django-rest-framework/rest_framework/utils/encoders.py
2014-12-04 03:11:42 +01:00

122 lines
4.4 KiB
Python

"""
Helper classes for parsers.
"""
from __future__ import unicode_literals
from django.db.models.query import QuerySet
from django.utils import six, timezone
from django.utils.encoding import force_text
from django.utils.functional import Promise
from rest_framework.compat import OrderedDict
import datetime
import decimal
import types
import json
class JSONEncoder(json.JSONEncoder):
"""
JSONEncoder subclass that knows how to encode date/time/timedelta,
decimal types, generators and other basic python objects.
"""
def default(self, obj):
# For Date Time string spec, see ECMA 262
# http://ecma-international.org/ecma-262/5.1/#sec-15.9.1.15
if isinstance(obj, Promise):
return force_text(obj)
elif isinstance(obj, datetime.datetime):
representation = obj.isoformat()
if obj.microsecond:
representation = representation[:23] + representation[26:]
if representation.endswith('+00:00'):
representation = representation[:-6] + 'Z'
return representation
elif isinstance(obj, datetime.date):
return obj.isoformat()
elif isinstance(obj, datetime.time):
if timezone and timezone.is_aware(obj):
raise ValueError("JSON can't represent timezone-aware times.")
representation = obj.isoformat()
if obj.microsecond:
representation = representation[:12]
return representation
elif isinstance(obj, datetime.timedelta):
return six.text_type(obj.total_seconds())
elif isinstance(obj, decimal.Decimal):
# Serializers will coerce decimals to strings by default.
return float(obj)
elif isinstance(obj, QuerySet):
return tuple(obj)
elif hasattr(obj, 'tolist'):
# Numpy arrays and array scalars.
return obj.tolist()
elif hasattr(obj, '__getitem__'):
try:
return dict(obj)
except:
pass
elif hasattr(obj, '__iter__'):
return tuple(item for item in obj)
return super(JSONEncoder, self).default(obj)
try:
import yaml
except ImportError:
SafeDumper = None
else:
# Adapted from http://pyyaml.org/attachment/ticket/161/use_ordered_dict.py
class SafeDumper(yaml.SafeDumper):
"""
Handles decimals as strings.
Handles OrderedDicts as usual dicts, but preserves field order, rather
than the usual behaviour of sorting the keys.
"""
def represent_decimal(self, data):
return self.represent_scalar('tag:yaml.org,2002:str', six.text_type(data))
def represent_mapping(self, tag, mapping, flow_style=None):
value = []
node = yaml.MappingNode(tag, value, flow_style=flow_style)
if self.alias_key is not None:
self.represented_objects[self.alias_key] = node
best_style = True
if hasattr(mapping, 'items'):
mapping = list(mapping.items())
if not isinstance(mapping, OrderedDict):
mapping.sort()
for item_key, item_value in mapping:
node_key = self.represent_data(item_key)
node_value = self.represent_data(item_value)
if not (isinstance(node_key, yaml.ScalarNode) and not node_key.style):
best_style = False
if not (isinstance(node_value, yaml.ScalarNode) and not node_value.style):
best_style = False
value.append((node_key, node_value))
if flow_style is None:
if self.default_flow_style is not None:
node.flow_style = self.default_flow_style
else:
node.flow_style = best_style
return node
SafeDumper.add_representer(
decimal.Decimal,
SafeDumper.represent_decimal
)
SafeDumper.add_representer(
OrderedDict,
yaml.representer.SafeRepresenter.represent_dict
)
# SafeDumper.add_representer(
# DictWithMetadata,
# yaml.representer.SafeRepresenter.represent_dict
# )
# SafeDumper.add_representer(
# OrderedDictWithMetadata,
# yaml.representer.SafeRepresenter.represent_dict
# )
SafeDumper.add_representer(
types.GeneratorType,
yaml.representer.SafeRepresenter.represent_list
)