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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
48 import copy, etree
49 from urlparse import urljoin
50
51 try:
52 set
53 except NameError:
54 from sets import Set as set
55
56 XINCLUDE = "{http://www.w3.org/2001/XInclude}"
57
58 XINCLUDE_INCLUDE = XINCLUDE + "include"
59 XINCLUDE_FALLBACK = XINCLUDE + "fallback"
60
61 ##
62 # Fatal include error.
63
66
67 ##
68 # ET compatible default loader.
69 # This loader reads an included resource from disk.
70 #
71 # @param href Resource reference.
72 # @param parse Parse mode. Either "xml" or "text".
73 # @param encoding Optional text encoding.
74 # @return The expanded resource. If the parse mode is "xml", this
75 # is an ElementTree instance. If the parse mode is "text", this
76 # is a Unicode string. If the loader fails, it can return None
77 # or raise an IOError exception.
78 # @throws IOError If the loader fails to load the resource.
79
81 file = open(href)
82 if parse == "xml":
83 data = etree.parse(file).getroot()
84 else:
85 data = file.read()
86 if encoding:
87 data = data.decode(encoding)
88 file.close()
89 return data
90
91 ##
92 # Default loader used by lxml.etree - handles custom resolvers properly
93 #
94
96 if parse == "xml":
97 data = etree.parse(href, parser).getroot()
98 else:
99 data = open(href).read()
100 if encoding:
101 data = data.decode(encoding)
102 return data
103
104 ##
105 # Wrapper for ET compatibility - drops the parser
106
110 return load
111
112
113 ##
114 # Expand XInclude directives.
115 #
116 # @param elem Root element.
117 # @param loader Optional resource loader. If omitted, it defaults
118 # to {@link default_loader}. If given, it should be a callable
119 # that implements the same interface as <b>default_loader</b>.
120 # @throws FatalIncludeError If the function fails to include a given
121 # resource, or if the tree contains malformed XInclude elements.
122 # @throws IOError If the function fails to load a given resource.
123 # @returns the node or its replacement if it was an XInclude node
124
126 if hasattr(elem, 'getroot'):
127 tree = elem
128 elem = elem.getroot()
129 else:
130 tree = elem.getroottree()
131 if hasattr(tree, 'docinfo'):
132 base_url = tree.docinfo.URL
133 _include(elem, loader, base_url=base_url)
134
136 if loader is not None:
137 load_include = _wrap_et_loader(loader)
138 else:
139 load_include = _lxml_default_loader
140
141 if _parent_hrefs is None:
142 _parent_hrefs = set()
143
144 parser = elem.getroottree().parser
145
146 include_elements = list(
147 elem.getiterator('{http://www.w3.org/2001/XInclude}*'))
148
149 for e in include_elements:
150 if e.tag == XINCLUDE_INCLUDE:
151 # process xinclude directive
152 href = urljoin(base_url, e.get("href"))
153 parse = e.get("parse", "xml")
154 parent = e.getparent()
155 if parse == "xml":
156 if href in _parent_hrefs:
157 raise FatalIncludeError(
158 "recursive include of %r detected" % href
159 )
160 _parent_hrefs.add(href)
161 node = load_include(href, parse, parser=parser)
162 if node is None:
163 raise FatalIncludeError(
164 "cannot load %r as %r" % (href, parse)
165 )
166 node = _include(node, loader, _parent_hrefs)
167 if e.tail:
168 node.tail = (node.tail or "") + e.tail
169 if parent is None:
170 return node # replaced the root node!
171 parent.replace(e, node)
172 elif parse == "text":
173 text = load_include(href, parse, encoding=e.get("encoding"))
174 if text is None:
175 raise FatalIncludeError(
176 "cannot load %r as %r" % (href, parse)
177 )
178 predecessor = e.getprevious()
179 if predecessor is not None:
180 predecessor.tail = (predecessor.tail or "") + text
181 elif parent is None:
182 return text # replaced the root node!
183 else:
184 parent.text = (parent.text or "") + text + (e.tail or "")
185 parent.remove(e)
186 else:
187 raise FatalIncludeError(
188 "unknown parse type in xi:include tag (%r)" % parse
189 )
190 elif e.tag == XINCLUDE_FALLBACK:
191 parent = e.getparent()
192 if parent is not None and parent.tag != XINCLUDE_INCLUDE:
193 raise FatalIncludeError(
194 "xi:fallback tag must be child of xi:include (%r)" % e.tag
195 )
196 else:
197 raise FatalIncludeError(
198 "Invalid element found in XInclude namespace (%r)" % e.tag
199 )
200 return elem
201
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