from __future__ import absolute_import, division, print_function import copy from ._compat import iteritems from ._make import NOTHING, _obj_setattr, fields from .exceptions import AttrsAttributeNotFoundError def asdict( inst, recurse=True, filter=None, dict_factory=dict, retain_collection_types=False, ): """ Return the ``attrs`` attribute values of *inst* as a dict. Optionally recurse into other ``attrs``-decorated classes. :param inst: Instance of an ``attrs``-decorated class. :param bool recurse: Recurse into classes that are also ``attrs``-decorated. :param callable filter: A callable whose return code determines whether an attribute or element is included (``True``) or dropped (``False``). Is called with the :class:`attr.Attribute` as the first argument and the value as the second argument. :param callable dict_factory: A callable to produce dictionaries from. For example, to produce ordered dictionaries instead of normal Python dictionaries, pass in ``collections.OrderedDict``. :param bool retain_collection_types: Do not convert to ``list`` when encountering an attribute whose type is ``tuple`` or ``set``. Only meaningful if ``recurse`` is ``True``. :rtype: return type of *dict_factory* :raise attr.exceptions.NotAnAttrsClassError: If *cls* is not an ``attrs`` class. .. versionadded:: 16.0.0 *dict_factory* .. versionadded:: 16.1.0 *retain_collection_types* """ attrs = fields(inst.__class__) rv = dict_factory() for a in attrs: v = getattr(inst, a.name) if filter is not None and not filter(a, v): continue if recurse is True: if has(v.__class__): rv[a.name] = asdict( v, True, filter, dict_factory, retain_collection_types ) elif isinstance(v, (tuple, list, set)): cf = v.__class__ if retain_collection_types is True else list rv[a.name] = cf( [ _asdict_anything( i, filter, dict_factory, retain_collection_types ) for i in v ] ) elif isinstance(v, dict): df = dict_factory rv[a.name] = df( ( _asdict_anything( kk, filter, df, retain_collection_types ), _asdict_anything( vv, filter, df, retain_collection_types ), ) for kk, vv in iteritems(v) ) else: rv[a.name] = v else: rv[a.name] = v return rv def _asdict_anything(val, filter, dict_factory, retain_collection_types): """ ``asdict`` only works on attrs instances, this works on anything. """ if getattr(val.__class__, "__attrs_attrs__", None) is not None: # Attrs class. rv = asdict(val, True, filter, dict_factory, retain_collection_types) elif isinstance(val, (tuple, list, set)): cf = val.__class__ if retain_collection_types is True else list rv = cf( [ _asdict_anything( i, filter, dict_factory, retain_collection_types ) for i in val ] ) elif isinstance(val, dict): df = dict_factory rv = df( ( _asdict_anything(kk, filter, df, retain_collection_types), _asdict_anything(vv, filter, df, retain_collection_types), ) for kk, vv in iteritems(val) ) else: rv = val return rv def astuple( inst, recurse=True, filter=None, tuple_factory=tuple, retain_collection_types=False, ): """ Return the ``attrs`` attribute values of *inst* as a tuple. Optionally recurse into other ``attrs``-decorated classes. :param inst: Instance of an ``attrs``-decorated class. :param bool recurse: Recurse into classes that are also ``attrs``-decorated. :param callable filter: A callable whose return code determines whether an attribute or element is included (``True``) or dropped (``False``). Is called with the :class:`attr.Attribute` as the first argument and the value as the second argument. :param callable tuple_factory: A callable to produce tuples from. For example, to produce lists instead of tuples. :param bool retain_collection_types: Do not convert to ``list`` or ``dict`` when encountering an attribute which type is ``tuple``, ``dict`` or ``set``. Only meaningful if ``recurse`` is ``True``. :rtype: return type of *tuple_factory* :raise attr.exceptions.NotAnAttrsClassError: If *cls* is not an ``attrs`` class. .. versionadded:: 16.2.0 """ attrs = fields(inst.__class__) rv = [] retain = retain_collection_types # Very long. :/ for a in attrs: v = getattr(inst, a.name) if filter is not None and not filter(a, v): continue if recurse is True: if has(v.__class__): rv.append( astuple( v, recurse=True, filter=filter, tuple_factory=tuple_factory, retain_collection_types=retain, ) ) elif isinstance(v, (tuple, list, set)): cf = v.__class__ if retain is True else list rv.append( cf( [ astuple( j, recurse=True, filter=filter, tuple_factory=tuple_factory, retain_collection_types=retain, ) if has(j.__class__) else j for j in v ] ) ) elif isinstance(v, dict): df = v.__class__ if retain is True else dict rv.append( df( ( astuple( kk, tuple_factory=tuple_factory, retain_collection_types=retain, ) if has(kk.__class__) else kk, astuple( vv, tuple_factory=tuple_factory, retain_collection_types=retain, ) if has(vv.__class__) else vv, ) for kk, vv in iteritems(v) ) ) else: rv.append(v) else: rv.append(v) return rv if tuple_factory is list else tuple_factory(rv) def has(cls): """ Check whether *cls* is a class with ``attrs`` attributes. :param type cls: Class to introspect. :raise TypeError: If *cls* is not a class. :rtype: :class:`bool` """ return getattr(cls, "__attrs_attrs__", None) is not None def assoc(inst, **changes): """ Copy *inst* and apply *changes*. :param inst: Instance of a class with ``attrs`` attributes. :param changes: Keyword changes in the new copy. :return: A copy of inst with *changes* incorporated. :raise attr.exceptions.AttrsAttributeNotFoundError: If *attr_name* couldn't be found on *cls*. :raise attr.exceptions.NotAnAttrsClassError: If *cls* is not an ``attrs`` class. .. deprecated:: 17.1.0 Use :func:`evolve` instead. """ import warnings warnings.warn( "assoc is deprecated and will be removed after 2018/01.", DeprecationWarning, stacklevel=2, ) new = copy.copy(inst) attrs = fields(inst.__class__) for k, v in iteritems(changes): a = getattr(attrs, k, NOTHING) if a is NOTHING: raise AttrsAttributeNotFoundError( "{k} is not an attrs attribute on {cl}.".format( k=k, cl=new.__class__ ) ) _obj_setattr(new, k, v) return new def evolve(inst, **changes): """ Create a new instance, based on *inst* with *changes* applied. :param inst: Instance of a class with ``attrs`` attributes. :param changes: Keyword changes in the new copy. :return: A copy of inst with *changes* incorporated. :raise TypeError: If *attr_name* couldn't be found in the class ``__init__``. :raise attr.exceptions.NotAnAttrsClassError: If *cls* is not an ``attrs`` class. .. versionadded:: 17.1.0 """ cls = inst.__class__ attrs = fields(cls) for a in attrs: if not a.init: continue attr_name = a.name # To deal with private attributes. init_name = attr_name if attr_name[0] != "_" else attr_name[1:] if init_name not in changes: changes[init_name] = getattr(inst, attr_name) return cls(**changes)