|
|
- #
- # ElementTree
- # $Id: ElementInclude.py 1862 2004-06-18 07:31:02Z Fredrik $
- #
- # limited xinclude support for element trees
- #
- # history:
- # 2003-08-15 fl created
- # 2003-11-14 fl fixed default loader
- #
- # Copyright (c) 2003-2004 by Fredrik Lundh. All rights reserved.
- #
- # fredrik@pythonware.com
- # http://www.pythonware.com
- #
- # --------------------------------------------------------------------
- # The ElementTree toolkit is
- #
- # Copyright (c) 1999-2004 by Fredrik Lundh
- #
- # By obtaining, using, and/or copying this software and/or its
- # associated documentation, you agree that you have read, understood,
- # and will comply with the following terms and conditions:
- #
- # Permission to use, copy, modify, and distribute this software and
- # its associated documentation for any purpose and without fee is
- # hereby granted, provided that the above copyright notice appears in
- # all copies, and that both that copyright notice and this permission
- # notice appear in supporting documentation, and that the name of
- # Secret Labs AB or the author not be used in advertising or publicity
- # pertaining to distribution of the software without specific, written
- # prior permission.
- #
- # SECRET LABS AB AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD
- # TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANT-
- # ABILITY AND FITNESS. IN NO EVENT SHALL SECRET LABS AB OR THE AUTHOR
- # BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY
- # DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
- # WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
- # ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
- # OF THIS SOFTWARE.
- # --------------------------------------------------------------------
-
- """
- Limited XInclude support for the ElementTree package.
-
- While lxml.etree has full support for XInclude (see
- `etree.ElementTree.xinclude()`), this module provides a simpler, pure
- Python, ElementTree compatible implementation that supports a simple
- form of custom URL resolvers.
- """
-
- from lxml import etree
- try:
- from urlparse import urljoin
- from urllib2 import urlopen
- except ImportError:
- # Python 3
- from urllib.parse import urljoin
- from urllib.request import urlopen
-
- XINCLUDE = "{http://www.w3.org/2001/XInclude}"
-
- XINCLUDE_INCLUDE = XINCLUDE + "include"
- XINCLUDE_FALLBACK = XINCLUDE + "fallback"
- XINCLUDE_ITER_TAG = XINCLUDE + "*"
-
- ##
- # Fatal include error.
-
- class FatalIncludeError(etree.LxmlSyntaxError):
- pass
-
- ##
- # ET compatible default loader.
- # This loader reads an included resource from disk.
- #
- # @param href Resource reference.
- # @param parse Parse mode. Either "xml" or "text".
- # @param encoding Optional text encoding.
- # @return The expanded resource. If the parse mode is "xml", this
- # is an ElementTree instance. If the parse mode is "text", this
- # is a Unicode string. If the loader fails, it can return None
- # or raise an IOError exception.
- # @throws IOError If the loader fails to load the resource.
-
- def default_loader(href, parse, encoding=None):
- file = open(href, 'rb')
- if parse == "xml":
- data = etree.parse(file).getroot()
- else:
- data = file.read()
- if not encoding:
- encoding = 'utf-8'
- data = data.decode(encoding)
- file.close()
- return data
-
- ##
- # Default loader used by lxml.etree - handles custom resolvers properly
- #
-
- def _lxml_default_loader(href, parse, encoding=None, parser=None):
- if parse == "xml":
- data = etree.parse(href, parser).getroot()
- else:
- if "://" in href:
- f = urlopen(href)
- else:
- f = open(href, 'rb')
- data = f.read()
- f.close()
- if not encoding:
- encoding = 'utf-8'
- data = data.decode(encoding)
- return data
-
- ##
- # Wrapper for ET compatibility - drops the parser
-
- def _wrap_et_loader(loader):
- def load(href, parse, encoding=None, parser=None):
- return loader(href, parse, encoding)
- return load
-
-
- ##
- # Expand XInclude directives.
- #
- # @param elem Root element.
- # @param loader Optional resource loader. If omitted, it defaults
- # to {@link default_loader}. If given, it should be a callable
- # that implements the same interface as <b>default_loader</b>.
- # @param base_url The base URL of the original file, to resolve
- # relative include file references.
- # @throws FatalIncludeError If the function fails to include a given
- # resource, or if the tree contains malformed XInclude elements.
- # @throws IOError If the function fails to load a given resource.
- # @returns the node or its replacement if it was an XInclude node
-
- def include(elem, loader=None, base_url=None):
- if base_url is None:
- if hasattr(elem, 'getroot'):
- tree = elem
- elem = elem.getroot()
- else:
- tree = elem.getroottree()
- if hasattr(tree, 'docinfo'):
- base_url = tree.docinfo.URL
- elif hasattr(elem, 'getroot'):
- elem = elem.getroot()
- _include(elem, loader, base_url=base_url)
-
- def _include(elem, loader=None, _parent_hrefs=None, base_url=None):
- if loader is not None:
- load_include = _wrap_et_loader(loader)
- else:
- load_include = _lxml_default_loader
-
- if _parent_hrefs is None:
- _parent_hrefs = set()
-
- parser = elem.getroottree().parser
-
- include_elements = list(
- elem.iter(XINCLUDE_ITER_TAG))
-
- for e in include_elements:
- if e.tag == XINCLUDE_INCLUDE:
- # process xinclude directive
- href = urljoin(base_url, e.get("href"))
- parse = e.get("parse", "xml")
- parent = e.getparent()
- if parse == "xml":
- if href in _parent_hrefs:
- raise FatalIncludeError(
- "recursive include of %r detected" % href
- )
- _parent_hrefs.add(href)
- node = load_include(href, parse, parser=parser)
- if node is None:
- raise FatalIncludeError(
- "cannot load %r as %r" % (href, parse)
- )
- node = _include(node, loader, _parent_hrefs)
- if e.tail:
- node.tail = (node.tail or "") + e.tail
- if parent is None:
- return node # replaced the root node!
- parent.replace(e, node)
- elif parse == "text":
- text = load_include(href, parse, encoding=e.get("encoding"))
- if text is None:
- raise FatalIncludeError(
- "cannot load %r as %r" % (href, parse)
- )
- predecessor = e.getprevious()
- if predecessor is not None:
- predecessor.tail = (predecessor.tail or "") + text
- elif parent is None:
- return text # replaced the root node!
- else:
- parent.text = (parent.text or "") + text + (e.tail or "")
- parent.remove(e)
- else:
- raise FatalIncludeError(
- "unknown parse type in xi:include tag (%r)" % parse
- )
- elif e.tag == XINCLUDE_FALLBACK:
- parent = e.getparent()
- if parent is not None and parent.tag != XINCLUDE_INCLUDE:
- raise FatalIncludeError(
- "xi:fallback tag must be child of xi:include (%r)" % e.tag
- )
- else:
- raise FatalIncludeError(
- "Invalid element found in XInclude namespace (%r)" % e.tag
- )
- return elem
|