Gradio DownloadButton Docs

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DownloadButton

gradio.DownloadButton(···)

Description

Creates a button, that when clicked, allows a user to download a single file of arbitrary type.

Behavior

As input component: (Rarely used) passes the file as a str into the function.

Your function should accept one of these types:

def predict(
	value: str | None
)
	...

As output component: Expects a str or pathlib.Path filepath

Your function should return one of these types:

def predict(···) -> str | Path | None
	...	
	return value

Initialization

Parameter	Description
`label` str default: "Download"	Text to display on the button. Defaults to "Download".
`value` str \| Path \| Callable \| None default: None	A str or pathlib.Path filepath or URL to download, or a Callable that returns a str or pathlib.Path filepath or URL to download.
`every` float \| None default: None	If `value` is a callable, run the function 'every' number of seconds while the client connection is open. Has no effect otherwise. The event can be accessed (e.g. to cancel it) via this component's .load_event attribute.
`variant` Literal['primary', 'secondary', 'stop'] default: "secondary"	'primary' for main call-to-action, 'secondary' for a more subdued style, 'stop' for a stop button.
`visible` bool default: True	If False, component will be hidden.
`size` Literal['sm', 'lg'] \| None default: None	Size of the button. Can be "sm" or "lg".
`icon` str \| None default: None	URL or path to the icon file to display within the button. If None, no icon will be displayed.
`scale` int \| None default: None	relative size compared to adjacent Components. For example if Components A and B are in a Row, and A has scale=2, and B has scale=1, A will be twice as wide as B. Should be an integer. scale applies in Rows, and to top-level Components in Blocks where fill_height=True.
`min_width` int \| None default: None	minimum pixel width, will wrap if not sufficient screen space to satisfy this value. If a certain scale value results in this Component being narrower than min_width, the min_width parameter will be respected first.
`interactive` bool default: True	If False, the UploadButton will be in a disabled state.
`elem_id` str \| None default: None	An optional string that is assigned as the id of this component in the HTML DOM. Can be used for targeting CSS styles.
`elem_classes` list[str] \| str \| None default: None	An optional list of strings that are assigned as the classes of this component in the HTML DOM. Can be used for targeting CSS styles.
`render` bool default: True	If False, component will not render be rendered in the Blocks context. Should be used if the intention is to assign event listeners now but render the component later.

Shortcuts

Class	Interface String Shortcut	Initialization
`gradio.DownloadButton`	"downloadbutton"	Uses default values

Demos

from pathlib import Path
import gradio as gr

def upload_file(filepath):
    name = Path(filepath).name
    return [gr.UploadButton(visible=False), gr.DownloadButton(label=f"Download {name}", value=filepath, visible=True)]

def download_file():
    return [gr.UploadButton(visible=True), gr.DownloadButton(visible=False)]

with gr.Blocks() as demo:
    gr.Markdown("First upload a file and and then you'll be able download it (but only once!)")
    with gr.Row():
        u = gr.UploadButton("Upload a file", file_count="single")
        d = gr.DownloadButton("Download the file", visible=False)

    u.upload(upload_file, u, [u, d])
    d.click(download_file, None, [u, d])


if __name__ == "__main__":
    demo.launch()

Event Listeners

Description

Event listeners allow you to capture and respond to user interactions with the UI components you've defined in a Gradio Blocks app. When a user interacts with an element, such as changing a slider value or uploading an image, a function is called.

Supported Event Listeners

The DownloadButton component supports the following event listeners. Each event listener takes the same parameters, which are listed in the Event Arguments table below.

Listener	Description
`gradio.DownloadButton.click(fn, ···)`	Triggered when the DownloadButton is clicked.

Event Arguments

Parameter	Description
`fn` Callable \| None \| Literal['decorator'] default: "decorator"	the function to call when this event is triggered. Often a machine learning model's prediction function. Each parameter of the function corresponds to one input component, and the function should return a single value or a tuple of values, with each element in the tuple corresponding to one output component.
`inputs` Component \| list[Component] \| set[Component] \| None default: None	List of gradio.components to use as inputs. If the function takes no inputs, this should be an empty list.
`outputs` Component \| list[Component] \| None default: None	List of gradio.components to use as outputs. If the function returns no outputs, this should be an empty list.
`api_name` str \| None \| Literal[False] default: None	defines how the endpoint appears in the API docs. Can be a string, None, or False. If set to a string, the endpoint will be exposed in the API docs with the given name. If None (default), the name of the function will be used as the API endpoint. If False, the endpoint will not be exposed in the API docs and downstream apps (including those that `gr.load` this app) will not be able to use this event.
`scroll_to_output` bool default: False	If True, will scroll to output component on completion
`show_progress` Literal['full', 'minimal', 'hidden'] default: "full"	If True, will show progress animation while pending
`queue` bool \| None default: None	If True, will place the request on the queue, if the queue has been enabled. If False, will not put this event on the queue, even if the queue has been enabled. If None, will use the queue setting of the gradio app.
`batch` bool default: False	If True, then the function should process a batch of inputs, meaning that it should accept a list of input values for each parameter. The lists should be of equal length (and be up to length `max_batch_size`). The function is then required to return a tuple of lists (even if there is only 1 output component), with each list in the tuple corresponding to one output component.
`max_batch_size` int default: 4	Maximum number of inputs to batch together if this is called from the queue (only relevant if batch=True)
`preprocess` bool default: True	If False, will not run preprocessing of component data before running 'fn' (e.g. leaving it as a base64 string if this method is called with the `Image` component).
`postprocess` bool default: True	If False, will not run postprocessing of component data before returning 'fn' output to the browser.
`cancels` dict[str, Any] \| list[dict[str, Any]] \| None default: None	A list of other events to cancel when this listener is triggered. For example, setting cancels=[click_event] will cancel the click_event, where click_event is the return value of another components .click method. Functions that have not yet run (or generators that are iterating) will be cancelled, but functions that are currently running will be allowed to finish.
`every` float \| None default: None	Run this event 'every' number of seconds while the client connection is open. Interpreted in seconds.
`trigger_mode` Literal['once', 'multiple', 'always_last'] \| None default: None	If "once" (default for all events except `.change()`) would not allow any submissions while an event is pending. If set to "multiple", unlimited submissions are allowed while pending, and "always_last" (default for `.change()` and `.key_up()` events) would allow a second submission after the pending event is complete.
`js` str \| None default: None	Optional frontend js method to run before running 'fn'. Input arguments for js method are values of 'inputs' and 'outputs', return should be a list of values for output components.
`concurrency_limit` int \| None \| Literal['default'] default: "default"	If set, this is the maximum number of this event that can be running simultaneously. Can be set to None to mean no concurrency_limit (any number of this event can be running simultaneously). Set to "default" to use the default concurrency limit (defined by the `default_concurrency_limit` parameter in `Blocks.queue()`, which itself is 1 by default).
`concurrency_id` str \| None default: None	If set, this is the id of the concurrency group. Events with the same concurrency_id will be limited by the lowest set concurrency_limit.
`show_api` bool default: True	whether to show this event in the "view API" page of the Gradio app, or in the ".view_api()" method of the Gradio clients. Unlike setting api_name to False, setting show_api to False will still allow downstream apps to use this event. If fn is None, show_api will automatically be set to False.

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DownloadButton

Description
Behavior
Initialization
Shortcuts
Demos
Event Listeners