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"""
Helper classes for parsers.
"""
from __future__ import unicode_literals
from django.utils.datastructures import SortedDict
from django.utils.functional import Promise
from rest_framework.compat import timezone, force_text
from rest_framework.serializers import DictWithMetadata, SortedDictWithMetadata
import datetime
import decimal
import types
import json
class JSONEncoder(json.JSONEncoder):
"""
JSONEncoder subclass that knows how to encode date/time/timedelta,
decimal types, and generators.
"""
def default(self, o):
# For Date Time string spec, see ECMA 262
# http://ecma-international.org/ecma-262/5.1/#sec-15.9.1.15
if isinstance(o, Promise):
return force_text(o)
elif isinstance(o, datetime.datetime):
r = o.isoformat()
if o.microsecond:
r = r[:23] + r[26:]
if r.endswith('+00:00'):
r = r[:-6] + 'Z'
return r
elif isinstance(o, datetime.date):
return o.isoformat()
elif isinstance(o, datetime.time):
if timezone and timezone.is_aware(o):
raise ValueError("JSON can't represent timezone-aware times.")
r = o.isoformat()
if o.microsecond:
r = r[:12]
return r
elif isinstance(o, datetime.timedelta):
return str(o.total_seconds())
elif isinstance(o, decimal.Decimal):
return str(o)
elif hasattr(o, '__iter__'):
return [i for i in o]
return super(JSONEncoder, self).default(o)
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 SortedDicts 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', str(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, SortedDict):
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(SortedDict,
yaml.representer.SafeRepresenter.represent_dict)
SafeDumper.add_representer(DictWithMetadata,
yaml.representer.SafeRepresenter.represent_dict)
SafeDumper.add_representer(SortedDictWithMetadata,
yaml.representer.SafeRepresenter.represent_dict)
SafeDumper.add_representer(types.GeneratorType,
yaml.representer.SafeRepresenter.represent_list)
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