FileDropper#

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import io
import panel as pn
pn.extension('filedropper')

The FileDropper allows the user to upload one or more files to the server. It is built on top of the FilePond library, if you use this component extensively consider donating to them. The FileDropper is similar to the FileInput widget but additionally adds support for chunked uploads, making it possible to upload large files. The UI also supports previews for image files. Unlike FileInput the uploaded files are stored as dictionary of bytes object indexed by the filename.


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#


    

  • accepted_filetypes (list): List of accepted file types. Can be mimetypes, file extensions or wild cards. For instance ['image/*'] will accept all images while ['.png', 'image/jpeg'] will only accepts PNGs and JPEGs.
    • 

  • chunk_size (int): Size in bytes per chunk transferred across the WebSocket (default=10000000, i.e. 10MB).
    • 

  • layout (Literal[“circle”, “compact”, “integrated”] | None): Compact mode will remove padding, integrated mode is used to render FilePond as part of a bigger element (and should not be used with multiple=True. Circle mode adjusts the item position offsets so buttons and progress indicators don’t fall outside of the circular shape.
    • 

  • max_file_size (str): Maximum size of a file as a string with units given in KB or MB, e.g. 5MB or 750KB.
    • 

  • max_files (int): Maximum number of files that can be uploaded if multiple=True.
    • 

  • max_total_file_size (str): Maximum size of all uploaded files, as a string with units given in KB or MB, e.g. 5MB or 750KB.
    • 

  • mime_type (dict[str, str]): A dictionary containing the mimetypes for each of the uploaded files indexed by their filename.
    • 

  • multiple (bool): Whether to allow uploading multiple files.
    • 

  • value (dict[str, str | bytes]): A dictionary containing the uploaded file(s) as bytes or string objects indexed by the filename. Files that have a text/* mimetype will automatically be decoded as utf-8.
    • 





file_dropper = pn.widgets.FileDropper()

file_dropper







            
            
Try uploading an image or PDF file and you will see a preview of the uploaded file.


To read out the content of the file you can access the value parameter, which holds a dictionary mapping from the filename to a string or bytestring containing the file’s contents. Any filetype that declares a text/* mimetype will automatically be decoded into a string. The mimetype itself is made available on the mime_type parameter expressed as a MIME type, e.g. image/png or text/csv, again expressed as a dictionary mapping from filename to filetype.


file_dropper.value





{}








Filetypes#


The accepted_filetypes parameter restricts what files the user can pick from. This consists of a list of mimetypes that also allows wildcards. 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_dropper = pn.widgets.FileDropper(accepted_filetypes=['.png', 'image/jpeg'])

file_dropper







            
            
To allow uploading multiple files we can also set multiple=True:


file_dropper = pn.widgets.FileInput(multiple=True)

file_dropper







            
            




Layout#


The FileDropper allows for a few different layout options:


    

  • "compact": Remove margins.
    • 

  • "integrated": Removes background and other styling. Useful when the component is embedded inside a larger component.
    • 

  • "circle": Circular upload area useful for profile picture uploads.
    • 



pn.Row(
    pn.widgets.FileDropper(layout="compact"),
    pn.widgets.FileDropper(layout="integrated", styles={'background-color': 'black', 'border-radius': '1em', 'color': 'white'}),
    pn.widgets.FileDropper(layout="circle"),
)







            
            




Upload size limits#


Unlike the FileInput widget the FileDropper widget bypasses restrictions to the maximum file size imposed by web browsers, Bokeh, Tornado, notebooks, etc. by chunking large uploads. This makes it feasible to upload much larger files than would otherwise be possible. The default chunk_size is 10MB (which is expressed in as 10000000 bytes). Even if it is possible to increase this limit by setting some parameters (described below), bear in mind that the FileInput widget is not meant to upload large files. You can configure max_file_size, max_total_file_size (limiting the total upload size if you have set multiple=True) and max_files to provide an upper bound on the amount of data that can be uploaded.






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_dropper.controls(jslink=True), file_dropper)







            
            


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