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.utils import six from django.utils.translation import string_concat, ugettext_lazy as _ __all__ = ['ArrayField'] class AttributeSetter(object): def __init__(self, name, value): setattr(self, name, value) 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)) super(ArrayField, self).__init__(**kwargs) 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.', hint=None, 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, hint=None, 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) 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, '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 value_to_string(self, obj): values = [] vals = self._get_val_from_obj(obj) base_field = self.base_field for val in vals: 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 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 i, part in enumerate(value): try: self.base_field.validate(part, model_instance) except exceptions.ValidationError as e: raise exceptions.ValidationError( string_concat(self.error_messages['item_invalid'], e.message), code='item_invalid', params={'nth': i}, ) 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 i, part in enumerate(value): try: self.base_field.run_validators(part) except exceptions.ValidationError as e: raise exceptions.ValidationError( string_concat(self.error_messages['item_invalid'], ' '.join(e.messages)), code='item_invalid', params={'nth': i}, ) 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' % 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' % 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' % 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) return 'array_length(%s, 1)' % lhs, params 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)