657 lines
25 KiB
Python
657 lines
25 KiB
Python
# ext/declarative/base.py
|
|
# Copyright (C) 2005-2015 the SQLAlchemy authors and contributors
|
|
# <see AUTHORS file>
|
|
#
|
|
# This module is part of SQLAlchemy and is released under
|
|
# the MIT License: http://www.opensource.org/licenses/mit-license.php
|
|
"""Internal implementation for declarative."""
|
|
|
|
from ...schema import Table, Column
|
|
from ...orm import mapper, class_mapper, synonym
|
|
from ...orm.interfaces import MapperProperty
|
|
from ...orm.properties import ColumnProperty, CompositeProperty
|
|
from ...orm.attributes import QueryableAttribute
|
|
from ...orm.base import _is_mapped_class
|
|
from ... import util, exc
|
|
from ...util import topological
|
|
from ...sql import expression
|
|
from ... import event
|
|
from . import clsregistry
|
|
import collections
|
|
import weakref
|
|
from sqlalchemy.orm import instrumentation
|
|
|
|
declared_attr = declarative_props = None
|
|
|
|
|
|
def _declared_mapping_info(cls):
|
|
# deferred mapping
|
|
if _DeferredMapperConfig.has_cls(cls):
|
|
return _DeferredMapperConfig.config_for_cls(cls)
|
|
# regular mapping
|
|
elif _is_mapped_class(cls):
|
|
return class_mapper(cls, configure=False)
|
|
else:
|
|
return None
|
|
|
|
|
|
def _resolve_for_abstract(cls):
|
|
if cls is object:
|
|
return None
|
|
|
|
if _get_immediate_cls_attr(cls, '__abstract__', strict=True):
|
|
for sup in cls.__bases__:
|
|
sup = _resolve_for_abstract(sup)
|
|
if sup is not None:
|
|
return sup
|
|
else:
|
|
return None
|
|
else:
|
|
return cls
|
|
|
|
|
|
def _get_immediate_cls_attr(cls, attrname, strict=False):
|
|
"""return an attribute of the class that is either present directly
|
|
on the class, e.g. not on a superclass, or is from a superclass but
|
|
this superclass is a mixin, that is, not a descendant of
|
|
the declarative base.
|
|
|
|
This is used to detect attributes that indicate something about
|
|
a mapped class independently from any mapped classes that it may
|
|
inherit from.
|
|
|
|
"""
|
|
if not issubclass(cls, object):
|
|
return None
|
|
|
|
for base in cls.__mro__:
|
|
_is_declarative_inherits = hasattr(base, '_decl_class_registry')
|
|
if attrname in base.__dict__ and (
|
|
base is cls or
|
|
((base in cls.__bases__ if strict else True)
|
|
and not _is_declarative_inherits)
|
|
):
|
|
return getattr(base, attrname)
|
|
else:
|
|
return None
|
|
|
|
|
|
def _as_declarative(cls, classname, dict_):
|
|
global declared_attr, declarative_props
|
|
if declared_attr is None:
|
|
from .api import declared_attr
|
|
declarative_props = (declared_attr, util.classproperty)
|
|
|
|
if _get_immediate_cls_attr(cls, '__abstract__', strict=True):
|
|
return
|
|
|
|
_MapperConfig.setup_mapping(cls, classname, dict_)
|
|
|
|
|
|
class _MapperConfig(object):
|
|
|
|
@classmethod
|
|
def setup_mapping(cls, cls_, classname, dict_):
|
|
defer_map = _get_immediate_cls_attr(
|
|
cls_, '_sa_decl_prepare_nocascade', strict=True) or \
|
|
hasattr(cls_, '_sa_decl_prepare')
|
|
|
|
if defer_map:
|
|
cfg_cls = _DeferredMapperConfig
|
|
else:
|
|
cfg_cls = _MapperConfig
|
|
cfg_cls(cls_, classname, dict_)
|
|
|
|
def __init__(self, cls_, classname, dict_):
|
|
|
|
self.cls = cls_
|
|
|
|
# dict_ will be a dictproxy, which we can't write to, and we need to!
|
|
self.dict_ = dict(dict_)
|
|
self.classname = classname
|
|
self.mapped_table = None
|
|
self.properties = util.OrderedDict()
|
|
self.declared_columns = set()
|
|
self.column_copies = {}
|
|
self._setup_declared_events()
|
|
|
|
# temporary registry. While early 1.0 versions
|
|
# set up the ClassManager here, by API contract
|
|
# we can't do that until there's a mapper.
|
|
self.cls._sa_declared_attr_reg = {}
|
|
|
|
self._scan_attributes()
|
|
|
|
clsregistry.add_class(self.classname, self.cls)
|
|
|
|
self._extract_mappable_attributes()
|
|
|
|
self._extract_declared_columns()
|
|
|
|
self._setup_table()
|
|
|
|
self._setup_inheritance()
|
|
|
|
self._early_mapping()
|
|
|
|
def _early_mapping(self):
|
|
self.map()
|
|
|
|
def _setup_declared_events(self):
|
|
if _get_immediate_cls_attr(self.cls, '__declare_last__'):
|
|
@event.listens_for(mapper, "after_configured")
|
|
def after_configured():
|
|
self.cls.__declare_last__()
|
|
|
|
if _get_immediate_cls_attr(self.cls, '__declare_first__'):
|
|
@event.listens_for(mapper, "before_configured")
|
|
def before_configured():
|
|
self.cls.__declare_first__()
|
|
|
|
def _scan_attributes(self):
|
|
cls = self.cls
|
|
dict_ = self.dict_
|
|
column_copies = self.column_copies
|
|
mapper_args_fn = None
|
|
table_args = inherited_table_args = None
|
|
tablename = None
|
|
|
|
for base in cls.__mro__:
|
|
class_mapped = base is not cls and \
|
|
_declared_mapping_info(base) is not None and \
|
|
not _get_immediate_cls_attr(
|
|
base, '_sa_decl_prepare_nocascade', strict=True)
|
|
|
|
if not class_mapped and base is not cls:
|
|
self._produce_column_copies(base)
|
|
|
|
for name, obj in vars(base).items():
|
|
if name == '__mapper_args__':
|
|
if not mapper_args_fn and (
|
|
not class_mapped or
|
|
isinstance(obj, declarative_props)
|
|
):
|
|
# don't even invoke __mapper_args__ until
|
|
# after we've determined everything about the
|
|
# mapped table.
|
|
# make a copy of it so a class-level dictionary
|
|
# is not overwritten when we update column-based
|
|
# arguments.
|
|
mapper_args_fn = lambda: dict(cls.__mapper_args__)
|
|
elif name == '__tablename__':
|
|
if not tablename and (
|
|
not class_mapped or
|
|
isinstance(obj, declarative_props)
|
|
):
|
|
tablename = cls.__tablename__
|
|
elif name == '__table_args__':
|
|
if not table_args and (
|
|
not class_mapped or
|
|
isinstance(obj, declarative_props)
|
|
):
|
|
table_args = cls.__table_args__
|
|
if not isinstance(
|
|
table_args, (tuple, dict, type(None))):
|
|
raise exc.ArgumentError(
|
|
"__table_args__ value must be a tuple, "
|
|
"dict, or None")
|
|
if base is not cls:
|
|
inherited_table_args = True
|
|
elif class_mapped:
|
|
if isinstance(obj, declarative_props):
|
|
util.warn("Regular (i.e. not __special__) "
|
|
"attribute '%s.%s' uses @declared_attr, "
|
|
"but owning class %s is mapped - "
|
|
"not applying to subclass %s."
|
|
% (base.__name__, name, base, cls))
|
|
continue
|
|
elif base is not cls:
|
|
# we're a mixin, abstract base, or something that is
|
|
# acting like that for now.
|
|
if isinstance(obj, Column):
|
|
# already copied columns to the mapped class.
|
|
continue
|
|
elif isinstance(obj, MapperProperty):
|
|
raise exc.InvalidRequestError(
|
|
"Mapper properties (i.e. deferred,"
|
|
"column_property(), relationship(), etc.) must "
|
|
"be declared as @declared_attr callables "
|
|
"on declarative mixin classes.")
|
|
elif isinstance(obj, declarative_props):
|
|
oldclassprop = isinstance(obj, util.classproperty)
|
|
if not oldclassprop and obj._cascading:
|
|
dict_[name] = column_copies[obj] = \
|
|
ret = obj.__get__(obj, cls)
|
|
setattr(cls, name, ret)
|
|
else:
|
|
if oldclassprop:
|
|
util.warn_deprecated(
|
|
"Use of sqlalchemy.util.classproperty on "
|
|
"declarative classes is deprecated.")
|
|
dict_[name] = column_copies[obj] = \
|
|
ret = getattr(cls, name)
|
|
if isinstance(ret, (Column, MapperProperty)) and \
|
|
ret.doc is None:
|
|
ret.doc = obj.__doc__
|
|
|
|
if inherited_table_args and not tablename:
|
|
table_args = None
|
|
|
|
self.table_args = table_args
|
|
self.tablename = tablename
|
|
self.mapper_args_fn = mapper_args_fn
|
|
|
|
def _produce_column_copies(self, base):
|
|
cls = self.cls
|
|
dict_ = self.dict_
|
|
column_copies = self.column_copies
|
|
# copy mixin columns to the mapped class
|
|
for name, obj in vars(base).items():
|
|
if isinstance(obj, Column):
|
|
if getattr(cls, name) is not obj:
|
|
# if column has been overridden
|
|
# (like by the InstrumentedAttribute of the
|
|
# superclass), skip
|
|
continue
|
|
elif obj.foreign_keys:
|
|
raise exc.InvalidRequestError(
|
|
"Columns with foreign keys to other columns "
|
|
"must be declared as @declared_attr callables "
|
|
"on declarative mixin classes. ")
|
|
elif name not in dict_ and not (
|
|
'__table__' in dict_ and
|
|
(obj.name or name) in dict_['__table__'].c
|
|
):
|
|
column_copies[obj] = copy_ = obj.copy()
|
|
copy_._creation_order = obj._creation_order
|
|
setattr(cls, name, copy_)
|
|
dict_[name] = copy_
|
|
|
|
def _extract_mappable_attributes(self):
|
|
cls = self.cls
|
|
dict_ = self.dict_
|
|
|
|
our_stuff = self.properties
|
|
|
|
for k in list(dict_):
|
|
|
|
if k in ('__table__', '__tablename__', '__mapper_args__'):
|
|
continue
|
|
|
|
value = dict_[k]
|
|
if isinstance(value, declarative_props):
|
|
value = getattr(cls, k)
|
|
|
|
elif isinstance(value, QueryableAttribute) and \
|
|
value.class_ is not cls and \
|
|
value.key != k:
|
|
# detect a QueryableAttribute that's already mapped being
|
|
# assigned elsewhere in userland, turn into a synonym()
|
|
value = synonym(value.key)
|
|
setattr(cls, k, value)
|
|
|
|
if (isinstance(value, tuple) and len(value) == 1 and
|
|
isinstance(value[0], (Column, MapperProperty))):
|
|
util.warn("Ignoring declarative-like tuple value of attribute "
|
|
"%s: possibly a copy-and-paste error with a comma "
|
|
"left at the end of the line?" % k)
|
|
continue
|
|
elif not isinstance(value, (Column, MapperProperty)):
|
|
# using @declared_attr for some object that
|
|
# isn't Column/MapperProperty; remove from the dict_
|
|
# and place the evaluated value onto the class.
|
|
if not k.startswith('__'):
|
|
dict_.pop(k)
|
|
setattr(cls, k, value)
|
|
continue
|
|
# we expect to see the name 'metadata' in some valid cases;
|
|
# however at this point we see it's assigned to something trying
|
|
# to be mapped, so raise for that.
|
|
elif k == 'metadata':
|
|
raise exc.InvalidRequestError(
|
|
"Attribute name 'metadata' is reserved "
|
|
"for the MetaData instance when using a "
|
|
"declarative base class."
|
|
)
|
|
prop = clsregistry._deferred_relationship(cls, value)
|
|
our_stuff[k] = prop
|
|
|
|
def _extract_declared_columns(self):
|
|
our_stuff = self.properties
|
|
|
|
# set up attributes in the order they were created
|
|
our_stuff.sort(key=lambda key: our_stuff[key]._creation_order)
|
|
|
|
# extract columns from the class dict
|
|
declared_columns = self.declared_columns
|
|
name_to_prop_key = collections.defaultdict(set)
|
|
for key, c in list(our_stuff.items()):
|
|
if isinstance(c, (ColumnProperty, CompositeProperty)):
|
|
for col in c.columns:
|
|
if isinstance(col, Column) and \
|
|
col.table is None:
|
|
_undefer_column_name(key, col)
|
|
if not isinstance(c, CompositeProperty):
|
|
name_to_prop_key[col.name].add(key)
|
|
declared_columns.add(col)
|
|
elif isinstance(c, Column):
|
|
_undefer_column_name(key, c)
|
|
name_to_prop_key[c.name].add(key)
|
|
declared_columns.add(c)
|
|
# if the column is the same name as the key,
|
|
# remove it from the explicit properties dict.
|
|
# the normal rules for assigning column-based properties
|
|
# will take over, including precedence of columns
|
|
# in multi-column ColumnProperties.
|
|
if key == c.key:
|
|
del our_stuff[key]
|
|
|
|
for name, keys in name_to_prop_key.items():
|
|
if len(keys) > 1:
|
|
util.warn(
|
|
"On class %r, Column object %r named "
|
|
"directly multiple times, "
|
|
"only one will be used: %s" %
|
|
(self.classname, name, (", ".join(sorted(keys))))
|
|
)
|
|
|
|
def _setup_table(self):
|
|
cls = self.cls
|
|
tablename = self.tablename
|
|
table_args = self.table_args
|
|
dict_ = self.dict_
|
|
declared_columns = self.declared_columns
|
|
|
|
declared_columns = self.declared_columns = sorted(
|
|
declared_columns, key=lambda c: c._creation_order)
|
|
table = None
|
|
|
|
if hasattr(cls, '__table_cls__'):
|
|
table_cls = util.unbound_method_to_callable(cls.__table_cls__)
|
|
else:
|
|
table_cls = Table
|
|
|
|
if '__table__' not in dict_:
|
|
if tablename is not None:
|
|
|
|
args, table_kw = (), {}
|
|
if table_args:
|
|
if isinstance(table_args, dict):
|
|
table_kw = table_args
|
|
elif isinstance(table_args, tuple):
|
|
if isinstance(table_args[-1], dict):
|
|
args, table_kw = table_args[0:-1], table_args[-1]
|
|
else:
|
|
args = table_args
|
|
|
|
autoload = dict_.get('__autoload__')
|
|
if autoload:
|
|
table_kw['autoload'] = True
|
|
|
|
cls.__table__ = table = table_cls(
|
|
tablename, cls.metadata,
|
|
*(tuple(declared_columns) + tuple(args)),
|
|
**table_kw)
|
|
else:
|
|
table = cls.__table__
|
|
if declared_columns:
|
|
for c in declared_columns:
|
|
if not table.c.contains_column(c):
|
|
raise exc.ArgumentError(
|
|
"Can't add additional column %r when "
|
|
"specifying __table__" % c.key
|
|
)
|
|
self.local_table = table
|
|
|
|
def _setup_inheritance(self):
|
|
table = self.local_table
|
|
cls = self.cls
|
|
table_args = self.table_args
|
|
declared_columns = self.declared_columns
|
|
for c in cls.__bases__:
|
|
c = _resolve_for_abstract(c)
|
|
if c is None:
|
|
continue
|
|
if _declared_mapping_info(c) is not None and \
|
|
not _get_immediate_cls_attr(
|
|
c, '_sa_decl_prepare_nocascade', strict=True):
|
|
self.inherits = c
|
|
break
|
|
else:
|
|
self.inherits = None
|
|
|
|
if table is None and self.inherits is None and \
|
|
not _get_immediate_cls_attr(cls, '__no_table__'):
|
|
|
|
raise exc.InvalidRequestError(
|
|
"Class %r does not have a __table__ or __tablename__ "
|
|
"specified and does not inherit from an existing "
|
|
"table-mapped class." % cls
|
|
)
|
|
elif self.inherits:
|
|
inherited_mapper = _declared_mapping_info(self.inherits)
|
|
inherited_table = inherited_mapper.local_table
|
|
inherited_mapped_table = inherited_mapper.mapped_table
|
|
|
|
if table is None:
|
|
# single table inheritance.
|
|
# ensure no table args
|
|
if table_args:
|
|
raise exc.ArgumentError(
|
|
"Can't place __table_args__ on an inherited class "
|
|
"with no table."
|
|
)
|
|
# add any columns declared here to the inherited table.
|
|
for c in declared_columns:
|
|
if c.primary_key:
|
|
raise exc.ArgumentError(
|
|
"Can't place primary key columns on an inherited "
|
|
"class with no table."
|
|
)
|
|
if c.name in inherited_table.c:
|
|
if inherited_table.c[c.name] is c:
|
|
continue
|
|
raise exc.ArgumentError(
|
|
"Column '%s' on class %s conflicts with "
|
|
"existing column '%s'" %
|
|
(c, cls, inherited_table.c[c.name])
|
|
)
|
|
inherited_table.append_column(c)
|
|
if inherited_mapped_table is not None and \
|
|
inherited_mapped_table is not inherited_table:
|
|
inherited_mapped_table._refresh_for_new_column(c)
|
|
|
|
def _prepare_mapper_arguments(self):
|
|
properties = self.properties
|
|
if self.mapper_args_fn:
|
|
mapper_args = self.mapper_args_fn()
|
|
else:
|
|
mapper_args = {}
|
|
|
|
# make sure that column copies are used rather
|
|
# than the original columns from any mixins
|
|
for k in ('version_id_col', 'polymorphic_on',):
|
|
if k in mapper_args:
|
|
v = mapper_args[k]
|
|
mapper_args[k] = self.column_copies.get(v, v)
|
|
|
|
assert 'inherits' not in mapper_args, \
|
|
"Can't specify 'inherits' explicitly with declarative mappings"
|
|
|
|
if self.inherits:
|
|
mapper_args['inherits'] = self.inherits
|
|
|
|
if self.inherits and not mapper_args.get('concrete', False):
|
|
# single or joined inheritance
|
|
# exclude any cols on the inherited table which are
|
|
# not mapped on the parent class, to avoid
|
|
# mapping columns specific to sibling/nephew classes
|
|
inherited_mapper = _declared_mapping_info(self.inherits)
|
|
inherited_table = inherited_mapper.local_table
|
|
|
|
if 'exclude_properties' not in mapper_args:
|
|
mapper_args['exclude_properties'] = exclude_properties = \
|
|
set([c.key for c in inherited_table.c
|
|
if c not in inherited_mapper._columntoproperty])
|
|
exclude_properties.difference_update(
|
|
[c.key for c in self.declared_columns])
|
|
|
|
# look through columns in the current mapper that
|
|
# are keyed to a propname different than the colname
|
|
# (if names were the same, we'd have popped it out above,
|
|
# in which case the mapper makes this combination).
|
|
# See if the superclass has a similar column property.
|
|
# If so, join them together.
|
|
for k, col in list(properties.items()):
|
|
if not isinstance(col, expression.ColumnElement):
|
|
continue
|
|
if k in inherited_mapper._props:
|
|
p = inherited_mapper._props[k]
|
|
if isinstance(p, ColumnProperty):
|
|
# note here we place the subclass column
|
|
# first. See [ticket:1892] for background.
|
|
properties[k] = [col] + p.columns
|
|
result_mapper_args = mapper_args.copy()
|
|
result_mapper_args['properties'] = properties
|
|
self.mapper_args = result_mapper_args
|
|
|
|
def map(self):
|
|
self._prepare_mapper_arguments()
|
|
if hasattr(self.cls, '__mapper_cls__'):
|
|
mapper_cls = util.unbound_method_to_callable(
|
|
self.cls.__mapper_cls__)
|
|
else:
|
|
mapper_cls = mapper
|
|
|
|
self.cls.__mapper__ = mp_ = mapper_cls(
|
|
self.cls,
|
|
self.local_table,
|
|
**self.mapper_args
|
|
)
|
|
del self.cls._sa_declared_attr_reg
|
|
return mp_
|
|
|
|
|
|
class _DeferredMapperConfig(_MapperConfig):
|
|
_configs = util.OrderedDict()
|
|
|
|
def _early_mapping(self):
|
|
pass
|
|
|
|
@property
|
|
def cls(self):
|
|
return self._cls()
|
|
|
|
@cls.setter
|
|
def cls(self, class_):
|
|
self._cls = weakref.ref(class_, self._remove_config_cls)
|
|
self._configs[self._cls] = self
|
|
|
|
@classmethod
|
|
def _remove_config_cls(cls, ref):
|
|
cls._configs.pop(ref, None)
|
|
|
|
@classmethod
|
|
def has_cls(cls, class_):
|
|
# 2.6 fails on weakref if class_ is an old style class
|
|
return isinstance(class_, type) and \
|
|
weakref.ref(class_) in cls._configs
|
|
|
|
@classmethod
|
|
def config_for_cls(cls, class_):
|
|
return cls._configs[weakref.ref(class_)]
|
|
|
|
@classmethod
|
|
def classes_for_base(cls, base_cls, sort=True):
|
|
classes_for_base = [m for m in cls._configs.values()
|
|
if issubclass(m.cls, base_cls)]
|
|
if not sort:
|
|
return classes_for_base
|
|
|
|
all_m_by_cls = dict(
|
|
(m.cls, m)
|
|
for m in classes_for_base
|
|
)
|
|
|
|
tuples = []
|
|
for m_cls in all_m_by_cls:
|
|
tuples.extend(
|
|
(all_m_by_cls[base_cls], all_m_by_cls[m_cls])
|
|
for base_cls in m_cls.__bases__
|
|
if base_cls in all_m_by_cls
|
|
)
|
|
return list(
|
|
topological.sort(
|
|
tuples,
|
|
classes_for_base
|
|
)
|
|
)
|
|
|
|
def map(self):
|
|
self._configs.pop(self._cls, None)
|
|
return super(_DeferredMapperConfig, self).map()
|
|
|
|
|
|
def _add_attribute(cls, key, value):
|
|
"""add an attribute to an existing declarative class.
|
|
|
|
This runs through the logic to determine MapperProperty,
|
|
adds it to the Mapper, adds a column to the mapped Table, etc.
|
|
|
|
"""
|
|
|
|
if '__mapper__' in cls.__dict__:
|
|
if isinstance(value, Column):
|
|
_undefer_column_name(key, value)
|
|
cls.__table__.append_column(value)
|
|
cls.__mapper__.add_property(key, value)
|
|
elif isinstance(value, ColumnProperty):
|
|
for col in value.columns:
|
|
if isinstance(col, Column) and col.table is None:
|
|
_undefer_column_name(key, col)
|
|
cls.__table__.append_column(col)
|
|
cls.__mapper__.add_property(key, value)
|
|
elif isinstance(value, MapperProperty):
|
|
cls.__mapper__.add_property(
|
|
key,
|
|
clsregistry._deferred_relationship(cls, value)
|
|
)
|
|
elif isinstance(value, QueryableAttribute) and value.key != key:
|
|
# detect a QueryableAttribute that's already mapped being
|
|
# assigned elsewhere in userland, turn into a synonym()
|
|
value = synonym(value.key)
|
|
cls.__mapper__.add_property(
|
|
key,
|
|
clsregistry._deferred_relationship(cls, value)
|
|
)
|
|
else:
|
|
type.__setattr__(cls, key, value)
|
|
else:
|
|
type.__setattr__(cls, key, value)
|
|
|
|
|
|
def _declarative_constructor(self, **kwargs):
|
|
"""A simple constructor that allows initialization from kwargs.
|
|
|
|
Sets attributes on the constructed instance using the names and
|
|
values in ``kwargs``.
|
|
|
|
Only keys that are present as
|
|
attributes of the instance's class are allowed. These could be,
|
|
for example, any mapped columns or relationships.
|
|
"""
|
|
cls_ = type(self)
|
|
for k in kwargs:
|
|
if not hasattr(cls_, k):
|
|
raise TypeError(
|
|
"%r is an invalid keyword argument for %s" %
|
|
(k, cls_.__name__))
|
|
setattr(self, k, kwargs[k])
|
|
_declarative_constructor.__name__ = '__init__'
|
|
|
|
|
|
def _undefer_column_name(key, column):
|
|
if column.key is None:
|
|
column.key = key
|
|
if column.name is None:
|
|
column.name = key
|