langchain_utils.py

from langchain_openai import ChatOpenAI
from langchain_core.output_parsers import StrOutputParser
from langchain_core.prompts import ChatPromptTemplate, MessagesPlaceholder
from langchain.chains import create_history_aware_retriever, create_retrieval_chain
from langchain.chains.combine_documents import create_stuff_documents_chain
from typing import List
from typing_extensions import List, TypedDict
from langchain_core.documents import Document
import os
from pinecone_utilis import vectorstore
from dotenv import load_dotenv
load_dotenv()
OPENAI_API_KEY=os.getenv("OPENAI_API_KEY")
retriever = vectorstore.as_retriever(search_kwargs={"k": 2})

output_parser = StrOutputParser()

contextualize_q_system_prompt = (
    "Given a chat history and the latest user question "
    "which might reference context in the chat history, "
    "formulate a standalone question which can be understood "
    "without the chat history. Do NOT answer the question, "
    "just reformulate it if needed and otherwise return it as is."
)

contextualize_q_prompt = ChatPromptTemplate.from_messages([
    ("system", contextualize_q_system_prompt),
    MessagesPlaceholder("chat_history"),
    ("human", "{input}"),
])

qa_prompt = ChatPromptTemplate.from_messages([
    ("system", "You are a helpful AI assistant. Use the following context to answer the user's question."),
    ("system", "Context: {context}"),
    MessagesPlaceholder(variable_name="chat_history"),
    ("human", "{input}")
])

class State(TypedDict):
    messages: List[BaseMessage]