pdf-chatbot / app.py
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import gradio as gr
import os
from huggingface_hub import login
import torch
from transformers import AutoTokenizer, AutoModelForCausalLM
import transformers
from langchain_community.document_loaders import PyPDFLoader
from langchain.text_splitter import RecursiveCharacterTextSplitter
from langchain_community.vectorstores import Chroma
from langchain.chains import ConversationalRetrievalChain
from langchain_community.embeddings import HuggingFaceEmbeddings
from langchain_community.llms import HuggingFacePipeline
from langchain.memory import ConversationBufferMemory
import spaces
from pathlib import Path
import chromadb
from unidecode import unidecode
import re
# Global variables
global_llm = None
global_tokenizer = None
hf_token = os.environ.get("HUGGINGFACEHUB_API_TOKEN")
if not hf_token:
raise ValueError("Hugging Face token not found. Please set the HF_TOKEN environment variable.")
# Log in to Hugging Face
login(token=hf_token)
list_llm = ["mistralai/Mistral-7B-Instruct-v0.2", "mistralai/Mixtral-8x7B-Instruct-v0.1", "mistralai/Mistral-7B-Instruct-v0.1"]
list_llm_simple = [os.path.basename(llm) for llm in list_llm]
@spaces.GPU
def load_doc(list_file_path, chunk_size, chunk_overlap):
loaders = [PyPDFLoader(x) for x in list_file_path]
pages = []
for loader in loaders:
pages.extend(loader.load())
text_splitter = RecursiveCharacterTextSplitter(
chunk_size=chunk_size,
chunk_overlap=chunk_overlap)
doc_splits = text_splitter.split_documents(pages)
return doc_splits
def create_db(splits, collection_name):
if torch.cuda.is_available():
os.environ["CUDA_VISIBLE_DEVICES"] = "0"
embedding = HuggingFaceEmbeddings(
model_name="sentence-transformers/all-MiniLM-L6-v2",
model_kwargs={"use_auth_token": hf_token}
)
new_client = chromadb.EphemeralClient()
vectordb = Chroma.from_documents(
documents=splits,
embedding=embedding,
client=new_client,
collection_name=collection_name,
)
return vectordb
def create_collection_name(filepath):
collection_name = Path(filepath).stem
collection_name = collection_name.replace(" ", "-")
collection_name = unidecode(collection_name)
collection_name = re.sub('[^A-Za-z0-9]+', '-', collection_name)
collection_name = collection_name[:50]
if len(collection_name) < 3:
collection_name = collection_name + 'xyz'
if not collection_name[0].isalnum():
collection_name = 'A' + collection_name[1:]
if not collection_name[-1].isalnum():
collection_name = collection_name[:-1] + 'Z'
return collection_name
def initialize_global_llm(llm_model, temperature, max_tokens, top_k, progress=gr.Progress()):
global global_llm, global_tokenizer
if global_llm is None:
progress(0.1, desc="Initializing HF tokenizer...")
global_tokenizer = AutoTokenizer.from_pretrained(llm_model, use_auth_token=hf_token)
progress(0.3, desc="Loading model...")
try:
model = AutoModelForCausalLM.from_pretrained(
llm_model,
use_auth_token=hf_token,
torch_dtype=torch.float16,
device_map="auto"
)
except RuntimeError as e:
if "CUDA out of memory" in str(e):
raise gr.Error("GPU memory exceeded. Try a smaller model or reduce batch size.")
else:
raise e
progress(0.5, desc="Initializing HF pipeline...")
pipeline = transformers.pipeline(
"text-generation",
model=model,
tokenizer=global_tokenizer,
torch_dtype=torch.float16,
device_map="auto",
max_new_tokens=max_tokens,
do_sample=True,
top_k=top_k,
num_return_sequences=1,
eos_token_id=global_tokenizer.eos_token_id
)
global_llm = HuggingFacePipeline(pipeline=pipeline, model_kwargs={'temperature': temperature})
progress(0.9, desc="LLM initialization complete!")
return "LLM initialized successfully!"
else:
progress(0.9, desc="Using previously initialized LLM.")
return "Using previously initialized LLM."
def initialize_database(list_file_obj, chunk_size, chunk_overlap, progress=gr.Progress()):
if list_file_obj is None or len(list_file_obj) == 0:
return None, None, "Error: No files uploaded. Please upload PDF files first."
list_file_path = [x.name for x in list_file_obj if x is not None]
if not list_file_path:
return None, None, "Error: No valid files found. Please upload PDF files."
progress(0.1, desc="Creating collection name...")
collection_name = create_collection_name(list_file_path[0])
progress(0.25, desc="Loading document...")
doc_splits = load_doc(list_file_path, chunk_size, chunk_overlap)
progress(0.5, desc="Generating vector database...")
vector_db = create_db(doc_splits, collection_name)
progress(0.9, desc="Done!")
return vector_db, collection_name, "Complete!"
def initialize_LLM(llm_option, llm_temperature, max_tokens, top_k, vector_db, progress=gr.Progress()):
llm_name = list_llm[llm_option]
global_llm = initialize_global_llm(llm_name, llm_temperature, max_tokens, top_k, progress)
memory = ConversationBufferMemory(
memory_key="chat_history",
output_key='answer',
return_messages=True
)
retriever = vector_db.as_retriever()
qa_chain = ConversationalRetrievalChain.from_llm(
global_llm,
retriever=retriever,
chain_type="stuff",
memory=memory,
return_source_documents=True,
verbose=False,
)
return qa_chain, "Complete!"
def format_chat_history(message, chat_history):
formatted_chat_history = []
for user_message, bot_message in chat_history:
formatted_chat_history.append(f"User: {user_message}")
formatted_chat_history.append(f"Assistant: {bot_message}")
return formatted_chat_history
def conversation(qa_chain, message, history):
formatted_chat_history = format_chat_history(message, history)
response = qa_chain({"question": message, "chat_history": formatted_chat_history})
response_answer = response["answer"]
if response_answer.find("Helpful Answer:") != -1:
response_answer = response_answer.split("Helpful Answer:")[-1]
response_sources = response["source_documents"]
response_source1 = response_sources[0].page_content.strip()
response_source2 = response_sources[1].page_content.strip()
response_source3 = response_sources[2].page_content.strip()
response_source1_page = response_sources[0].metadata["page"] + 1
response_source2_page = response_sources[1].metadata["page"] + 1
response_source3_page = response_sources[2].metadata["page"] + 1
new_history = history + [(message, response_answer)]
return qa_chain, gr.update(value=""), new_history, response_source1, response_source1_page, response_source2, response_source2_page, response_source3, response_source3_page
def demo():
with gr.Blocks(theme="base") as demo:
vector_db = gr.State()
qa_chain = gr.State()
collection_name = gr.State()
gr.Markdown(
"""<center><h2>GPU-Accelerated PDF-based Chatbot</center></h2>
<h3>Ask any questions about your PDF documents</h3>""")
gr.Markdown(
"""<b>Note:</b> This AI assistant uses GPU acceleration for faster processing.
It performs retrieval-augmented generation (RAG) from your PDF documents using Langchain and open-source LLMs.
This chatbot takes past questions into account and includes document references.""")
with gr.Tab("Step 1 - Initialize LLM"):
llm_btn = gr.Radio(list_llm_simple, label="LLM models", value=list_llm_simple[0], type="index", info="Choose your LLM model")
with gr.Accordion("Advanced options - LLM model", open=False):
slider_temperature = gr.Slider(minimum=0.01, maximum=1.0, value=0.7, step=0.1, label="Temperature", info="Model temperature", interactive=True)
slider_maxtokens = gr.Slider(minimum=224, maximum=4096, value=1024, step=32, label="Max Tokens", info="Model max tokens", interactive=True)
slider_topk = gr.Slider(minimum=1, maximum=10, value=3, step=1, label="top-k samples", info="Model top-k samples", interactive=True)
llm_progress = gr.Textbox(value="Not initialized", label="LLM initialization status")
init_llm_btn = gr.Button("Initialize LLM")
with gr.Tab("Step 2 - Upload PDF"):
document = gr.Files(height=100, file_count="multiple", file_types=["pdf"], interactive=True, label="Upload your PDF documents (single or multiple)")
with gr.Tab("Step 3 - Process document"):
db_btn = gr.Radio(["ChromaDB"], label="Vector database type", value = "ChromaDB", type="index", info="Choose your vector database")
with gr.Accordion("Advanced options - Document text splitter", open=False):
slider_chunk_size = gr.Slider(minimum = 100, maximum = 1000, value=600, step=20, label="Chunk size", info="Chunk size", interactive=True)
slider_chunk_overlap = gr.Slider(minimum = 10, maximum = 200, value=40, step=10, label="Chunk overlap", info="Chunk overlap", interactive=True)
db_progress = gr.Textbox(label="Vector database initialization", value="None")
db_btn = gr.Button("Generate vector database")
with gr.Tab("Step 4 - Initialize QA chain"):
llm_progress = gr.Textbox(value="None",label="QA chain initialization")
qachain_btn = gr.Button("Initialize Question Answering chain")
with gr.Tab("Step 5 - Chatbot"):
chatbot = gr.Chatbot(height=300)
with gr.Accordion("Advanced - Document references", open=False):
with gr.Row():
doc_source1 = gr.Textbox(label="Reference 1", lines=2, container=True, scale=20)
source1_page = gr.Number(label="Page", scale=1)
with gr.Row():
doc_source2 = gr.Textbox(label="Reference 2", lines=2, container=True, scale=20)
source2_page = gr.Number(label="Page", scale=1)
with gr.Row():
doc_source3 = gr.Textbox(label="Reference 3", lines=2, container=True, scale=20)
source3_page = gr.Number(label="Page", scale=1)
with gr.Row():
msg = gr.Textbox(placeholder="Type message (e.g. 'What is this document about?')", container=True)
with gr.Row():
submit_btn = gr.Button("Submit message")
clear_btn = gr.ClearButton([msg, chatbot], value="Clear conversation")
# Event handlers
init_llm_btn.click(
initialize_global_llm,
inputs=[llm_btn, slider_temperature, slider_maxtokens, slider_topk],
outputs=[llm_progress]
)
db_btn.click(initialize_database,
inputs=[document, slider_chunk_size, slider_chunk_overlap],
outputs=[vector_db, collection_name, db_progress])
qachain_btn.click(initialize_LLM,
inputs=[llm_btn, slider_temperature, slider_maxtokens, slider_topk, vector_db],
outputs=[qa_chain, llm_progress]).then(lambda:[None,"",0,"",0,"",0],
inputs=None,
outputs=[chatbot, doc_source1, source1_page, doc_source2, source2_page, doc_source3, source3_page],
queue=False)
# Chatbot events
msg.submit(conversation,
inputs=[qa_chain, msg, chatbot],
outputs=[qa_chain, msg, chatbot, doc_source1, source1_page, doc_source2, source2_page, doc_source3, source3_page],
queue=False)
submit_btn.click(conversation,
inputs=[qa_chain, msg, chatbot],
outputs=[qa_chain, msg, chatbot, doc_source1, source1_page, doc_source2, source2_page, doc_source3, source3_page],
queue=False)
clear_btn.click(lambda:[None,"",0,"",0,"",0],
inputs=None,
outputs=[chatbot, doc_source1, source1_page, doc_source2, source2_page, doc_source3, source3_page],
queue=False)
demo.queue().launch(debug=True)
if __name__ == "__main__":
demo()