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1 #
2 # ElementTree
3 # $Id: ElementInclude.py 1862 2004-06-18 07:31:02Z Fredrik $
4 #
5 # limited xinclude support for element trees
6 #
7 # history:
8 # 2003-08-15 fl created
9 # 2003-11-14 fl fixed default loader
10 #
11 # Copyright (c) 2003-2004 by Fredrik Lundh. All rights reserved.
12 #
13 # fredrik@pythonware.com
14 # http://www.pythonware.com
15 #
16 # --------------------------------------------------------------------
17 # The ElementTree toolkit is
18 #
19 # Copyright (c) 1999-2004 by Fredrik Lundh
20 #
21 # By obtaining, using, and/or copying this software and/or its
22 # associated documentation, you agree that you have read, understood,
23 # and will comply with the following terms and conditions:
24 #
25 # Permission to use, copy, modify, and distribute this software and
26 # its associated documentation for any purpose and without fee is
27 # hereby granted, provided that the above copyright notice appears in
28 # all copies, and that both that copyright notice and this permission
29 # notice appear in supporting documentation, and that the name of
30 # Secret Labs AB or the author not be used in advertising or publicity
31 # pertaining to distribution of the software without specific, written
32 # prior permission.
33 #
34 # SECRET LABS AB AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD
35 # TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANT-
36 # ABILITY AND FITNESS. IN NO EVENT SHALL SECRET LABS AB OR THE AUTHOR
37 # BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY
38 # DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
39 # WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
40 # ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
41 # OF THIS SOFTWARE.
42 # --------------------------------------------------------------------
43
44 """
45 Limited XInclude support for the ElementTree package.
46
47 While lxml.etree has full support for XInclude (see
48 `etree.ElementTree.xinclude()`), this module provides a simpler, pure
49 Python, ElementTree compatible implementation that supports a simple
50 form of custom URL resolvers.
51 """
52
53 from lxml import etree
54 try:
55 from urlparse import urljoin
56 from urllib2 import urlopen
57 except ImportError:
58 # Python 3
59 from urllib.parse import urljoin
60 from urllib.request import urlopen
61
62 XINCLUDE = "{http://www.w3.org/2001/XInclude}"
63
64 XINCLUDE_INCLUDE = XINCLUDE + "include"
65 XINCLUDE_FALLBACK = XINCLUDE + "fallback"
66 XINCLUDE_ITER_TAG = XINCLUDE + "*"
67
68 ##
69 # Fatal include error.
70
73
74 ##
75 # ET compatible default loader.
76 # This loader reads an included resource from disk.
77 #
78 # @param href Resource reference.
79 # @param parse Parse mode. Either "xml" or "text".
80 # @param encoding Optional text encoding.
81 # @return The expanded resource. If the parse mode is "xml", this
82 # is an ElementTree instance. If the parse mode is "text", this
83 # is a Unicode string. If the loader fails, it can return None
84 # or raise an IOError exception.
85 # @throws IOError If the loader fails to load the resource.
86
88 file = open(href, 'rb')
89 if parse == "xml":
90 data = etree.parse(file).getroot()
91 else:
92 data = file.read()
93 if not encoding:
94 encoding = 'utf-8'
95 data = data.decode(encoding)
96 file.close()
97 return data
98
99 ##
100 # Default loader used by lxml.etree - handles custom resolvers properly
101 #
102
104 if parse == "xml":
105 data = etree.parse(href, parser).getroot()
106 else:
107 if "://" in href:
108 f = urlopen(href)
109 else:
110 f = open(href, 'rb')
111 data = f.read()
112 f.close()
113 if not encoding:
114 encoding = 'utf-8'
115 data = data.decode(encoding)
116 return data
117
118 ##
119 # Wrapper for ET compatibility - drops the parser
120
124 return load
125
126
127 ##
128 # Expand XInclude directives.
129 #
130 # @param elem Root element.
131 # @param loader Optional resource loader. If omitted, it defaults
132 # to {@link default_loader}. If given, it should be a callable
133 # that implements the same interface as <b>default_loader</b>.
134 # @throws FatalIncludeError If the function fails to include a given
135 # resource, or if the tree contains malformed XInclude elements.
136 # @throws IOError If the function fails to load a given resource.
137 # @returns the node or its replacement if it was an XInclude node
138
140 if base_url is None:
141 if hasattr(elem, 'getroot'):
142 tree = elem
143 elem = elem.getroot()
144 else:
145 tree = elem.getroottree()
146 if hasattr(tree, 'docinfo'):
147 base_url = tree.docinfo.URL
148 elif hasattr(elem, 'getroot'):
149 elem = elem.getroot()
150 _include(elem, loader, base_url=base_url)
151
153 if loader is not None:
154 load_include = _wrap_et_loader(loader)
155 else:
156 load_include = _lxml_default_loader
157
158 if _parent_hrefs is None:
159 _parent_hrefs = set()
160
161 parser = elem.getroottree().parser
162
163 include_elements = list(
164 elem.iter(XINCLUDE_ITER_TAG))
165
166 for e in include_elements:
167 if e.tag == XINCLUDE_INCLUDE:
168 # process xinclude directive
169 href = urljoin(base_url, e.get("href"))
170 parse = e.get("parse", "xml")
171 parent = e.getparent()
172 if parse == "xml":
173 if href in _parent_hrefs:
174 raise FatalIncludeError(
175 "recursive include of %r detected" % href
176 )
177 _parent_hrefs.add(href)
178 node = load_include(href, parse, parser=parser)
179 if node is None:
180 raise FatalIncludeError(
181 "cannot load %r as %r" % (href, parse)
182 )
183 node = _include(node, loader, _parent_hrefs)
184 if e.tail:
185 node.tail = (node.tail or "") + e.tail
186 if parent is None:
187 return node # replaced the root node!
188 parent.replace(e, node)
189 elif parse == "text":
190 text = load_include(href, parse, encoding=e.get("encoding"))
191 if text is None:
192 raise FatalIncludeError(
193 "cannot load %r as %r" % (href, parse)
194 )
195 predecessor = e.getprevious()
196 if predecessor is not None:
197 predecessor.tail = (predecessor.tail or "") + text
198 elif parent is None:
199 return text # replaced the root node!
200 else:
201 parent.text = (parent.text or "") + text + (e.tail or "")
202 parent.remove(e)
203 else:
204 raise FatalIncludeError(
205 "unknown parse type in xi:include tag (%r)" % parse
206 )
207 elif e.tag == XINCLUDE_FALLBACK:
208 parent = e.getparent()
209 if parent is not None and parent.tag != XINCLUDE_INCLUDE:
210 raise FatalIncludeError(
211 "xi:fallback tag must be child of xi:include (%r)" % e.tag
212 )
213 else:
214 raise FatalIncludeError(
215 "Invalid element found in XInclude namespace (%r)" % e.tag
216 )
217 return elem
218
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