app.py

import streamlit as st
from haystack.document_stores import InMemoryDocumentStore
from haystack.nodes import TransformersSummarizer, PreProcessor, PDFToTextConverter, TfidfRetriever
from haystack.schema import Document
import logging

document_store = InMemoryDocumentStore()
preprocessor = PreProcessor(
    clean_empty_lines=True,
    clean_whitespace=True,
    clean_header_footer=True,
    split_by="word",
    split_length=100,
    split_respect_sentence_boundary=True,
    split_overlap=3
)
summarizer = TransformersSummarizer(model_name_or_path="google/pegasus-xsum")


def pdf_to_document_store(pdf_files):
    converter = PDFToTextConverter(remove_numeric_tables=True, valid_languages=["en"])
    documents = []
    for pdf in pdf_files:
        st.write(pdf.name)
        doc = converter.convert(file_path=pdf.name, meta=None)[0]
        documents.append(doc)
    st.write(len(documents))
    preprocessed_docs = preprocessor.process(documents)
    document_store.write_documents(preprocessed_docs)
    return None

def summarize(files):
    pdf_to_document_store(files)
    summary = summarizer.predict(documents=document_store.get_all_documents(), generate_single_summary=True)
    st.write(summary)
    
uploaded_files = st.file_uploader("Choose PDF files", accept_multiple_files=True)

if uploaded_files is not None:
    st.write(len(uploaded_files))
    if st.button('Summarize Documents'):
        document_store.delete_documents()
        summarize(uploaded_files)

if st.button('Calculate num of docs'):
    st.write(document_store.get_document_count())