django1/django/contrib/postgres/fields/array.py

264 lines
8.3 KiB
Python

import json
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, Lookup, Transform, IntegerField
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.rel:
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_prep_value(self, value):
if isinstance(value, list) or isinstance(value, tuple):
return [self.base_field.get_prep_value(i) for i in value]
return value
def get_db_prep_lookup(self, lookup_type, value, connection, prepared=False):
if lookup_type == 'contains':
return [self.get_prep_value(value)]
return super(ArrayField, self).get_db_prep_lookup(lookup_type, value,
connection, prepared=False)
def deconstruct(self):
name, path, args, kwargs = super(ArrayField, self).deconstruct()
path = 'django.contrib.postgres.fields.ArrayField'
args.insert(0, self.base_field)
kwargs['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 get_default(self):
"""Overridden from the default to prevent string-mangling."""
if self.has_default():
if callable(self.default):
return self.default()
return self.default
return ''
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 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)
class ArrayContainsLookup(Lookup):
lookup_name = 'contains'
def as_sql(self, qn, connection):
lhs, lhs_params = self.process_lhs(qn, connection)
rhs, rhs_params = self.process_rhs(qn, connection)
params = lhs_params + rhs_params
type_cast = self.lhs.source.db_type(connection)
return '%s @> %s::%s' % (lhs, rhs, type_cast), params
ArrayField.register_lookup(ArrayContainsLookup)
class ArrayContainedByLookup(Lookup):
lookup_name = 'contained_by'
def as_sql(self, qn, connection):
lhs, lhs_params = self.process_lhs(qn, connection)
rhs, rhs_params = self.process_rhs(qn, connection)
params = lhs_params + rhs_params
return '%s <@ %s' % (lhs, rhs), params
ArrayField.register_lookup(ArrayContainedByLookup)
class ArrayOverlapLookup(Lookup):
lookup_name = 'overlap'
def as_sql(self, qn, connection):
lhs, lhs_params = self.process_lhs(qn, connection)
rhs, rhs_params = self.process_rhs(qn, connection)
params = lhs_params + rhs_params
return '%s && %s' % (lhs, rhs), params
ArrayField.register_lookup(ArrayOverlapLookup)
class ArrayLenTransform(Transform):
lookup_name = 'len'
@property
def output_field(self):
return IntegerField()
def as_sql(self, qn, connection):
lhs, params = qn.compile(self.lhs)
return 'array_length(%s, 1)' % lhs, params
ArrayField.register_lookup(ArrayLenTransform)
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, qn, connection):
lhs, params = qn.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, qn, connection):
lhs, params = qn.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)