파일을 업로드할 때 스트리밍이 되지 않고 버퍼링하던 버그 수정

src/routes/api/file/upload/+server.ts

@@ -1,19 +1,57 @@
+import Busboy from "@fastify/busboy";
 import { error, text } from "@sveltejs/kit";
+import { Readable, Writable } from "stream";
 import { authorize } from "$lib/server/modules/auth";
 import { fileUploadRequest } from "$lib/server/schemas";
 import { uploadFile } from "$lib/server/services/file";
 import type { RequestHandler } from "./$types";
 
+const parseFormData = async (contentType: string, body: ReadableStream<Uint8Array>) => {
+  return new Promise<{ metadata: string; content: Readable }>((resolve, reject) => {
+    let metadata: string | null = null;
+    let content: Readable | null = null;
+
+    const bb = Busboy({ headers: { "content-type": contentType } });
+    bb.on("field", (fieldname, val) => {
+      if (fieldname !== "metadata") return reject(new Error("Invalid request body"));
+      if (metadata || content) return reject(new Error("Invalid request body")); // metadata must be first
+      metadata = val;
+    });
+    bb.on("file", (fieldname, file) => {
+      if (fieldname !== "content") return reject(new Error("Invalid request body"));
+      if (!metadata || content) return reject(new Error("Invalid request body")); // metadata must be first
+      content = file;
+      resolve({ metadata, content });
+    });
+    bb.on("finish", () => reject(new Error("Invalid request body")));
+    bb.on("error", (e) => reject(e));
+
+    body.pipeTo(Writable.toWeb(bb));
+  });
+};
+
 export const POST: RequestHandler = async ({ locals, request }) => {
   const { userId } = await authorize(locals, "activeClient");
 
-  const form = await request.formData();
-  const metadata = form.get("metadata");
-  const content = form.get("content");
-  if (typeof metadata !== "string" || !(content instanceof File)) {
+  const contentTypeHeader = request.headers.get("Content-Type");
+  if (!contentTypeHeader?.startsWith("multipart/form-data") || !request.body) {
     error(400, "Invalid request body");
   }
 
+  let metadata;
+  let content;
+
+  try {
+    const formData = await parseFormData(contentTypeHeader, request.body);
+    metadata = formData.metadata;
+    content = formData.content;
+  } catch (e) {
+    if (e instanceof Error && e.message === "Invalid request body") {
+      error(400, "Invalid request body");
+    }
+    throw e;
+  }
+
   const zodRes = fileUploadRequest.safeParse(JSON.parse(metadata));
   if (!zodRes.success) error(400, "Invalid request body");
   const {
@@ -53,7 +91,7 @@ export const POST: RequestHandler = async ({ locals, request }) => {
       encLastModifiedAt: lastModifiedAt,
       encLastModifiedAtIv: lastModifiedAtIv,
     },
-    content.stream(),
+    content,
   );
   return text("File uploaded", { headers: { "Content-Type": "text/plain" } });
 };