From 533bb149a00d49b8dfdeb35bd02d114815beb55f Mon Sep 17 00:00:00 2001
From: Kyle Barron <kylebarron2@gmail.com>
Date: Tue, 16 Feb 2021 19:26:03 -0700
Subject: [PATCH 1/5] Subclass from Enum

---
 pystac/catalog.py     | 15 +++++++++------
 pystac/link.py        |  6 +++++-
 pystac/media_type.py  |  8 +++++++-
 pystac/stac_object.py |  6 +++++-
 4 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/pystac/catalog.py b/pystac/catalog.py
index 3215b0835..4cf86abd6 100644
--- a/pystac/catalog.py
+++ b/pystac/catalog.py
@@ -1,5 +1,6 @@
 import os
 from copy import deepcopy
+from enum import Enum
 
 import pystac
 from pystac import STACError
@@ -9,8 +10,10 @@
 from pystac.cache import ResolvedObjectCache
 from pystac.utils import (is_absolute_href, make_absolute_href)
 
+class CatalogType(str, Enum):
+    def __str__(self):
+        return str(self.value)
 
-class CatalogType:
     SELF_CONTAINED = 'SELF_CONTAINED'
     """A 'self-contained catalog' is one that is designed for portability.
     Users may want to download a catalog from online and be able to use it on their
@@ -38,8 +41,8 @@ class CatalogType:
         `The best practices documentation on published catalogs <https://github.com/radiantearth/stac-spec/blob/v0.8.1/best-practices.md#published-catalogs>`_
     """ # noqa E501
 
-    @staticmethod
-    def determine_type(stac_json):
+    @classmethod
+    def determine_type(cls, stac_json):
         """Determines the catalog type based on a STAC JSON dict.
 
         Only applies to Catalogs or Collections
@@ -61,12 +64,12 @@ def determine_type(stac_json):
 
         if self_link:
             if relative:
-                return CatalogType.RELATIVE_PUBLISHED
+                return cls.RELATIVE_PUBLISHED
             else:
-                return CatalogType.ABSOLUTE_PUBLISHED
+                return cls.ABSOLUTE_PUBLISHED
         else:
             if relative:
-                return CatalogType.SELF_CONTAINED
+                return cls.SELF_CONTAINED
             else:
                 return None
 
diff --git a/pystac/link.py b/pystac/link.py
index afe06934a..290420323 100644
--- a/pystac/link.py
+++ b/pystac/link.py
@@ -1,12 +1,16 @@
 from copy import (copy, deepcopy)
+from enum import Enum
 
 from pystac import STACError
 from pystac.stac_io import STAC_IO
 from pystac.utils import (make_absolute_href, make_relative_href, is_absolute_href)
 
 
-class LinkType:
+class LinkType(str, Enum):
     """Enumerates link types; used to determine if a link is absolute or relative."""
+    def __str__(self):
+        return str(self.value)
+
     ABSOLUTE = 'ABSOLUTE'
     RELATIVE = 'RELATIVE'
 
diff --git a/pystac/media_type.py b/pystac/media_type.py
index 89f0790f3..5bc4c2798 100644
--- a/pystac/media_type.py
+++ b/pystac/media_type.py
@@ -1,6 +1,12 @@
-class MediaType:
+from enum import Enum
+
+
+class MediaType(str, Enum):
     """A list of common media types that can be used in STAC Asset and Link metadata.
     """
+    def __str__(self):
+        return str(self.value)
+
     COG = 'image/tiff; application=geotiff; profile=cloud-optimized'
     GEOJSON = 'application/geo+json'
     GEOPACKAGE = 'application/geopackage+sqlite3'
diff --git a/pystac/stac_object.py b/pystac/stac_object.py
index bd24a72de..ed3557d74 100644
--- a/pystac/stac_object.py
+++ b/pystac/stac_object.py
@@ -1,4 +1,5 @@
 from abc import (ABC, abstractmethod)
+from enum import Enum
 
 import pystac
 from pystac import STACError
@@ -8,7 +9,10 @@
 from pystac.extensions import ExtensionError
 
 
-class STACObjectType:
+class STACObjectType(str, Enum):
+    def __str__(self):
+        return str(self.value)
+
     CATALOG = 'CATALOG'
     COLLECTION = 'COLLECTION'
     ITEM = 'ITEM'

From ef83a0b76f0a67c826e232e68ea9e1f45cf5f415 Mon Sep 17 00:00:00 2001
From: Kyle Barron <kylebarron2@gmail.com>
Date: Tue, 16 Feb 2021 19:30:02 -0700
Subject: [PATCH 2/5] Lint

---
 pystac/catalog.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pystac/catalog.py b/pystac/catalog.py
index 4cf86abd6..9c2f164b9 100644
--- a/pystac/catalog.py
+++ b/pystac/catalog.py
@@ -10,6 +10,7 @@
 from pystac.cache import ResolvedObjectCache
 from pystac.utils import (is_absolute_href, make_absolute_href)
 
+
 class CatalogType(str, Enum):
     def __str__(self):
         return str(self.value)

From fa8e9c2a378644cebb6205102f801624f764f042 Mon Sep 17 00:00:00 2001
From: Kyle Barron <kylebarron2@gmail.com>
Date: Tue, 16 Feb 2021 21:22:54 -0700
Subject: [PATCH 3/5] Add more enums

---
 pystac/extensions/__init__.py | 6 +++++-
 pystac/extensions/label.py    | 4 +++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/pystac/extensions/__init__.py b/pystac/extensions/__init__.py
index d3464ac30..0b18e899d 100644
--- a/pystac/extensions/__init__.py
+++ b/pystac/extensions/__init__.py
@@ -1,4 +1,5 @@
 # flake8: noqa
+from enum import Enum
 
 
 class ExtensionError(Exception):
@@ -7,8 +8,11 @@ class ExtensionError(Exception):
     pass
 
 
-class Extensions:
+class Extensions(str, Enum):
     """Enumerates the IDs of common extensions."""
+    def __str__(self):
+        return str(self.value)
+
     CHECKSUM = 'checksum'
     COLLECTION_ASSETS = 'collection-assets'
     DATACUBE = 'datacube'
diff --git a/pystac/extensions/label.py b/pystac/extensions/label.py
index 7190567f5..5f34d9d90 100644
--- a/pystac/extensions/label.py
+++ b/pystac/extensions/label.py
@@ -1,5 +1,7 @@
 """STAC Model classes for Label extension.
 """
+from enum import Enum
+
 from pystac import STACError
 from pystac.extensions import Extensions
 from pystac.extensions.base import (ItemExtension, ExtensionDefinition, ExtendedObject)
@@ -7,7 +9,7 @@
 from pystac.link import Link
 
 
-class LabelType:
+class LabelType(str, Enum):
     """Enumerates valid label types (RASTER or VECTOR)."""
     VECTOR = 'vector'
     RASTER = 'raster'

From 04e0d26bb91203bfd90fc9c4b44c42014476a119 Mon Sep 17 00:00:00 2001
From: Kyle Barron <kylebarron2@gmail.com>
Date: Fri, 19 Feb 2021 11:45:46 -0700
Subject: [PATCH 4/5] Add changelog entry

---
 CHANGELOG.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 966f4651e..186d1ee2c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,10 @@
 
 - Fix handling of optional properties when using apply on view extension ([#259](https://github.com/stac-utils/pystac/pull/259))
 
+### Changed
+
+- Subclass relevant classes from `enum.Enum`. This allows iterating over the class' contents. The `__str__` method is overwritten so this should not break backwards compatibility. ([#261](https://github.com/stac-utils/pystac/pull/261))
+
 ## [v0.5.4]
 
 ### Added

From 9f776b38c424093997e3cd2ed1afd4b1e9a0e993 Mon Sep 17 00:00:00 2001
From: Kyle Barron <kylebarron2@gmail.com>
Date: Fri, 19 Feb 2021 11:57:52 -0700
Subject: [PATCH 5/5] Add missing str override

---
 pystac/extensions/label.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/pystac/extensions/label.py b/pystac/extensions/label.py
index 5f34d9d90..d4e5e69b3 100644
--- a/pystac/extensions/label.py
+++ b/pystac/extensions/label.py
@@ -11,6 +11,9 @@
 
 class LabelType(str, Enum):
     """Enumerates valid label types (RASTER or VECTOR)."""
+    def __str__(self):
+        return str(self.value)
+
     VECTOR = 'vector'
     RASTER = 'raster'