From ead620521e9157f68c7da64ecb8ab7478e1cab8c Mon Sep 17 00:00:00 2001
From: cabbagenom <calumcalder@hotmail.co.uk>
Date: Sat, 26 Mar 2016 18:10:02 +0000
Subject: [PATCH 1/3] DateTimeField to_representation can handle strings. Fixes
 #4013.

---
 rest_framework/fields.py | 14 ++++++++++++++
 tests/test_fields.py     |  9 +++++++++
 2 files changed, 23 insertions(+)

diff --git a/rest_framework/fields.py b/rest_framework/fields.py
index 2a08e09ff..16074b76a 100644
--- a/rest_framework/fields.py
+++ b/rest_framework/fields.py
@@ -1072,10 +1072,24 @@ class DateTimeField(Field):
             return value
 
         if output_format.lower() == ISO_8601:
+            if isinstance(value, str):
+                format_strings = (format_prefix + timezone_extension
+                                  for format_prefix in ('%Y-%m-%dT%H:%M', '%Y-%m-%dT%H:%M:%S', '%Y-%m-%dT%H:%M:%S.%f')
+                                  for timezone_extension in ('', '%Z', '%z'))
+                for format_string in format_strings:
+                    try:
+                        value = datetime.datetime.strptime(value, format_string)
+                        break
+                    except ValueError:
+                        pass
+                else:
+                    raise ValueError('DateTime String %s did not match any valid format string.' % value)
+
             value = value.isoformat()
             if value.endswith('+00:00'):
                 value = value[:-6] + 'Z'
             return value
+
         return value.strftime(output_format)
 
 
diff --git a/tests/test_fields.py b/tests/test_fields.py
index cefb45605..cce0181fa 100644
--- a/tests/test_fields.py
+++ b/tests/test_fields.py
@@ -978,6 +978,15 @@ class TestDateTimeField(FieldValues):
     outputs = {
         datetime.datetime(2001, 1, 1, 13, 00): '2001-01-01T13:00:00',
         datetime.datetime(2001, 1, 1, 13, 00, tzinfo=timezone.UTC()): '2001-01-01T13:00:00Z',
+        '2001-01-01T01:01': '2001-01-01T01:01:00',
+        '2001-01-01T01:01:01': '2001-01-01T01:01:01',
+        '2001-01-01T01:01:01.01': '2001-01-01T01:01:01.010000',
+        '2001-01-01T01:01+0100': '2001-01-01T01:01:00+01:00',
+        '2001-01-01T01:01:01+0100': '2001-01-01T01:01:01+01:00',
+        '2001-01-01T01:01:01.01+0100': '2001-01-01T01:01:01.010000+01:00',
+        '2001-01-01T01:01UTC': '2001-01-01T01:01:00',
+        '2001-01-01T01:01:01UTC': '2001-01-01T01:01:01',
+        '2001-01-01T01:01:01.01UTC': '2001-01-01T01:01:01.010000',
         None: None,
         '': None,
     }

From e61a4f19cf5f89c2506a5f6a3e61b0d2d864efc2 Mon Sep 17 00:00:00 2001
From: cabbagenom <calumcalder@hotmail.co.uk>
Date: Sun, 27 Mar 2016 12:08:52 +0100
Subject: [PATCH 2/3] DateTimeField to_representation string check str ->
 six.string_types

---
 rest_framework/fields.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/rest_framework/fields.py b/rest_framework/fields.py
index 16074b76a..d4496a2e8 100644
--- a/rest_framework/fields.py
+++ b/rest_framework/fields.py
@@ -1072,7 +1072,7 @@ class DateTimeField(Field):
             return value
 
         if output_format.lower() == ISO_8601:
-            if isinstance(value, str):
+            if isinstance(value, six.string_types):
                 format_strings = (format_prefix + timezone_extension
                                   for format_prefix in ('%Y-%m-%dT%H:%M', '%Y-%m-%dT%H:%M:%S', '%Y-%m-%dT%H:%M:%S.%f')
                                   for timezone_extension in ('', '%Z', '%z'))

From 8966d8e4586ca240ef8a89a0734c6049a43172f8 Mon Sep 17 00:00:00 2001
From: cabbagenom <calumcalder@hotmail.co.uk>
Date: Sun, 27 Mar 2016 12:17:51 +0100
Subject: [PATCH 3/3] DateTimeField tests reflect Python 2's strptime
 limitations.

Given that Python 2's datetime.datetime.strptime function does not
accept '+HHMM' strings with the format directive '%z', the tests for
accepting such strings have been ommitted for python 2.
---
 tests/test_fields.py | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/tests/test_fields.py b/tests/test_fields.py
index cce0181fa..b31f59c7f 100644
--- a/tests/test_fields.py
+++ b/tests/test_fields.py
@@ -981,9 +981,10 @@ class TestDateTimeField(FieldValues):
         '2001-01-01T01:01': '2001-01-01T01:01:00',
         '2001-01-01T01:01:01': '2001-01-01T01:01:01',
         '2001-01-01T01:01:01.01': '2001-01-01T01:01:01.010000',
-        '2001-01-01T01:01+0100': '2001-01-01T01:01:00+01:00',
-        '2001-01-01T01:01:01+0100': '2001-01-01T01:01:01+01:00',
-        '2001-01-01T01:01:01.01+0100': '2001-01-01T01:01:01.010000+01:00',
+        # Caveat of Python 2's datetime module does not allow '+HHMM' ISO-8601 strings to be parsed in Python 2's strptime
+        '2001-01-01T01:01+0100' if six.PY3 else None: '2001-01-01T01:01:00+01:00' if six.PY3 else None,
+        '2001-01-01T01:01:01+0100' if six.PY3 else None: '2001-01-01T01:01:01+01:00' if six.PY3 else None,
+        '2001-01-01T01:01:01.01+0100' if six.PY3 else None: '2001-01-01T01:01:01.010000+01:00' if six.PY3 else None,
         '2001-01-01T01:01UTC': '2001-01-01T01:01:00',
         '2001-01-01T01:01:01UTC': '2001-01-01T01:01:01',
         '2001-01-01T01:01:01.01UTC': '2001-01-01T01:01:01.010000',