Obtaining data from layout elements out of callbacks

Dash Python
1

Is it possible?
Thank you!

2

are you able to describe your problem a little better? there isn’t too much context provided to help.

3

Ok, sorry for that, I regarded it as a trivial matter. The thing is I want to create and download a file with data from graphs. I use two buttons for that. One of them generates the file in the local server from within a callback and the other one allows to download it from another device (phone, tablet…), but this time using a Flask server.route direction
I would like to join both actions in a single “Generate and download” button.
I’ve got stuck trying with requests library (How do you specify the download path from a external device like a mobile phone?) or trying embedding the callback into the server.route direction.
Now I’m thinking about collecting data from layout from within the server.route clause but not using a callback.
So any idea?

Here is the chunk of code:

@server.route("/download/<path:path>")
def download_report(path):
         return send_from_directory(FILE_DIRECTORY,path,as_attachment=True)


app.layout=html.Div([
           html.Div([
                 html.A(html.Button('Download file'), href="download/file.docx")
                 dcc.Graph(
                    id='crossfilter-indicator-scatter',
                    hoverData={'points': [{'customdata': 'Spain'}]}
                 ),
            ], style={'display': 'inline-block', 'width': '49%'}
           ),
           
           html.Div([
                 html.Div([
                      dcc.Graph(id='x-time-series'),
                      html.Button(id="generate-file-button", n_clicks=0, children="Generate file"),
                     
  
 
                       
                   
                      
           html.Div(id='file-content',
                    style={'display': 'none'},
                    children='{"columns":["country_name","Year","Indicator_Name","Value"],"index":[6,16,26],"data":[["Spain",1962,"Agriculture.value added (% of GDP)",null],["Spain",1967,"Agriculture.value added (% of GDP)",null],["Spain",1972,"Agriculture.value added (% of GDP)",null]]}'
           ),
           html.Div(id='garbage-generate-file-button',
                    style={'display': 'none'},
                    children=''
           )
    ])        

@app.callback(
    dash.dependencies.Output('garbage-generate-file-button','children'),
    [dash.dependencies.Input('generate-file-button','n_clicks')],
    [dash.dependencies.State('graph','figure'),
     dash.dependencies.State('file-content', 'children')])  
def imprime_x(n_clicks,figure,dff_text):
        
        ... #Various preprocessing code sentences

        document=Document()
        document.add_heading(title)
        document.add_picture('picture.png', width=Inches(7), height=Inches(8))
 
        table = document.add_table(rows=1, cols=2, style='Colorful List Accent 1')
        document.save('file.docx')
        return json.dumps(dff_dicc)
4

Here is a chuck of code I use to create an excel file (via openpyxl) when a user presses a button on the app. The file is created within the download_file function.

The browser handles the prompt to where to save (Firefox opens a dialog box, Chrome automatically downloads to the Downloads folder on my laptop).

Not sure if this helps but it could spawn an idea or two.

@app.server.route('/download_file/')
def download_file():
    # Process inputs
    slider_date = flask.request.args.get('slider')
    station_v = flask.request.args.get('station_v')
    ...

    # Create excel file
    wb = excel.create_workbook(...)
    
    #  ...code to create excel file using openpyxl...

    # Set filename
    desired_filename = 'yourfilename.xlsx'

    with NamedTemporaryFile() as tmp:
        wb.save(tmp.name)
        str_io = io.BytesIO(tmp.read())

    return flask.send_file(str_io,
                           attachment_filename=desired_filename,
                           as_attachment=True)