app.py

from flask import Flask, jsonify, request, send_file
from gtts import gTTS
from langchain.chains import ConversationalRetrievalChain
from langchain.chat_models import ChatOpenAI
from langchain.document_loaders import TextLoader
from langchain.embeddings import OpenAIEmbeddings
from langchain.indexes import VectorstoreIndexCreator
from langchain.indexes.vectorstore import VectorStoreIndexWrapper
from langchain.vectorstores import Chroma
from langchain.memory import ConversationBufferMemory
import os

app = Flask(__name__)
os.environ["OPENAI_API_KEY"] = "YOUR_API_KEY"
PERSIST = True

query = None  

def main_func(message, history):
    global query  
    chat_history = history  
    if PERSIST and os.path.exists("persist"):
        print("Reusing index...\n")
        vectorstore = Chroma(persist_directory="persist", embedding_function=OpenAIEmbeddings())
        index = VectorStoreIndexWrapper(vectorstore=vectorstore)
    else:
        loader = TextLoader("new.txt")
        if PERSIST:
            index = VectorstoreIndexCreator(vectorstore_kwargs={"persist_directory": "persist"}).from_loaders([loader])
        else:
            index = VectorstoreIndexCreator().from_loaders([loader])

    print(index)

    memory = ConversationBufferMemory(memory_key="chat_history", return_messages=True)
    chain = ConversationalRetrievalChain.from_llm(llm=ChatOpenAI(), retriever=index.vectorstore.as_retriever(), memory=memory, verbose=True)

    query = message
    result = chain({"question": query, "chat_history": chat_history})
    print(result['answer'])
    chat_history.append((query, result['answer']))
    return result['answer']

@app.route('/generate-text/<input_text>', methods=['POST'])
def generate_text(input_text):
    global query  
    generated_text = main_func(input_text, [])

    tts = gTTS(text=generated_text, lang='en')
    tts.save("output.mp3")

    return jsonify({
        'generated_text': generated_text,
        'audio_url': request.host_url + 'audio'
    })

@app.route('/audio')
def get_audio():
    return send_file("output.mp3", as_attachment=True)

if __name__ == "__main__":
    app.run(debug=True)