app.py

import os
import json
import gradio as gr
import pandas as pd
from tempfile import NamedTemporaryFile
from typing import List
from langchain_core.prompts import ChatPromptTemplate
from langchain_community.vectorstores import FAISS
from langchain_community.document_loaders import PyPDFLoader
from langchain_core.output_parsers import StrOutputParser
from langchain_community.embeddings import HuggingFaceEmbeddings
from langchain_text_splitters import RecursiveCharacterTextSplitter
from langchain_community.llms import HuggingFaceHub
from langchain_core.runnables import RunnableParallel, RunnablePassthrough
from langchain_core.documents import Document
huggingface_token = os.environ.get("HUGGINGFACE_TOKEN")

def load_and_split_document_basic(file):
   """Loads and splits the document into pages."""
   loader = PyPDFLoader(file.name)
   data = loader.load_and_split()
   return data
def load_and_split_document_recursive(file: NamedTemporaryFile) -> List[Document]:
   """Loads and splits the document into chunks."""
   loader = PyPDFLoader(file.name)
   pages = loader.load()
   text_splitter = RecursiveCharacterTextSplitter(
       chunk_size=1000,
       chunk_overlap=200,
       length_function=len,
   )
   chunks = text_splitter.split_documents(pages)
   return chunks
def get_embeddings():
   return HuggingFaceEmbeddings(model_name="sentence-transformers/all-mpnet-base-v2")
def create_or_update_database(data, embeddings):
   if os.path.exists("faiss_database"):
       db = FAISS.load_local("faiss_database", embeddings, allow_dangerous_deserialization=True)
       db.add_documents(data)
   else:
       db = FAISS.from_documents(data, embeddings)
   db.save_local("faiss_database")
def clear_cache():
   if os.path.exists("faiss_database"):
       os.remove("faiss_database")
       return "Cache cleared successfully."
   else:
       return "No cache to clear."
prompt = """
Answer the question based only on the following context:
{context}
Question: {question}
Provide a concise and direct answer to the question:
"""
def get_model(temperature, top_p, repetition_penalty):
   return HuggingFaceHub(
       repo_id="mistralai/Mistral-7B-Instruct-v0.3",
       model_kwargs={
           "temperature": temperature,
           "top_p": top_p,
           "repetition_penalty": repetition_penalty,
           "max_length": 2000
       },
       huggingfacehub_api_token=huggingface_token
   )
def generate_chunked_response(model, prompt, max_tokens=2000, max_chunks=5):
   full_response = ""
   for i in range(max_chunks):
       chunk = model(prompt + full_response, max_new_tokens=max_tokens)
       full_response += chunk
       if chunk.strip().endswith((".", "!", "?")):
           break
   return full_response.strip()
def response(database, model, question):
   prompt_val = ChatPromptTemplate.from_template(prompt)
   retriever = database.as_retriever()
   context = retriever.get_relevant_documents(question)
   context_str = "\n".join([doc.page_content for doc in context])
   formatted_prompt = prompt_val.format(context=context_str, question=question)
   ans = generate_chunked_response(model, formatted_prompt)
   return ans
def update_vectors(files, use_recursive_splitter):
   if not files:
       return "Please upload at least one PDF file."
   embed = get_embeddings()
   total_chunks = 0
   for file in files:
       if use_recursive_splitter:
           data = load_and_split_document_recursive(file)
       else:
           data = load_and_split_document_basic(file)
       create_or_update_database(data, embed)
       total_chunks += len(data)
   return f"Vector store updated successfully. Processed {total_chunks} chunks from {len(files)} files."
def ask_question(question, temperature, top_p, repetition_penalty):
   if not question:
       return "Please enter a question."
   embed = get_embeddings()
   database = FAISS.load_local("faiss_database", embed, allow_dangerous_deserialization=True)
   model = get_model(temperature, top_p, repetition_penalty)
   return response(database, model, question)
def extract_db_to_excel():
   embed = get_embeddings()
   database = FAISS.load_local("faiss_database", embed, allow_dangerous_deserialization=True)
   documents = database.docstore._dict.values()
   data = [{"page_content": doc.page_content, "metadata": json.dumps(doc.metadata)} for doc in documents]
   df = pd.DataFrame(data)
   with NamedTemporaryFile(delete=False, suffix='.xlsx') as tmp:
       excel_path = tmp.name
       df.to_excel(excel_path, index=False)
   return excel_path
# Gradio interface
with gr.Blocks() as demo:
   gr.Markdown("# Chat with your PDF documents")
   with gr.Row():
       file_input = gr.Files(label="Upload your PDF documents", file_types=[".pdf"])
       update_button = gr.Button("Update Vector Store")
       use_recursive_splitter = gr.Checkbox(label="Use Recursive Text Splitter", value=False)
   update_output = gr.Textbox(label="Update Status")
   update_button.click(update_vectors, inputs=[file_input, use_recursive_splitter], outputs=update_output)
   with gr.Row():
       question_input = gr.Textbox(label="Ask a question about your documents")
       temperature_slider = gr.Slider(label="Temperature", minimum=0.0, maximum=1.0, value=0.5, step=0.1)
       top_p_slider = gr.Slider(label="Top P", minimum=0.0, maximum=1.0, value=0.9, step=0.1)
       repetition_penalty_slider = gr.Slider(label="Repetition Penalty", minimum=1.0, maximum=2.0, value=1.0, step=0.1)
       submit_button = gr.Button("Submit")
   answer_output = gr.Textbox(label="Answer")
   submit_button.click(ask_question, inputs=[question_input, temperature_slider, top_p_slider, repetition_penalty_slider], outputs=answer_output)
   extract_button = gr.Button("Extract Database to Excel")
   excel_output = gr.File(label="Download Excel File")
   extract_button.click(extract_db_to_excel, inputs=[], outputs=excel_output)
   clear_button = gr.Button("Clear Cache")
   clear_output = gr.Textbox(label="Cache Status")
   clear_button.click(clear_cache, inputs=[], outputs=clear_output)
if __name__ == "__main__":
   demo.launch()