1 | """
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2 | YAML serializer.
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3 |
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4 | Requires PyYaml (http://pyyaml.org/), but that's checked for in __init__.
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5 | """
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6 |
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7 | from StringIO import StringIO
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8 | import decimal
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9 | import yaml
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10 |
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11 | from django.db import models
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12 | from django.core.serializers.python import Serializer as PythonSerializer
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13 | from django.core.serializers.python import Deserializer as PythonDeserializer
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14 |
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15 | # Use the C (faster) implementation if possible
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16 | try:
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17 | from yaml import CLoader as Loader
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18 | from yaml import CSafeDumper as SafeDumper
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19 | except ImportError:
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20 | from yaml import Loader, SafeDumper
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21 |
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22 | class DjangoSafeDumper(SafeDumper):
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23 | def represent_decimal(self, data):
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24 | return self.represent_scalar('tag:yaml.org,2002:str', str(data))
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25 |
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26 | DjangoSafeDumper.add_representer(decimal.Decimal, DjangoSafeDumper.represent_decimal)
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27 |
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28 | class Serializer(PythonSerializer):
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29 | """
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30 | Convert a queryset to YAML.
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31 | """
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32 |
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33 | internal_use_only = False
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34 |
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35 | def handle_field(self, obj, field):
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36 | # A nasty special case: base YAML doesn't support serialization of time
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37 | # types (as opposed to dates or datetimes, which it does support). Since
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38 | # we want to use the "safe" serializer for better interoperability, we
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39 | # need to do something with those pesky times. Converting 'em to strings
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40 | # isn't perfect, but it's better than a "!!python/time" type which would
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41 | # halt deserialization under any other language.
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42 | if isinstance(field, models.TimeField) and getattr(obj, field.name) is not None:
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43 | self._current[field.name] = str(getattr(obj, field.name))
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44 | else:
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45 | super(Serializer, self).handle_field(obj, field)
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46 |
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47 | def end_serialization(self):
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48 | self.options.pop('stream', None)
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49 | self.options.pop('fields', None)
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50 | self.options.pop('use_natural_keys', None)
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51 | yaml.dump(self.objects, self.stream, Dumper=DjangoSafeDumper, **self.options)
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52 |
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53 | def getvalue(self):
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54 | return self.stream.getvalue()
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55 |
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56 | def Deserializer(stream_or_string, **options):
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57 | """
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58 | Deserialize a stream or string of YAML data.
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59 | """
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60 | if isinstance(stream_or_string, basestring):
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61 | stream = StringIO(stream_or_string)
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62 | else:
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63 | stream = stream_or_string
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64 | for obj in PythonDeserializer(yaml.load(stream, Loader=Loader), **options):
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65 | yield obj
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66 |
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