I have a page that displays a list of files in a directory. When the user clicks on the Download button, all of these files are zipped into a single file, which is then offered for download. I know how to send this file to the browser when the button is clicked, and I know how to reload the current page (or redirect to a different one), but is it possible to do both in the same step? Or would it make more sense to redirect to a different page with a download link?

My download is initiated with the Flask API's send_from_directory. Relevant test code:

@app.route('/download', methods=['GET','POST'])
def download():
    error=None
    # ...

    if request.method == 'POST':
        if download_list == None or len(download_list) < 1:
            error = 'No files to download'
        else:
            timestamp = dt.now().strftime('%Y%m%d:%H%M%S')
            zfname = 'reports-' + str(timestamp) + '.zip'
            zf = zipfile.ZipFile(downloaddir + zfname, 'a')
            for f in download_list:
                zf.write(downloaddir + f, f)
            zf.close()

            # TODO: remove zipped files, move zip to archive

            return send_from_directory(downloaddir, zfname, as_attachment=True)

    return render_template('download.html', error=error, download_list=download_list)

Update: As a workaround, I am now loading a new page with the button click, which lets the user initiate the download (using send_from_directory) before returning to the updated listing.

html download flask
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