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1 """ |
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2 A Python "serializer". Doesn't do much serializing per se -- just converts to |
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3 and from basic Python data types (lists, dicts, strings, etc.). Useful as a basis for |
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4 other serializers. |
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5 """ |
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6 |
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7 from django.conf import settings |
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8 from django.core.serializers import base |
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9 from django.db import models |
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10 from django.utils.encoding import smart_unicode, is_protected_type |
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11 |
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12 class Serializer(base.Serializer): |
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13 """ |
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14 Serializes a QuerySet to basic Python objects. |
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15 """ |
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16 |
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17 internal_use_only = True |
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18 |
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19 def start_serialization(self): |
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20 self._current = None |
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21 self.objects = [] |
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22 |
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23 def end_serialization(self): |
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24 pass |
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25 |
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26 def start_object(self, obj): |
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27 self._current = {} |
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28 |
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29 def end_object(self, obj): |
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30 self.objects.append({ |
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31 "model" : smart_unicode(obj._meta), |
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32 "pk" : smart_unicode(obj._get_pk_val(), strings_only=True), |
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33 "fields" : self._current |
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34 }) |
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35 self._current = None |
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36 |
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37 def handle_field(self, obj, field): |
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38 value = field._get_val_from_obj(obj) |
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39 # Protected types (i.e., primitives like None, numbers, dates, |
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40 # and Decimals) are passed through as is. All other values are |
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41 # converted to string first. |
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42 if is_protected_type(value): |
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43 self._current[field.name] = value |
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44 else: |
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45 self._current[field.name] = field.value_to_string(obj) |
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46 |
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47 def handle_fk_field(self, obj, field): |
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48 related = getattr(obj, field.name) |
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49 if related is not None: |
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50 if field.rel.field_name == related._meta.pk.name: |
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51 # Related to remote object via primary key |
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52 related = related._get_pk_val() |
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53 else: |
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54 # Related to remote object via other field |
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55 related = getattr(related, field.rel.field_name) |
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56 self._current[field.name] = smart_unicode(related, strings_only=True) |
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57 |
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58 def handle_m2m_field(self, obj, field): |
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59 if field.creates_table: |
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60 self._current[field.name] = [smart_unicode(related._get_pk_val(), strings_only=True) |
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61 for related in getattr(obj, field.name).iterator()] |
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62 |
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63 def getvalue(self): |
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64 return self.objects |
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65 |
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66 def Deserializer(object_list, **options): |
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67 """ |
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68 Deserialize simple Python objects back into Django ORM instances. |
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69 |
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70 It's expected that you pass the Python objects themselves (instead of a |
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71 stream or a string) to the constructor |
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72 """ |
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73 models.get_apps() |
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74 for d in object_list: |
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75 # Look up the model and starting build a dict of data for it. |
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76 Model = _get_model(d["model"]) |
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77 data = {Model._meta.pk.attname : Model._meta.pk.to_python(d["pk"])} |
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78 m2m_data = {} |
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79 |
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80 # Handle each field |
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81 for (field_name, field_value) in d["fields"].iteritems(): |
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82 if isinstance(field_value, str): |
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83 field_value = smart_unicode(field_value, options.get("encoding", settings.DEFAULT_CHARSET), strings_only=True) |
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84 |
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85 field = Model._meta.get_field(field_name) |
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86 |
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87 # Handle M2M relations |
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88 if field.rel and isinstance(field.rel, models.ManyToManyRel): |
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89 m2m_convert = field.rel.to._meta.pk.to_python |
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90 m2m_data[field.name] = [m2m_convert(smart_unicode(pk)) for pk in field_value] |
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91 |
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92 # Handle FK fields |
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93 elif field.rel and isinstance(field.rel, models.ManyToOneRel): |
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94 if field_value is not None: |
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95 data[field.attname] = field.rel.to._meta.get_field(field.rel.field_name).to_python(field_value) |
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96 else: |
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97 data[field.attname] = None |
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98 |
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99 # Handle all other fields |
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100 else: |
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101 data[field.name] = field.to_python(field_value) |
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102 |
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103 yield base.DeserializedObject(Model(**data), m2m_data) |
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104 |
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105 def _get_model(model_identifier): |
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106 """ |
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107 Helper to look up a model from an "app_label.module_name" string. |
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108 """ |
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109 try: |
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110 Model = models.get_model(*model_identifier.split(".")) |
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111 except TypeError: |
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112 Model = None |
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113 if Model is None: |
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114 raise base.DeserializationError(u"Invalid model identifier: '%s'" % model_identifier) |
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115 return Model |