chatbot-template/app/(chat)/api/files/upload/route.ts

import { NextResponse } from "next/server";
import { z } from "zod";

import { auth } from "@/app/(auth)/auth";

const MAX_FILE_SIZE = 5 * 1024 * 1024;
const ALLOWED_TYPES = ["image/jpeg", "image/png", "image/webp", "image/gif"];

const FileSchema = z.object({
  file: z
    .instanceof(Blob)
    .refine((file) => file.size <= MAX_FILE_SIZE, {
      message: "File size should be less than 5MB",
    })
    .refine((file) => ALLOWED_TYPES.includes(file.type), {
      message: "File type should be JPEG, PNG, WebP, or GIF",
    }),
});

export async function POST(request: Request) {
  const session = await auth();

  if (!session) {
    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
  }

  if (request.body === null) {
    return new Response("Request body is empty", { status: 400 });
  }

  try {
    const formData = await request.formData();
    const file = formData.get("file") as Blob;

    if (!file) {
      return NextResponse.json({ error: "No file uploaded" }, { status: 400 });
    }

    const validatedFile = FileSchema.safeParse({ file });

    if (!validatedFile.success) {
      const errorMessage = validatedFile.error.errors
        .map((error) => error.message)
        .join(", ");
      return NextResponse.json({ error: errorMessage }, { status: 400 });
    }

    const filename = (formData.get("file") as File).name;
    const safeName = filename.replace(/[^a-zA-Z0-9._-]/g, "_");
    const buffer = Buffer.from(await file.arrayBuffer());
    const dataUrl = `data:${file.type};base64,${buffer.toString("base64")}`;

    return NextResponse.json({
      url: dataUrl,
      pathname: safeName,
      contentType: file.type,
    });
  } catch (_error) {
    return NextResponse.json(
      { error: "Failed to process request" },
      { status: 500 }
    );
  }
}