app.py

from langchain.vectorstores.chroma import Chroma
from langchain.text_splitter import CharacterTextSplitter
from langchain.document_loaders import DirectoryLoader, TextLoader
from langchain.text_splitter import RecursiveCharacterTextSplitter
from langchain.embeddings import SentenceTransformerEmbeddings
import gradio as gr
import os

from langchain.embeddings import OpenAIEmbeddings
from langchain.chat_models import ChatOpenAI
from langchain.chains import ConversationalRetrievalChain
from langchain.memory import ConversationBufferMemory
from dotenv import load_dotenv
load_dotenv()

def create_embeddings_from_txt(file_path: str) -> None:
    loader = loader = TextLoader(file_path=file_path)
    documents = loader.load()
    text_splitter = RecursiveCharacterTextSplitter(chunk_size=500, chunk_overlap=100)
    texts = text_splitter.split_documents(documents)
    embeddings = SentenceTransformerEmbeddings(model_name="all-MiniLM-L6-v2")
    persist_directory = 'db'
    vectordb = Chroma.from_documents(
        documents=texts,
        embedding=embeddings,
        persist_directory=persist_directory
    )
    vectordb.persist()

def create_conversation() -> ConversationalRetrievalChain:

    persist_directory = 'db'
    embeddings = OpenAIEmbeddings(
        openai_api_key=os.getenv('OPENAI_API_KEY')
    )
    db = Chroma(
        persist_directory=persist_directory,
        embedding_function=embeddings
    )
    memory = ConversationBufferMemory(
        memory_key='chat_history',
        return_messages=False
    )
    qa = ConversationalRetrievalChain.from_llm(
        llm=ChatOpenAI(),
        chain_type='stuff',
        retriever=db.as_retriever(),
        memory=memory,
        get_chat_history=lambda h: h,
        verbose=True
    )

    return qa

file_path = "./shipping.txt"
create_embeddings_from_txt(file_path)
qa = create_conversation()


def add_text(history, text):
    history = history + [(text, None)]
    return history, ""


def bot(history):
    res = qa(
        {
            'question': history[-1][0],
            'chat_history': history[:-1]
        }
    )
    history[-1][1] = res['answer']
    return history


with gr.Blocks() as demo:
    chatbot = gr.Chatbot([], elem_id="chatbot",
                         label='Document GPT')
    with gr.Row():
        with gr.Column(scale=0.80):
            txt = gr.Textbox(
                show_label=False,
                placeholder="Enter text and press enter",
            )
        with gr.Column(scale=0.10):
            submit_btn = gr.Button(
                'Submit',
                variant='primary'
            )
        with gr.Column(scale=0.10):
            clear_btn = gr.Button(
                'Clear',
                variant='stop'
            )

    txt.submit(add_text, [chatbot, txt], [chatbot, txt]).then(
        bot, chatbot, chatbot
    )

    submit_btn.click(add_text, [chatbot, txt], [chatbot, txt]).then(
        bot, chatbot, chatbot
    )

    clear_btn.click(lambda: None, None, chatbot, queue=False)

if __name__ == '__main__':
    demo.launch()