app.py

import tempfile
import streamlit as st
import os

def create_pdf_download_button(pdf_path):
    # Check if the PDF file exists
    if not os.path.exists(pdf_path):
        st.error(f"The PDF file '{os.path.basename(pdf_path)}' was not found.")
        return
    
    # Create a download link
    st.markdown(
        f"""
        <a href="data:application/pdf;base64,{base64_encode_file(pdf_path)}"
           download="{os.path.basename(pdf_path)}"
           class="streamlit-button">
        Download PDF
        </a>
        """,
        unsafe_allow_html=True,
    )

def base64_encode_file(file_path):
    # Read the file contents
    with open(file_path, "rb") as file:
        encoded_data = base64.b64encode(file.read()).decode()
    
    return encoded_data

def main():
    if "tmp_dir" not in st.session_state:
        st.session_state.tmp_dir = tempfile.TemporaryDirectory()
    if "temp_pdf_path" not in st.session_state:
        st.session_state.temp_pdf_path = None
    
    uploaded_file = st.file_uploader("Choose a PDF file", type="pdf")
    
    if uploaded_file:
        pdf_file = uploaded_file
        temp_pdf_path = os.path.join(st.session_state.tmp_dir, "pdf_file")
        with open(temp_pdf_path, "wb") as f:
            f.write(pdf_file.getvalue())
        st.session_state.temp_pdf_path = temp_pdf_path
        uploaded_file = None
    
        create_pdf_download_button(st.session_state.temp_pdf_path)


if __name__ == "__main__":
    main()