How to upload a file and provide that to a python program using dash?

Hi,

I am a bioinformatician with intermediate knowledge of Python. I am relatively new to dash.

I already have a python program which takes 3 arguments - 2 files and one integer and processes something from the files based on the integer value. I wish to make this available online so that it is accessible across the internet. I know this is possible using python dash.

As a starting point, what I wish to just have a drag and drop UI from which user can browse and upload the file. And now I just want to provide that file to my already created program. It does not work. Right now I just wish that the uploaded file’s name prints in the console.

import dash
from dash.dependencies import Input, Output
import dash_core_components as dcc
import dash_html_components as html

app = dash.Dash()

app.layout = html.Div([
    dcc.Upload(
        id='upload-data',
        children=html.Div([
            'Drag and Drop or ',
            html.A('Select Files')
        ]),
        style={
            'width': '50%',
            'height': '60px',
            'lineHeight': '60px',	
            'borderWidth': '1px',
            'borderStyle': 'dashed',
            'borderRadius': '5px',
            'textAlign': 'center',
            'margin': '10px'
        },
        # Allow multiple files to be uploaded
        multiple=True
    ),
    html.Div(id='output-data-upload')
])

@app.callback(Output('upload-data'),
              [
              Input('upload-data'),
              ])

def parse_data(input_data):
    file=output-data-upload
    print "filename is ", file
 
    

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