FileInput#

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import io
import panel as pn
pn.extension()

The FileInput widget allows uploading one or more files from the frontend and makes the filename, file data and MIME type available in Python. To upload large files, use the FileDropper widget.


Discover more on using widgets to add interactivity to your applications in the how-to guides on interactivity. Alternatively, learn how to set up callbacks and (JS-)links between parameters or how to use them as part of declarative UIs with Param.




Parameters:#


For details on other options for customizing the component see the layout and styling how-to guides.




Core#


    

  • accept (str):  A list of file input filters that restrict what files the user can pick from
    • 

  • directory (str): If directories is upload instead of files
    • 

  • filename (str/list): The filename(s) of the uploaded file(s)
    • 

  • mime_type (str/list): The mime type(s) of the uploaded file(s)
    • 

  • multiple (boolean): Whether to allow uploading multiple files
    • 

  • value (bytes/list): A bytes object containing the file data or if multiple is set a list of bytes objects.
    • 





file_input = pn.widgets.FileInput()

file_input








To read out the content of the file you can access the value parameter, which holds a bytestring containing the file’s contents. Additionally information about the file type is made available on the filetype parameter expressed as a MIME type, e.g. image/png or text/csv.


file_input.value





The widget also has a save method that allows saving the uploaded data to a file or BytesIO object.


# File
if file_input.value is not None:
    file_input.save('test.png')

# BytesIO object
if file_input.value is not None:
    out = io.BytesIO()
    file_input.save(out)





The accept parameter restricts what files the user can pick from. This consists of comma-separated list of standard HTML
file input filters. Values can be:


    

  • <file extension> - Specific file extension(s) (e.g: .gif, .jpg, .png, .doc) are pickable
    • 

  • audio/* - all sound files are pickable
    • 

  • video/* - all video files are pickable
    • 

  • image/* - all image files are pickable
    • 

  • <media type> - A valid IANA Media Type, with no parameters.
    • 



file_input = pn.widgets.FileInput(accept='.csv,.json')

file_input








To allow uploading multiple files we can also set multiple=True or if you want to upload a whole directory directory=True:


file_input = pn.widgets.FileInput(accept='.png', multiple=True)

file_input








When uploading one or more files the filename, mime_type and value parameters will now be lists.


You can also clear the file input with the .clear() method.


file_input.clear()











Upload size limits#


While the FileInput widget doesn’t set any limit on the size of a file that can be selected by a user, the infrastructure onto which Panel relies (web browsers, Bokeh, Tornado, notebooks, kubernetes etc.) limits significantly what is actually possible. By default the FileInput widget allows to upload data that is in the order of 10 MB. To increase these limits see the Websocket Configuration Guide.






Controls#


The FileInput widget exposes a number of options which can be changed from both Python and Javascript. Try out the effect of these parameters interactively:


pn.Row(file_input.controls(jslink=True), file_input)










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