Official download component

[chriddyp]

There are a few ways that you can download content with Dash:

1. href URI links: https://community.plot.ly/t/download-raw-data/4700/21
2. Static URLs with URL parameters: https://community.plot.ly/t/allowing-users-to-download-csv-on-click/5550/12

The former apparently doesn't work in IE11 (plotly/dash-recipes#11) and the latter is a little bit out of the Dash framework (URL parameters instead of just inputs).

So, maybe there is a case for a proper download component.

[chriddyp]

We could possible draw inspiration from here: https://github.com/axetroy/react-download

[amarvin]

I've also used Flask functionality for this.

To serve static files:

import os
import dash
from flask import send_from_directory

app = dash.Dash()
STATIC_PATH = os.path.join(app.server.root_path, 'static')
# define layout...
#  add links with, for example: href='/static/test.csv'

@app.server.route('/static/<filename>')
def serve_static(filename):
    return send_from_directory(STATIC_PATH, filename)

Serving dynamic files is also possible with Flask: https://matthewmoisen.com/blog/how-to-download-a-csv-file-in-flask/, which looks similar to URI links, but supports older web browsers

[ieipi]

+1 for the feature.

[raghavendrajain]

Hi. Is it is implemented already now? @chriddyp

[amarvin]

Dash has a default static files folder "assets" so any files there can be linked to as "assets/FILENAME.X" so you can use that for e.g. CSS files and downloadable static files. For a downloadable static file just add a link on the page.

Dynamic file downloads still requires an URI link creation.

[raghavendrajain]

Thannk you @amarvin.

[vcmorini]

Another workaround:
https://community.plotly.com/t/download-large-csv-file/39389