m9dicts.convert_to() - Code Metrics - Inspection of "refactor: consolidate common code to some utility..." - ssato/python-m9dicts - Measure and Improve Code Quality continuously with Scrutinizer

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by Satoru

created 2016-01-14 09:07 UTC

m9dicts.convert_to() B

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cc	5
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loc	32
rs	8.0896

#
# Copyright (C) 2011 - 2015 Red Hat, Inc.
# Copyright (C) 2011 - 2016 Satoru SATOH <ssato redhat.com>
# License: MIT
#
"""Functions operate on m9dicts objects.

.. versionchanged: 0.1.0

   - splitted / forked from python-anyconfig; old history was available in its
     mdict branch:
     https://github.com/ssato/python-anyconfig/blob/mdict/anyconfig/mergeabledict.py

"""
from __future__ import absolute_import

import collections
import functools
import operator
import re

import m9dicts.compat
import m9dicts.globals
import m9dicts.dicts
import m9dicts.utils


PATH_SEPS = ('/', '.')

_JSNP_GET_ARRAY_IDX_REG = re.compile(r"(?:0|[1-9][0-9]*)")
_JSNP_SET_ARRAY_IDX = re.compile(r"(?:0|[1-9][0-9]*|-)")


def _jsnp_unescape(jsn_s):
    """
    Parse and decode given encoded JSON Pointer expression, convert ~1 to
    / and ~0 to ~.

    .. note:: JSON Pointer: http://tools.ietf.org/html/rfc6901

    >>> _jsnp_unescape("/a~1b")
    '/a/b'
    >>> _jsnp_unescape("~1aaa~1~0bbb")
    '/aaa/~bbb'
    """
    return jsn_s.replace('~1', '/').replace('~0', '~')


def _split_path(path, seps=PATH_SEPS):
    """
    Parse path expression and return list of path items.

    :param path: Path expression may contain separator chars.
    :param seps: Separator char candidates.
    :return: A list of keys to fetch object[s] later.

    >>> assert _split_path('') == []
    >>> assert _split_path('/') == ['']  # JSON Pointer spec expects this.
    >>> for p in ('/a', '.a', 'a', 'a.'):
    ...     assert _split_path(p) == ['a'], p
    >>> assert _split_path('/a/b/c') == _split_path('a.b.c') == ['a', 'b', 'c']
    >>> assert _split_path('abc') == ['abc']
    """
    if not path:
        return []

    for sep in seps:
        if sep in path:
            if path == sep:  # Special case, '/' or '.' only.
                return ['']
            return [x for x in path.split(sep) if x]

    return [path]


def mk_nested_dic(path, val, seps=PATH_SEPS):
    """
    Make a nested dict iteratively.

    :param path: Path expression to make a nested dict
    :param val: Value to set
    :param seps: Separator char candidates

    >>> mk_nested_dic("a.b.c", 1)
    {'a': {'b': {'c': 1}}}
    >>> mk_nested_dic("/a/b/c", 1)
    {'a': {'b': {'c': 1}}}
    """
    ret = None
    for key in reversed(_split_path(path, seps)):
        ret = {key: val if ret is None else ret.copy()}

    return ret


def get(dic, path, seps=PATH_SEPS, idx_reg=_JSNP_GET_ARRAY_IDX_REG):
    """getter for nested dicts.

    :param dic: a dict[-like] object
    :param path: Path expression to point object wanted
    :param seps: Separator char candidates
    :return: A tuple of (result_object, error_message)

    >>> d = {'a': {'b': {'c': 0, 'd': [1, 2]}}, '': 3}
    >>> assert get(d, '/') == (3, '')  # key becomes '' (empty string).
    >>> assert get(d, "/a/b/c") == (0, '')
    >>> sorted(get(d, "a.b")[0].items())
    [('c', 0), ('d', [1, 2])]
    >>> (get(d, "a.b.d"), get(d, "/a/b/d/1"))
    (([1, 2], ''), (2, ''))
    >>> get(d, "a.b.key_not_exist")  # doctest: +ELLIPSIS
    (None, "'...'")
    >>> get(d, "/a/b/d/2")
    (None, 'list index out of range')
    >>> get(d, "/a/b/d/-")  # doctest: +ELLIPSIS
    (None, 'list indices must be integers...')
    """
    items = [_jsnp_unescape(p) for p in _split_path(path, seps)]
    if not items:
        return (dic, '')
    try:
        if len(items) == 1:
            return (dic[items[0]], '')

        prnt = functools.reduce(operator.getitem, items[:-1], dic)
        arr = m9dicts.utils.is_list_like(prnt) and idx_reg.match(items[-1])
        return (prnt[int(items[-1])], '') if arr else (prnt[items[-1]], '')

    except (TypeError, KeyError, IndexError) as exc:
        return (None, str(exc))


def set_(dic, path, val, seps=PATH_SEPS):
    """setter for nested dicts.

    :param dic: a dict[-like] object support recursive merge operations
    :param path: Path expression to point object wanted
    :param seps: Separator char candidates

    >>> d = dict(a=1, b=dict(c=2, ))
    >>> set_(d, 'a.b.d', 3)
    >>> d['a']['b']['d']
    3
    """
    dic.update(mk_nested_dic(path, val, seps))


def check_merge(merge):
    """Check if given `merge` is valid and ValueError will be raised if not.
    """
    if merge not in m9dicts.globals.MERGE_STRATEGIES:
        raise ValueError("Wrong merge strategy: %r" % merge)


def _make_from_namedtuple(obj, merge=m9dicts.globals.MS_DICTS,
                          _ntpl_cls_key=m9dicts.globals.NTPL_CLS_KEY,
                          **options):
    """
    :param obj: A namedtuple object
    :param merge:
        Specify strategy from MERGE_STRATEGIES of how to merge results loaded
        from multiple configuration files.
    :param _ntpl_cls_key:
        Special keyword to embedded the class name of namedtuple object to the
        MergeableDict object created. It's a hack and not elegant but I don't
        think there are another ways to make same namedtuple object from the
        MergeableDict object created from it.
    """
    ocls = m9dicts.dicts.get_mdict_class(merge=merge, ordered=True)
    mdict = ocls((k, make(getattr(obj, k), **options)) for k in obj._fields)
    mdict[_ntpl_cls_key] = obj.__class__.__name__

    return mdict


def _make_recur(obj, cls, make_fn, **options):
    """
    :param obj: An original mapping object
    :param cls: Another mapping class to make/convert to
    :param make_fn: Function to make/convert to
    """
    return cls((k, None if v is None else make_fn(v, **options))
               for k, v in obj.items())


def _make_iter(obj, make_fn, **options):
    """
    :param obj: An original mapping object
    :param make_fn: Function to make/convert to
    """
    return type(obj)(make_fn(v, **options) for v in obj)


def make(obj=None, ordered=False, merge=m9dicts.globals.MS_DICTS, **options):
    """
    Factory function to create a dict-like object[s] supports merge operation
    from a mapping or a list of mapping objects such as dict, [dict],
    namedtuple, [namedtuple].

    :param obj: A dict or other object[s] or None
    :param ordered:
        Choose the class keeps key order if True or `obj` is a namedtuple.
    :param merge: see :func:`_make_from_namedtuple` (above).
    :return: A dict-like object[s] supports merge operation or `obj` itself
    """
    check_merge(merge)
    cls = m9dicts.dicts.get_mdict_class(merge=merge, ordered=ordered)
    if obj is None:
        return cls()

    options.update(ordered=ordered, merge=merge)
    if m9dicts.utils.is_dict_like(obj):
        return _make_recur(obj, cls, make, **options)
    elif m9dicts.utils.is_namedtuple(obj):
        return _make_from_namedtuple(obj, **options)
    elif m9dicts.utils.is_list_like(obj):
        return _make_iter(obj, make, **options)
    else:
        return obj


def _convert_to_namedtuple(obj, _ntpl_cls_key=m9dicts.globals.NTPL_CLS_KEY,
                           **options):
    """Convert a dict-like object to a namedtuple.

    :param obj: A m9dicts objects or other primitive object
    :param _ntpl_cls_key: see :func:`_make_from_namedtuple`
    """
    _name = obj.get(_ntpl_cls_key, "NamedTuple")
    _keys = [k for k in obj.keys() if k != _ntpl_cls_key]
    _vals = [convert_to(obj[k], **options) for k in _keys]
    return collections.namedtuple(_name, _keys)(*_vals)


def convert_to(obj, ordered=False, to_namedtuple=False, **options):
    """
    Convert a dict-like object[s] support merge operation to a dict or
    namedtuple object recursively. Borrowed basic idea and implementation from
    bunch.unbunchify. (bunch is distributed under MIT license same as this.)

    .. note::
       - Given `obj` doesn't keep key order and if `to_namedtuple` is True,
         then the order of fields of result namedtuple object becomes random.
       - namedtuple object cannot have fields start with '_', So it'll fail if
         to convert dicts has such keys.

    :param obj: A m9dicts objects or other primitive object
    :param ordered: Create an OrderedDict instead of dict to keep the key order
    :param to_namedtuple: Convert `obj` to namedtuple instead of a dict
    :param options:
        Optional keyword arguments such as _ntpl_cls_key. see
        :func:`_make_from_namedtuple` for more its details.

    :return: A dict or namedtuple object if to_namedtuple is True
    """
    options.update(ordered=ordered, to_namedtuple=to_namedtuple)
    if m9dicts.utils.is_dict_like(obj):
        if to_namedtuple:
            return _convert_to_namedtuple(obj, **options)
        else:
            cls = m9dicts.compat.OrderedDict if ordered else dict
            return _make_recur(obj, cls, convert_to, **options)
    elif m9dicts.utils.is_list_like(obj):
        return _make_iter(obj, convert_to, **options)
    else:
        return obj

# vim:sw=4:ts=4:et:


1			#
2			# Copyright (C) 2011 - 2015 Red Hat, Inc.
3			# Copyright (C) 2011 - 2016 Satoru SATOH <ssato redhat.com>
4			# License: MIT
5			#
6			"""Functions operate on m9dicts objects.
7
8			.. versionchanged: 0.1.0
9
10			- splitted / forked from python-anyconfig; old history was available in its
11			mdict branch:
12			https://github.com/ssato/python-anyconfig/blob/mdict/anyconfig/mergeabledict.py
13
14			"""
15			from __future__ import absolute_import
16
17			import collections
18			import functools
19			import operator
20			import re
21
22			import m9dicts.compat
23			import m9dicts.globals
24			import m9dicts.dicts
25			import m9dicts.utils
26
27
28			PATH_SEPS = ('/', '.')
29
30			_JSNP_GET_ARRAY_IDX_REG = re.compile(r"(?:0\|[1-9][0-9]*)")
31			_JSNP_SET_ARRAY_IDX = re.compile(r"(?:0\|[1-9][0-9]*\|-)")
32
33
34			def _jsnp_unescape(jsn_s):
35			"""
36			Parse and decode given encoded JSON Pointer expression, convert ~1 to
37			/ and ~0 to ~.
38
39			.. note:: JSON Pointer: http://tools.ietf.org/html/rfc6901
40
41			>>> _jsnp_unescape("/a~1b")
42			'/a/b'
43			>>> _jsnp_unescape("~1aaa~1~0bbb")
44			'/aaa/~bbb'
45			"""
46			return jsn_s.replace('~1', '/').replace('~0', '~')
47
48
49			def _split_path(path, seps=PATH_SEPS):
50			"""
51			Parse path expression and return list of path items.
52
53			:param path: Path expression may contain separator chars.
54			:param seps: Separator char candidates.
55			:return: A list of keys to fetch object[s] later.
56
57			>>> assert _split_path('') == []
58			>>> assert _split_path('/') == [''] # JSON Pointer spec expects this.
59			>>> for p in ('/a', '.a', 'a', 'a.'):
60			... assert _split_path(p) == ['a'], p
61			>>> assert _split_path('/a/b/c') == _split_path('a.b.c') == ['a', 'b', 'c']
62			>>> assert _split_path('abc') == ['abc']
63			"""
64			if not path:
65			return []
66
67			for sep in seps:
68			if sep in path:
69			if path == sep: # Special case, '/' or '.' only.
70			return ['']
71			return [x for x in path.split(sep) if x]
72
73			return [path]
74
75
76			def mk_nested_dic(path, val, seps=PATH_SEPS):
77			"""
78			Make a nested dict iteratively.
79
80			:param path: Path expression to make a nested dict
81			:param val: Value to set
82			:param seps: Separator char candidates
83
84			>>> mk_nested_dic("a.b.c", 1)
85			{'a': {'b': {'c': 1}}}
86			>>> mk_nested_dic("/a/b/c", 1)
87			{'a': {'b': {'c': 1}}}
88			"""
89			ret = None
90			for key in reversed(_split_path(path, seps)):
91			ret = {key: val if ret is None else ret.copy()}
92
93			return ret
94
95
96			def get(dic, path, seps=PATH_SEPS, idx_reg=_JSNP_GET_ARRAY_IDX_REG):
97			"""getter for nested dicts.
98
99			:param dic: a dict[-like] object
100			:param path: Path expression to point object wanted
101			:param seps: Separator char candidates
102			:return: A tuple of (result_object, error_message)
103
104			>>> d = {'a': {'b': {'c': 0, 'd': [1, 2]}}, '': 3}
105			>>> assert get(d, '/') == (3, '') # key becomes '' (empty string).
106			>>> assert get(d, "/a/b/c") == (0, '')
107			>>> sorted(get(d, "a.b")[0].items())
108			[('c', 0), ('d', [1, 2])]
109			>>> (get(d, "a.b.d"), get(d, "/a/b/d/1"))
110			(([1, 2], ''), (2, ''))
111			>>> get(d, "a.b.key_not_exist") # doctest: +ELLIPSIS
112			(None, "'...'")
113			>>> get(d, "/a/b/d/2")
114			(None, 'list index out of range')
115			>>> get(d, "/a/b/d/-") # doctest: +ELLIPSIS
116			(None, 'list indices must be integers...')
117			"""
118			items = [_jsnp_unescape(p) for p in _split_path(path, seps)]
119			if not items:
120			return (dic, '')
121			try:
122			if len(items) == 1:
123			return (dic[items[0]], '')
124
125			prnt = functools.reduce(operator.getitem, items[:-1], dic)
126			arr = m9dicts.utils.is_list_like(prnt) and idx_reg.match(items[-1])
127			return (prnt[int(items[-1])], '') if arr else (prnt[items[-1]], '')
128
129			except (TypeError, KeyError, IndexError) as exc:
130			return (None, str(exc))
131
132
133			def set_(dic, path, val, seps=PATH_SEPS):
134			"""setter for nested dicts.
135
136			:param dic: a dict[-like] object support recursive merge operations
137			:param path: Path expression to point object wanted
138			:param seps: Separator char candidates
139
140			>>> d = dict(a=1, b=dict(c=2, ))
141			>>> set_(d, 'a.b.d', 3)
142			>>> d['a']['b']['d']
143			3
144			"""
145			dic.update(mk_nested_dic(path, val, seps))
146
147
148			def check_merge(merge):
149			"""Check if given `merge` is valid and ValueError will be raised if not.
150			"""
151			if merge not in m9dicts.globals.MERGE_STRATEGIES:
152			raise ValueError("Wrong merge strategy: %r" % merge)
153
154
155			def _make_from_namedtuple(obj, merge=m9dicts.globals.MS_DICTS,
156			_ntpl_cls_key=m9dicts.globals.NTPL_CLS_KEY,
157			**options):
158			"""
159			:param obj: A namedtuple object
160			:param merge:
161			Specify strategy from MERGE_STRATEGIES of how to merge results loaded
162			from multiple configuration files.
163			:param _ntpl_cls_key:
164			Special keyword to embedded the class name of namedtuple object to the
165			MergeableDict object created. It's a hack and not elegant but I don't
166			think there are another ways to make same namedtuple object from the
167			MergeableDict object created from it.
168			"""
169			ocls = m9dicts.dicts.get_mdict_class(merge=merge, ordered=True)
170			mdict = ocls((k, make(getattr(obj, k), **options)) for k in obj._fields)
171			mdict[_ntpl_cls_key] = obj.__class__.__name__
172
173			return mdict
174
175
176			def _make_recur(obj, cls, make_fn, **options):
177			"""
178			:param obj: An original mapping object
179			:param cls: Another mapping class to make/convert to
180			:param make_fn: Function to make/convert to
181			"""
182			return cls((k, None if v is None else make_fn(v, **options))
183			for k, v in obj.items())
184
185
186			def _make_iter(obj, make_fn, **options):
187			"""
188			:param obj: An original mapping object
189			:param make_fn: Function to make/convert to
190			"""
191			return type(obj)(make_fn(v, **options) for v in obj)
192
193
194			def make(obj=None, ordered=False, merge=m9dicts.globals.MS_DICTS, **options):
195			"""
196			Factory function to create a dict-like object[s] supports merge operation
197			from a mapping or a list of mapping objects such as dict, [dict],
198			namedtuple, [namedtuple].
199
200			:param obj: A dict or other object[s] or None
201			:param ordered:
202			Choose the class keeps key order if True or `obj` is a namedtuple.
203			:param merge: see :func:`_make_from_namedtuple` (above).
204			:return: A dict-like object[s] supports merge operation or `obj` itself
205			"""
206			check_merge(merge)
207			cls = m9dicts.dicts.get_mdict_class(merge=merge, ordered=ordered)
208			if obj is None:
209			return cls()
210
211			options.update(ordered=ordered, merge=merge)
212			if m9dicts.utils.is_dict_like(obj):
213			return _make_recur(obj, cls, make, **options)
214			elif m9dicts.utils.is_namedtuple(obj):
215			return _make_from_namedtuple(obj, **options)
216			elif m9dicts.utils.is_list_like(obj):
217			return _make_iter(obj, make, **options)
218			else:
219			return obj
220
221
222			def _convert_to_namedtuple(obj, _ntpl_cls_key=m9dicts.globals.NTPL_CLS_KEY,
223			**options):
224			"""Convert a dict-like object to a namedtuple.
225
226			:param obj: A m9dicts objects or other primitive object
227			:param _ntpl_cls_key: see :func:`_make_from_namedtuple`
228			"""
229			_name = obj.get(_ntpl_cls_key, "NamedTuple")
230			_keys = [k for k in obj.keys() if k != _ntpl_cls_key]
231			_vals = [convert_to(obj[k], **options) for k in _keys]
232			return collections.namedtuple(_name, _keys)(*_vals)
233
234
235			def convert_to(obj, ordered=False, to_namedtuple=False, **options):
236			"""
237			Convert a dict-like object[s] support merge operation to a dict or
238			namedtuple object recursively. Borrowed basic idea and implementation from
239			bunch.unbunchify. (bunch is distributed under MIT license same as this.)
240
241			.. note::
242			- Given `obj` doesn't keep key order and if `to_namedtuple` is True,
243			then the order of fields of result namedtuple object becomes random.
244			- namedtuple object cannot have fields start with '_', So it'll fail if
245			to convert dicts has such keys.
246
247			:param obj: A m9dicts objects or other primitive object
248			:param ordered: Create an OrderedDict instead of dict to keep the key order
249			:param to_namedtuple: Convert `obj` to namedtuple instead of a dict
250			:param options:
251			Optional keyword arguments such as _ntpl_cls_key. see
252			:func:`_make_from_namedtuple` for more its details.
253
254			:return: A dict or namedtuple object if to_namedtuple is True
255			"""
256			options.update(ordered=ordered, to_namedtuple=to_namedtuple)
257			if m9dicts.utils.is_dict_like(obj):
258			if to_namedtuple:
259			return _convert_to_namedtuple(obj, **options)
260			else:
261			cls = m9dicts.compat.OrderedDict if ordered else dict
262			return _make_recur(obj, cls, convert_to, **options)
263			elif m9dicts.utils.is_list_like(obj):
264			return _make_iter(obj, convert_to, **options)
265			else:
266			return obj
267
268			# vim:sw=4:ts=4:et:
269

ssato / python-m9dicts

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