Problem

The Streamlit app reloads entirely when clicking on a st.download_button. In my case, I think it should not: download buttons are different from buttons and should not trigger a reload of the app. They should only trigger a download.

I perfectly understand that a click on a button does reload the app (to recompute) but downloads don't change the view, downloads don't trigger computations etc.

I also know about the cache, but it is not always a proper solution: what about apps with a st.forms? The user should not have to click on yet another button to generate the same view that has not changed one bit. The same goes if several files can be downloaded: it can be very cumbersome to do such a simple task.

Solution

Several options:

1. Stop reloading the app for a st.download_button
2. Add a parameter to trigger (or not) a reload of the page when clicking on a st.download_button.

Additional context

See this discourse: https://discuss.streamlit.io/t/stop-page-from-reloading-after-using-downloader/18744

And this code to reproduce the problem exposed above:

import streamlit as st

def long_computation():
    import time
    time.sleep(10)

st.header("TEST DOWNLOAD BUTTON")

with st.spinner("Running a long computation.."):
    long_computation()

st.download_button("Download", "a")

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