PySTAC extensions reference

This package contains proper PySTAC implementations for the upstream Open Science Catalog and Themes STAC specifications. They provide typed accessors, schema registration, object-type checks, serialization, and extension hooks.

They are implementations of the published specifications within this client; they do not redefine or replace those specifications.

OSC extension

Import from osc_metadata_client.osc_extension.

API	Purpose
`OscExtension.ext(obj, add_if_missing=False)`	Access OSC fields on a PySTAC `Collection` or `Item`.
`apply_project(...)`	Set the mutually exclusive OSC project shape.
`apply_product(...)`	Set the mutually exclusive OSC product shape.
`OscType`	`project` and `product` values.
`OscStatus`	`planned`, `ongoing`, and `completed` values.
`SCHEMA_URI`	`https://stac-extensions.github.io/osc/v1.0.0/schema.json`

Supported properties are osc:type, osc:status, osc:workflows, osc:project, osc:region, osc:variables, osc:missions, and osc:experiment.

from osc_metadata_client.osc_extension import OscExtension, OscStatus

osc = OscExtension.ext(collection, add_if_missing=True)
osc.apply_product(
    status=OscStatus.COMPLETED,
    project="project-001",
    experiment="experiment-001",
)

Themes extension

Import from osc_metadata_client.themes_extension.

API	Purpose
`ThemesExtension.ext(obj, add_if_missing=False)`	Access themes on a PySTAC `Catalog`, `Collection`, or `Item`.
`ThemesExtension.summaries(collection, ...)`	Access themes in Collection summaries.
`Theme`	A controlled vocabulary scheme and its concepts.
`ThemeConcept`	A concept identifier with optional title, description, and URL.
`SCHEMA_URI`	`https://stac-extensions.github.io/themes/v1.0.0/schema.json`

from osc_metadata_client.themes_extension import (
    Theme,
    ThemeConcept,
    ThemesExtension,
)

themes = ThemesExtension.ext(collection, add_if_missing=True)
themes.apply([
    Theme(
        scheme="https://github.com/stac-extensions/osc#theme",
        concepts=[ThemeConcept(id="land")],
    )
])

Passing add_if_missing=True adds the correct schema URI to stac_extensions. Without it, accessing an undeclared extension raises PySTAC's ExtensionNotImplemented. Unsupported PySTAC object types raise ExtensionTypeError.