From 5655e44118e4a226c4091f72fb87015dc718bf0b Mon Sep 17 00:00:00 2001
From: Tom Booth <tombooth@gmail.com>
Date: Tue, 29 Apr 2014 18:21:56 +0100
Subject: [PATCH] Backdrop read api should always return UTC

Consumers of backdrop will always want datetimes to be represented as
UTC. Previously they had no timezone attached, which was rather confusing
as the ISODate in mongo had a timezone.

This commit will force all datetime objects coming out of backdrop into
UTC before writing them out to JSON.
---
 backdrop/read/api.py                     |  3 ++-
 tests/read/test_read_api_json_encoder.py | 28 ++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 1 deletion(-)
 create mode 100644 tests/read/test_read_api_json_encoder.py

diff --git a/backdrop/read/api.py b/backdrop/read/api.py
index fcae0a8a..dd15b50a 100644
--- a/backdrop/read/api.py
+++ b/backdrop/read/api.py
@@ -12,6 +12,7 @@
 from ..core.data_set import DataSet
 from ..core.database import InvalidOperationError
 from ..core.repository import DataSetConfigRepository
+from ..core.timeutils import as_utc
 
 
 GOVUK_ENV = getenv("GOVUK_ENV", "development")
@@ -43,7 +44,7 @@ def default(self, obj):
         if isinstance(obj, ObjectId):
             return str(obj)
         if isinstance(obj, datetime.datetime):
-            return obj.isoformat()
+            return as_utc(obj).isoformat()
         return json.JSONEncoder.default(self, obj)
 app.json_encoder = JsonEncoder
 
diff --git a/tests/read/test_read_api_json_encoder.py b/tests/read/test_read_api_json_encoder.py
new file mode 100644
index 00000000..78d3a9cb
--- /dev/null
+++ b/tests/read/test_read_api_json_encoder.py
@@ -0,0 +1,28 @@
+import unittest
+import pytz
+
+from hamcrest import *
+from datetime import datetime
+from backdrop.read.api import JsonEncoder
+
+
+class TestReadAPIJSONEcoder(unittest.TestCase):
+
+    def test_with_utc_date(self):
+        obj = {'date': datetime(2014, 4, 29, 1, 0, 0, 0, pytz.utc)}
+        assert_that(
+            JsonEncoder().encode(obj),
+            is_('{"date": "2014-04-29T01:00:00+00:00"}'))
+
+    def test_with_est_date(self):
+        est = pytz.timezone('US/Eastern')
+        obj = {'date': datetime(2014, 4, 29, 1, 0, 0, 0, est)}
+        assert_that(
+            JsonEncoder().encode(obj),
+            is_('{"date": "2014-04-29T06:00:00+00:00"}'))
+
+    def test_with_no_tz_date(self):
+        obj = {'date': datetime(2014, 4, 29, 1, 0)}
+        assert_that(
+            JsonEncoder().encode(obj),
+            is_('{"date": "2014-04-29T01:00:00+00:00"}'))