_parse_attrs() - Code Metrics - Inspection of "refactor: rename some test classes" - ssato/python-anyconfig - Measure and Improve Code Quality continuously with Scrutinizer

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Push — master ( 11a6df...bffa60 )

by Satoru

created 2017-02-19 19:38 UTC

_parse_attrs() A

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#
# Copyright (C) 2011 - 2017 Satoru SATOH <ssato @ redhat.com>
# License: MIT
#
# Some XML modules may be missing and Base.{load,dumps}_impl are not overriden:
# pylint: disable=import-error, duplicate-except
"""XML files parser backend, should be available always.

- Format to support: XML, e.g. http://www.w3.org/TR/xml11/
- Requirements: one of the followings

  - xml.etree.cElementTree in standard lib if python >= 2.5
  - xml.etree.ElementTree in standard lib if python >= 2.5
  - elementtree.ElementTree (otherwise)

- Development Status: 3 - Alpha
- Limitations:

  - '<prefix>attrs', '<prefix>text' and '<prefix>children' are used as special
    parameter to keep XML structure of original data. You have to cusomize
    <prefix> (default: '@') if any config parameters conflict with some of
    them.

  - Some data or structures of original XML file may be lost if make it backed
    to XML file; XML file - (anyconfig.load) -> config - (anyconfig.dump) ->
    XML file

  - XML specific features (namespace, etc.) may not be processed correctly.

- Special Options:

  - tags: A dict provide special parameter names to distinguish between
    attributes, text and children nodes.

  - merge_attrs: Merge attributes and mix with children nodes. Please note that
    information of attributes are lost after loaded.

  - ac_parse_value: Try to parse values, elements' text and attributes.

History:

.. versionchanged:: 0.8.99

   - Add special options, tags, merge_attrs and ac_parse_value
   - Remove special option, pprefix which conflicts another option tags

.. versionchanged:: 0.8.0

   - Try to make a nested dict w/o extra dict having keys of attrs, text and
     children from XML string/file as much as possible.
   - Support namespaces partially.

.. versionchanged:: 0.1.0

   - Added XML dump support.
"""
from __future__ import absolute_import
from io import BytesIO

import operator
import re
try:
    import xml.etree.cElementTree as ET
except ImportError:
    import xml.etree.ElementTree as ET
except ImportError:
    import elementtree.ElementTree as ET

import anyconfig.backend.base
import anyconfig.compat
import anyconfig.mdicts
import anyconfig.utils
import anyconfig.parser


_TAGS = dict(attrs="@attrs", text="@text", children="@children")
_ET_NS_RE = re.compile(r"^{(\S+)}(\S+)$")


def _iterparse(xmlfile):
    """
    Avoid bug in python 3.{2,3}. See http://bugs.python.org/issue9257.

    :param xmlfile: XML file or file-like object
    """
    try:
        return ET.iterparse(xmlfile, events=("start-ns", ))
    except TypeError:
        return ET.iterparse(xmlfile, events=(b"start-ns", ))


def flip(tpl):
    """
    >>> flip((1, 2))
    (2, 1)
    """
    return (tpl[1], tpl[0])


def _namespaces_from_file(xmlfile):
    """
    :param xmlfile: XML file or file-like object
    :return: {namespace_uri: namespace_prefix} or {}
    """
    return dict(flip(t) for _, t in _iterparse(xmlfile))


def _tweak_ns(tag, nspaces=None, **options):
    """
    :param tag: XML tag element
    :param nspaces: A namespaces dict, {uri: prefix} or None
    :param options: Extra keyword options

    >>> _tweak_ns("a", {})
    'a'
    >>> _tweak_ns("a", {"http://example.com/ns/val/": "val"})
    'a'
    >>> _tweak_ns("{http://example.com/ns/val/}a",
    ...           {"http://example.com/ns/val/": "val"})
    'val:a'
    """
    if nspaces:
        matched = _ET_NS_RE.match(tag)
        if matched:
            (uri, tag) = matched.groups()
            prefix = nspaces.get(uri, False)
            if prefix:
                return "%s:%s" % (prefix, tag)

    return tag


def _dicts_have_unique_keys(dics):
    """
    :param dics: [<dict or dict-like object>], must not be [] or [{...}]
    :return: True if all keys of each dict of `dics` are unique

    # Enable the followings if to allow dics is [], [{...}]:
    # >>> all(_dicts_have_unique_keys([d]) for [d]
    # ...     in ({}, {'a': 0}, {'a': 1, 'b': 0}))
    # True
    # >>> _dicts_have_unique_keys([{}, {'a': 1}, {'b': 2, 'c': 0}])
    # True

    >>> _dicts_have_unique_keys([{}, {'a': 1}, {'a': 2}])
    False
    >>> _dicts_have_unique_keys([{}, {'a': 1}, {'b': 2}, {'b': 3, 'c': 0}])
    False
    >>> _dicts_have_unique_keys([{}, {}])
    True
    """
    key_itr = anyconfig.compat.from_iterable(d.keys() for d in dics)
    return len(set(key_itr)) == sum(len(d) for d in dics)


def _merge_dicts(dics, to_container=dict):
    """
    :param dics: [<dict/-like object must not have same keys each other>]
    :param to_container: callble to make a container object
    :return: <container> object

    >>> _merge_dicts(({}, ))
    {}
    >>> _merge_dicts(({'a': 1}, ))
    {'a': 1}
    >>> sorted(kv for kv in _merge_dicts(({'a': 1}, {'b': 2})).items())
    [('a', 1), ('b', 2)]
    """
    dic_itr = anyconfig.compat.from_iterable(d.items() for d in dics)
    return to_container(anyconfig.compat.OrderedDict(dic_itr))


def _parse_text(val, **options):
    """
    :return: Parsed value or value itself depends on `ac_parse_value`
    """
    if val and options.get("ac_parse_value", False):
        return anyconfig.parser.parse_single(val)
    else:
        return val


def _process_elem_text(elem, dic, subdic, text="@text", **options):
    """
    :param elem: ET Element object which has elem.text
    :param dic: <container> (dict[-like]) object converted from elem
    :param subdic: Sub <container> object converted from elem
    :param options:
        Keyword options, see the description of :func:`elem_to_container` for
        more details.

    :return: None but updating elem.text, dic and subdic as side effects
    """
    elem.text = elem.text.strip()
    if elem.text:
        etext = _parse_text(elem.text, **options)
        if len(elem) or elem.attrib:
            subdic[text] = etext
        else:
            dic[elem.tag] = etext  # Only text, e.g. <a>text</a>


def _parse_attrs(elem, to_container=dict, **options):
    """
    :param elem: ET Element object has attributes (elem.attrib)
    :param to_container: callble to make a container object
    :return: Parsed value or value itself depends on `ac_parse_value`
    """
    if options.get("ac_parse_value", False):
        return to_container(dict((k, anyconfig.parser.parse_single(v))
                                 for k, v in elem.attrib.items()))
    else:
        return to_container(elem.attrib)


def _process_elem_attrs(elem, dic, subdic, to_container=dict, attrs="@attrs",
                        **options):
    """
    :param elem: ET Element object or None
    :param dic: <container> (dict[-like]) object converted from elem
    :param subdic: Sub <container> object converted from elem
    :param options:
        Keyword options, see the description of :func:`elem_to_container` for
        more details.

    :return: None but updating dic and subdic as side effects
    """
    adic = _parse_attrs(elem, to_container=to_container, **options)
    if not elem.text and not len(elem) and options.get("merge_attrs"):
        dic[elem.tag] = adic
    else:
        subdic[attrs] = adic


def _process_children_elems(elem, dic, subdic, to_container=dict,
                            children="@children", **options):
    """
    :param elem: ET Element object or None
    :param dic: <container> (dict[-like]) object converted from elem
    :param subdic: Sub <container> object converted from elem
    :param to_container: callble to make a container object
    :param children: Tag for children nodes
    :param options:
        Keyword options, see the description of :func:`elem_to_container` for
        more details.

    :return: None but updating dic and subdic as side effects
    """
    cdics = [elem_to_container(c, to_container=to_container, **options)
             for c in elem]
    merge_attrs = options.get("merge_attrs", False)
    sdics = [to_container(elem.attrib) if merge_attrs else subdic] + cdics

    if _dicts_have_unique_keys(sdics):  # ex. <a><b>1</b><c>c</c></a>
        dic[elem.tag] = _merge_dicts(sdics, to_container)
    elif not subdic:  # There are no attrs nor text and only these children.
        dic[elem.tag] = cdics
    else:
        subdic[children] = cdics


def elem_to_container(elem, to_container=dict, **options):
    """
    Convert XML ElementTree Element to a collection of container objects.

    Elements are transformed to a node under special tagged nodes, attrs, text
    and children, to store the type of these elements basically, however, in
    some special cases like the followings, these nodes are attached to the
    parent node directly for later convenience.

    - There is only text element
    - There are only children elements each has unique keys among all

    :param elem: ET Element object or None
    :param to_container: callble to make a container object
    :param options: Keyword options

        - nspaces: A namespaces dict, {uri: prefix} or None
        - attrs, text, children: Tags for special nodes to keep XML info
        - merge_attrs: Merge attributes and mix with children nodes, and the
          information of attributes are lost after its transformation.
    """
    dic = to_container()
    if elem is None:
        return dic

    subdic = dic[_tweak_ns(elem.tag, **options)] = to_container()
    options["to_container"] = to_container

    if elem.text:
        _process_elem_text(elem, dic, subdic, **options)

    if elem.attrib:
        _process_elem_attrs(elem, dic, subdic, **options)

    if len(elem):
        _process_children_elems(elem, dic, subdic, **options)
    elif not elem.text and not elem.attrib:  # ex. <tag/>.
        dic[elem.tag] = None

    return dic


def _complement_tag_options(options):
    """
    :param options: Keyword options :: dict
    """
    if not all(nt in options for nt in _TAGS.keys()):
        tags = options.get("tags", {})
        for ntype, tag in _TAGS.items():
            options[ntype] = (tags if ntype in tags else _TAGS)[ntype]

    return options


def root_to_container(root, to_container=dict, nspaces=None, **options):
    """
    Convert XML ElementTree Root Element to a collection of container objects.

    :param root: etree root object or None
    :param to_container: callble to make a container object
    :param nspaces: A namespaces dict, {uri: prefix} or None
    :param options: Keyword options,

        - tags: Dict of tags for special nodes to keep XML info, attributes,
          text and children nodes, e.g. {"attrs": "@attrs", "text": "#text"}
    """
    tree = to_container()
    if root is None:
        return tree

    if nspaces:
        for uri, prefix in nspaces.items():
            root.attrib["xmlns:" + prefix if prefix else "xmlns"] = uri

    return elem_to_container(root, to_container=to_container, nspaces=nspaces,
                             **_complement_tag_options(options))


def _elem_from_descendants(children_nodes, **options):
    """
    :param children_nodes: A list of child dict objects
    :param options: Keyword options, see :func:`container_to_etree`
    """
    for child in children_nodes:  # child should be a dict-like object.
        for ckey, cval in anyconfig.compat.iteritems(child):
            celem = ET.Element(ckey)
            container_to_etree(cval, parent=celem, **options)
            yield celem


def _get_or_update_parent(key, val, parent=None, **options):
    """
    :param key: Key of current child (dict{,-like} object)
    :param val: Value of current child (dict{,-like} object or [dict{,...}])
    :param parent: XML ElementTree parent node object or None
    :param options: Keyword options, see :func:`container_to_etree`
    """
    elem = ET.Element(key)

    vals = val if anyconfig.utils.is_iterable(val) else [val]
    for val in vals:
        container_to_etree(val, parent=elem, **options)

    if parent is None:  # 'elem' is the top level etree.
        return elem
    else:
        parent.append(elem)
        return parent


_ATC = ("attrs", "text", "children")


def container_to_etree(obj, parent=None, **options):
    """
    Convert a dict-like object to XML ElementTree.

    :param obj: Container instance to convert to
    :param parent: XML ElementTree parent node object or None
    :param options: Keyword options,

        - tags: Dict of tags for special nodes to keep XML info, attributes,
          text and children nodes, e.g. {"attrs": "@attrs", "text": "#text"}
    """
    _str = str if options.get("ac_parse_value") else anyconfig.utils.noop

    if not anyconfig.mdicts.is_dict_like(obj):
        obj = False if obj is None else _str(obj)
        if parent is not None and obj:
            parent.text = obj  # Parent is a leaf text node.
        return  # All attributes and text should be set already.

    options = _complement_tag_options(options)
    (attrs, text, children) = operator.itemgetter(*_ATC)(options)

    for key, val in anyconfig.compat.iteritems(obj):
        if key == attrs:
            for attr, aval in anyconfig.compat.iteritems(val):
                parent.set(attr, _str(aval))
        elif key == text:
            parent.text = _str(val)
        elif key == children:
            for celem in _elem_from_descendants(val, **options):
                parent.append(celem)
        else:
            parent = _get_or_update_parent(key, val, parent=parent, **options)

    return ET.ElementTree(parent)


def etree_write(tree, stream):
    """
    Write XML ElementTree `root` content into `stream`.

    .. note:
       It seems that ET.ElementTree.write() cannot process a parameter
       'xml_declaration' in python 2.6.

    :param tree: XML ElementTree object
    :param stream: File or file-like object can write to
    """
    if anyconfig.compat.IS_PYTHON_2_6:
        tree.write(stream, encoding='UTF-8')
    else:
        tree.write(stream, encoding='UTF-8', xml_declaration=True)


class Parser(anyconfig.backend.base.ToStreamDumper):
    """
    Parser for XML files.
    """
    _type = "xml"
    _extensions = ["xml"]
    _open_flags = ('rb', 'wb')
    _load_opts = _dump_opts = ["tags", "merge_attrs", "ac_parse_value"]

    def load_from_string(self, content, to_container, **opts):
        """
        Load config from XML snippet (a string `content`).

        :param content:
            XML snippet string of str (python 2) or bytes (python 3) type
        :param to_container: callble to make a container object
        :param opts: optional keyword parameters passed to

        :return: Dict-like object holding config parameters
        """
        root = ET.fromstring(content)
        if anyconfig.compat.IS_PYTHON_3:
            stream = BytesIO(content)
        else:
            stream = anyconfig.compat.StringIO(content)
        nspaces = _namespaces_from_file(stream)
        return root_to_container(root, to_container=to_container,
                                 nspaces=nspaces, **opts)

    def load_from_path(self, filepath, to_container, **opts):
        """
        :param filepath: XML file path
        :param to_container: callble to make a container object
        :param opts: optional keyword parameters to be sanitized

        :return: Dict-like object holding config parameters
        """
        root = ET.parse(filepath).getroot()
        nspaces = _namespaces_from_file(filepath)
        return root_to_container(root, to_container=to_container,
                                 nspaces=nspaces, **opts)

    def load_from_stream(self, stream, to_container, **opts):
        """
        :param stream: XML file or file-like object
        :param to_container: callble to make a container object
        :param opts: optional keyword parameters to be sanitized

        :return: Dict-like object holding config parameters
        """
        root = ET.parse(stream).getroot()
        path = anyconfig.utils.get_path_from_stream(stream)
        nspaces = _namespaces_from_file(path)
        return root_to_container(root, to_container=to_container,
                                 nspaces=nspaces, **opts)

    def dump_to_string(self, cnf, **opts):
        """
        :param cnf: Configuration data to dump
        :param opts: optional keyword parameters

        :return: string represents the configuration
        """
        tree = container_to_etree(cnf, **opts)
        buf = BytesIO()
        etree_write(tree, buf)
        return buf.getvalue()

    def dump_to_stream(self, cnf, stream, **opts):
        """
        :param cnf: Configuration data to dump
        :param stream: Config file or file like object write to
        :param opts: optional keyword parameters
        """
        tree = container_to_etree(cnf, **opts)
        etree_write(tree, stream)

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


1			#
2			# Copyright (C) 2011 - 2017 Satoru SATOH <ssato @ redhat.com>
3			# License: MIT
4			#
5			# Some XML modules may be missing and Base.{load,dumps}_impl are not overriden:
6			# pylint: disable=import-error, duplicate-except
7			"""XML files parser backend, should be available always.
8
9			- Format to support: XML, e.g. http://www.w3.org/TR/xml11/
10			- Requirements: one of the followings
11
12			- xml.etree.cElementTree in standard lib if python >= 2.5
13			- xml.etree.ElementTree in standard lib if python >= 2.5
14			- elementtree.ElementTree (otherwise)
15
16			- Development Status: 3 - Alpha
17			- Limitations:
18
19			- '<prefix>attrs', '<prefix>text' and '<prefix>children' are used as special
20			parameter to keep XML structure of original data. You have to cusomize
21			<prefix> (default: '@') if any config parameters conflict with some of
22			them.
23
24			- Some data or structures of original XML file may be lost if make it backed
25			to XML file; XML file - (anyconfig.load) -> config - (anyconfig.dump) ->
26			XML file
27
28			- XML specific features (namespace, etc.) may not be processed correctly.
29
30			- Special Options:
31
32			- tags: A dict provide special parameter names to distinguish between
33			attributes, text and children nodes.
34
35			- merge_attrs: Merge attributes and mix with children nodes. Please note that
36			information of attributes are lost after loaded.
37
38			- ac_parse_value: Try to parse values, elements' text and attributes.
39
40			History:
41
42			.. versionchanged:: 0.8.99
43
44			- Add special options, tags, merge_attrs and ac_parse_value
45			- Remove special option, pprefix which conflicts another option tags
46
47			.. versionchanged:: 0.8.0
48
49			- Try to make a nested dict w/o extra dict having keys of attrs, text and
50			children from XML string/file as much as possible.
51			- Support namespaces partially.
52
53			.. versionchanged:: 0.1.0
54
55			- Added XML dump support.
56			"""
57			from __future__ import absolute_import
58			from io import BytesIO
59
60			import operator
61			import re
62			try:
63			import xml.etree.cElementTree as ET
64			except ImportError:
65			import xml.etree.ElementTree as ET
66			except ImportError:
67			import elementtree.ElementTree as ET
68
69			import anyconfig.backend.base
70			import anyconfig.compat
71			import anyconfig.mdicts
72			import anyconfig.utils
73			import anyconfig.parser
74
75
76			_TAGS = dict(attrs="@attrs", text="@text", children="@children")
77			_ET_NS_RE = re.compile(r"^{(\S+)}(\S+)$")
78
79
80			def _iterparse(xmlfile):
81			"""
82			Avoid bug in python 3.{2,3}. See http://bugs.python.org/issue9257.
83
84			:param xmlfile: XML file or file-like object
85			"""
86			try:
87			return ET.iterparse(xmlfile, events=("start-ns", ))
88			except TypeError:
89			return ET.iterparse(xmlfile, events=(b"start-ns", ))
90
91
92			def flip(tpl):
93			"""
94			>>> flip((1, 2))
95			(2, 1)
96			"""
97			return (tpl[1], tpl[0])
98
99
100			def _namespaces_from_file(xmlfile):
101			"""
102			:param xmlfile: XML file or file-like object
103			:return: {namespace_uri: namespace_prefix} or {}
104			"""
105			return dict(flip(t) for _, t in _iterparse(xmlfile))
106
107
108			def _tweak_ns(tag, nspaces=None, **options):
109			"""
110			:param tag: XML tag element
111			:param nspaces: A namespaces dict, {uri: prefix} or None
112			:param options: Extra keyword options
113
114			>>> _tweak_ns("a", {})
115			'a'
116			>>> _tweak_ns("a", {"http://example.com/ns/val/": "val"})
117			'a'
118			>>> _tweak_ns("{http://example.com/ns/val/}a",
119			... {"http://example.com/ns/val/": "val"})
120			'val:a'
121			"""
122			if nspaces:
123			matched = _ET_NS_RE.match(tag)
124			if matched:
125			(uri, tag) = matched.groups()
126			prefix = nspaces.get(uri, False)
127			if prefix:
128			return "%s:%s" % (prefix, tag)
129
130			return tag
131
132
133			def _dicts_have_unique_keys(dics):
134			"""
135			:param dics: [<dict or dict-like object>], must not be [] or [{...}]
136			:return: True if all keys of each dict of `dics` are unique
137
138			# Enable the followings if to allow dics is [], [{...}]:
139			# >>> all(_dicts_have_unique_keys([d]) for [d]
140			# ... in ({}, {'a': 0}, {'a': 1, 'b': 0}))
141			# True
142			# >>> _dicts_have_unique_keys([{}, {'a': 1}, {'b': 2, 'c': 0}])
143			# True
144
145			>>> _dicts_have_unique_keys([{}, {'a': 1}, {'a': 2}])
146			False
147			>>> _dicts_have_unique_keys([{}, {'a': 1}, {'b': 2}, {'b': 3, 'c': 0}])
148			False
149			>>> _dicts_have_unique_keys([{}, {}])
150			True
151			"""
152			key_itr = anyconfig.compat.from_iterable(d.keys() for d in dics)
153			return len(set(key_itr)) == sum(len(d) for d in dics)
154
155
156			def _merge_dicts(dics, to_container=dict):
157			"""
158			:param dics: [<dict/-like object must not have same keys each other>]
159			:param to_container: callble to make a container object
160			:return: <container> object
161
162			>>> _merge_dicts(({}, ))
163			{}
164			>>> _merge_dicts(({'a': 1}, ))
165			{'a': 1}
166			>>> sorted(kv for kv in _merge_dicts(({'a': 1}, {'b': 2})).items())
167			[('a', 1), ('b', 2)]
168			"""
169			dic_itr = anyconfig.compat.from_iterable(d.items() for d in dics)
170			return to_container(anyconfig.compat.OrderedDict(dic_itr))
171
172
173			def _parse_text(val, **options):
174			"""
175			:return: Parsed value or value itself depends on `ac_parse_value`
176			"""
177			if val and options.get("ac_parse_value", False):
178			return anyconfig.parser.parse_single(val)
179			else:
180			return val
181
182
183			def _process_elem_text(elem, dic, subdic, text="@text", **options):
184			"""
185			:param elem: ET Element object which has elem.text
186			:param dic: <container> (dict[-like]) object converted from elem
187			:param subdic: Sub <container> object converted from elem
188			:param options:
189			Keyword options, see the description of :func:`elem_to_container` for
190			more details.
191
192			:return: None but updating elem.text, dic and subdic as side effects
193			"""
194			elem.text = elem.text.strip()
195			if elem.text:
196			etext = _parse_text(elem.text, **options)
197			if len(elem) or elem.attrib:
198			subdic[text] = etext
199			else:
200			dic[elem.tag] = etext # Only text, e.g. <a>text</a>
201
202
203			def _parse_attrs(elem, to_container=dict, **options):
204			"""
205			:param elem: ET Element object has attributes (elem.attrib)
206			:param to_container: callble to make a container object
207			:return: Parsed value or value itself depends on `ac_parse_value`
208			"""
209			if options.get("ac_parse_value", False):
210			return to_container(dict((k, anyconfig.parser.parse_single(v))
211			for k, v in elem.attrib.items()))
212			else:
213			return to_container(elem.attrib)
214
215
216			def _process_elem_attrs(elem, dic, subdic, to_container=dict, attrs="@attrs",
217			**options):
218			"""
219			:param elem: ET Element object or None
220			:param dic: <container> (dict[-like]) object converted from elem
221			:param subdic: Sub <container> object converted from elem
222			:param options:
223			Keyword options, see the description of :func:`elem_to_container` for
224			more details.
225
226			:return: None but updating dic and subdic as side effects
227			"""
228			adic = _parse_attrs(elem, to_container=to_container, **options)
229			if not elem.text and not len(elem) and options.get("merge_attrs"):
230			dic[elem.tag] = adic
231			else:
232			subdic[attrs] = adic
233
234
235			def _process_children_elems(elem, dic, subdic, to_container=dict,
236			children="@children", **options):
237			"""
238			:param elem: ET Element object or None
239			:param dic: <container> (dict[-like]) object converted from elem
240			:param subdic: Sub <container> object converted from elem
241			:param to_container: callble to make a container object
242			:param children: Tag for children nodes
243			:param options:
244			Keyword options, see the description of :func:`elem_to_container` for
245			more details.
246
247			:return: None but updating dic and subdic as side effects
248			"""
249			cdics = [elem_to_container(c, to_container=to_container, **options)
250			for c in elem]
251			merge_attrs = options.get("merge_attrs", False)
252			sdics = [to_container(elem.attrib) if merge_attrs else subdic] + cdics
253
254			if _dicts_have_unique_keys(sdics): # ex. <a><b>1</b><c>c</c></a>
255			dic[elem.tag] = _merge_dicts(sdics, to_container)
256			elif not subdic: # There are no attrs nor text and only these children.
257			dic[elem.tag] = cdics
258			else:
259			subdic[children] = cdics
260
261
262			def elem_to_container(elem, to_container=dict, **options):
263			"""
264			Convert XML ElementTree Element to a collection of container objects.
265
266			Elements are transformed to a node under special tagged nodes, attrs, text
267			and children, to store the type of these elements basically, however, in
268			some special cases like the followings, these nodes are attached to the
269			parent node directly for later convenience.
270
271			- There is only text element
272			- There are only children elements each has unique keys among all
273
274			:param elem: ET Element object or None
275			:param to_container: callble to make a container object
276			:param options: Keyword options
277
278			- nspaces: A namespaces dict, {uri: prefix} or None
279			- attrs, text, children: Tags for special nodes to keep XML info
280			- merge_attrs: Merge attributes and mix with children nodes, and the
281			information of attributes are lost after its transformation.
282			"""
283			dic = to_container()
284			if elem is None:
285			return dic
286
287			subdic = dic[_tweak_ns(elem.tag, **options)] = to_container()
288			options["to_container"] = to_container
289
290			if elem.text:
291			_process_elem_text(elem, dic, subdic, **options)
292
293			if elem.attrib:
294			_process_elem_attrs(elem, dic, subdic, **options)
295
296			if len(elem):
297			_process_children_elems(elem, dic, subdic, **options)
298			elif not elem.text and not elem.attrib: # ex. <tag/>.
299			dic[elem.tag] = None
300
301			return dic
302
303
304			def _complement_tag_options(options):
305			"""
306			:param options: Keyword options :: dict
307			"""
308			if not all(nt in options for nt in _TAGS.keys()):
309			tags = options.get("tags", {})
310			for ntype, tag in _TAGS.items():
311			options[ntype] = (tags if ntype in tags else _TAGS)[ntype]
312
313			return options
314
315
316			def root_to_container(root, to_container=dict, nspaces=None, **options):
317			"""
318			Convert XML ElementTree Root Element to a collection of container objects.
319
320			:param root: etree root object or None
321			:param to_container: callble to make a container object
322			:param nspaces: A namespaces dict, {uri: prefix} or None
323			:param options: Keyword options,
324
325			- tags: Dict of tags for special nodes to keep XML info, attributes,
326			text and children nodes, e.g. {"attrs": "@attrs", "text": "#text"}
327			"""
328			tree = to_container()
329			if root is None:
330			return tree
331
332			if nspaces:
333			for uri, prefix in nspaces.items():
334			root.attrib["xmlns:" + prefix if prefix else "xmlns"] = uri
335
336			return elem_to_container(root, to_container=to_container, nspaces=nspaces,
337			**_complement_tag_options(options))
338
339
340			def _elem_from_descendants(children_nodes, **options):
341			"""
342			:param children_nodes: A list of child dict objects
343			:param options: Keyword options, see :func:`container_to_etree`
344			"""
345			for child in children_nodes: # child should be a dict-like object.
346			for ckey, cval in anyconfig.compat.iteritems(child):
347			celem = ET.Element(ckey)
348			container_to_etree(cval, parent=celem, **options)
349			yield celem
350
351
352			def _get_or_update_parent(key, val, parent=None, **options):
353			"""
354			:param key: Key of current child (dict{,-like} object)
355			:param val: Value of current child (dict{,-like} object or [dict{,...}])
356			:param parent: XML ElementTree parent node object or None
357			:param options: Keyword options, see :func:`container_to_etree`
358			"""
359			elem = ET.Element(key)
360
361			vals = val if anyconfig.utils.is_iterable(val) else [val]
362			for val in vals:
363			container_to_etree(val, parent=elem, **options)
364
365			if parent is None: # 'elem' is the top level etree.
366			return elem
367			else:
368			parent.append(elem)
369			return parent
370
371
372			_ATC = ("attrs", "text", "children")
373
374
375			def container_to_etree(obj, parent=None, **options):
376			"""
377			Convert a dict-like object to XML ElementTree.
378
379			:param obj: Container instance to convert to
380			:param parent: XML ElementTree parent node object or None
381			:param options: Keyword options,
382
383			- tags: Dict of tags for special nodes to keep XML info, attributes,
384			text and children nodes, e.g. {"attrs": "@attrs", "text": "#text"}
385			"""
386			_str = str if options.get("ac_parse_value") else anyconfig.utils.noop
387
388			if not anyconfig.mdicts.is_dict_like(obj):
389			obj = False if obj is None else _str(obj)
390			if parent is not None and obj:
391			parent.text = obj # Parent is a leaf text node.
392			return # All attributes and text should be set already.
393
394			options = _complement_tag_options(options)
395			(attrs, text, children) = operator.itemgetter(*_ATC)(options)
396
397			for key, val in anyconfig.compat.iteritems(obj):
398			if key == attrs:
399			for attr, aval in anyconfig.compat.iteritems(val):
400			parent.set(attr, _str(aval))
401			elif key == text:
402			parent.text = _str(val)
403			elif key == children:
404			for celem in _elem_from_descendants(val, **options):
405			parent.append(celem)
406			else:
407			parent = _get_or_update_parent(key, val, parent=parent, **options)
408
409			return ET.ElementTree(parent)
410
411
412			def etree_write(tree, stream):
413			"""
414			Write XML ElementTree `root` content into `stream`.
415
416			.. note:
417			It seems that ET.ElementTree.write() cannot process a parameter
418			'xml_declaration' in python 2.6.
419
420			:param tree: XML ElementTree object
421			:param stream: File or file-like object can write to
422			"""
423			if anyconfig.compat.IS_PYTHON_2_6:
424			tree.write(stream, encoding='UTF-8')
425			else:
426			tree.write(stream, encoding='UTF-8', xml_declaration=True)
427
428
429			class Parser(anyconfig.backend.base.ToStreamDumper):
430			"""
431			Parser for XML files.
432			"""
433			_type = "xml"
434			_extensions = ["xml"]
435			_open_flags = ('rb', 'wb')
436			_load_opts = _dump_opts = ["tags", "merge_attrs", "ac_parse_value"]
437
438			def load_from_string(self, content, to_container, **opts):
439			"""
440			Load config from XML snippet (a string `content`).
441
442			:param content:
443			XML snippet string of str (python 2) or bytes (python 3) type
444			:param to_container: callble to make a container object
445			:param opts: optional keyword parameters passed to
446
447			:return: Dict-like object holding config parameters
448			"""
449			root = ET.fromstring(content)
450			if anyconfig.compat.IS_PYTHON_3:
451			stream = BytesIO(content)
452			else:
453			stream = anyconfig.compat.StringIO(content)
454			nspaces = _namespaces_from_file(stream)
455			return root_to_container(root, to_container=to_container,
456			nspaces=nspaces, **opts)
457
458			def load_from_path(self, filepath, to_container, **opts):
459			"""
460			:param filepath: XML file path
461			:param to_container: callble to make a container object
462			:param opts: optional keyword parameters to be sanitized
463
464			:return: Dict-like object holding config parameters
465			"""
466			root = ET.parse(filepath).getroot()
467			nspaces = _namespaces_from_file(filepath)
468			return root_to_container(root, to_container=to_container,
469			nspaces=nspaces, **opts)
470
471			def load_from_stream(self, stream, to_container, **opts):
472			"""
473			:param stream: XML file or file-like object
474			:param to_container: callble to make a container object
475			:param opts: optional keyword parameters to be sanitized
476
477			:return: Dict-like object holding config parameters
478			"""
479			root = ET.parse(stream).getroot()
480			path = anyconfig.utils.get_path_from_stream(stream)
481			nspaces = _namespaces_from_file(path)
482			return root_to_container(root, to_container=to_container,
483			nspaces=nspaces, **opts)
484
485			def dump_to_string(self, cnf, **opts):
486			"""
487			:param cnf: Configuration data to dump
488			:param opts: optional keyword parameters
489
490			:return: string represents the configuration
491			"""
492			tree = container_to_etree(cnf, **opts)
493			buf = BytesIO()
494			etree_write(tree, buf)
495			return buf.getvalue()
496
497			def dump_to_stream(self, cnf, stream, **opts):
498			"""
499			:param cnf: Configuration data to dump
500			:param stream: Config file or file like object write to
501			:param opts: optional keyword parameters
502			"""
503			tree = container_to_etree(cnf, **opts)
504			etree_write(tree, stream)
505
506			# vim:sw=4:ts=4:et:
507

ssato / python-anyconfig

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