• 1.10
  • dev
  • Documentation version: 1.11

Kod źródłowy modułu django.contrib.postgres.fields.array

import json

from django.contrib.postgres import lookups
from django.contrib.postgres.forms import SimpleArrayField
from django.contrib.postgres.validators import ArrayMaxLengthValidator
from django.core import checks, exceptions
from django.db.models import Field, IntegerField, Transform
from django.db.models.lookups import Exact, In
from django.utils import six
from django.utils.translation import ugettext_lazy as _

from ..utils import prefix_validation_error
from .utils import AttributeSetter

__all__ = ['ArrayField']


[dokumenty]class ArrayField(Field): empty_strings_allowed = False default_error_messages = { 'item_invalid': _('Item %(nth)s in the array did not validate: '), 'nested_array_mismatch': _('Nested arrays must have the same length.'), } def __init__(self, base_field, size=None, **kwargs): self.base_field = base_field self.size = size if self.size: self.default_validators = self.default_validators[:] self.default_validators.append(ArrayMaxLengthValidator(self.size)) # For performance, only add a from_db_value() method if the base field # implements it. if hasattr(self.base_field, 'from_db_value'): self.from_db_value = self._from_db_value super(ArrayField, self).__init__(**kwargs) @property def model(self): try: return self.__dict__['model'] except KeyError: raise AttributeError("'%s' object has no attribute 'model'" % self.__class__.__name__) @model.setter def model(self, model): self.__dict__['model'] = model self.base_field.model = model def check(self, **kwargs): errors = super(ArrayField, self).check(**kwargs) if self.base_field.remote_field: errors.append( checks.Error( 'Base field for array cannot be a related field.', obj=self, id='postgres.E002' ) ) else: # Remove the field name checks as they are not needed here. base_errors = self.base_field.check() if base_errors: messages = '\n '.join('%s (%s)' % (error.msg, error.id) for error in base_errors) errors.append( checks.Error( 'Base field for array has errors:\n %s' % messages, obj=self, id='postgres.E001' ) ) return errors def set_attributes_from_name(self, name): super(ArrayField, self).set_attributes_from_name(name) self.base_field.set_attributes_from_name(name) @property def description(self): return 'Array of %s' % self.base_field.description def db_type(self, connection): size = self.size or '' return '%s[%s]' % (self.base_field.db_type(connection), size) def get_db_prep_value(self, value, connection, prepared=False): if isinstance(value, list) or isinstance(value, tuple): return [self.base_field.get_db_prep_value(i, connection, prepared=False) for i in value] return value def deconstruct(self): name, path, args, kwargs = super(ArrayField, self).deconstruct() if path == 'django.contrib.postgres.fields.array.ArrayField': path = 'django.contrib.postgres.fields.ArrayField' kwargs.update({ 'base_field': self.base_field.clone(), 'size': self.size, }) return name, path, args, kwargs def to_python(self, value): if isinstance(value, six.string_types): # Assume we're deserializing vals = json.loads(value) value = [self.base_field.to_python(val) for val in vals] return value def _from_db_value(self, value, expression, connection, context): if value is None: return value return [ self.base_field.from_db_value(item, expression, connection, context) for item in value ] def value_to_string(self, obj): values = [] vals = self.value_from_object(obj) base_field = self.base_field for val in vals: if val is None: values.append(None) else: obj = AttributeSetter(base_field.attname, val) values.append(base_field.value_to_string(obj)) return json.dumps(values) def get_transform(self, name): transform = super(ArrayField, self).get_transform(name) if transform: return transform if '_' not in name: try: index = int(name) except ValueError: pass else: index += 1 # postgres uses 1-indexing return IndexTransformFactory(index, self.base_field) try: start, end = name.split('_') start = int(start) + 1 end = int(end) # don't add one here because postgres slices are weird except ValueError: pass else: return SliceTransformFactory(start, end) def validate(self, value, model_instance): super(ArrayField, self).validate(value, model_instance) for index, part in enumerate(value): try: self.base_field.validate(part, model_instance) except exceptions.ValidationError as error: raise prefix_validation_error( error, prefix=self.error_messages['item_invalid'], code='item_invalid', params={'nth': index}, ) if isinstance(self.base_field, ArrayField): if len({len(i) for i in value}) > 1: raise exceptions.ValidationError( self.error_messages['nested_array_mismatch'], code='nested_array_mismatch', ) def run_validators(self, value): super(ArrayField, self).run_validators(value) for index, part in enumerate(value): try: self.base_field.run_validators(part) except exceptions.ValidationError as error: raise prefix_validation_error( error, prefix=self.error_messages['item_invalid'], code='item_invalid', params={'nth': index}, ) def formfield(self, **kwargs): defaults = { 'form_class': SimpleArrayField, 'base_field': self.base_field.formfield(), 'max_length': self.size, } defaults.update(kwargs) return super(ArrayField, self).formfield(**defaults)
@ArrayField.register_lookup class ArrayContains(lookups.DataContains): def as_sql(self, qn, connection): sql, params = super(ArrayContains, self).as_sql(qn, connection) sql = '%s::%s' % (sql, self.lhs.output_field.db_type(connection)) return sql, params @ArrayField.register_lookup class ArrayContainedBy(lookups.ContainedBy): def as_sql(self, qn, connection): sql, params = super(ArrayContainedBy, self).as_sql(qn, connection) sql = '%s::%s' % (sql, self.lhs.output_field.db_type(connection)) return sql, params @ArrayField.register_lookup class ArrayExact(Exact): def as_sql(self, qn, connection): sql, params = super(ArrayExact, self).as_sql(qn, connection) sql = '%s::%s' % (sql, self.lhs.output_field.db_type(connection)) return sql, params @ArrayField.register_lookup class ArrayOverlap(lookups.Overlap): def as_sql(self, qn, connection): sql, params = super(ArrayOverlap, self).as_sql(qn, connection) sql = '%s::%s' % (sql, self.lhs.output_field.db_type(connection)) return sql, params @ArrayField.register_lookup class ArrayLenTransform(Transform): lookup_name = 'len' output_field = IntegerField() def as_sql(self, compiler, connection): lhs, params = compiler.compile(self.lhs) # Distinguish NULL and empty arrays return ( 'CASE WHEN %(lhs)s IS NULL THEN NULL ELSE ' 'coalesce(array_length(%(lhs)s, 1), 0) END' ) % {'lhs': lhs}, params @ArrayField.register_lookup class ArrayInLookup(In): def get_prep_lookup(self): values = super(ArrayInLookup, self).get_prep_lookup() # In.process_rhs() expects values to be hashable, so convert lists # to tuples. prepared_values = [] for value in values: if hasattr(value, 'resolve_expression'): prepared_values.append(value) else: prepared_values.append(tuple(value)) return prepared_values class IndexTransform(Transform): def __init__(self, index, base_field, *args, **kwargs): super(IndexTransform, self).__init__(*args, **kwargs) self.index = index self.base_field = base_field def as_sql(self, compiler, connection): lhs, params = compiler.compile(self.lhs) return '%s[%s]' % (lhs, self.index), params @property def output_field(self): return self.base_field class IndexTransformFactory(object): def __init__(self, index, base_field): self.index = index self.base_field = base_field def __call__(self, *args, **kwargs): return IndexTransform(self.index, self.base_field, *args, **kwargs) class SliceTransform(Transform): def __init__(self, start, end, *args, **kwargs): super(SliceTransform, self).__init__(*args, **kwargs) self.start = start self.end = end def as_sql(self, compiler, connection): lhs, params = compiler.compile(self.lhs) return '%s[%s:%s]' % (lhs, self.start, self.end), params class SliceTransformFactory(object): def __init__(self, start, end): self.start = start self.end = end def __call__(self, *args, **kwargs): return SliceTransform(self.start, self.end, *args, **kwargs)
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