Merge pull request #193 from schwehr/version-extension

Add support for the version extension.

Author: lossyrob

docs/api.rst

@@ -254,12 +254,12 @@ LabelStatistics
 Pointcloud Extension
 --------------------
 
-Implements the `Projection Extension <https://github.com/radiantearth/stac-spec/tree/v1.0.0-beta.2/extensions/pointcloud>`_.
+Implements the `Point Cloud Extension <https://github.com/radiantearth/stac-spec/tree/v1.0.0-beta.2/extensions/pointcloud>`_.
 
 PointcloudItemExt
 ~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pystac.extensions.projection.PointcloudItemExt
+.. autoclass:: pystac.extensions.pointcloud.PointcloudItemExt
    :members:
    :undoc-members:
    :show-inheritance:
@@ -306,6 +306,27 @@ SingleFileSTACCatalogExt
    :members:
    :undoc-members:
 
+Version Extension
+-----------------
+
+Implements the `Version Extension <https://github.com/radiantearth/stac-spec/tree/v1.0.0-beta.2/extensions/version>`_.
+
+VersionCollectionExt
+~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: pystac.extensions.version.VersionCollectionExt
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
+VersionItemExt
+~~~~~~~~~~~~~~
+
+.. autoclass:: pystac.extensions.version.VersionItemExt
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
 View Geometry Extension
 -----------------------
 

pystac/__init__.py

@@ -32,18 +32,20 @@ class STACError(Exception):
 from pystac import extensions
 import pystac.extensions.eo
 import pystac.extensions.label
-import pystac.extensions.projection
 import pystac.extensions.pointcloud
-import pystac.extensions.view
+import pystac.extensions.projection
 import pystac.extensions.single_file_stac
 import pystac.extensions.timestamps
+import pystac.extensions.version
+import pystac.extensions.view
 
 STAC_EXTENSIONS = extensions.base.RegisteredSTACExtensions([
     extensions.eo.EO_EXTENSION_DEFINITION, extensions.label.LABEL_EXTENSION_DEFINITION,
     extensions.pointcloud.POINTCLOUD_EXTENSION_DEFINITION,
     extensions.projection.PROJECTION_EXTENSION_DEFINITION,
-    extensions.view.VIEW_EXTENSION_DEFINITION, extensions.single_file_stac.SFS_EXTENSION_DEFINITION,
-    extensions.timestamps.TIMESTAMPS_EXTENSION_DEFINITION
+    extensions.single_file_stac.SFS_EXTENSION_DEFINITION,
+    extensions.timestamps.TIMESTAMPS_EXTENSION_DEFINITION,
+    extensions.version.VERSION_EXTENSION_DEFINITION, extensions.view.VIEW_EXTENSION_DEFINITION
 ])
 
 

pystac/extensions/version.py

@@ -0,0 +1,160 @@
+"""Implement the version extension.
+
+https://github.com/radiantearth/stac-spec/tree/dev/extensions/version
+"""
+
+import pystac
+from pystac import collection
+from pystac import Extensions
+from pystac import item
+from pystac import link
+from pystac.extensions import base
+
+VERSION = 'version'
+DEPRECATED = 'deprecated'
+LATEST = 'latest-version'
+PREDECESSOR = 'predecessor-version'
+SUCCESSOR = 'successor-version'
+
+# Media type for links.
+MEDIA_TYPE = 'application/json'
+
+
+class VersionItemExt(base.ItemExtension):
+    """Add an asset version string to a STAC Item."""
+    def __init__(self, an_item):
+        self.item = an_item
+
+    def apply(self, version, deprecated=None, latest=None, predecessor=None, successor=None):
+        self.version = version
+        if deprecated is not None:
+            self.deprecated = deprecated
+        if latest:
+            self.latest = latest
+        if predecessor:
+            self.predecessor = predecessor
+        if successor:
+            self.successor = successor
+
+    @property
+    def version(self):
+        return self.item.properties.get(VERSION)
+
+    @version.setter
+    def version(self, v):
+        self.item.properties[VERSION] = v
+
+    @property
+    def deprecated(self):
+        return bool(self.item.properties.get(DEPRECATED))
+
+    @deprecated.setter
+    def deprecated(self, v):
+        if not isinstance(v, bool):
+            raise pystac.STACError(DEPRECATED + ' must be a bool')
+        self.item.properties[DEPRECATED] = v
+
+    @property
+    def latest(self):
+        return next(self.item.get_stac_objects(LATEST), None)
+
+    @latest.setter
+    def latest(self, source_item):
+        self.item.add_link(link.Link(LATEST, source_item, MEDIA_TYPE))
+
+    @property
+    def predecessor(self):
+        return next(self.item.get_stac_objects(PREDECESSOR), None)
+
+    @predecessor.setter
+    def predecessor(self, source_item):
+        self.item.add_link(link.Link(PREDECESSOR, source_item, MEDIA_TYPE))
+
+    @property
+    def successor(self):
+        return next(self.item.get_stac_objects(SUCCESSOR), None)
+
+    @successor.setter
+    def successor(self, source_item):
+        self.item.add_link(link.Link(SUCCESSOR, source_item, MEDIA_TYPE))
+
+    @classmethod
+    def from_item(cls, an_item):
+        return cls(an_item)
+
+    @classmethod
+    def _object_links(cls):
+        return [LATEST, PREDECESSOR, SUCCESSOR]
+
+
+class VersionCollectionExt(base.CollectionExtension):
+    """Add an asset version string to a STAC Collection."""
+    def __init__(self, a_collection):
+        self.collection = a_collection
+
+    @property
+    def version(self):
+        return self.collection.extra_fields.get(VERSION)
+
+    @version.setter
+    def version(self, v):
+        self.collection.extra_fields[VERSION] = v
+
+    @property
+    def deprecated(self):
+        return bool(self.collection.extra_fields.get(DEPRECATED))
+
+    @deprecated.setter
+    def deprecated(self, v):
+        if not isinstance(v, bool):
+            raise pystac.STACError(DEPRECATED + ' must be a bool')
+        self.collection.extra_fields[DEPRECATED] = v
+
+    @property
+    def latest(self):
+        return next(self.collection.get_stac_objects(LATEST), None)
+
+    @latest.setter
+    def latest(self, source_collection):
+        self.collection.add_link(link.Link(LATEST, source_collection, MEDIA_TYPE))
+
+    @property
+    def predecessor(self):
+        return next(self.collection.get_stac_objects(PREDECESSOR), None)
+
+    @predecessor.setter
+    def predecessor(self, source_collection):
+        self.collection.add_link(link.Link(PREDECESSOR, source_collection, MEDIA_TYPE))
+
+    @property
+    def successor(self):
+        return next(self.collection.get_stac_objects(SUCCESSOR), None)
+
+    @successor.setter
+    def successor(self, source_collection):
+        self.collection.add_link(link.Link(SUCCESSOR, source_collection, MEDIA_TYPE))
+
+    @classmethod
+    def from_collection(cls, a_collection):
+        return cls(a_collection)
+
+    @classmethod
+    def _object_links(cls):
+        return [LATEST, PREDECESSOR, SUCCESSOR]
+
+    def apply(self, version, deprecated=None, latest=None, predecessor=None, successor=None):
+        self.version = version
+        if deprecated is not None:
+            self.deprecated = deprecated
+        if latest:
+            self.latest = latest
+        if predecessor:
+            self.predecessor = predecessor
+        if successor:
+            self.successor = successor
+
+
+VERSION_EXTENSION_DEFINITION = base.ExtensionDefinition(Extensions.VERSION, [
+    base.ExtendedObject(item.Item, VersionItemExt),
+    base.ExtendedObject(collection.Collection, VersionCollectionExt)
+])