadMode === "url"}
                                     />
                                 </div>
                                 <p className="text-xs text-foreground/55">URL 변경 시 기존 미리보기는 자동으로 초기화됩니다.</p>
                             </div>
+                        ) : (
+                            <div className="space-y-2">
+                                <label className="block text-sm text-foreground/80">파일 선택</label>
+                                <div
+                                    className="flex flex-col items-center justify-center gap-3 border-2 border-dashed border-border/60 bg-white/5 py-12 transition hover:border-foreground/30 hover:bg-white/10 cursor-pointer"
+                                    onClick={() => fileInputRef.current?.click()}
+                                >
+                                    <svg className="h-10 w-10 text-foreground/30" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                                        <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={1.5} d="M12 4v16m8-8H4" />
+                                    </svg>
+                                    <div className="text-center">
+                                        <p className="text-sm font-medium">클릭하여 이미지나 영상을 선택하세요</p>
+                                        <p className="mt-1 text-xs text-foreground/40">여러 파일을 동시에 선택할 수 있습니다.</p>
+                                    </div>
+                                    <input
+                                        ref={fileInputRef}
+                                        type="file"
+                                        multiple
+                                        accept="image/*,video/*"
+                                        className="hidden"
+                                        onChange={handleFileChange}
+                                    />
+                                </div>
+                            </div>
+                        )}
 
                         <div className="grid gap-4 sm:grid-cols-2">
                             <div className="space-y-2">