feat: add an image upload endpoint for the Import extension demo

src/app/api/upload-image/route.tsx

@@ -0,0 +1,23 @@
+import { NextResponse } from 'next/server'
+
+/**
+ * This function is called as the `imageUploadCallback` for the `Import` extension.
+ * This in no way is a good implementation as it will store the image within the document, bloating the document size.
+ * If implementing this in a real-world scenario, you should upload the image to a cloud storage service and return the URL to the image.
+ * It also is not even checking the proper mime type of the file, which is a security risk.
+ */
+export async function POST(request: Request) {
+  const formData = await request.formData()
+  const file = formData.get('file') as File
+
+  if (!file) {
+    return NextResponse.json({ error: 'No file provided' }, { status: 400 })
+  }
+
+  const arrayBuffer = await file.arrayBuffer()
+  const base64String = Buffer.from(arrayBuffer).toString('base64')
+  const mimeType = file.type
+  const base64Url = `data:${mimeType};base64,${base64String}`
+
+  return NextResponse.json({ url: base64Url }, { status: 200 })
+}