custom Module

custom Module

class panel.custom.AnyWidgetComponent(*, loading, align, aspect_ratio, css_classes, design, height, height_policy, margin, max_height, max_width, min_height, min_width, sizing_mode, styles, stylesheets, tags, visible, width, width_policy, name)

Bases: ReactComponent

The AnyWidgetComponent allows you to create custom Panel components in the style of an AnyWidget component. Specifically this component type creates shims that make it possible to reuse AnyWidget ESM code as is, without having to adapt the callbacks to use Bokeh APIs.

Reference: https://panel.holoviz.org/reference/custom_components/AnyWidgetComponent.html

```python import param import panel as pn

pn.extension()

class CounterWidget(pn.custom.AnyWidgetComponent):

_esm = “”” function render({ model, el }) { let count = () => model.get(“value”); let btn = document.createElement(“button”); btn.innerHTML = count is ${count()}; btn.addEventListener(“click”, () => {

model.set(“value”, count() + 1); model.save_changes();

}); model.on(“change:value”, () => {

btn.innerHTML = count is ${count()};

}); el.appendChild(btn); } export default { render }; “”” value = param.Integer()

CounterWidget().servable() ```

Parameters inherited from:

panel.viewable.Layoutable: align, aspect_ratio, css_classes, design, height, min_width, min_height, max_width, max_height, margin, styles, stylesheets, tags, width, width_policy, height_policy, sizing_mode, visible

panel.viewable.Viewable: loading

clone(**params) → Viewable

Makes a copy of the object sharing the same parameters.

Arguments

params: Keyword arguments override the parameters on the clone.

Returns

Cloned Viewable object

controls(parameters: list[str] = [], jslink: bool = True, **kwargs) → BasePanel

Creates a set of widgets which allow manipulating the parameters on this instance. By default all parameters which support linking are exposed, but an explicit list of parameters can be provided.

Arguments

parameters: list(str)

An explicit list of parameters to return controls for.

jslink: bool

Whether to use jslinks instead of Python based links. This does not allow using all types of parameters.

kwargs: dict

Additional kwargs to pass to the Param pane(s) used to generate the controls widgets.

Returns

A layout of the controls

embed(max_states: int = 1000, max_opts: int = 3, json: bool = False, json_prefix: str = '', save_path: str = './', load_path: str | None = None, progress: bool = False, states={}) → None

Renders a static version of a panel in a notebook by evaluating the set of states defined by the widgets in the model. Note this will only work well for simple apps with a relatively small state space.

Arguments

max_states: int

The maximum number of states to embed

max_opts: int

The maximum number of states for a single widget

json: boolean (default=True)

Whether to export the data to json files

json_prefix: str (default=’’)

Prefix for JSON filename

save_path: str (default=’./’)

The path to save json files to

load_path: str (default=None)

The path or URL the json files will be loaded from.

progress: boolean (default=False)

Whether to report progress

states: dict (default={})

A dictionary specifying the widget values to embed for each widget

get_root(doc: Document | None = None, comm: Comm | None = None, preprocess: bool = True) → Model

Returns the root model and applies pre-processing hooks

Arguments

doc: bokeh.Document

Bokeh document the bokeh model will be attached to.

comm: pyviz_comms.Comm

Optional pyviz_comms when working in notebook

preprocess: boolean (default=True)

Whether to run preprocessing hooks

Returns

Returns the bokeh model corresponding to this panel object

jscallback(args: dict[str, Any] = {}, **callbacks: str) → Callback

Allows defining a JS callback to be triggered when a property changes on the source object. The keyword arguments define the properties that trigger a callback and the JS code that gets executed.

Arguments

args: dict

A mapping of objects to make available to the JS callback

callbacks: dict

A mapping between properties on the source model and the code to execute when that property changes

Returns

callback: Callback

The Callback which can be used to disable the callback.

jslink(target: JSLinkTarget, code: dict[str, str] = None, args: dict | None = None, bidirectional: bool = False, **links: str) → Link

Links properties on the this Reactive object to those on the target Reactive object in JS code.

Supports two modes, either specify a mapping between the source and target model properties as keywords or provide a dictionary of JS code snippets which maps from the source parameter to a JS code snippet which is executed when the property changes.

Arguments

target: panel.viewable.Viewable | bokeh.model.Model | holoviews.core.dimension.Dimensioned

The target to link the value to.

code: dict

Custom code which will be executed when the widget value changes.

args: dict

A mapping of objects to make available to the JS callback

bidirectional: boolean

Whether to link source and target bi-directionally

links: dict

A mapping between properties on the source model and the target model property to link it to.

Returns

link: GenericLink

The GenericLink which can be used unlink the widget and the target model.

link(target: Parameterized, callbacks: dict[str, str | Callable] | None = None, bidirectional: bool = False, **links: str) → Watcher

Links the parameters on this Reactive object to attributes on the target Parameterized object.

Supports two modes, either specify a mapping between the source and target object parameters as keywords or provide a dictionary of callbacks which maps from the source parameter to a callback which is triggered when the parameter changes.

Arguments

target: param.Parameterized

The target object of the link.

callbacks: dict | None

Maps from a parameter in the source object to a callback.

bidirectional: bool

Whether to link source and target bi-directionally

links: dict

Maps between parameters on this object to the parameters on the supplied object.

on_event(event: str, callback: Callable) → None

Registers a callback to be executed when the specified DOM event is triggered.

Arguments

event: str

Name of the DOM event to add an event listener to.

callback: callable

A callable which will be given the DOMEvent object.

on_msg(callback: Callable) → None

Registers a callback to be executed when a message event containing arbitrary data is received.

Arguments

event: str

Name of the DOM event to add an event listener to.

callback: callable

A callable which will be given the msg data.

save(filename: str | PathLike | IO, title: str | None = None, resources: Resources | None = None, template: str | Template | None = None, template_variables: dict[str, Any] = {}, embed: bool = False, max_states: int = 1000, max_opts: int = 3, embed_json: bool = False, json_prefix: str = '', save_path: str = './', load_path: str | None = None, progress: bool = True, embed_states: dict[Any, Any] = {}, as_png: bool | None = None, **kwargs) → None

Saves Panel objects to file.

Arguments

filename: str or file-like object

Filename to save the plot to

title: string

Optional title for the plot

resources: bokeh resources

One of the valid bokeh.resources (e.g. CDN or INLINE)

template:

passed to underlying io.save

template_variables:

passed to underlying io.save

embed: bool

Whether the state space should be embedded in the saved file.

max_states: int

The maximum number of states to embed

max_opts: int

The maximum number of states for a single widget

embed_json: boolean (default=True)

Whether to export the data to json files

json_prefix: str (default=’’)

Prefix for the auto-generated json directory

save_path: str (default=’./’)

The path to save json files to

load_path: str (default=None)

The path or URL the json files will be loaded from.

progress: boolean (default=True)

Whether to report progress

embed_states: dict (default={})

A dictionary specifying the widget values to embed for each widget

as_png: boolean (default=None)

To save as a .png. If None save_png will be true if filename is string and ends with png.

select(selector: type | Callable[[Viewable], bool] | None = None) → list[Viewable]

Iterates over the Viewable and any potential children in the applying the Selector.

Arguments

selector: type or callable or None

The selector allows selecting a subset of Viewables by declaring a type or callable function to filter by.

Returns

viewables: list(Viewable)

send(msg: dict)

Sends a custom event containing the provided message to the frontend.

Arguments

msg: dict

servable(title: str | None = None, location: bool | 'Location' = True, area: str = 'main', target: str | None = None) → ServableMixin

Serves the object or adds it to the configured pn.state.template if in a panel serve context, writes to the DOM if in a pyodide context and returns the Panel object to allow it to display itself in a notebook context.

Arguments

titlestr

A string title to give the Document (if served as an app)

locationboolean or panel.io.location.Location

Whether to create a Location component to observe and set the URL location.

area: str (deprecated)

The area of a template to add the component too. Only has an effect if pn.config.template has been set.

target: str

Target area to write to. If a template has been configured on pn.config.template this refers to the target area in the template while in pyodide this refers to the ID of the DOM node to write to.

Returns

The Panel object itself

server_doc(doc: Document | None = None, title: str | None = None, location: bool | 'Location' = True) → Document

Returns a serveable bokeh Document with the panel attached

Arguments

docbokeh.Document (optional)

The bokeh Document to attach the panel to as a root, defaults to bokeh.io.curdoc()

titlestr

A string title to give the Document

locationboolean or panel.io.location.Location

Whether to create a Location component to observe and set the URL location.

Returns

docbokeh.Document

The bokeh document the panel was attached to

show(title: str | None = None, port: int = 0, address: str | None = None, websocket_origin: str | None = None, threaded: bool = False, verbose: bool = True, open: bool = True, location: bool | 'Location' = True, **kwargs) → StoppableThread' | 'Server

Starts a Bokeh server and displays the Viewable in a new tab.

Arguments

titlestr | None

A string title to give the Document (if served as an app)

port: int (optional, default=0)

Allows specifying a specific port

addressstr

The address the server should listen on for HTTP requests.

websocket_origin: str or list(str) (optional)

A list of hosts that can connect to the websocket. This is typically required when embedding a server app in an external web site. If None, “localhost” is used.

threaded: boolean (optional, default=False)

Whether to launch the Server on a separate thread, allowing interactive use.

verbose: boolean (optional, default=True)

Whether to print the address and port

openboolean (optional, default=True)

Whether to open the server in a new browser tab

locationboolean or panel.io.location.Location

Whether to create a Location component to observe and set the URL location.

Returns

server: bokeh.server.Server or panel.io.server.StoppableThread

Returns the Bokeh server instance or the thread the server was launched on (if threaded=True)

class panel.custom.JSComponent(*, loading, align, aspect_ratio, css_classes, design, height, height_policy, margin, max_height, max_width, min_height, min_width, sizing_mode, styles, stylesheets, tags, visible, width, width_policy, name)

Bases: ReactiveESM

The JSComponent allows you to create custom Panel components using Javascript and CSS without the complexities of Javascript build tools.

A JSComponent subclass provides bi-directional syncing of its parameters with arbitrary HTML elements, attributes and properties. The key part of the subclass is the _esm variable. Use this to define a render function as shown in the example below.

Reference: https://panel.holoviz.org/reference/custom_components/JSComponent.html

```python import panel as pn import param

pn.extension()

class CounterButton(pn.custom.JSComponent):

value = param.Integer()

_esm = “”” export function render({ model }) {

let btn = document.createElement(“button”); btn.innerHTML = count is ${model.value}; btn.addEventListener(“click”, () => {

model.value += 1

}); model.on(‘value’, () => {

btn.innerHTML = count is ${model.value};

}) return btn

CounterButton().servable() ```

Parameters inherited from:

panel.viewable.Layoutable: align, aspect_ratio, css_classes, design, height, min_width, min_height, max_width, max_height, margin, styles, stylesheets, tags, width, width_policy, height_policy, sizing_mode, visible

panel.viewable.Viewable: loading

clone(**params) → Viewable

Makes a copy of the object sharing the same parameters.

Arguments

params: Keyword arguments override the parameters on the clone.

Returns

Cloned Viewable object

controls(parameters: list[str] = [], jslink: bool = True, **kwargs) → BasePanel

Creates a set of widgets which allow manipulating the parameters on this instance. By default all parameters which support linking are exposed, but an explicit list of parameters can be provided.

Arguments

parameters: list(str)

An explicit list of parameters to return controls for.

jslink: bool

Whether to use jslinks instead of Python based links. This does not allow using all types of parameters.

kwargs: dict

Additional kwargs to pass to the Param pane(s) used to generate the controls widgets.

Returns

A layout of the controls

embed(max_states: int = 1000, max_opts: int = 3, json: bool = False, json_prefix: str = '', save_path: str = './', load_path: str | None = None, progress: bool = False, states={}) → None

Renders a static version of a panel in a notebook by evaluating the set of states defined by the widgets in the model. Note this will only work well for simple apps with a relatively small state space.

Arguments

max_states: int

The maximum number of states to embed

max_opts: int

The maximum number of states for a single widget

json: boolean (default=True)

Whether to export the data to json files

json_prefix: str (default=’’)

Prefix for JSON filename

save_path: str (default=’./’)

The path to save json files to

load_path: str (default=None)

The path or URL the json files will be loaded from.

progress: boolean (default=False)

Whether to report progress

states: dict (default={})

A dictionary specifying the widget values to embed for each widget

get_root(doc: Document | None = None, comm: Comm | None = None, preprocess: bool = True) → Model

Returns the root model and applies pre-processing hooks

Arguments

doc: bokeh.Document

Bokeh document the bokeh model will be attached to.

comm: pyviz_comms.Comm

Optional pyviz_comms when working in notebook

preprocess: boolean (default=True)

Whether to run preprocessing hooks

Returns

Returns the bokeh model corresponding to this panel object

jscallback(args: dict[str, Any] = {}, **callbacks: str) → Callback

Allows defining a JS callback to be triggered when a property changes on the source object. The keyword arguments define the properties that trigger a callback and the JS code that gets executed.

Arguments

args: dict

A mapping of objects to make available to the JS callback

callbacks: dict

A mapping between properties on the source model and the code to execute when that property changes

Returns

callback: Callback

The Callback which can be used to disable the callback.

jslink(target: JSLinkTarget, code: dict[str, str] = None, args: dict | None = None, bidirectional: bool = False, **links: str) → Link

Links properties on the this Reactive object to those on the target Reactive object in JS code.

Supports two modes, either specify a mapping between the source and target model properties as keywords or provide a dictionary of JS code snippets which maps from the source parameter to a JS code snippet which is executed when the property changes.

Arguments

target: panel.viewable.Viewable | bokeh.model.Model | holoviews.core.dimension.Dimensioned

The target to link the value to.

code: dict

Custom code which will be executed when the widget value changes.

args: dict

A mapping of objects to make available to the JS callback

bidirectional: boolean

Whether to link source and target bi-directionally

links: dict

A mapping between properties on the source model and the target model property to link it to.

Returns

link: GenericLink

The GenericLink which can be used unlink the widget and the target model.

link(target: Parameterized, callbacks: dict[str, str | Callable] | None = None, bidirectional: bool = False, **links: str) → Watcher

Links the parameters on this Reactive object to attributes on the target Parameterized object.

Supports two modes, either specify a mapping between the source and target object parameters as keywords or provide a dictionary of callbacks which maps from the source parameter to a callback which is triggered when the parameter changes.

Arguments

target: param.Parameterized

The target object of the link.

callbacks: dict | None

Maps from a parameter in the source object to a callback.

bidirectional: bool

Whether to link source and target bi-directionally

links: dict

Maps between parameters on this object to the parameters on the supplied object.

on_event(event: str, callback: Callable) → None

Registers a callback to be executed when the specified DOM event is triggered.

Arguments

event: str

Name of the DOM event to add an event listener to.

callback: callable

A callable which will be given the DOMEvent object.

on_msg(callback: Callable) → None

Registers a callback to be executed when a message event containing arbitrary data is received.

Arguments

event: str

Name of the DOM event to add an event listener to.

callback: callable

A callable which will be given the msg data.

save(filename: str | PathLike | IO, title: str | None = None, resources: Resources | None = None, template: str | Template | None = None, template_variables: dict[str, Any] = {}, embed: bool = False, max_states: int = 1000, max_opts: int = 3, embed_json: bool = False, json_prefix: str = '', save_path: str = './', load_path: str | None = None, progress: bool = True, embed_states: dict[Any, Any] = {}, as_png: bool | None = None, **kwargs) → None

Saves Panel objects to file.

Arguments

filename: str or file-like object

Filename to save the plot to

title: string

Optional title for the plot

resources: bokeh resources

One of the valid bokeh.resources (e.g. CDN or INLINE)

template:

passed to underlying io.save

template_variables:

passed to underlying io.save

embed: bool

Whether the state space should be embedded in the saved file.

max_states: int

The maximum number of states to embed

max_opts: int

The maximum number of states for a single widget

embed_json: boolean (default=True)

Whether to export the data to json files

json_prefix: str (default=’’)

Prefix for the auto-generated json directory

save_path: str (default=’./’)

The path to save json files to

load_path: str (default=None)

The path or URL the json files will be loaded from.

progress: boolean (default=True)

Whether to report progress

embed_states: dict (default={})

A dictionary specifying the widget values to embed for each widget

as_png: boolean (default=None)

To save as a .png. If None save_png will be true if filename is string and ends with png.

select(selector: type | Callable[[Viewable], bool] | None = None) → list[Viewable]

Iterates over the Viewable and any potential children in the applying the Selector.

Arguments

selector: type or callable or None

The selector allows selecting a subset of Viewables by declaring a type or callable function to filter by.

Returns

viewables: list(Viewable)

servable(title: str | None = None, location: bool | 'Location' = True, area: str = 'main', target: str | None = None) → ServableMixin

Serves the object or adds it to the configured pn.state.template if in a panel serve context, writes to the DOM if in a pyodide context and returns the Panel object to allow it to display itself in a notebook context.

Arguments

titlestr

A string title to give the Document (if served as an app)

locationboolean or panel.io.location.Location

Whether to create a Location component to observe and set the URL location.

area: str (deprecated)

The area of a template to add the component too. Only has an effect if pn.config.template has been set.

target: str

Target area to write to. If a template has been configured on pn.config.template this refers to the target area in the template while in pyodide this refers to the ID of the DOM node to write to.

Returns

The Panel object itself

server_doc(doc: Document | None = None, title: str | None = None, location: bool | 'Location' = True) → Document

Returns a serveable bokeh Document with the panel attached

Arguments

docbokeh.Document (optional)

The bokeh Document to attach the panel to as a root, defaults to bokeh.io.curdoc()

titlestr

A string title to give the Document

locationboolean or panel.io.location.Location

Whether to create a Location component to observe and set the URL location.

Returns

docbokeh.Document

The bokeh document the panel was attached to

show(title: str | None = None, port: int = 0, address: str | None = None, websocket_origin: str | None = None, threaded: bool = False, verbose: bool = True, open: bool = True, location: bool | 'Location' = True, **kwargs) → StoppableThread' | 'Server

Starts a Bokeh server and displays the Viewable in a new tab.

Arguments

titlestr | None

A string title to give the Document (if served as an app)

port: int (optional, default=0)

Allows specifying a specific port

addressstr

The address the server should listen on for HTTP requests.

websocket_origin: str or list(str) (optional)

A list of hosts that can connect to the websocket. This is typically required when embedding a server app in an external web site. If None, “localhost” is used.

threaded: boolean (optional, default=False)

Whether to launch the Server on a separate thread, allowing interactive use.

verbose: boolean (optional, default=True)

Whether to print the address and port

openboolean (optional, default=True)

Whether to open the server in a new browser tab

locationboolean or panel.io.location.Location

Whether to create a Location component to observe and set the URL location.

Returns

server: bokeh.server.Server or panel.io.server.StoppableThread

Returns the Bokeh server instance or the thread the server was launched on (if threaded=True)

class panel.custom.PyComponent(*, loading, align, aspect_ratio, css_classes, design, height, height_policy, margin, max_height, max_width, min_height, min_width, sizing_mode, styles, stylesheets, tags, visible, width, width_policy, name)

Bases: Viewable, Layoutable

The PyComponent combines the convenience of Viewer components that allow creating custom components by declaring a __panel__ method with the ability of controlling layout and styling related parameters directly on the class. Internally the PyComponent will forward layout parameters to the underlying object, which is created lazily on render.

Reference: https://panel.holoviz.org/reference/custom_components/PyComponent.html

```python import panel as pn import param

pn.extension()

class CounterButton(pn.custom.PyComponent, pn.widgets.WidgetBase):

value = param.Integer(default=0)

def __panel__(self):

return pn.widgets.Button(

name=self._button_name, on_click=self._on_click

)

def _on_click(self, event):

self.value += 1

@param.depends(“value”) def _button_name(self):

return f”count is {self.value}”

CounterButton().servable() ```

Parameters inherited from:

panel.viewable.Layoutable: align, aspect_ratio, css_classes, design, height, min_width, min_height, max_width, max_height, margin, styles, stylesheets, tags, width, width_policy, height_policy, sizing_mode, visible

panel.viewable.Viewable: loading

clone(**params) → Viewable

Makes a copy of the object sharing the same parameters.

Arguments

params: Keyword arguments override the parameters on the clone.

Returns

Cloned Viewable object

embed(max_states: int = 1000, max_opts: int = 3, json: bool = False, json_prefix: str = '', save_path: str = './', load_path: str | None = None, progress: bool = False, states={}) → None

Renders a static version of a panel in a notebook by evaluating the set of states defined by the widgets in the model. Note this will only work well for simple apps with a relatively small state space.

Arguments

max_states: int

The maximum number of states to embed

max_opts: int

The maximum number of states for a single widget

json: boolean (default=True)

Whether to export the data to json files

json_prefix: str (default=’’)

Prefix for JSON filename

save_path: str (default=’./’)

The path to save json files to

load_path: str (default=None)

The path or URL the json files will be loaded from.

progress: boolean (default=False)

Whether to report progress

states: dict (default={})

A dictionary specifying the widget values to embed for each widget

get_root(doc: Document | None = None, comm: Comm | None = None, preprocess: bool = True) → Model

Returns the root model and applies pre-processing hooks

Arguments

doc: bokeh.Document

Bokeh document the bokeh model will be attached to.

comm: pyviz_comms.Comm

Optional pyviz_comms when working in notebook

preprocess: boolean (default=True)

Whether to run preprocessing hooks

Returns

Returns the bokeh model corresponding to this panel object

save(filename: str | PathLike | IO, title: str | None = None, resources: Resources | None = None, template: str | Template | None = None, template_variables: dict[str, Any] = {}, embed: bool = False, max_states: int = 1000, max_opts: int = 3, embed_json: bool = False, json_prefix: str = '', save_path: str = './', load_path: str | None = None, progress: bool = True, embed_states: dict[Any, Any] = {}, as_png: bool | None = None, **kwargs) → None

Saves Panel objects to file.

Arguments

filename: str or file-like object

Filename to save the plot to

title: string

Optional title for the plot

resources: bokeh resources

One of the valid bokeh.resources (e.g. CDN or INLINE)

template:

passed to underlying io.save

template_variables:

passed to underlying io.save

embed: bool

Whether the state space should be embedded in the saved file.

max_states: int

The maximum number of states to embed

max_opts: int

The maximum number of states for a single widget

embed_json: boolean (default=True)

Whether to export the data to json files

json_prefix: str (default=’’)

Prefix for the auto-generated json directory

save_path: str (default=’./’)

The path to save json files to

load_path: str (default=None)

The path or URL the json files will be loaded from.

progress: boolean (default=True)

Whether to report progress

embed_states: dict (default={})

A dictionary specifying the widget values to embed for each widget

as_png: boolean (default=None)

To save as a .png. If None save_png will be true if filename is string and ends with png.

select(selector: type | Callable[[Viewable], bool] | None = None) → list[Viewable]

Iterates over the Viewable and any potential children in the applying the Selector.

Arguments

selector: type or callable or None

The selector allows selecting a subset of Viewables by declaring a type or callable function to filter by.

Returns

viewables: list(Viewable)

servable(title: str | None = None, location: bool | 'Location' = True, area: str = 'main', target: str | None = None) → ServableMixin

Serves the object or adds it to the configured pn.state.template if in a panel serve context, writes to the DOM if in a pyodide context and returns the Panel object to allow it to display itself in a notebook context.

Arguments

titlestr

A string title to give the Document (if served as an app)

locationboolean or panel.io.location.Location

Whether to create a Location component to observe and set the URL location.

area: str (deprecated)

The area of a template to add the component too. Only has an effect if pn.config.template has been set.

target: str

Target area to write to. If a template has been configured on pn.config.template this refers to the target area in the template while in pyodide this refers to the ID of the DOM node to write to.

Returns

The Panel object itself

server_doc(doc: Document | None = None, title: str | None = None, location: bool | 'Location' = True) → Document

Returns a serveable bokeh Document with the panel attached

Arguments

docbokeh.Document (optional)

The bokeh Document to attach the panel to as a root, defaults to bokeh.io.curdoc()

titlestr

A string title to give the Document

locationboolean or panel.io.location.Location

Whether to create a Location component to observe and set the URL location.

Returns

docbokeh.Document

The bokeh document the panel was attached to

show(title: str | None = None, port: int = 0, address: str | None = None, websocket_origin: str | None = None, threaded: bool = False, verbose: bool = True, open: bool = True, location: bool | 'Location' = True, **kwargs) → StoppableThread' | 'Server

Starts a Bokeh server and displays the Viewable in a new tab.

Arguments

titlestr | None

A string title to give the Document (if served as an app)

port: int (optional, default=0)

Allows specifying a specific port

addressstr

The address the server should listen on for HTTP requests.

websocket_origin: str or list(str) (optional)

A list of hosts that can connect to the websocket. This is typically required when embedding a server app in an external web site. If None, “localhost” is used.

threaded: boolean (optional, default=False)

Whether to launch the Server on a separate thread, allowing interactive use.

verbose: boolean (optional, default=True)

Whether to print the address and port

openboolean (optional, default=True)

Whether to open the server in a new browser tab

locationboolean or panel.io.location.Location

Whether to create a Location component to observe and set the URL location.

Returns

server: bokeh.server.Server or panel.io.server.StoppableThread

Returns the Bokeh server instance or the thread the server was launched on (if threaded=True)

class panel.custom.ReactComponent(*, loading, align, aspect_ratio, css_classes, design, height, height_policy, margin, max_height, max_width, min_height, min_width, sizing_mode, styles, stylesheets, tags, visible, width, width_policy, name)

Bases: ReactiveESM

The ReactComponent allows you to create custom Panel components using React without the complexities of Javascript build tools.

A ReactComponent subclass provides bi-directional syncing of its parameters with arbitrary HTML elements, attributes and properties. The key part of the subclass is the _esm variable. Use this to define a render function as shown in the example below.

Reference: https://panel.holoviz.org/reference/custom_components/ReactComponent.html

```python import panel as pn import param

class CounterButton(pn.custom.ReactComponent):

value = param.Integer()

_esm = “”” export function render({model}) { const [value, setValue] = model.useState(“value”); return (

<button onClick={e => setValue(value+1)}> count is {value} </button>

“””

CounterButton().servable() ```

Parameters inherited from:

panel.viewable.Layoutable: align, aspect_ratio, css_classes, design, height, min_width, min_height, max_width, max_height, margin, styles, stylesheets, tags, width, width_policy, height_policy, sizing_mode, visible

panel.viewable.Viewable: loading

clone(**params) → Viewable

Makes a copy of the object sharing the same parameters.

Arguments

params: Keyword arguments override the parameters on the clone.

Returns

Cloned Viewable object

controls(parameters: list[str] = [], jslink: bool = True, **kwargs) → BasePanel

Creates a set of widgets which allow manipulating the parameters on this instance. By default all parameters which support linking are exposed, but an explicit list of parameters can be provided.

Arguments

parameters: list(str)

An explicit list of parameters to return controls for.

jslink: bool

Whether to use jslinks instead of Python based links. This does not allow using all types of parameters.

kwargs: dict

Additional kwargs to pass to the Param pane(s) used to generate the controls widgets.

Returns

A layout of the controls

embed(max_states: int = 1000, max_opts: int = 3, json: bool = False, json_prefix: str = '', save_path: str = './', load_path: str | None = None, progress: bool = False, states={}) → None

Renders a static version of a panel in a notebook by evaluating the set of states defined by the widgets in the model. Note this will only work well for simple apps with a relatively small state space.

Arguments

max_states: int

The maximum number of states to embed

max_opts: int

The maximum number of states for a single widget

json: boolean (default=True)

Whether to export the data to json files

json_prefix: str (default=’’)

Prefix for JSON filename

save_path: str (default=’./’)

The path to save json files to

load_path: str (default=None)

The path or URL the json files will be loaded from.

progress: boolean (default=False)

Whether to report progress

states: dict (default={})

A dictionary specifying the widget values to embed for each widget

get_root(doc: Document | None = None, comm: Comm | None = None, preprocess: bool = True) → Model

Returns the root model and applies pre-processing hooks

Arguments

doc: bokeh.Document

Bokeh document the bokeh model will be attached to.

comm: pyviz_comms.Comm

Optional pyviz_comms when working in notebook

preprocess: boolean (default=True)

Whether to run preprocessing hooks

Returns

Returns the bokeh model corresponding to this panel object

jscallback(args: dict[str, Any] = {}, **callbacks: str) → Callback

Allows defining a JS callback to be triggered when a property changes on the source object. The keyword arguments define the properties that trigger a callback and the JS code that gets executed.

Arguments

args: dict

A mapping of objects to make available to the JS callback

callbacks: dict

A mapping between properties on the source model and the code to execute when that property changes

Returns

callback: Callback

The Callback which can be used to disable the callback.

jslink(target: JSLinkTarget, code: dict[str, str] = None, args: dict | None = None, bidirectional: bool = False, **links: str) → Link

Links properties on the this Reactive object to those on the target Reactive object in JS code.

Supports two modes, either specify a mapping between the source and target model properties as keywords or provide a dictionary of JS code snippets which maps from the source parameter to a JS code snippet which is executed when the property changes.

Arguments

target: panel.viewable.Viewable | bokeh.model.Model | holoviews.core.dimension.Dimensioned

The target to link the value to.

code: dict

Custom code which will be executed when the widget value changes.

args: dict

A mapping of objects to make available to the JS callback

bidirectional: boolean

Whether to link source and target bi-directionally

links: dict

A mapping between properties on the source model and the target model property to link it to.

Returns

link: GenericLink

The GenericLink which can be used unlink the widget and the target model.

link(target: Parameterized, callbacks: dict[str, str | Callable] | None = None, bidirectional: bool = False, **links: str) → Watcher

Links the parameters on this Reactive object to attributes on the target Parameterized object.

Supports two modes, either specify a mapping between the source and target object parameters as keywords or provide a dictionary of callbacks which maps from the source parameter to a callback which is triggered when the parameter changes.

Arguments

target: param.Parameterized

The target object of the link.

callbacks: dict | None

Maps from a parameter in the source object to a callback.

bidirectional: bool

Whether to link source and target bi-directionally

links: dict

Maps between parameters on this object to the parameters on the supplied object.

on_event(event: str, callback: Callable) → None

Registers a callback to be executed when the specified DOM event is triggered.

Arguments

event: str

Name of the DOM event to add an event listener to.

callback: callable

A callable which will be given the DOMEvent object.

on_msg(callback: Callable) → None

Registers a callback to be executed when a message event containing arbitrary data is received.

Arguments

event: str

Name of the DOM event to add an event listener to.

callback: callable

A callable which will be given the msg data.

save(filename: str | PathLike | IO, title: str | None = None, resources: Resources | None = None, template: str | Template | None = None, template_variables: dict[str, Any] = {}, embed: bool = False, max_states: int = 1000, max_opts: int = 3, embed_json: bool = False, json_prefix: str = '', save_path: str = './', load_path: str | None = None, progress: bool = True, embed_states: dict[Any, Any] = {}, as_png: bool | None = None, **kwargs) → None

Saves Panel objects to file.

Arguments

filename: str or file-like object

Filename to save the plot to

title: string

Optional title for the plot

resources: bokeh resources

One of the valid bokeh.resources (e.g. CDN or INLINE)

template:

passed to underlying io.save

template_variables:

passed to underlying io.save

embed: bool

Whether the state space should be embedded in the saved file.

max_states: int

The maximum number of states to embed

max_opts: int

The maximum number of states for a single widget

embed_json: boolean (default=True)

Whether to export the data to json files

json_prefix: str (default=’’)

Prefix for the auto-generated json directory

save_path: str (default=’./’)

The path to save json files to

load_path: str (default=None)

The path or URL the json files will be loaded from.

progress: boolean (default=True)

Whether to report progress

embed_states: dict (default={})

A dictionary specifying the widget values to embed for each widget

as_png: boolean (default=None)

To save as a .png. If None save_png will be true if filename is string and ends with png.

select(selector: type | Callable[[Viewable], bool] | None = None) → list[Viewable]

Iterates over the Viewable and any potential children in the applying the Selector.

Arguments

selector: type or callable or None

The selector allows selecting a subset of Viewables by declaring a type or callable function to filter by.

Returns

viewables: list(Viewable)

servable(title: str | None = None, location: bool | 'Location' = True, area: str = 'main', target: str | None = None) → ServableMixin

Serves the object or adds it to the configured pn.state.template if in a panel serve context, writes to the DOM if in a pyodide context and returns the Panel object to allow it to display itself in a notebook context.

Arguments

titlestr

A string title to give the Document (if served as an app)

locationboolean or panel.io.location.Location

Whether to create a Location component to observe and set the URL location.

area: str (deprecated)

The area of a template to add the component too. Only has an effect if pn.config.template has been set.

target: str

Target area to write to. If a template has been configured on pn.config.template this refers to the target area in the template while in pyodide this refers to the ID of the DOM node to write to.

Returns

The Panel object itself

server_doc(doc: Document | None = None, title: str | None = None, location: bool | 'Location' = True) → Document

Returns a serveable bokeh Document with the panel attached

Arguments

docbokeh.Document (optional)

The bokeh Document to attach the panel to as a root, defaults to bokeh.io.curdoc()

titlestr

A string title to give the Document

locationboolean or panel.io.location.Location

Whether to create a Location component to observe and set the URL location.

Returns

docbokeh.Document

The bokeh document the panel was attached to

show(title: str | None = None, port: int = 0, address: str | None = None, websocket_origin: str | None = None, threaded: bool = False, verbose: bool = True, open: bool = True, location: bool | 'Location' = True, **kwargs) → StoppableThread' | 'Server

Starts a Bokeh server and displays the Viewable in a new tab.

Arguments

titlestr | None

A string title to give the Document (if served as an app)

port: int (optional, default=0)

Allows specifying a specific port

addressstr

The address the server should listen on for HTTP requests.

websocket_origin: str or list(str) (optional)

A list of hosts that can connect to the websocket. This is typically required when embedding a server app in an external web site. If None, “localhost” is used.

threaded: boolean (optional, default=False)

Whether to launch the Server on a separate thread, allowing interactive use.

verbose: boolean (optional, default=True)

Whether to print the address and port

openboolean (optional, default=True)

Whether to open the server in a new browser tab

locationboolean or panel.io.location.Location

Whether to create a Location component to observe and set the URL location.

Returns

server: bokeh.server.Server or panel.io.server.StoppableThread

Returns the Bokeh server instance or the thread the server was launched on (if threaded=True)

class panel.custom.ReactiveESM(*, loading, align, aspect_ratio, css_classes, design, height, height_policy, margin, max_height, max_width, min_height, min_width, sizing_mode, styles, stylesheets, tags, visible, width, width_policy, name)

Bases: ReactiveCustomBase

The ReactiveESM classes allow you to create custom Panel components using HTML, CSS and/ or Javascript and without the complexities of Javascript build tools.

A ReactiveESM subclass provides bi-directional syncing of its parameters with arbitrary HTML elements, attributes and properties. The key part of the subclass is the _esm variable. Use this to define a render function as shown in the example below.

```python import panel as pn import param

pn.extension()

class CounterButton(pn.custom.ReactiveESM):

value = param.Integer()

_esm = “”” export function render({ model }) {

let btn = document.createElement(“button”); btn.innerHTML = count is ${model.value}; btn.addEventListener(“click”, () => {

model.value += 1

}); model.on(‘value’, () => {

btn.innerHTML = count is ${model.value};

}) return btn

CounterButton().servable() ```

Parameters inherited from:

panel.viewable.Layoutable: align, aspect_ratio, css_classes, design, height, min_width, min_height, max_width, max_height, margin, styles, stylesheets, tags, width, width_policy, height_policy, sizing_mode, visible

panel.viewable.Viewable: loading

clone(**params) → Viewable

Makes a copy of the object sharing the same parameters.

Arguments

params: Keyword arguments override the parameters on the clone.

Returns

Cloned Viewable object

controls(parameters: list[str] = [], jslink: bool = True, **kwargs) → BasePanel

Creates a set of widgets which allow manipulating the parameters on this instance. By default all parameters which support linking are exposed, but an explicit list of parameters can be provided.

Arguments

parameters: list(str)

An explicit list of parameters to return controls for.

jslink: bool

Whether to use jslinks instead of Python based links. This does not allow using all types of parameters.

kwargs: dict

Additional kwargs to pass to the Param pane(s) used to generate the controls widgets.

Returns

A layout of the controls

embed(max_states: int = 1000, max_opts: int = 3, json: bool = False, json_prefix: str = '', save_path: str = './', load_path: str | None = None, progress: bool = False, states={}) → None

Renders a static version of a panel in a notebook by evaluating the set of states defined by the widgets in the model. Note this will only work well for simple apps with a relatively small state space.

Arguments

max_states: int

The maximum number of states to embed

max_opts: int

The maximum number of states for a single widget

json: boolean (default=True)

Whether to export the data to json files

json_prefix: str (default=’’)

Prefix for JSON filename

save_path: str (default=’./’)

The path to save json files to

load_path: str (default=None)

The path or URL the json files will be loaded from.

progress: boolean (default=False)

Whether to report progress

states: dict (default={})

A dictionary specifying the widget values to embed for each widget

get_root(doc: Document | None = None, comm: Comm | None = None, preprocess: bool = True) → Model

Returns the root model and applies pre-processing hooks

Arguments

doc: bokeh.Document

Bokeh document the bokeh model will be attached to.

comm: pyviz_comms.Comm

Optional pyviz_comms when working in notebook

preprocess: boolean (default=True)

Whether to run preprocessing hooks

Returns

Returns the bokeh model corresponding to this panel object

jscallback(args: dict[str, Any] = {}, **callbacks: str) → Callback

Allows defining a JS callback to be triggered when a property changes on the source object. The keyword arguments define the properties that trigger a callback and the JS code that gets executed.

Arguments

args: dict

A mapping of objects to make available to the JS callback

callbacks: dict

A mapping between properties on the source model and the code to execute when that property changes

Returns

callback: Callback

The Callback which can be used to disable the callback.

jslink(target: JSLinkTarget, code: dict[str, str] = None, args: dict | None = None, bidirectional: bool = False, **links: str) → Link

Links properties on the this Reactive object to those on the target Reactive object in JS code.

Supports two modes, either specify a mapping between the source and target model properties as keywords or provide a dictionary of JS code snippets which maps from the source parameter to a JS code snippet which is executed when the property changes.

Arguments

target: panel.viewable.Viewable | bokeh.model.Model | holoviews.core.dimension.Dimensioned

The target to link the value to.

code: dict

Custom code which will be executed when the widget value changes.

args: dict

A mapping of objects to make available to the JS callback

bidirectional: boolean

Whether to link source and target bi-directionally

links: dict

A mapping between properties on the source model and the target model property to link it to.

Returns

link: GenericLink

The GenericLink which can be used unlink the widget and the target model.

link(target: Parameterized, callbacks: dict[str, str | Callable] | None = None, bidirectional: bool = False, **links: str) → Watcher

Links the parameters on this Reactive object to attributes on the target Parameterized object.

Supports two modes, either specify a mapping between the source and target object parameters as keywords or provide a dictionary of callbacks which maps from the source parameter to a callback which is triggered when the parameter changes.

Arguments

target: param.Parameterized

The target object of the link.

callbacks: dict | None

Maps from a parameter in the source object to a callback.

bidirectional: bool

Whether to link source and target bi-directionally

links: dict

Maps between parameters on this object to the parameters on the supplied object.

on_event(event: str, callback: Callable) → None

Registers a callback to be executed when the specified DOM event is triggered.

Arguments

event: str

Name of the DOM event to add an event listener to.

callback: callable

A callable which will be given the DOMEvent object.

on_msg(callback: Callable) → None

Registers a callback to be executed when a message event containing arbitrary data is received.

Arguments

event: str

Name of the DOM event to add an event listener to.

callback: callable

A callable which will be given the msg data.

save(filename: str | PathLike | IO, title: str | None = None, resources: Resources | None = None, template: str | Template | None = None, template_variables: dict[str, Any] = {}, embed: bool = False, max_states: int = 1000, max_opts: int = 3, embed_json: bool = False, json_prefix: str = '', save_path: str = './', load_path: str | None = None, progress: bool = True, embed_states: dict[Any, Any] = {}, as_png: bool | None = None, **kwargs) → None

Saves Panel objects to file.

Arguments

filename: str or file-like object

Filename to save the plot to

title: string

Optional title for the plot

resources: bokeh resources

One of the valid bokeh.resources (e.g. CDN or INLINE)

template:

passed to underlying io.save

template_variables:

passed to underlying io.save

embed: bool

Whether the state space should be embedded in the saved file.

max_states: int

The maximum number of states to embed

max_opts: int

The maximum number of states for a single widget

embed_json: boolean (default=True)

Whether to export the data to json files

json_prefix: str (default=’’)

Prefix for the auto-generated json directory

save_path: str (default=’./’)

The path to save json files to

load_path: str (default=None)

The path or URL the json files will be loaded from.

progress: boolean (default=True)

Whether to report progress

embed_states: dict (default={})

A dictionary specifying the widget values to embed for each widget

as_png: boolean (default=None)

To save as a .png. If None save_png will be true if filename is string and ends with png.

select(selector: type | Callable[[Viewable], bool] | None = None) → list[Viewable]

Iterates over the Viewable and any potential children in the applying the Selector.

Arguments

selector: type or callable or None

The selector allows selecting a subset of Viewables by declaring a type or callable function to filter by.

Returns

viewables: list(Viewable)

servable(title: str | None = None, location: bool | 'Location' = True, area: str = 'main', target: str | None = None) → ServableMixin

Serves the object or adds it to the configured pn.state.template if in a panel serve context, writes to the DOM if in a pyodide context and returns the Panel object to allow it to display itself in a notebook context.

Arguments

titlestr

A string title to give the Document (if served as an app)

locationboolean or panel.io.location.Location

Whether to create a Location component to observe and set the URL location.

area: str (deprecated)

The area of a template to add the component too. Only has an effect if pn.config.template has been set.

target: str

Target area to write to. If a template has been configured on pn.config.template this refers to the target area in the template while in pyodide this refers to the ID of the DOM node to write to.

Returns

The Panel object itself

server_doc(doc: Document | None = None, title: str | None = None, location: bool | 'Location' = True) → Document

Returns a serveable bokeh Document with the panel attached

Arguments

docbokeh.Document (optional)

The bokeh Document to attach the panel to as a root, defaults to bokeh.io.curdoc()

titlestr

A string title to give the Document

locationboolean or panel.io.location.Location

Whether to create a Location component to observe and set the URL location.

Returns

docbokeh.Document

The bokeh document the panel was attached to

show(title: str | None = None, port: int = 0, address: str | None = None, websocket_origin: str | None = None, threaded: bool = False, verbose: bool = True, open: bool = True, location: bool | 'Location' = True, **kwargs) → StoppableThread' | 'Server

Starts a Bokeh server and displays the Viewable in a new tab.

Arguments

titlestr | None

A string title to give the Document (if served as an app)

port: int (optional, default=0)

Allows specifying a specific port

addressstr

The address the server should listen on for HTTP requests.

websocket_origin: str or list(str) (optional)

A list of hosts that can connect to the websocket. This is typically required when embedding a server app in an external web site. If None, “localhost” is used.

threaded: boolean (optional, default=False)

Whether to launch the Server on a separate thread, allowing interactive use.

verbose: boolean (optional, default=True)

Whether to print the address and port

openboolean (optional, default=True)

Whether to open the server in a new browser tab

locationboolean or panel.io.location.Location

Whether to create a Location component to observe and set the URL location.

Returns

server: bokeh.server.Server or panel.io.server.StoppableThread

Returns the Bokeh server instance or the thread the server was launched on (if threaded=True)

class panel.custom.ReactiveESMMetaclass(name: str, bases: tuple[type, ...], dict_: Mapping[str, Any])

Bases: ReactiveMetaBase

property abstract

Return True if the class has an attribute __abstract set to True. Subclasses will return False unless they themselves have __abstract set to true. This mechanism allows a class to declare itself to be abstract (e.g. to avoid it being offered as an option in a GUI), without the “abstract” property being inherited by its subclasses (at least one of which is presumably not abstract).

get_param_descriptor(param_name)

Goes up the class hierarchy (starting from the current class) looking for a Parameter class attribute param_name. As soon as one is found as a class attribute, that Parameter is returned along with the class in which it is declared.

mro()

Return a type’s method resolution order.