Merge pull request #69 from azavea/rde/iso8601

Modified output datetime strings to ISO8601.

pystac/collection.py

@@ -5,6 +5,7 @@
 from pystac import STACError
 from pystac.catalog import Catalog
 from pystac.link import Link
+from pystac.utils import datetime_to_str
 
 
 class Collection(Catalog):
@@ -335,12 +336,10 @@ def to_dict(self):
             end = None
 
             if i[0]:
-                start = '{}Z'.format(i[0].replace(microsecond=0,
-                                                  tzinfo=None).isoformat())
+                start = datetime_to_str(i[0])
 
             if i[1]:
-                end = '{}Z'.format(i[1].replace(microsecond=0,
-                                                tzinfo=None).isoformat())
+                end = datetime_to_str(i[1])
 
             encoded_intervals.append([start, end])
 

pystac/item.py

@@ -8,7 +8,7 @@
 from pystac.link import Link, LinkType
 from pystac.stac_object import STACObject
 from pystac.utils import (is_absolute_href, make_absolute_href,
-                          make_relative_href)
+                          make_relative_href, datetime_to_str)
 from pystac.collection import Collection
 
 
@@ -173,8 +173,7 @@ def to_dict(self, include_self_link=True):
         assets = dict(
             map(lambda x: (x[0], x[1].to_dict()), self.assets.items()))
 
-        self.properties['datetime'] = '{}Z'.format(
-            self.datetime.replace(microsecond=0, tzinfo=None))
+        self.properties['datetime'] = datetime_to_str(self.datetime)
 
         d = {
             'type': 'Feature',

pystac/utils.py

@@ -129,3 +129,15 @@ def is_absolute_href(href):
     """
     parsed = _urlparse(href)
     return parsed.scheme != '' or _pathlib.isabs(parsed.path)
+
+
+def datetime_to_str(dt):
+    """Convert a python datetime to an ISO8601 stirng
+
+    Args:
+        dt (datetime): The datetime to convert.
+
+    Returns:
+        str: The ISO8601 formatted string representing the datetime.
+    """
+    return dt.strftime('%Y-%m-%dT%H:%M:%SZ')

tests/test_item.py

@@ -36,3 +36,15 @@ def test_asset_absolute_href(self):
         expected_href = 'http://cool-sat.com/catalog/CS3-20160503_132130_04/data.geojson'
         actual_href = rel_asset.get_absolute_href()
         self.assertEqual(expected_href, actual_href)
+
+    def test_datetime_ISO8601_format(self):
+        m = TestCases.get_path(
+            'data-files/itemcollections/sample-item-collection.json')
+        with open(m) as f:
+            item_dict = json.load(f)['features'][0]
+
+        item = Item.from_dict(item_dict)
+
+        formatted_time = item.to_dict()['properties']['datetime']
+
+        self.assertEqual('2016-05-03T13:22:30Z', formatted_time)