Context#

Context is an advanced feature of Seamless that allows you to customize the rendering process of Seamless components.

The default context is created using the Context.standard method and has the following features in order:

  • SocketIO Feature: This feature allows you to connect between the client and server using SocketIO.

    from seamless.context import Context
from seamless.extra.state import SocketIOTransport

context = Context()
context.add_feature(SocketIOTransport)

  • Component Repository: A repository for storing components - this handles the component event and allows you to store and retrieve components after the initial render.

    from seamless.context import Context
from seamless.extra.components import ComponentsFeature

context = Context()
context.add_feature(ComponentsFeature)

  • Events Feature: This feature allows you to connect between HTML events and Python functions.

    from seamless.context import Context
from seamless.extra.events import EventsFeature

context = Context()
context.add_feature(EventsFeature, claim_time=30)

  • State Feature: This feature allows you to manage the state of components on the client-side.

    from seamless.context import Context
from seamless.extra.state import StateFeature

context = Context()
context.add_feature(StateFeature)

The standard context also comes with the following property transformers in order:

  • Class Transformer: Changes the class_name property key to class and converts the value to a string if it is a list.

    from seamless.context import Context
from seamless.extra.transformers.class_transformer import class_transformer

context = Context()
context.add_prop_transformer(*class_transformer())

  • Simple Transformer: Converts the properties in this list except for class_name.

    from seamless.context import Context
from seamless.extra.transformers.simple_transformer import simple_transformer

context = Context()
context.add_prop_transformer(*simple_transformer())

  • HTML Events Transformer: Converts the properties keys from on_{event} to on{event}. This works only when the property value is a string, JS and Python functions are handled by a different transformers.

    from seamless.context import Context
from seamless.extra.transformers.html_events_transformer import html_events_transformer

context = Context()
context.add_prop_transformer(*html_events_transformer())

  • Dash Transformer: Converts the properties keys from dash_case (AKA snake_case) to kebab-case. This works only for properties with primitive values.

    from seamless.context import Context
from seamless.extra.transformers.dash_transformer import dash_transformer

context = Context()
context.add_prop_transformer(*dash_transformer())

  • Initialize Script Transformer: Attaching the code in the init property to the seamless:init attribute.

    from seamless.context import Context
from seamless.extra.transformers.js_transformer import init_transformer

context = Context()
context.add_prop_transformer(*init_transformer())

  • JS Transformer: Attaching the code in all properties that start with on_ to the corresponding HTML event. The transformer will add the attachEventListener method to the element inside the seamless:init attribute and remove the property from the element.

    from seamless.context import Context
from seamless.extra.transformers.js_transformer import js_transformer

context = Context()
context.add_prop_transformer(*js_transformer())

  • Style Transformer: Converts the properties with StyleObject as value to a css string.

    from seamless.context import Context
from seamless.extra.transformers.style_transformer import style_transformer

context = Context()
context.add_prop_transformer(*style_transformer())
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