Fix query JSON body and improve error handling

backend/api.py

@@ -136,17 +136,24 @@ class QueryRequest(BaseModel):
 # This Endpoint Load the VectorDataBase and answer the User question
 @app.post("/query")
 async def get_response(req: QueryRequest):
-    vectorstore = get_vectorstore()
-    retriever = vectorstore.as_retriever(
-        search_type="mmr",
-        search_kwargs={"k": 3}
-    )
-    chain = get_rag_chain(retriever)
-    response = chain.invoke(req.input)
+    try:
+        vectorstore = get_vectorstore()
+        retriever = vectorstore.as_retriever(
+            search_type="mmr",
+            search_kwargs={"k": 3}
+        )
+        chain = get_rag_chain(retriever)
+        response = chain.invoke(req.input)
 
-    system_stats["total_queries"] += 1
+        system_stats["total_queries"] += 1
 
-    return {
-        "question": req.input,
-        "response": response.content
-    }
+        return {
+            "question": req.input,
+            "response": response.content
+        }
+
+    except Exception as e:
+        raise HTTPException(
+            status_code=500,
+            detail=f"Query processing failed: {str(e)}"
+        )