statelit 0.0.0b1

Easy state management in Streamlit with Pydantic.

Easy state management in Streamlit with Pydantic.

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StatelitModel Attributes and Methods

The following attributes and methods are part of the public API and are considered stable.

StatelitModel().pydantic_obj

Pydantic object being used by the StatelitModel().

StatelitModel().widget()

Render a single widget for a single field.

Parameters:

• field_name: str (required) - String name of the field to render a widget for.
• key_suffix: Optional[str] = None - Suffix to apply to the state key.
• run_post_callback: bool = True - If true, run the "post callback" for this field before returning a value.
• **kwargs - Additional keyword arguments that will be passed to the Streamlit callback.

Returns: (Any) The value output by the Streamlit callback (i.e. the value of the widget), after running the post callback if run_post_callback is True.

StatelitModel().form()

Renders all widgets for the entire Pydantic BaseModel. Widgets are rendered in the order they're defined in the model.

Parameters:

• key_suffix: Optional[str] = None - Suffix to apply to the state key.
• exclude: Optional[List[str]] = None - Which field names to exclude from rendering.
• **kwargs - Additional keyword arguments that will be passed to the Streamlit callback.

Returns: (pydantic.BaseModel) The Pydantic model object, pydantic_obj.

StatelitModel().code()

Renders Markdown syntax highlighted version of the JSON state.

Returns: (str) JSON representation of the state.

StatelitModel().text_area()

Renders the JSON state as a text field. The JSON can be modified, and changing its value will update all other fields to match.

Parameters:

• key_suffix: Optional[str] = None - Suffix to apply to the state key.
• exclude: Optional[List[str]] = None - Which field names to exclude from rendering.
• **kwargs - Additional keyword arguments that will be passed to the Streamlit callback.

Returns: (str) The output of the text widget, which should be a JSON representation of the state.

StatelitModel().lazy_text_area()

Renders the JSON state as a "lazy" text field. The JSON can be modified, but changes won't be saved until the "Apply" button is pressed.

Parameters:

• key_suffix: Optional[str] = None - Suffix to apply to the state key.
• exclude: Optional[List[str]] = None - Which field names to exclude from rendering.
• **kwargs - Additional keyword arguments that will be passed to the Streamlit callback.

Returns: (str) The output of the text widget, which should be a JSON representation of the state.

Types

The following implementations are considered stable:

Type	Widget	Notes
float	st.number_input
int	st.number_input
str	st.text_input or st.text_area	st.text_area is used if the default value contains a \n; otherwise, st.text_input is used.
enum.Enum	st.selectbox	st.radio is also a good choice; set the streamlit_widget kwarg in the Field() to use that.
datetime.date	st.date_input
datetime.time	st.time_input
pydantic.ConstrainedInt	st.slider	Used when both ge/gt and le/lt are set; otherwise, use st.number_input
pydantic.ConstrainedFloat	st.slider	Used when both ge/gt and le/lt are set; otherwise, use st.number_input
pydantic.color.Color	st.color_picker	Colors are always converted to hex values.

The following implementations are considered experimental and are potentially subject to some future changes:

Type	Widget	Notes
datetime.datetime	st.date_input	Time component is always cast to 00:00:00. For true datetimes, at the moment, it is suggested you use separate datetime.date and datetime.times and manually combine them.

Notes on internals

Most users do not need this.

Note that the API is under development, and this may change as the project is developed. None of this is considered part of the public API.

StatefulObject class

The StatefulObject class consists of shared internals for both model and field instances.

There are three types of state: base, replicated, and lazy:

• base state is the source of truth for all state.
• replicated state is always kept in sync with base state. If replicated state changes, then base state is updated.
• lazy state is updated when base state updates, but changes to lazy state will not update the base state by itself (for example, updating a lazy-state text field does not update base state, but a button may trigger a callable that updates the base state from the lazy state).

State is represented by keys associated with each object. Note that keys are by default assigned automatically. If you want to support more dynamic rendering (that makes when widgets are rendered non-deterministic), please set a key_suffix=.

StatefulObjects also have methods that allow for conversion between Statelit and Pydantic called to_statelit and to_pydantic.

FieldFactory

Trademark & Copyright

Streamlit is a trademark of Streamlit Inc.

This package is unaffiliated with Streamlit Inc. and Pydantic.