444 lines
13 KiB
Python
444 lines
13 KiB
Python
#column field types
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from copy import copy
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from datetime import datetime
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import re
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from uuid import uuid1, uuid4
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from cql.query import cql_quote
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from cqlengine.exceptions import ValidationError
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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 = copy(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 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 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, primary_key=False, index=False, db_field=None, default=None, required=True):
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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, all others are cluster keys
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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?
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"""
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self.primary_key = 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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#only the model meta class should touch this
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self._partition_key = False
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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.db_field_name, 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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class Bytes(Column):
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db_type = 'blob'
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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', True) 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 DateTime(Column):
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db_type = 'timestamp'
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def __init__(self, **kwargs):
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super(DateTime, self).__init__(**kwargs)
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def to_python(self, value):
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if isinstance(value, datetime):
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return value
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return datetime.utcfromtimestamp(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 not isinstance(value, datetime):
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raise ValidationError("'{}' is not a datetime object".format(value))
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epoch = datetime(1970, 1, 1)
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return long((value - epoch).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 __init__(self, default=lambda:uuid4(), **kwargs):
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super(UUID, self).__init__(default=default, **kwargs)
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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 not self.re_uuid.match(val):
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raise ValidationError("{} is not a valid uuid".format(value))
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return _UUID(val)
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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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def __init__(self, **kwargs):
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kwargs.setdefault('default', lambda: uuid1())
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super(TimeUUID, self).__init__(**kwargs)
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class Boolean(Column):
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db_type = 'boolean'
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def to_python(self, value):
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return bool(value)
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def to_database(self, value):
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return bool(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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class Counter(Column):
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#TODO: counter field
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def __init__(self, **kwargs):
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super(Counter, self).__init__(**kwargs)
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raise NotImplementedError
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class ContainerValueManager(BaseValueManager):
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pass
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class ContainerQuoter(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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class BaseContainerColumn(Column):
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"""
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Base Container type
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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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if not issubclass(value_type, Column):
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raise ValidationError('value_type must be a column class')
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if issubclass(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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self.value_type = value_type
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self.value_col = self.value_type()
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super(BaseContainerColumn, self).__init__(**kwargs)
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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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db_type = self.db_type.format(self.value_type.db_type)
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return '{} {}'.format(self.db_field_name, db_type)
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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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class Quoter(ContainerQuoter):
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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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def __init__(self, value_type, strict=True, **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, **kwargs)
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def validate(self, value):
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val = super(Set, self).validate(value)
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if val is None: return
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types = (set,) if self.strict else (set, list, tuple)
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if not isinstance(val, types):
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if self.strict:
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raise ValidationError('{} is not a set object'.format(val))
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else:
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raise ValidationError('{} cannot be coerced to a set object'.format(val))
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return {self.value_col.validate(v) for v in val}
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def to_database(self, value):
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return self.Quoter({self.value_col.to_database(v) for v in value})
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class List(BaseContainerColumn):
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"""
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Stores a list of ordered values
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http://www.datastax.com/docs/1.2/cql_cli/using/collections_list
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"""
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db_type = 'list<{}>'
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class Quoter(ContainerQuoter):
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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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def validate(self, value):
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val = super(List, self).validate(value)
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if val is None: return
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if not isinstance(val, (set, list, tuple)):
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raise ValidationError('{} is not a list object'.format(val))
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return [self.value_col.validate(v) for v in val]
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def to_database(self, value):
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return self.Quoter([self.value_col.to_database(v) for v in value])
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class Map(BaseContainerColumn):
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"""
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Stores a key -> value map (dictionary)
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http://www.datastax.com/docs/1.2/cql_cli/using/collections_map
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"""
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db_type = 'map<{}, {}>'
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class Quoter(ContainerQuoter):
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def __str__(self):
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cq = cql_quote
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return '{' + ', '.join([cq(k) + ':' + cq(v) for k,v in self.value.items()]) + '}'
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def __init__(self, key_type, value_type, **kwargs):
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"""
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:param key_type: a column class indicating the types of the key
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:param value_type: a column class indicating the types of the value
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"""
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if not issubclass(value_type, Column):
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raise ValidationError('key_type must be a column class')
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if issubclass(value_type, BaseContainerColumn):
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raise ValidationError('container types cannot be nested')
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if key_type.db_type is None:
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raise ValidationError('key_type cannot be an abstract column type')
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self.key_type = key_type
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self.key_col = self.key_type()
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super(Map, self).__init__(value_type, **kwargs)
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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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db_type = self.db_type.format(
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self.key_type.db_type,
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self.value_type.db_type
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)
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return '{} {}'.format(self.db_field_name, db_type)
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def validate(self, value):
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val = super(Map, self).validate(value)
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if val is None: return
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if not isinstance(val, dict):
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raise ValidationError('{} is not a dict object'.format(val))
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return {self.key_col.validate(k):self.value_col.validate(v) for k,v in val.items()}
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def to_python(self, value):
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if value is not None:
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return {self.key_col.to_python(k):self.value_col.to_python(v) for k,v in value.items()}
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def to_database(self, value):
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return self.Quoter({self.key_col.to_database(k):self.value_col.to_database(v) for k,v in value.items()})
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