render.download

render.download(
    self,
    fn=None,
    *,
    filename=None,
    media_type=None,
    encoding='utf-8',
    label='Download',
)

Decorator to register a function to handle a download.

This decorator is used to register a function that will be called when the user clicks a download link or button. The decorated function may be sync or async, and should do one of the following:

  • Return a string. This will be assumed to be a filename; Shiny will return this file to the browser, and the downloaded file will have the same filename as the original, with an inferred mime type. This is the most convenient IF the file already exists on disk. But if the function must create a temporary file, then this method should not be used, because the temporary file will not be deleted by Shiny. Use the yield method instead.
  • yield one or more strings or bytestrings (b"..." or io.BytesIO().getvalue()). If strings are yielded, they'll be encoded in UTF-8. (This is better for temp files as after you're done yielding you can delete the temp file, or use a tempfile.TemporaryFile context manager) With this method, it's important that the @render.download decorator have a filename argument, as the decorated function won't help with that.

Parameters

filename : Optional[str | Callable[[], str]] = None

The filename of the download.

media_type : None | str | Callable[[], str] = None

The media type of the download.

encoding : str = 'utf-8'

The encoding of the download.

label : TagChild = 'Download'

(Express only) A label for the button. Defaults to “Download”.

Returns

:

The decorated function.

See Also

Examples

Loading...