Update app.py

app.py

@@ -2,6 +2,9 @@ import gradio as gr
 from huggingface_hub import InferenceClient
 
 ##########
+import os
+from dotenv import load_dotenv
+
 from langchain.vectorstores import Chroma
 from langchain.embeddings import OpenAIEmbeddings
 
@@ -13,6 +16,18 @@ from langchain.embeddings import HuggingFaceEmbeddings
 
 import gradio as gr
 
+MODEL   = "gpt-4o-mini"
+db_name = "vector_db"
+
+load_dotenv()
+os.environ['OPENAI_API_KEY'] = os.getenv('OPENAI_API_KEY', 'your-key-if-not-using-env')
+
+vectorstore = Chroma(persist_directory=db_name, embedding_function=OpenAIEmbeddings())
+llm         = ChatOpenAI(temperature=0.7, model_name=MODEL)
+memory      = ConversationBufferMemory(memory_key='chat_history', return_messages=True)
+retriever   = vectorstore.as_retriever()
+conversation_chain = ConversationalRetrievalChain.from_llm(llm=llm, retriever=retriever, memory=memory)
+
 """
 For more information on `huggingface_hub` Inference API support, please check the docs: https://huggingface.co/docs/huggingface_hub/v0.22.2/en/guides/inference
 """