rag_engine.py

import os
from typing import List
from langchain.document_loaders import PyPDFLoader, TextLoader
from langchain.text_splitter import RecursiveCharacterTextSplitter
from langchain.embeddings.openai import OpenAIEmbeddings
from langchain.vectorstores.pinecone import Pinecone
from langchain.chains import RetrievalQA
from langchain.chat_models import ChatOpenAI
from langchain.memory import ChatMessageHistory, ConversationBufferMemory
from langchain.docstore.document import Document
import pinecone
import chainlit as cl
from chainlit.types import AskFileResponse

pinecone.init(
    api_key="2b6aa6bf-2e20-4445-a560-f7dd4952e59e",
    environment="gcp-starter",
)

index_name = "skandhaar"
text_splitter = RecursiveCharacterTextSplitter(chunk_size=1000, chunk_overlap=200)
embeddings = OpenAIEmbeddings()

namespaces = set()

welcome_message = """Welcome to the Chainlit PDF QA demo! To get started:
1. Upload a PDF or text file
"""


def process_file(file: AskFileResponse):
    import tempfile

    if file.type == "text/plain":
        Loader = TextLoader
    elif file.type == "application/pdf":
        Loader = PyPDFLoader

    with tempfile.NamedTemporaryFile(mode="wb", delete=False) as tempfile:
        if file.type == "text/plain":
            tempfile.write(file.content)
        elif file.type == "application/pdf":
            with open(tempfile.name, "wb") as f:
                f.write(file.content)

        loader = Loader(tempfile.name)
        documents = loader.load()
        docs = text_splitter.split_documents(documents)
        for i, doc in enumerate(docs):
            doc.metadata["source"] = f"source_{i}"
        return docs


def get_docsearch(file: AskFileResponse):
    docs = process_file(file)

    # Save data in the user session
    cl.user_session.set("docs", docs)

    # Create a unique namespace for the file
    namespace = str(hash(file.content))

    if namespace in namespaces:
        docsearch = Pinecone.from_existing_index(
            index_name=index_name, embedding=embeddings
        )
    else:
        docsearch = Pinecone.from_documents(
            docs, embeddings, index_name=index_name
        )
        namespaces.add(namespace)

    return docsearch


@cl.on_chat_start
async def start():
    await cl.Avatar(
        name="Chatbot",
        url="https://avatars.githubusercontent.com/u/128686189?s=400&u=a1d1553023f8ea0921fba0debbe92a8c5f840dd9&v=4",
    ).send()
    
    files = None
    while files is None:
        files = await cl.AskFileMessage(
            content=welcome_message,
            accept=["text/plain", "application/pdf"],
            max_size_mb=20,
            timeout=180,
            disable_human_feedback=True,
        ).send()

    for file in files:
        msg = cl.Message(
            content=f"Processing `{file.name}`...", disable_human_feedback=True
        )
        await msg.send()

        # No async implementation in the Pinecone client, fallback to sync
        docsearch = await cl.make_async(get_docsearch)(file)

        message_history = ChatMessageHistory()

        memory = ConversationBufferMemory(
            memory_key="chat_history",
            output_key="result",
            chat_memory=message_history,
            return_messages=True,
        )

        chain = RetrievalQA.from_chain_type(
            ChatOpenAI(model_name="gpt-3.5-turbo", temperature=0, streaming=True, openai_api_key="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"),
            chain_type="stuff",
            retriever=docsearch.as_retriever(),
            return_source_documents=True,
        )

        # Let the user know that the system is ready
        msg.content = f"`{file.name}` processed. You can now ask questions!"
        await msg.update()

        cl.user_session.set("chain", chain)


@cl.on_message
async def main(message: cl.Message):
    chain = cl.user_session.get("chain")  # type: ConversationalRetrievalChain
    cb = cl.AsyncLangchainCallbackHandler()
    res = await chain.acall(message.content, callbacks=[cb])
    answer = res["result"]
    source_documents = res["source_documents"]  # type: List[Document]

    text_elements = []  # type: List[cl.Text]

    if source_documents:
        for source_idx, source_doc in enumerate(source_documents):
            source_name = f"source_{source_idx}"
            # Create the text element referenced in the message
            text_elements.append(
                cl.Text(content=source_doc.page_content, name=source_name)
            )
        source_names = [text_el.name for text_el in text_elements]

        if source_names:
            answer += f"\nSources: {', '.join(source_names)}"
        else:
            answer += "\nNo sources found"

    await cl.Message(content=answer, elements=text_elements).send()