Add DurationField

Author: ticosax

docs/api-guide/fields.md

@@ -302,6 +302,16 @@ Corresponds to `django.db.models.fields.TimeField`
 
 Format strings may either be [Python strftime formats][strftime] which explicitly specify the format, or the special string `'iso-8601'`, which indicates that [ISO 8601][iso8601] style times should be used. (eg `'12:34:56.000000'`)
 
+## DurationField
+
+A Duration representation.
+Corresponds to `django.db.models.fields.Duration` for Django>=1.8
+otherwise to `django.db.models.fields.BigIntegerField`.
+The representation is a string following this format `'[DD] [HH:[MM:]]ss[.uuuuuu]'`
+
+
+**Signature:** `DurationField()`
+
 ---
 
 # Choice selection fields

rest_framework/compat.py

@@ -5,6 +5,9 @@
 
 # flake8: noqa
 from __future__ import unicode_literals
+import datetime
+from datetime import timedelta
+import re
 from django.core.exceptions import ImproperlyConfigured
 from django.conf import settings
 from django.utils.encoding import force_text
@@ -258,3 +261,78 @@ def apply_markdown(text):
     SHORT_SEPARATORS = (b',', b':')
     LONG_SEPARATORS = (b', ', b': ')
     INDENT_SEPARATORS = (b',', b': ')
+
+
+if django.VERSION >= (1, 8):
+    from django.utils.dateparse import parse_duration
+    from django.utils.duration import duration_string
+    from django.db.models import DurationField
+else:
+    from django.db.models import BigIntegerField
+
+    class DurationField(BigIntegerField):
+        def get_db_prep_value(self, value, connection, prepared=False):
+            if value is None:
+                return None
+            return total_seconds(value) * 1000000
+
+
+    # Backported from django 1.8
+    standard_duration_re = re.compile(
+        r'^'
+        r'(?:(?P<days>-?\d+) )?'
+        r'((?:(?P<hours>\d+):)(?=\d+:\d+))?'
+        r'(?:(?P<minutes>\d+):)?'
+        r'(?P<seconds>\d+)'
+        r'(?:\.(?P<microseconds>\d{1,6})\d{0,6})?'
+        r'$'
+    )
+
+    # Support the sections of ISO 8601 date representation that are accepted by
+    # timedelta
+    iso8601_duration_re = re.compile(
+        r'^P'
+        r'(?:(?P<days>\d+(.\d+)?)D)?'
+        r'(?:T'
+        r'(?:(?P<hours>\d+(.\d+)?)H)?'
+        r'(?:(?P<minutes>\d+(.\d+)?)M)?'
+        r'(?:(?P<seconds>\d+(.\d+)?)S)?'
+        r')?'
+        r'$'
+    )
+
+    def parse_duration(value):
+        """Parses a duration string and returns a datetime.timedelta.
+
+        The preferred format for durations in Django is '%d %H:%M:%S.%f'.
+
+        Also supports ISO 8601 representation.
+        """
+        match = standard_duration_re.match(value)
+        if not match:
+            match = iso8601_duration_re.match(value)
+        if match:
+            kw = match.groupdict()
+            if kw.get('microseconds'):
+                kw['microseconds'] = kw['microseconds'].ljust(6, unicode_to_repr('0'))
+            kw = dict((k, float(v)) for k, v in six.iteritems(kw) if v is not None)
+            return datetime.timedelta(**kw)
+
+    def duration_string(duration):
+        days = duration.days
+        seconds = duration.seconds
+        microseconds = duration.microseconds
+
+        minutes = seconds // 60
+        seconds = seconds % 60
+
+        hours = minutes // 60
+        minutes = minutes % 60
+
+        string = '{0:02d}:{1:02d}:{2:02d}'.format(hours, minutes, seconds)
+        if days:
+            string = '{0} '.format(days) + string
+        if microseconds:
+            string += '.{0:06d}'.format(microseconds)
+
+        return string

rest_framework/fields.py

@@ -12,7 +12,7 @@
 from rest_framework.compat import (
     EmailValidator, MinValueValidator, MaxValueValidator,
     MinLengthValidator, MaxLengthValidator, URLValidator, OrderedDict,
-    unicode_repr, unicode_to_repr
+    unicode_repr, unicode_to_repr, parse_duration, duration_string,
 )
 from rest_framework.exceptions import ValidationError
 from rest_framework.settings import api_settings
@@ -1003,6 +1003,23 @@ def to_representation(self, value):
         return value.strftime(self.format)
 
 
+class DurationField(Field):
+    default_error_messages = {
+        'invalid': _('Duration has wrong format. Use one of these formats instead: {format}.'),
+    }
+
+    def to_internal_value(self, value):
+        if isinstance(value, datetime.timedelta):
+            return value
+        parsed = parse_duration(value)
+        if parsed is not None:
+            return parsed
+        self.fail('invalid', format='[DD] [HH:[MM:]]ss[.uuuuuu]')
+
+    def to_representation(self, value):
+        return duration_string(value)
+
+
 # Choice types...
 
 class ChoiceField(Field):

rest_framework/serializers.py

@@ -15,7 +15,11 @@
 from django.db.models.fields import FieldDoesNotExist, Field as DjangoModelField
 from django.db.models import query
 from django.utils.translation import ugettext_lazy as _
-from rest_framework.compat import postgres_fields, unicode_to_repr
+from rest_framework.compat import (
+    postgres_fields,
+    unicode_to_repr,
+    DurationField as ModelDurationField,
+)
 from rest_framework.utils import model_meta
 from rest_framework.utils.field_mapping import (
     get_url_kwargs, get_field_kwargs,
@@ -42,7 +46,6 @@
 from rest_framework.relations import *  # NOQA
 from rest_framework.fields import *  # NOQA
 
-
 # We assume that 'validators' are intended for the child serializer,
 # rather than the parent serializer.
 LIST_SERIALIZER_KWARGS = (
@@ -716,6 +719,7 @@ class ModelSerializer(Serializer):
         models.DateField: DateField,
         models.DateTimeField: DateTimeField,
         models.DecimalField: DecimalField,
+        ModelDurationField: DurationField,
         models.EmailField: EmailField,
         models.Field: ModelField,
         models.FileField: FileField,

tests/test_compat.py

@@ -0,0 +1,13 @@
+from datetime import timedelta
+
+import django
+from django.db import connection
+import pytest
+
+
+@pytest.mark.skipif(django.VERSION >= (1, 8),
+                    reason='Django1.8+ have native DurationField')
+def test_duration_field():
+    from rest_framework.compat import DurationField
+    delta = timedelta(seconds=1)
+    assert DurationField().get_db_prep_value(delta, connection) == 1 * 1e6

tests/test_fields.py

@@ -905,6 +905,26 @@ class TestNoOutputFormatTimeField(FieldValues):
     field = serializers.TimeField(format=None)
 
 
+class TestDurationField(FieldValues):
+    """
+    Valid and invalid values for `DurationField`.
+    """
+    valid_inputs = {
+        '13': datetime.timedelta(seconds=13),
+        '3 08:32:01.000123': datetime.timedelta(days=3, hours=8, minutes=32, seconds=1, microseconds=123),
+        '08:01': datetime.timedelta(minutes=8, seconds=1),
+        datetime.timedelta(days=3, hours=8, minutes=32, seconds=1, microseconds=123): datetime.timedelta(days=3, hours=8, minutes=32, seconds=1, microseconds=123),
+    }
+    invalid_inputs = {
+        'abc': ['Duration has wrong format. Use one of these formats instead: [DD] [HH:[MM:]]ss[.uuuuuu].'],
+        '3 08:32 01.123': ['Duration has wrong format. Use one of these formats instead: [DD] [HH:[MM:]]ss[.uuuuuu].'],
+    }
+    outputs = {
+        datetime.timedelta(days=3, hours=8, minutes=32, seconds=1, microseconds=123): '3 08:32:01.000123',
+    }
+    field = serializers.DurationField()
+
+
 # Choice types...
 
 class TestChoiceField(FieldValues):

tests/test_model_serializer.py

@@ -12,7 +12,7 @@
 from django.test import TestCase
 from django.utils import six
 from rest_framework import serializers
-from rest_framework.compat import unicode_repr
+from rest_framework.compat import unicode_repr, DurationField as ModelDurationField
 
 
 def dedent(blocktext):
@@ -45,6 +45,7 @@ class RegularFieldsModel(models.Model):
     date_field = models.DateField()
     datetime_field = models.DateTimeField()
     decimal_field = models.DecimalField(max_digits=3, decimal_places=1)
+    duration_field = ModelDurationField()
     email_field = models.EmailField(max_length=100)
     float_field = models.FloatField()
     integer_field = models.IntegerField()
@@ -138,6 +139,7 @@ class Meta:
                 date_field = DateField()
                 datetime_field = DateTimeField()
                 decimal_field = DecimalField(decimal_places=1, max_digits=3)
+                duration_field = DurationField()
                 email_field = EmailField(max_length=100)
                 float_field = FloatField()
                 integer_field = IntegerField()