Update app.py

app.py

@@ -7,6 +7,7 @@ from langchain_huggingface import HuggingFaceEndpoint, HuggingFaceEmbeddings  #
 from langchain_community.document_loaders import PyPDFLoader  # ✅ Fixed Import
 import time
 
+# Ensure required packages are up-to-date
 os.system("pip install -U huggingface_hub langchain_huggingface langchain_core langchain")
 
 # Define paths for cybersecurity training PDFs
@@ -19,7 +20,7 @@ PDF_FILES = [
 
 # Fetch Hugging Face API token securely from environment variables
 HUGGINGFACE_API_KEY = os.getenv("HUGGINGFACEHUB_API_TOKEN")
-if HUGGINGFACE_API_KEY is None:
+if not HUGGINGFACE_API_KEY:
     raise ValueError("❌ Hugging Face API token is missing! Set it in Hugging Face Spaces Secrets.")
 
 # Load PDFs into ChromaDB
@@ -53,6 +54,11 @@ qa_chain = RetrievalQA.from_chain_type(llm=llm, retriever=vector_db.as_retriever
 def chatbot_response(question):
     """Handles chatbot queries with a typing effect"""
     response = qa_chain.invoke(question)  # ✅ Use `invoke` instead of deprecated `run`
+    
+    # Ensure response is a string to avoid errors
+    if not isinstance(response, str):
+        response = str(response)
+
     displayed_response = ""
     for char in response:
         displayed_response += char