import io
import dash
import dash_html_components as html
from flask import send_file
import pandas as pd


app = dash.Dash()
app.layout = html.Div(
    children=[html.A("download excel", href="/download_excel/")])


@app.server.route("/download_excel/")
def download_excel():
    # Create DF
    d = {"col1": [1, 2], "col2": [3, 4]}
    df = pd.DataFrame(data=d)

    # Convert DF
    buf = io.BytesIO()
    excel_writer = pd.ExcelWriter(buf, engine="xlsxwriter")
    df.to_excel(excel_writer, sheet_name="sheet1")
    excel_writer.save()
    excel_data = buf.getvalue()
    buf.seek(0)

    return send_file(
        buf,
        mimetype = 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
        attachment_filename="test11311.xlsx",
        as_attachment=True,
        cache_timeout=0
    )


if __name__ == "__main__":
    app.run_server(debug=True)