feat(mcp): add document inbox tools and PDF transfers

backend/src/utils/fileBuffer.ts

@@ -2,17 +2,21 @@ import { GetObjectCommand } from "@aws-sdk/client-s3"
 import { s3 } from "./s3"
 import { secrets } from "./secrets"
 
-export const streamToBuffer = async (stream: any): Promise<Buffer> => {
+export const streamToBuffer = async (stream: any, maxBytes = Infinity): Promise<Buffer> => {
     const chunks: Buffer[] = []
+    let size = 0
 
     for await (const chunk of stream) {
-        chunks.push(Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk))
+        const buffer = Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk)
+        size += buffer.length
+        if (size > maxBytes) throw new Error("Die Datei ist für Base64 zu groß. Bitte den Download mit format: url verwenden.")
+        chunks.push(buffer)
     }
 
     return Buffer.concat(chunks)
 }
 
-export const loadFileBuffer = async (path: string): Promise<Buffer> => {
+export const loadFileBuffer = async (path: string, maxBytes = Infinity): Promise<Buffer> => {
     const response = await s3.send(new GetObjectCommand({
         Bucket: secrets.S3_BUCKET,
         Key: path,
@@ -22,5 +26,5 @@ export const loadFileBuffer = async (path: string): Promise<Buffer> => {
         throw new Error(`S3-Datei '${path}' enthält keinen lesbaren Inhalt.`)
     }
 
-    return streamToBuffer(response.Body)
+    return streamToBuffer(response.Body, maxBytes)
 }