Excel data to table on Dashing Dashboard

Question

I have been trying to convert a Dashing widget called spreadsheetDemo to use the Roo GEM to simplify it and allow for it to cater for local and Google Doc Excel files.(Simply the same just with Roo) I began by looking at other widgets and sources (similar to this just to a table not graph) that are already using Roo and I have tried to reuse their code for the file source in place of the original, resulting in my code below. I am trying to use Roo to access the local spreadsheet, take the headings and data for the 6 columns and rows and then push them to a table. I believe my problem may lie with accessing the speadsheet correctly. Everything is on the first workbook and starts in cell A1.

Sources I have used: https:// github.com/Shopify/dashing/issues/78#issuecomment-14940695

http:// stackoverflow.com/questions/29400811/use-with-excel-data-to-display-on-dashing-dashboard/29421179?newreg=5c8c7db27d104f5ab3b855c8ea729bc8

require 'roo'

#Tried using roo-xls as it started throwing errors saying I needed too.
#require 'roo-xls'


EM.kqueue = EM.kqueue?
file_path = "#{Dir.pwd}/spreadsheet.xls"

def fetch_spreadsheet_data(path)
  s = Roo::Excel.new(path)

    ws = workbook.sheets[0]

  # create an array to hold the lines
    rows = Array.new
    header = Array.new

  # other variables
    up = ws.updated.localtime
    up = up.strftime "%d.%m.%Y %H:%M"

    #workbook.default_sheet = workbook.sheets[0]


    # fill lines
    for row in 1..ws.num_rows
      if row == 1
          header.push({ :c1 => ws[row, 1], :c2 => ws[row, 2], :c3 => ws[row, 3], :c4 => ws[row, 4], :c5 => ws[row, 5], :c6 => ws[row, 6]})
      else
        rows.push({ :c1 => ws[row, 1], :c2 => ws[row, 2], :c3 => ws[row, 3], :c4 => ws[row, 4], :c5 => ws[row, 5], :c6 => ws[row, 6]})
      end
    end 
        send_event('spread', :modified => up, :header => header, :rows => rows)
        rescue => err
    #puts "Exception: #{err}"
end



module Handler
  def file_modified
    fetch_spreadsheet_data(path)
  end
end

fetch_spreadsheet_data(file_path)

end

Answer 1

It contains a feature named "Download." The user is prompted to download something when you return something to it. As an example, your code might look like this:

import io
import dash
import dash_html_components as html
from dash.dependencies import Input, Output, State
from dash.exceptions import PreventUpdate
from dash_extensions import Download
import dash_table
from flask import Flask
import pandas as pd

server = Flask(__name__)
app = dash.Dash(server=server)

df = pd.read_csv('https://raw.githubusercontent.com/plotly/datasets/master/solar.csv')

app.layout = html.Div(
                [
                    Download(id="download"),
                    html.Button("Save",
                                id="save-button"),
                    html.Div("Press button to save data at your desktop",
                             id="output-1"),
                    dash_table.DataTable(
                        id='table',
                        columns=[{"name": i, "id": i} for i in df.columns],
                        data=df.to_dict('records'),
                    )
                ]
            )


@app.callback(
Output("download", "data"),
Input("save-button", "n_clicks"),
State("table", "data"))
def download_as_csv(n_clicks, table_data):
    df = pd.DataFrame.from_dict(table_data)
    if not n_clicks:
      raise PreventUpdate
    download_buffer = io.StringIO()
    df.to_csv(download_buffer, index=False)
    download_buffer.seek(0)
    return dict(content=download_buffer.getvalue(), filename="some_filename.csv")

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