app_st.py

import os
import streamlit as st
from streamlit_chat import message

from langchain.llms import OpenAIChat, HuggingFaceHub
from langchain.chat_models import ChatOpenAI
from langchain.prompts import PromptTemplate
from langchain.chains import LLMChain, SequentialChain
from langchain.memory import ConversationBufferMemory
from langchain.utilities import WikipediaAPIWrapper

# App framework
st.title('LangChain')
prompt = st.text_area('Enter your prompt here')

# Prompt templates
title_template = PromptTemplate(
    input_variables = ['topic'],
    template = 'Write me a story title about {topic}.',
)

script_template = PromptTemplate(
    input_variables = ['title', 'wikipedia_research'],
    template = 'Write me a script about {title}, based on the following research: {wikipedia_research}.',
)

# Memory
title_memory = ConversationBufferMemory(input_key='topic', memory_key='chat_history')
script_memory = ConversationBufferMemory(input_key='title', memory_key='chat_history')

# Chains

# MosaicML
# llm = HuggingFaceHub(repo_id="mosaicml/mpt-7b", model_kwargs={'temperature': 0.1, 'max_length': 1000})

# OpenAI
llm = ChatOpenAI(temperature=0.1, model='gpt-3.5-turbo')
title_chain = LLMChain(llm=llm, prompt=title_template, verbose=True, output_key='title', memory=title_memory)
script_chain = LLMChain(llm=llm, prompt=script_template, verbose=True, output_key='script', memory=script_memory)
# sequential_chain = SequentialChain(chains=[title_chain, script_chain], verbose=True, input_variables=['topic'], output_variables=['title', 'script'])

# Wikipedia
wiki = WikipediaAPIWrapper()

if 'generated' not in st.session_state:
    st.session_state['generated'] = []

if 'past' not in st.session_state:
    st.session_state['past'] = []

if prompt:
    title = title_chain.run(topic=prompt)
    wikipedia_research = wiki.run(prompt)
    script = script_chain.run(title=title, wikipedia_research=wikipedia_research)

    st.session_state.past.append(prompt)
    st.session_state.generated.append(title)
    st.session_state.generated.append(script)

    if st.session_state['generated']:
        for i in range(len(st.session_state['generated']) - 1, -1, -1):
            message(st.session_state['generated'][i], key=str(i))
            message(st.session_state['past'][i], key=str(i) + '_user', is_user=True)

    with st.expander('Title History'):
        st.info(title_memory.buffer)

    with st.expander('Chat History'):
        st.info(script_memory.buffer)

    with st.expander('Wiki History'):
        st.info(wikipedia_research)