express.render.download_button

express.render.download_button(
    fn=None,
    *,
    filename=None,
    media_type=None,
    encoding='utf-8',
    label='Download',
    width=None,
)

Reactively render a download button.

Register a function that generates a download, and (in Express) auto-place a download button. The decorated function may be sync or async, and should either return a filename (str) to send an existing file, or yield one or more strings or bytestrings for a generated file (in which case pass a filename argument).

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”.
width : str | None = None: (Express only) The width of the button.

Returns

The decorated function.

Tip

In Shiny Core, pair this with download_button in the UI (the decorated function’s name should match the id).

Examples

#| standalone: true
#| components: [editor, viewer]
#| layout: vertical
#| viewerHeight: 400

## file: app.py
import asyncio
import random
from datetime import date

from shiny.express import render


@render.download_button(
    filename=lambda: f"新型-{date.today().isoformat()}-{random.randint(100, 999)}.csv"
)
async def downloadData():
    await asyncio.sleep(0.25)
    yield "one,two,three\n"
    yield "新,1,2\n"
    yield "型,4,5\n"


## file: mtcars.csv
mpg,cyl,disp,hp,drat,wt,qsec,vs,am,gear,carb
21,6,160,110,3.9,2.62,16.46,0,1,4,4
21,6,160,110,3.9,2.875,17.02,0,1,4,4
22.8,4,108,93,3.85,2.32,18.61,1,1,4,1
21.4,6,258,110,3.08,3.215,19.44,1,0,3,1
18.7,8,360,175,3.15,3.44,17.02,0,0,3,2
18.1,6,225,105,2.76,3.46,20.22,1,0,3,1
14.3,8,360,245,3.21,3.57,15.84,0,0,3,4
24.4,4,146.7,62,3.69,3.19,20,1,0,4,2
22.8,4,140.8,95,3.92,3.15,22.9,1,0,4,2
19.2,6,167.6,123,3.92,3.44,18.3,1,0,4,4
17.8,6,167.6,123,3.92,3.44,18.9,1,0,4,4
16.4,8,275.8,180,3.07,4.07,17.4,0,0,3,3
17.3,8,275.8,180,3.07,3.73,17.6,0,0,3,3
15.2,8,275.8,180,3.07,3.78,18,0,0,3,3
10.4,8,472,205,2.93,5.25,17.98,0,0,3,4
10.4,8,460,215,3,5.424,17.82,0,0,3,4
14.7,8,440,230,3.23,5.345,17.42,0,0,3,4
32.4,4,78.7,66,4.08,2.2,19.47,1,1,4,1
30.4,4,75.7,52,4.93,1.615,18.52,1,1,4,2
33.9,4,71.1,65,4.22,1.835,19.9,1,1,4,1
21.5,4,120.1,97,3.7,2.465,20.01,1,0,3,1
15.5,8,318,150,2.76,3.52,16.87,0,0,3,2
15.2,8,304,150,3.15,3.435,17.3,0,0,3,2
13.3,8,350,245,3.73,3.84,15.41,0,0,3,4
19.2,8,400,175,3.08,3.845,17.05,0,0,3,2
27.3,4,79,66,4.08,1.935,18.9,1,1,4,1
26,4,120.3,91,4.43,2.14,16.7,0,1,5,2
30.4,4,95.1,113,3.77,1.513,16.9,1,1,5,2
15.8,8,351,264,4.22,3.17,14.5,0,1,5,4
19.7,6,145,175,3.62,2.77,15.5,0,1,5,6
15,8,301,335,3.54,3.57,14.6,0,1,5,8
21.4,4,121,109,4.11,2.78,18.6,1,1,4,2

express.render.download_button

Parameters

Returns

Tip

See Also

Examples