app.py

import gradio as gr
from langchain_core.pydantic_v1 import BaseModel, Field
from langchain.prompts import HumanMessagePromptTemplate, ChatPromptTemplate
from langchain.output_parsers import TextIteratorStreamer
from transformers import AutoModelForCausalLM, AutoTokenizer

# Load the Hugging Face model and tokenizer
model_name = "KvrParaskevi/Llama-2-7b-Hotel-Booking-Model"
model = AutoModelForCausalLM.from_pretrained(model_name)
tokenizer = AutoTokenizer.from_pretrained(model_name)

# Define the Langchain chatbot function
def chatbot(message, history):
    # Create a Langchain prompt template
    prompt_template = HumanMessagePromptTemplate.from_message(message)
    # Create a Langchain chat prompt template
    chat_prompt_template = ChatPromptTemplate.from_messages([prompt_template])
    # Use the Langchain TextIteratorStreamer to generate responses
    streamer = TextIteratorStreamer(model, tokenizer, chat_prompt_template)
    response = streamer.generate()
    return response

# Create a Gradio chatbot interface
with gr.Blocks() as demo:
    chatbot_interface = gr.Chatbot()
    msg = gr.Textbox()
    clear = gr.Button("Clear")

    # Define the chatbot function as a Gradio interface
    demo.chatbot_interface = gr.Interface(
        fn=chatbot,
        inputs="text",
        outputs="text",
        title="Langchain Chatbot",
        description="A simple chatbot using Langchain and Hugging Face"
    )

    # Launch the Gradio app
    demo.launch()