create upload middleware

server/src/api/middleware/handleErrors.ts

@@ -1,11 +1,16 @@
 import type { NextFunction, Request, Response } from "express";
+import { MulterError } from "multer";
 import { logger } from "@/utils/logger.js";
 import { AppError } from "@/utils/AppError.js";
 
+// Multer throws MulterError, send 413 Payload Too Large / 400
+const multerErrorStatus = (error: MulterError): number => (error.code === "LIMIT_FILE_SIZE" ? 413 : 400);
+
 const handleErrors = (error: unknown, req: Request, res: Response, _next: NextFunction) => {
-	const status = error instanceof AppError ? error.status || 500 : 500;
+	const status =
+		error instanceof MulterError ? multerErrorStatus(error) : error instanceof AppError ? error.status || 500 : 500;
 	const message = error instanceof AppError ? error.message : error instanceof Error ? error.message : "Server error";
-	const service = error instanceof AppError ? error.service : "unknownService";
+	const service = error instanceof AppError ? error.service : error instanceof MulterError ? "uploadMiddleware" : "unknownService";
 	const method = error instanceof AppError ? error.method : "unknownMethod";
 	logger.error({
 		message: message,

server/src/api/middleware/upload.ts

@@ -0,0 +1,27 @@
+import multer from "multer";
+import { AppError } from "@/utils/AppError.js";
+import { ImageMimeTypes, MAX_IMAGE_SIZE_BYTES } from "@/types/upload.js";
+
+// Reusable multer instance for handling image uploads
+const imageUpload = multer({
+	limits: {
+		fileSize: MAX_IMAGE_SIZE_BYTES,
+		files: 1,
+	},
+	fileFilter: (_req, file, cb) => {
+		if (!(ImageMimeTypes as readonly string[]).includes(file.mimetype)) {
+			cb(
+				new AppError({
+					status: 415,
+					message: "File must be a valid image (jpeg, jpg, or png)",
+					service: "uploadMiddleware",
+					method: "fileFilter",
+				})
+			);
+			return;
+		}
+		cb(null, true);
+	},
+});
+
+export { imageUpload };