app.py

import os
import json
import gradio as gr
from llama_index import (
    VectorStoreIndex,
    download_loader,
)
import chromadb

from llama_index.llms import MistralAI
from llama_index.embeddings import MistralAIEmbedding
from llama_index.vector_stores import ChromaVectorStore
from llama_index.storage.storage_context import StorageContext
from llama_index import ServiceContext

title = "Gaia Mistral Chat RAG PDF Demo"
description = "Example of an assistant with Gradio, RAG from PDF documents and Mistral AI via its API"
placeholder = (
    "Vous pouvez me posez une question sur ce contexte, appuyer sur Entrée pour valider"
)
placeholder_url = "Extract text from this url"
llm_model = "mistral-small"

env_api_key = os.environ.get("MISTRAL_API_KEY")
query_engine = None

# Define LLMs
llm = MistralAI(api_key=env_api_key, model=llm_model)
embed_model = MistralAIEmbedding(model_name="mistral-embed", api_key=env_api_key)

# create client and a new collection
db = chromadb.PersistentClient(path="./chroma_db")
chroma_collection = db.get_or_create_collection("quickstart")

# set up ChromaVectorStore and load in data
vector_store = ChromaVectorStore(chroma_collection=chroma_collection)
storage_context = StorageContext.from_defaults(vector_store=vector_store)
service_context = ServiceContext.from_defaults(
    chunk_size=1024, llm=llm, embed_model=embed_model
)

PDFReader = download_loader("PDFReader")
loader = PDFReader()

index = VectorStoreIndex(
    [], service_context=service_context, storage_context=storage_context
)
query_engine = index.as_query_engine(similarity_top_k=5)


def get_documents_in_db():
    print("Fetching documents in DB")
    docs = []
    for item in chroma_collection.get(include=["metadatas"])["metadatas"]:
        docs.append(json.loads(item["_node_content"])["metadata"]["file_name"])
    docs = list(set(docs))
    print(f"Found {len(docs)} documents")
    out = "**List of files in db:**\n"
    for d in docs:
        out += " - " + d + "\n"

    return out


def empty_db():
    ids = chroma_collection.get()["ids"]
    chroma_collection.delete(ids)
    return get_documents_in_db()


def load_file(file):
    documents = loader.load_data(file=file)

    for doc in documents:
        index.insert(doc)

    return (
        gr.Textbox(visible=False),
        gr.Textbox(value=f"Document encoded ! You can ask questions", visible=True),
        get_documents_in_db(),
    )


def load_document(input_file):
    file_name = input_file.name.split("/")[-1]
    return gr.Textbox(value=f"Document loaded: {file_name}", visible=True)


with gr.Blocks() as demo:
    gr.Markdown(
        """ # Welcome to Gaia Level 3 Demo 
    
        Add a file before interacting with the Chat.
        This demo allows you to interact with a pdf file and then ask questions to Mistral APIs.
        Mistral will answer with the context extracted from your uploaded file.

        *The files will stay in the database unless there is 48h of inactivty or you re-build the space.*
        """
    )

    gr.Markdown(""" ### 1 / Extract data from PDF """)

    with gr.Row():
        with gr.Column():
            input_file = gr.File(
                label="Load a pdf",
                file_types=[".pdf"],
                file_count="single",
                type="filepath",
                interactive=True,
            )
            file_msg = gr.Textbox(
                label="Loaded documents:", container=False, visible=False
            )

            input_file.upload(
                fn=load_document,
                inputs=[
                    input_file,
                ],
                outputs=[file_msg],
                concurrency_limit=20,
            )

            help_msg = gr.Markdown(
                value="Once the document is loaded, press the Encode button below to add it to the db."
            )

            file_btn = gr.Button(value="Encode file ✅", interactive=True)
            btn_msg = gr.Textbox(container=False, visible=False)

            with gr.Row():
                db_list = gr.Markdown(value=get_documents_in_db)
                delete_btn = gr.Button(value="Empty db 🗑️", interactive=True, scale=0)

            file_btn.click(
                load_file,
                inputs=[input_file],
                outputs=[file_msg, btn_msg, db_list],
                show_progress="full",
            )
            delete_btn.click(empty_db, outputs=[db_list], show_progress="minimal")

    gr.Markdown(""" ### 2 / Ask a question about this context """)

    chatbot = gr.Chatbot()
    msg = gr.Textbox(placeholder=placeholder)
    clear = gr.ClearButton([msg, chatbot])

    def respond(message, chat_history):
        response = query_engine.query(message)
        chat_history.append((message, str(response)))
        return chat_history

    msg.submit(respond, [msg, chatbot], [chatbot])

demo.title = title

demo.launch()