736 lines
22 KiB
Python
736 lines
22 KiB
Python
#column field types
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from copy import deepcopy, copy
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from datetime import datetime
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from datetime import date
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import re
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from cassandra.cqltypes import DateType
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from cqlengine.exceptions import ValidationError
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from cassandra.encoder import cql_quote
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class BaseValueManager(object):
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def __init__(self, instance, column, value):
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self.instance = instance
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self.column = column
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self.previous_value = deepcopy(value)
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self.value = value
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@property
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def deleted(self):
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return self.value is None and self.previous_value is not None
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@property
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def changed(self):
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"""
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Indicates whether or not this value has changed.
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:rtype: boolean
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"""
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return self.value != self.previous_value
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def reset_previous_value(self):
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self.previous_value = copy(self.value)
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def getval(self):
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return self.value
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def setval(self, val):
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self.value = val
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def delval(self):
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self.value = None
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def get_property(self):
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_get = lambda slf: self.getval()
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_set = lambda slf, val: self.setval(val)
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_del = lambda slf: self.delval()
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if self.column.can_delete:
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return property(_get, _set, _del)
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else:
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return property(_get, _set)
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class ValueQuoter(object):
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"""
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contains a single value, which will quote itself for CQL insertion statements
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"""
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def __init__(self, value):
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self.value = value
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def __str__(self):
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raise NotImplementedError
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def __repr__(self):
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return self.__str__()
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def __eq__(self, other):
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if isinstance(other, self.__class__):
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return self.value == other.value
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return False
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class Column(object):
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#the cassandra type this column maps to
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db_type = None
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value_manager = BaseValueManager
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instance_counter = 0
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def __init__(self,
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primary_key=False,
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partition_key=False,
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index=False,
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db_field=None,
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default=None,
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required=False,
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clustering_order=None,
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polymorphic_key=False):
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"""
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:param primary_key: bool flag, indicates this column is a primary key. The first primary key defined
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on a model is the partition key (unless partition keys are set), all others are cluster keys
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:param partition_key: indicates that this column should be the partition key, defining
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more than one partition key column creates a compound partition key
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:param index: bool flag, indicates an index should be created for this column
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:param db_field: the fieldname this field will map to in the database
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:param default: the default value, can be a value or a callable (no args)
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:param required: boolean, is the field required? Model validation will raise and
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exception if required is set to True and there is a None value assigned
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:param clustering_order: only applicable on clustering keys (primary keys that are not partition keys)
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determines the order that the clustering keys are sorted on disk
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:param polymorphic_key: boolean, if set to True, this column will be used for saving and loading instances
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of polymorphic tables
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"""
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self.partition_key = partition_key
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self.primary_key = partition_key or primary_key
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self.index = index
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self.db_field = db_field
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self.default = default
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self.required = required
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self.clustering_order = clustering_order
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self.polymorphic_key = polymorphic_key
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#the column name in the model definition
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self.column_name = None
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self.value = None
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#keep track of instantiation order
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self.position = Column.instance_counter
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Column.instance_counter += 1
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def validate(self, value):
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"""
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Returns a cleaned and validated value. Raises a ValidationError
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if there's a problem
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"""
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if value is None:
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if self.has_default:
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return self.get_default()
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elif self.required:
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raise ValidationError('{} - None values are not allowed'.format(self.column_name or self.db_field))
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return value
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def to_python(self, value):
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"""
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Converts data from the database into python values
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raises a ValidationError if the value can't be converted
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"""
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return value
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def to_database(self, value):
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"""
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Converts python value into database value
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"""
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if value is None and self.has_default:
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return self.get_default()
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return value
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@property
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def has_default(self):
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return self.default is not None
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@property
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def is_primary_key(self):
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return self.primary_key
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@property
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def can_delete(self):
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return not self.primary_key
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def get_default(self):
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if self.has_default:
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if callable(self.default):
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return self.default()
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else:
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return self.default
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def get_column_def(self):
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"""
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Returns a column definition for CQL table definition
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"""
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return '{} {}'.format(self.cql, self.db_type)
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def set_column_name(self, name):
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"""
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Sets the column name during document class construction
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This value will be ignored if db_field is set in __init__
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"""
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self.column_name = name
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@property
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def db_field_name(self):
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""" Returns the name of the cql name of this column """
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return self.db_field or self.column_name
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@property
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def db_index_name(self):
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""" Returns the name of the cql index """
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return 'index_{}'.format(self.db_field_name)
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@property
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def cql(self):
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return self.get_cql()
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def get_cql(self):
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return '"{}"'.format(self.db_field_name)
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def _val_is_null(self, val):
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""" determines if the given value equates to a null value for the given column type """
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return val is None
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class Bytes(Column):
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db_type = 'blob'
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class Quoter(ValueQuoter):
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def __str__(self):
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return '0x' + self.value.encode('hex')
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def to_database(self, value):
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val = super(Bytes, self).to_database(value)
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if val is None: return
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return self.Quoter(val)
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def to_python(self, value):
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#return value[2:].decode('hex')
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return value
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class Ascii(Column):
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db_type = 'ascii'
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class Text(Column):
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db_type = 'text'
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def __init__(self, *args, **kwargs):
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self.min_length = kwargs.pop('min_length', 1 if kwargs.get('required', False) else None)
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self.max_length = kwargs.pop('max_length', None)
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super(Text, self).__init__(*args, **kwargs)
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def validate(self, value):
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value = super(Text, self).validate(value)
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if value is None: return
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if not isinstance(value, (basestring, bytearray)) and value is not None:
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raise ValidationError('{} is not a string'.format(type(value)))
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if self.max_length:
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if len(value) > self.max_length:
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raise ValidationError('{} is longer than {} characters'.format(self.column_name, self.max_length))
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if self.min_length:
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if len(value) < self.min_length:
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raise ValidationError('{} is shorter than {} characters'.format(self.column_name, self.min_length))
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return value
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class Integer(Column):
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db_type = 'int'
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def validate(self, value):
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val = super(Integer, self).validate(value)
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if val is None: return
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try:
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return long(val)
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except (TypeError, ValueError):
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raise ValidationError("{} can't be converted to integral value".format(value))
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def to_python(self, value):
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return self.validate(value)
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def to_database(self, value):
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return self.validate(value)
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class BigInt(Integer):
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db_type = 'bigint'
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class VarInt(Column):
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db_type = 'varint'
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def validate(self, value):
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val = super(VarInt, self).validate(value)
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if val is None:
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return
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try:
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return long(val)
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except (TypeError, ValueError):
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raise ValidationError(
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"{} can't be converted to integral value".format(value))
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def to_python(self, value):
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return self.validate(value)
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def to_database(self, value):
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return self.validate(value)
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class CounterValueManager(BaseValueManager):
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def __init__(self, instance, column, value):
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super(CounterValueManager, self).__init__(instance, column, value)
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self.value = self.value or 0
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self.previous_value = self.previous_value or 0
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class Counter(Integer):
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db_type = 'counter'
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value_manager = CounterValueManager
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def __init__(self,
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index=False,
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db_field=None,
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required=False):
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super(Counter, self).__init__(
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primary_key=False,
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partition_key=False,
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index=index,
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db_field=db_field,
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default=0,
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required=required,
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)
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class DateTime(Column):
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db_type = 'timestamp'
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def to_python(self, value):
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if value is None: return
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if isinstance(value, datetime):
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return value
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elif isinstance(value, date):
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return datetime(*(value.timetuple()[:6]))
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try:
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return datetime.utcfromtimestamp(value)
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except TypeError:
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return datetime.utcfromtimestamp(DateType.deserialize(value))
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def to_database(self, value):
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value = super(DateTime, self).to_database(value)
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if value is None: return
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if not isinstance(value, datetime):
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if isinstance(value, date):
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value = datetime(value.year, value.month, value.day)
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else:
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raise ValidationError("'{}' is not a datetime object".format(value))
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epoch = datetime(1970, 1, 1, tzinfo=value.tzinfo)
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offset = epoch.tzinfo.utcoffset(epoch).total_seconds() if epoch.tzinfo else 0
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return long(((value - epoch).total_seconds() - offset) * 1000)
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class Date(Column):
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db_type = 'timestamp'
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def to_python(self, value):
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if value is None: return
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if isinstance(value, datetime):
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return value.date()
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elif isinstance(value, date):
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return value
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try:
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return datetime.utcfromtimestamp(value).date()
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except TypeError:
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return datetime.utcfromtimestamp(DateType.deserialize(value)).date()
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def to_database(self, value):
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value = super(Date, self).to_database(value)
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if value is None: return
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if isinstance(value, datetime):
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value = value.date()
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if not isinstance(value, date):
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raise ValidationError("'{}' is not a date object".format(repr(value)))
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return long((value - date(1970, 1, 1)).total_seconds() * 1000)
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class UUID(Column):
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"""
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Type 1 or 4 UUID
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"""
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db_type = 'uuid'
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re_uuid = re.compile(r'[0-9a-f]{8}-?[0-9a-f]{4}-?[0-9a-f]{4}-?[0-9a-f]{4}-?[0-9a-f]{12}')
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def validate(self, value):
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val = super(UUID, self).validate(value)
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if val is None: return
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from uuid import UUID as _UUID
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if isinstance(val, _UUID): return val
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if isinstance(val, basestring) and self.re_uuid.match(val):
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return _UUID(val)
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raise ValidationError("{} is not a valid uuid".format(value))
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def to_python(self, value):
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return self.validate(value)
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def to_database(self, value):
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return self.validate(value)
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from uuid import UUID as pyUUID, getnode
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class TimeUUID(UUID):
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"""
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UUID containing timestamp
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"""
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db_type = 'timeuuid'
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@classmethod
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def from_datetime(self, dt):
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"""
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generates a UUID for a given datetime
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:param dt: datetime
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:type dt: datetime
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:return:
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"""
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global _last_timestamp
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epoch = datetime(1970, 1, 1, tzinfo=dt.tzinfo)
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offset = epoch.tzinfo.utcoffset(epoch).total_seconds() if epoch.tzinfo else 0
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timestamp = (dt - epoch).total_seconds() - offset
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node = None
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clock_seq = None
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nanoseconds = int(timestamp * 1e9)
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timestamp = int(nanoseconds // 100) + 0x01b21dd213814000L
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if clock_seq is None:
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import random
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clock_seq = random.randrange(1 << 14L) # instead of stable storage
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time_low = timestamp & 0xffffffffL
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time_mid = (timestamp >> 32L) & 0xffffL
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time_hi_version = (timestamp >> 48L) & 0x0fffL
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clock_seq_low = clock_seq & 0xffL
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clock_seq_hi_variant = (clock_seq >> 8L) & 0x3fL
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if node is None:
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node = getnode()
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return pyUUID(fields=(time_low, time_mid, time_hi_version,
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clock_seq_hi_variant, clock_seq_low, node), version=1)
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class Boolean(Column):
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db_type = 'boolean'
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def validate(self, value):
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""" Always returns a Python boolean. """
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value = super(Boolean, self).validate(value)
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return bool(value)
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def to_python(self, value):
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return self.validate(value)
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class Float(Column):
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db_type = 'double'
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def __init__(self, double_precision=True, **kwargs):
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self.db_type = 'double' if double_precision else 'float'
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super(Float, self).__init__(**kwargs)
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def validate(self, value):
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value = super(Float, self).validate(value)
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if value is None: return
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try:
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return float(value)
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except (TypeError, ValueError):
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raise ValidationError("{} is not a valid float".format(value))
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def to_python(self, value):
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return self.validate(value)
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def to_database(self, value):
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return self.validate(value)
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class Decimal(Column):
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db_type = 'decimal'
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def validate(self, value):
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from decimal import Decimal as _Decimal
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from decimal import InvalidOperation
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val = super(Decimal, self).validate(value)
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if val is None: return
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try:
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return _Decimal(val)
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except InvalidOperation:
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raise ValidationError("'{}' can't be coerced to decimal".format(val))
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def to_python(self, value):
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return self.validate(value)
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def to_database(self, value):
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return self.validate(value)
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class BaseContainerColumn(Column):
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"""
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Base Container type for collection-like columns.
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https://cassandra.apache.org/doc/cql3/CQL.html#collections
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"""
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def __init__(self, value_type, **kwargs):
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"""
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:param value_type: a column class indicating the types of the value
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"""
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inheritance_comparator = issubclass if isinstance(value_type, type) else isinstance
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if not inheritance_comparator(value_type, Column):
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raise ValidationError('value_type must be a column class')
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if inheritance_comparator(value_type, BaseContainerColumn):
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raise ValidationError('container types cannot be nested')
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if value_type.db_type is None:
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raise ValidationError('value_type cannot be an abstract column type')
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if isinstance(value_type, type):
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self.value_type = value_type
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self.value_col = self.value_type()
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else:
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self.value_col = value_type
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self.value_type = self.value_col.__class__
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super(BaseContainerColumn, self).__init__(**kwargs)
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def validate(self, value):
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value = super(BaseContainerColumn, self).validate(value)
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# It is dangerous to let collections have more than 65535.
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# See: https://issues.apache.org/jira/browse/CASSANDRA-5428
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if value is not None and len(value) > 65535:
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raise ValidationError("Collection can't have more than 65535 elements.")
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return value
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|
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def get_column_def(self):
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"""
|
|
Returns a column definition for CQL table definition
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"""
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db_type = self.db_type.format(self.value_type.db_type)
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return '{} {}'.format(self.cql, db_type)
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|
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def _val_is_null(self, val):
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return not val
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|
|
|
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class BaseContainerQuoter(ValueQuoter):
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def __nonzero__(self):
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return bool(self.value)
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|
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class Set(BaseContainerColumn):
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"""
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Stores a set of unordered, unique values
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http://www.datastax.com/docs/1.2/cql_cli/using/collections
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"""
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db_type = 'set<{}>'
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|
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class Quoter(BaseContainerQuoter):
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|
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def __str__(self):
|
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cq = cql_quote
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return '{' + ', '.join([cq(v) for v in self.value]) + '}'
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|
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def __init__(self, value_type, strict=True, default=set, **kwargs):
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"""
|
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:param value_type: a column class indicating the types of the value
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:param strict: sets whether non set values will be coerced to set
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type on validation, or raise a validation error, defaults to True
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"""
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self.strict = strict
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super(Set, self).__init__(value_type, default=default, **kwargs)
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|
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def validate(self, value):
|
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val = super(Set, self).validate(value)
|
|
if val is None: return
|
|
types = (set,) if self.strict else (set, list, tuple)
|
|
if not isinstance(val, types):
|
|
if self.strict:
|
|
raise ValidationError('{} is not a set object'.format(val))
|
|
else:
|
|
raise ValidationError('{} cannot be coerced to a set object'.format(val))
|
|
|
|
if None in val:
|
|
raise ValidationError("None not allowed in a set")
|
|
|
|
return {self.value_col.validate(v) for v in val}
|
|
|
|
def to_python(self, value):
|
|
if value is None: return set()
|
|
return {self.value_col.to_python(v) for v in value}
|
|
|
|
def to_database(self, value):
|
|
if value is None: return None
|
|
|
|
if isinstance(value, self.Quoter): return value
|
|
return self.Quoter({self.value_col.to_database(v) for v in value})
|
|
|
|
|
|
|
|
|
|
class List(BaseContainerColumn):
|
|
"""
|
|
Stores a list of ordered values
|
|
|
|
http://www.datastax.com/docs/1.2/cql_cli/using/collections_list
|
|
"""
|
|
db_type = 'list<{}>'
|
|
|
|
class Quoter(BaseContainerQuoter):
|
|
|
|
def __str__(self):
|
|
cq = cql_quote
|
|
return '[' + ', '.join([cq(v) for v in self.value]) + ']'
|
|
|
|
def __nonzero__(self):
|
|
return bool(self.value)
|
|
|
|
def __init__(self, value_type, default=list, **kwargs):
|
|
return super(List, self).__init__(value_type=value_type, default=default, **kwargs)
|
|
|
|
def validate(self, value):
|
|
val = super(List, self).validate(value)
|
|
if val is None: return
|
|
if not isinstance(val, (set, list, tuple)):
|
|
raise ValidationError('{} is not a list object'.format(val))
|
|
if None in val:
|
|
raise ValidationError("None is not allowed in a list")
|
|
return [self.value_col.validate(v) for v in val]
|
|
|
|
def to_python(self, value):
|
|
if value is None: return []
|
|
return [self.value_col.to_python(v) for v in value]
|
|
|
|
def to_database(self, value):
|
|
if value is None: return None
|
|
if isinstance(value, self.Quoter): return value
|
|
return self.Quoter([self.value_col.to_database(v) for v in value])
|
|
|
|
|
|
class Map(BaseContainerColumn):
|
|
"""
|
|
Stores a key -> value map (dictionary)
|
|
|
|
http://www.datastax.com/docs/1.2/cql_cli/using/collections_map
|
|
"""
|
|
|
|
db_type = 'map<{}, {}>'
|
|
|
|
class Quoter(BaseContainerQuoter):
|
|
|
|
def __str__(self):
|
|
cq = cql_quote
|
|
return '{' + ', '.join([cq(k) + ':' + cq(v) for k,v in self.value.items()]) + '}'
|
|
|
|
def get(self, key):
|
|
return self.value.get(key)
|
|
|
|
def keys(self):
|
|
return self.value.keys()
|
|
|
|
def items(self):
|
|
return self.value.items()
|
|
|
|
def __init__(self, key_type, value_type, default=dict, **kwargs):
|
|
"""
|
|
:param key_type: a column class indicating the types of the key
|
|
:param value_type: a column class indicating the types of the value
|
|
"""
|
|
inheritance_comparator = issubclass if isinstance(key_type, type) else isinstance
|
|
if not inheritance_comparator(key_type, Column):
|
|
raise ValidationError('key_type must be a column class')
|
|
if inheritance_comparator(key_type, BaseContainerColumn):
|
|
raise ValidationError('container types cannot be nested')
|
|
if key_type.db_type is None:
|
|
raise ValidationError('key_type cannot be an abstract column type')
|
|
|
|
if isinstance(key_type, type):
|
|
self.key_type = key_type
|
|
self.key_col = self.key_type()
|
|
else:
|
|
self.key_col = key_type
|
|
self.key_type = self.key_col.__class__
|
|
super(Map, self).__init__(value_type, default=default, **kwargs)
|
|
|
|
def get_column_def(self):
|
|
"""
|
|
Returns a column definition for CQL table definition
|
|
"""
|
|
db_type = self.db_type.format(
|
|
self.key_type.db_type,
|
|
self.value_type.db_type
|
|
)
|
|
return '{} {}'.format(self.cql, db_type)
|
|
|
|
def validate(self, value):
|
|
val = super(Map, self).validate(value)
|
|
if val is None: return
|
|
if not isinstance(val, dict):
|
|
raise ValidationError('{} is not a dict object'.format(val))
|
|
return {self.key_col.validate(k):self.value_col.validate(v) for k,v in val.items()}
|
|
|
|
def to_python(self, value):
|
|
if value is None:
|
|
return {}
|
|
if value is not None:
|
|
return {self.key_col.to_python(k): self.value_col.to_python(v) for k,v in value.items()}
|
|
|
|
def to_database(self, value):
|
|
if value is None: return None
|
|
if isinstance(value, self.Quoter): return value
|
|
return self.Quoter({self.key_col.to_database(k):self.value_col.to_database(v) for k,v in value.items()})
|
|
|
|
|
|
|
|
class _PartitionKeysToken(Column):
|
|
"""
|
|
virtual column representing token of partition columns.
|
|
Used by filter(pk__token=Token(...)) filters
|
|
"""
|
|
|
|
def __init__(self, model):
|
|
self.partition_columns = model._partition_keys.values()
|
|
super(_PartitionKeysToken, self).__init__(partition_key=True)
|
|
|
|
@property
|
|
def db_field_name(self):
|
|
return 'token({})'.format(', '.join(['"{}"'.format(c.db_field_name) for c in self.partition_columns]))
|
|
|
|
def to_database(self, value):
|
|
from cqlengine.functions import Token
|
|
assert isinstance(value, Token)
|
|
value.set_columns(self.partition_columns)
|
|
return value
|
|
|
|
def get_cql(self):
|
|
return "token({})".format(", ".join(c.cql for c in self.partition_columns))
|
|
|