st.download_button() should not rerun the entire page

Hi folks,

Please, consider the MWE below:

import streamlit as st
import pandas as pd

with st.form(key='form1'): 
   user_input = st.text_input("Insert text")
   submit = st.form_submit_button("Submit")

if submit:    
  st.warning("This part should not be lost after clicking the download button!")  
  st.write(user_input) 
   
   # Save dataframe as a .csv file
   df = pd.DataFrame({"v1": [1,2,3]})    
   file_name = "df.csv"
   file_path = f"./{file_name}"
   #
   df.to_csv(file_path)   
   # Create Download Button
   file_bytes = open(file_path, 'rb')
   st.download_button(label='Click to download',
                       data=file_bytes, 
                       file_name=file_name,
                       key='download_df')
   file_bytes.close()

Problem

st.download_button() reruns the entire page, erasing everything that was opened after clicking “Submit”. This behavior can be problematic, specially for applications that use st.form() like this one.

Solution

Having an option in st.download_button() to not rerun anything would be really great.

Thank you

[GitHunter0]

Thanks @vdonato !

Actually, I believe all suitable Streamlit components should have a rerun parameter with 3 options:

• rerun the entire page (currently the default behavior)
• rerun everything below the current component but nothing above
• rerun nothing

@kajarenc , I also don’t know how difficult it would be to implement it but in my view it would put Streamlit in another level of capabilities and fulfill the requirements of more intermediate/advanced developers.

Please let me know what you guys think about this and if I should open a separate issue for that.

Streamlit is awesome and with just a few improvements I believe it will be unstoppable.

[legendof-selda]

any update on this issue?