如何处理 Dash 中上传的 zip 文件？

Question

使用 dcc.Upload，您可以在 Dash Plotly 仪表板中构建拖放或基于按钮的上传功能。但是，文档中对处理特定文件类型（如 .zip）有限制。这是上传的片段 html:

dcc.Upload(
    id='upload_prediction',
    children=html.Div([
        'Drag and Drop or ',
        html.A('Select Files'),
        ' New Predictions (*.zip)'
    ]),
    style={
        'width': '100%',
        'height': '60px',
        'lineHeight': '60px',
        'borderWidth': '1px',
        'borderStyle': 'dashed',
        'borderRadius': '5px',
        'textAlign': 'center',
        'margin': '10px'
    },
    accept=".zip",
    multiple=True
)

然后当我尝试使用此代码段检查上传的文件时：

@app.callback(Output('output_uploaded', 'children'),
              [Input('upload_prediction', 'contents')],
              [State('upload_prediction', 'filename'),
               State('upload_prediction', 'last_modified')])
def test_callback(list_of_contents, list_of_names, list_of_dates):
    for content in list_of_contents:
        print(content)

上传后的content-type为‘data:application/x-zip-compressed;base64’。如何在 Dash Plotly 中处理此类文件（例如将其提取到某处）？

在 plotly 论坛上问了一个类似的问题，但没有答案： https://community.plot.ly/t/dcc-upload-zip-file/33976

Answer 1

Dash Plotly提供base64字符串格式的上传文件。您需要做的是先对其进行解码，然后将其作为字节字符串处理，稍后可用于初始化ZipFile class（这是python中的内置工具）。

import io
import base64
from zipfile import ZipFile


@app.callback(Output('output_uploaded', 'children'),
              [Input('upload_prediction', 'contents')],
              [State('upload_prediction', 'filename'),
               State('upload_prediction', 'last_modified')])
def update_output(list_of_contents, list_of_names, list_of_dates):
    for content, name, date in zip(list_of_contents, list_of_names, list_of_dates):
        # the content needs to be split. It contains the type and the real content
        content_type, content_string = content.split(',')
        # Decode the base64 string
        content_decoded = base64.b64decode(content_string)
        # Use BytesIO to handle the decoded content
        zip_str = io.BytesIO(content_decoded)
        # Now you can use ZipFile to take the BytesIO output
        zip_obj = ZipFile(zip_str, 'r')

        # you can do what you wanna do with the zip object here

如何处理 Dash 中上传的 zip 文件？

How to handle uploaded zip file in Dash plotly?

python

plotly

data-science

plotly-dash