| """ |
| A Python "serializer". Doesn't do much serializing per se -- just converts to |
| and from basic Python data types (lists, dicts, strings, etc.). Useful as a basis for |
| other serializers. |
| """ |
| |
| from django.conf import settings |
| from django.core.serializers import base |
| from django.db import models, DEFAULT_DB_ALIAS |
| from django.utils.encoding import smart_unicode, is_protected_type |
| |
| class Serializer(base.Serializer): |
| """ |
| Serializes a QuerySet to basic Python objects. |
| """ |
| |
| internal_use_only = True |
| |
| def start_serialization(self): |
| self._current = None |
| self.objects = [] |
| |
| def end_serialization(self): |
| pass |
| |
| def start_object(self, obj): |
| self._current = {} |
| |
| def end_object(self, obj): |
| self.objects.append({ |
| "model" : smart_unicode(obj._meta), |
| "pk" : smart_unicode(obj._get_pk_val(), strings_only=True), |
| "fields" : self._current |
| }) |
| self._current = None |
| |
| def handle_field(self, obj, field): |
| value = field._get_val_from_obj(obj) |
| # Protected types (i.e., primitives like None, numbers, dates, |
| # and Decimals) are passed through as is. All other values are |
| # converted to string first. |
| if is_protected_type(value): |
| self._current[field.name] = value |
| else: |
| self._current[field.name] = field.value_to_string(obj) |
| |
| def handle_fk_field(self, obj, field): |
| related = getattr(obj, field.name) |
| if related is not None: |
| if self.use_natural_keys and hasattr(related, 'natural_key'): |
| related = related.natural_key() |
| else: |
| if field.rel.field_name == related._meta.pk.name: |
| # Related to remote object via primary key |
| related = related._get_pk_val() |
| else: |
| # Related to remote object via other field |
| related = smart_unicode(getattr(related, field.rel.field_name), strings_only=True) |
| self._current[field.name] = related |
| |
| def handle_m2m_field(self, obj, field): |
| if field.rel.through._meta.auto_created: |
| if self.use_natural_keys and hasattr(field.rel.to, 'natural_key'): |
| m2m_value = lambda value: value.natural_key() |
| else: |
| m2m_value = lambda value: smart_unicode(value._get_pk_val(), strings_only=True) |
| self._current[field.name] = [m2m_value(related) |
| for related in getattr(obj, field.name).iterator()] |
| |
| def getvalue(self): |
| return self.objects |
| |
| def Deserializer(object_list, **options): |
| """ |
| Deserialize simple Python objects back into Django ORM instances. |
| |
| It's expected that you pass the Python objects themselves (instead of a |
| stream or a string) to the constructor |
| """ |
| db = options.pop('using', DEFAULT_DB_ALIAS) |
| models.get_apps() |
| for d in object_list: |
| # Look up the model and starting build a dict of data for it. |
| Model = _get_model(d["model"]) |
| data = {Model._meta.pk.attname : Model._meta.pk.to_python(d["pk"])} |
| m2m_data = {} |
| |
| # Handle each field |
| for (field_name, field_value) in d["fields"].iteritems(): |
| if isinstance(field_value, str): |
| field_value = smart_unicode(field_value, options.get("encoding", settings.DEFAULT_CHARSET), strings_only=True) |
| |
| field = Model._meta.get_field(field_name) |
| |
| # Handle M2M relations |
| if field.rel and isinstance(field.rel, models.ManyToManyRel): |
| if hasattr(field.rel.to._default_manager, 'get_by_natural_key'): |
| def m2m_convert(value): |
| if hasattr(value, '__iter__'): |
| return field.rel.to._default_manager.db_manager(db).get_by_natural_key(*value).pk |
| else: |
| return smart_unicode(field.rel.to._meta.pk.to_python(value)) |
| else: |
| m2m_convert = lambda v: smart_unicode(field.rel.to._meta.pk.to_python(v)) |
| m2m_data[field.name] = [m2m_convert(pk) for pk in field_value] |
| |
| # Handle FK fields |
| elif field.rel and isinstance(field.rel, models.ManyToOneRel): |
| if field_value is not None: |
| if hasattr(field.rel.to._default_manager, 'get_by_natural_key'): |
| if hasattr(field_value, '__iter__'): |
| obj = field.rel.to._default_manager.db_manager(db).get_by_natural_key(*field_value) |
| value = getattr(obj, field.rel.field_name) |
| # If this is a natural foreign key to an object that |
| # has a FK/O2O as the foreign key, use the FK value |
| if field.rel.to._meta.pk.rel: |
| value = value.pk |
| else: |
| value = field.rel.to._meta.get_field(field.rel.field_name).to_python(field_value) |
| data[field.attname] = value |
| else: |
| data[field.attname] = field.rel.to._meta.get_field(field.rel.field_name).to_python(field_value) |
| else: |
| data[field.attname] = None |
| |
| # Handle all other fields |
| else: |
| data[field.name] = field.to_python(field_value) |
| |
| yield base.DeserializedObject(Model(**data), m2m_data) |
| |
| def _get_model(model_identifier): |
| """ |
| Helper to look up a model from an "app_label.module_name" string. |
| """ |
| try: |
| Model = models.get_model(*model_identifier.split(".")) |
| except TypeError: |
| Model = None |
| if Model is None: |
| raise base.DeserializationError(u"Invalid model identifier: '%s'" % model_identifier) |
| return Model |
