Plotly-Dash 下载 DataFrame 到 CSV 不再适用于 send_data_frame

Question

以下 Python 代码片段直到最近一直在为我工作，我找不到任何更改的文档。我正在尝试使用 Plotly 的 dash_core_components 模块中的 send_data_frame 函数将 Pandas DataFrame 作为 CSV 文件写入磁盘。

import numpy as np
import pandas as pd
import dash
import dash_core_components as dcc
import dash_html_components as html
from dash.dependencies import Input, Output, State
import dash_bootstrap_components as dbc
from dash_extensions import Download
from dash_extensions.snippets import send_data_frame

layout = html.Div([
  ...
  ... # Trying to be as complete, but as brief as possible with my snippet.
  ...
  ... # The main gist is that there are 2 buttons on the page, one that
  ... # triggers a callback to download stock data (OHLC prices), and another
  ... # that saves the data to disk after it has been gathered.
])

# MAIN APP CALLBACK -- This downloads the OHLC data from Yahoo Finance.
@app.callback(
    Output('ohlcData', 'children'),
  [
    Input('button', 'n_clicks')
  ],[
    State('ticker', 'value')
  ], prevent_initial_call=True)
def get_ohlc_data(n_clicks, ticker):
  ohlc = getOHLC(ticker) # This works, but the method is not shown here
  df = ohlc.df

  # Write the OHLC DataFrame to a hidden DataFrame
  hiddenDF = df.to_json(date_format='iso', orient='split')

  return hiddenDF

# DOWNLOAD CSV CALLBACK -- This secondary callback finds the hiddenDiv and attempts to write it to disk as a CSV file.
@app.callback(
    Output('dataFrame', 'data'),
  [
    Input('button2', 'n_clicks')
  ],[
    State('ohlcData', 'children')
  ], prevent_initial_call=True)
def writeCSV(n_clicks, hiddenDiv):
  dfOHLC = pd.read_json(hiddenDiv, orient='split')
  dfOHLC.index.name = 'Date'
  return send_data_frame(dfOHLC.to_csv, 'OHLC.csv')

上周当我运行此代码时，当我尝试“下载”CSV 文件或将 CSV 文件保存到磁盘时，我会得到一个弹出窗口 window。现在我什至没有走那么远，而是收到一条警告（必须设置 debug=True），指出：

Failed component prop type: Invalid component prop `data` key `mime_type` supplied to Download.
Bad object: {
  "content": 
"[A really long string of characters]",
  "filename": "OHLC.csv",
  "mime_type": null,
  "base64": true
}
Valid keys: [
  "filename",
  "content",
  "base64",
  "type"
]

请帮忙！

鉴于错误信息，我猜测 Output('dataFrame', 'data') 中的输出选项 data 突然是一个无效参数。

Answer 1

当 Download 组件从 dash-extensions 迁移到 dash-core-components 时，mime_type 属性重命名为 type。您的错误表明您正在使用 dash-core-components 创建 Download 组件，但使用 send_data_frame 从 dash-extensions.

发送数据

如果您始终使用其中一个，它应该会起作用。但是，dash-core-components 组件将在未来得到支持，因此我建议使用该组件。

Plotly-Dash 下载 DataFrame 到 CSV 不再适用于 send_data_frame

Plotly-Dash download DataFrame to CSV no longer works with send_data_frame

python

plotly

plotly-dash