Introducing Gradio Clients


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A base class for defining methods that all input/output components should have.


As input component: Passes a value of arbitrary type through.

Your function should accept one of these types:
def predict(
	value: Any

As output component: Expects a value of arbitrary type, as long as it can be deepcopied.

Your function should return one of these types:
def predict(ยทยทยท) -> Any
	return value


Parameter Description


default: None

the initial value (of arbitrary type) of the state. The provided argument is deepcopied. If a callable is provided, the function will be called whenever the app loads to set the initial value of the state.



default: True

has no effect, but is included for consistency with other components.


int | float | None

default: None

The number of seconds the state should be stored for after it is created or updated. If None, the state will be stored indefinitely. Gradio automatically deletes state variables after a user closes the browser tab or refreshes the page, so this is useful for clearing state for potentially long running sessions.


Callable[[Any], None] | None

default: None

A function that is called when the state is deleted. The function should take the state value as an argument.

Event Listeners


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

Listener Description

State.change(fn, ยทยทยท)

Triggered when the value of the State changes either because of user input (e.g. a user types in a textbox) OR because of a function update (e.g. an image receives a value from the output of an event trigger). See .input() for a listener that is only triggered by user input.

Event Arguments

Parameter Description

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.


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.


Block | list[Block] | 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.


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.



default: False

If True, will scroll to output component on completion


Literal[('full', 'minimal', 'hidden')]

default: "full"

If True, will show progress animation while pending



default: True

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.



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.



default: 4

Maximum number of inputs to batch together if this is called from the queue (only relevant if batch=True)



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).



default: True

If False, will not run postprocessing of component data before returning 'fn' output to the browser.


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.


float | None

default: None

Run this event 'every' number of seconds while the client connection is open. Interpreted in seconds.


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.


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.


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).


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.



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 as well as the Clients to use this event. If fn is None, show_api will automatically be set to False.