"""
Implements the `Item Asset Definition Object
<https://github.com/radiantearth/stac-spec/blob/v1.1.0/collection-spec/collection-spec.md#item-asset-definition-object>`__
for use as values in the :attr:`~pystac.Collection.item_assets` dict.
"""
from __future__ import annotations
from copy import deepcopy
from typing import TYPE_CHECKING, Any
import pystac
if TYPE_CHECKING:
from pystac.extensions.ext import ItemAssetExt
ASSET_TITLE_PROP = "title"
ASSET_DESC_PROP = "description"
ASSET_TYPE_PROP = "type"
ASSET_ROLES_PROP = "roles"
[docs]
class ItemAssetDefinition:
"""Implementation of the `Item Asset Definition Object
<https://github.com/radiantearth/stac-spec/blob/v1.1.0/collection-spec/collection-spec.md#item-asset-definition-object>`__
for use as values in the :attr:`~pystac.Collection.item_assets` dict.
"""
properties: dict[str, Any]
owner: pystac.Collection | None
def __init__(
self, properties: dict[str, Any], owner: pystac.Collection | None = None
) -> None:
self.properties = properties
self.owner = owner
def __eq__(self, o: object) -> bool:
if not isinstance(o, ItemAssetDefinition):
return NotImplemented
return self.to_dict() == o.to_dict()
[docs]
@classmethod
def create(
cls,
title: str | None,
description: str | None,
media_type: str | None,
roles: list[str] | None,
extra_fields: dict[str, Any] | None = None,
) -> ItemAssetDefinition:
"""
Creates a new asset definition.
Args:
title : Displayed title for clients and users.
description : Description of the Asset providing additional details,
such as how it was processed or created.
`CommonMark 0.29 <http://commonmark.org/>`__ syntax MAY be used
for rich text representation.
media_type : `media type\
<https://github.com/radiantearth/stac-spec/tree/v1.1.0/catalog-spec/catalog-spec.md#media-types>`__
of the asset.
roles : `semantic roles
<https://github.com/radiantearth/stac-spec/tree/v1.1.0/item-spec/item-spec.md#asset-role-types>`__
of the asset, similar to the use of rel in links.
extra_fields : Additional fields on the asset definition, e.g. from
extensions.
"""
asset_defn = cls({})
asset_defn.apply(
title=title,
description=description,
media_type=media_type,
roles=roles,
extra_fields=extra_fields,
)
return asset_defn
[docs]
def apply(
self,
title: str | None,
description: str | None,
media_type: str | None,
roles: list[str] | None,
extra_fields: dict[str, Any] | None = None,
) -> None:
"""
Sets the properties for this asset definition.
Args:
title : Displayed title for clients and users.
description : Description of the Asset providing additional details,
such as how it was processed or created.
`CommonMark 0.29 <http://commonmark.org/>`__ syntax MAY be used
for rich text representation.
media_type : `media type\
<https://github.com/radiantearth/stac-spec/tree/v1.0.0/catalog-spec/catalog-spec.md#media-types>`__
of the asset.
roles : `semantic roles
<https://github.com/radiantearth/stac-spec/tree/v1.0.0/item-spec/item-spec.md#asset-role-types>`__
of the asset, similar to the use of rel in links.
extra_fields : Additional fields on the asset definition, e.g. from
extensions.
"""
if extra_fields:
self.properties.update(extra_fields)
self.title = title
self.description = description
self.media_type = media_type
self.roles = roles
self.owner = None
[docs]
def set_owner(self, obj: pystac.Collection) -> None:
"""Sets the owning item of this ItemAssetDefinition.
The owning item will be used to resolve relative HREFs of this asset.
Args:
obj: The Collection that owns this asset.
"""
self.owner = obj
@property
def title(self) -> str | None:
"""Gets or sets the displayed title for clients and users."""
return self.properties.get(ASSET_TITLE_PROP)
@title.setter
def title(self, v: str | None) -> None:
if v is None:
self.properties.pop(ASSET_TITLE_PROP, None)
else:
self.properties[ASSET_TITLE_PROP] = v
@property
def description(self) -> str | None:
"""Gets or sets a description of the Asset providing additional details, such as
how it was processed or created. `CommonMark 0.29 <http://commonmark.org/>`__
syntax MAY be used for rich text representation."""
return self.properties.get(ASSET_DESC_PROP)
@description.setter
def description(self, v: str | None) -> None:
if v is None:
self.properties.pop(ASSET_DESC_PROP, None)
else:
self.properties[ASSET_DESC_PROP] = v
@property
def media_type(self) -> str | None:
"""Gets or sets the `media type
<https://github.com/radiantearth/stac-spec/tree/v1.0.0/catalog-spec/catalog-spec.md#media-types>`__
of the asset."""
return self.properties.get(ASSET_TYPE_PROP)
@media_type.setter
def media_type(self, v: str | None) -> None:
if v is None:
self.properties.pop(ASSET_TYPE_PROP, None)
else:
self.properties[ASSET_TYPE_PROP] = v
@property
def roles(self) -> list[str] | None:
"""Gets or sets the `semantic roles
<https://github.com/radiantearth/stac-spec/tree/v1.0.0/item-spec/item-spec.md#asset-role-types>`__
of the asset, similar to the use of rel in links."""
return self.properties.get(ASSET_ROLES_PROP)
@roles.setter
def roles(self, v: list[str] | None) -> None:
if v is None:
self.properties.pop(ASSET_ROLES_PROP, None)
else:
self.properties[ASSET_ROLES_PROP] = v
[docs]
def to_dict(self) -> dict[str, Any]:
"""Returns a dictionary representing this ``ItemAssetDefinition``."""
return deepcopy(self.properties)
[docs]
def create_asset(self, href: str) -> pystac.Asset:
"""Creates a new :class:`~pystac.Asset` instance using the fields from this
``ItemAssetDefinition`` and the given ``href``."""
return pystac.Asset(
href=href,
title=self.title,
description=self.description,
media_type=self.media_type,
roles=self.roles,
extra_fields={
k: v
for k, v in self.properties.items()
if k
not in {
ASSET_TITLE_PROP,
ASSET_DESC_PROP,
ASSET_TYPE_PROP,
ASSET_ROLES_PROP,
}
},
)
@property
def ext(self) -> ItemAssetExt:
"""Accessor for extension classes on this item_asset
Example::
collection.item_assets["data"].ext.proj.epsg = 4326
"""
from pystac.extensions.ext import ItemAssetExt
return ItemAssetExt(stac_object=self)
class _ItemAssets(dict): # type:ignore
"""Private class for exposing item_assets as a dict
This class coerces values to ``ItemAssetDefinition``s and
sets that owner on all ``ItemAssetDefinition``s to the collection
that it is owned by.
"""
collection: pystac.Collection
def __init__(self, collection: pystac.Collection) -> None:
self.collection = collection
if not collection.extra_fields.get("item_assets"):
collection.extra_fields["item_assets"] = {}
self.update(collection.extra_fields["item_assets"])
def __setitem__(self, key: str, value: Any) -> None:
if isinstance(value, ItemAssetDefinition):
asset_definition = value
asset_definition.set_owner(self.collection)
else:
asset_definition = ItemAssetDefinition(value, self.collection)
self.collection.extra_fields["item_assets"][key] = asset_definition.properties
super().__setitem__(key, asset_definition)
def update(self, *args: Any, **kwargs: Any) -> None:
for k, v in dict(*args, **kwargs).items():
self[k] = v