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"""Lightweight XML support for Python.
XML is an inherently hierarchical data format, and the most natural way to
represent it is with a tree. This module has two classes for this purpose:
1. ElementTree represents the whole XML document as a tree and
2. Element represents a single node in this tree.
Interactions with the whole document (reading and writing to/from files) are
usually done on the ElementTree level. Interactions with a single XML element
and its sub-elements are done on the Element level.
Element is a flexible container object designed to store hierarchical data
structures in memory. It can be described as a cross between a list and a
dictionary. Each Element has a number of properties associated with it:
'tag' - a string containing the element's name.
'attributes' - a Python dictionary storing the element's attributes.
'text' - a string containing the element's text content.
'tail' - an optional string containing text after the element's end tag.
And a number of child elements stored in a Python sequence.
To create an element instance, use the Element constructor,
or the SubElement factory function.
You can also use the ElementTree class to wrap an element structure
and convert it to and from XML.
"""
#---------------------------------------------------------------------
# Licensed to PSF under a Contributor Agreement.
# See https://www.python.org/psf/license for licensing details.
#
# ElementTree
# Copyright (c) 1999-2008 by Fredrik Lundh. All rights reserved.
#
# fredrik@pythonware.com
# http://www.pythonware.com
# --------------------------------------------------------------------
# The ElementTree toolkit is
#
# Copyright (c) 1999-2008 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.
# --------------------------------------------------------------------
__all__ = [
# public symbols
"Comment",
"dump",
"Element", "ElementTree",
"fromstring", "fromstringlist",
"indent", "iselement", "iterparse",
"parse", "ParseError",
"PI", "ProcessingInstruction",
"QName",
"SubElement",
"tostring", "tostringlist",
"TreeBuilder",
"VERSION",
"XML", "XMLID",
"XMLParser", "XMLPullParser",
"register_namespace",
"canonicalize", "C14NWriterTarget",
]
VERSION = "1.3.0"
import sys
import re
import warnings
import io
import collections
import collections.abc
import contextlib
import weakref
from . import ElementPath
class ParseError(SyntaxError):
"""An error when parsing an XML document.
In addition to its exception value, a ParseError contains
two extra attributes:
'code' - the specific exception code
'position' - the line and column of the error
"""
pass
# --------------------------------------------------------------------
def iselement(element):
"""Return True if *element* appears to be an Element."""
return hasattr(element, 'tag')
class Element:
"""An XML element.
This class is the reference implementation of the Element interface.
An element's length is its number of subelements. That means if you
want to check if an element is truly empty, you should check BOTH
its length AND its text attribute.
The element tag, attribute names, and attribute values can be either
bytes or strings.
*tag* is the element name. *attrib* is an optional dictionary containing
element attributes. *extra* are additional element attributes given as
keyword arguments.
Example form:
<tag attrib>text<child/>...</tag>tail
"""
tag = None
"""The element's name."""
attrib = None
"""Dictionary of the element's attributes."""
text = None
"""
Text before first subelement. This is either a string or the value None.
Note that if there is no text, this attribute may be either
None or the empty string, depending on the parser.
"""
tail = None
"""
Text after this element's end tag, but before the next sibling element's
start tag. This is either a string or the value None. Note that if there
was no text, this attribute may be either None or an empty string,
depending on the parser.
"""
def __init__(self, tag, attrib={}, **extra):
if not isinstance(attrib, dict):
raise TypeError("attrib must be dict, not %s" % (
attrib.__class__.__name__,))
self.tag = tag
self.attrib = {**attrib, **extra}
self._children = []
def __repr__(self):
return "<%s %r at %#x>" % (self.__class__.__name__, self.tag, id(self))
def makeelement(self, tag, attrib):
"""Create a new element with the same type.
*tag* is a string containing the element name.
*attrib* is a dictionary containing the element attributes.
Do not call this method, use the SubElement factory function instead.
"""
return self.__class__(tag, attrib)
def copy(self):
"""Return copy of current element.
This creates a shallow copy. Subelements will be shared with the
original tree.
"""
warnings.warn(
"elem.copy() is deprecated. Use copy.copy(elem) instead.",
DeprecationWarning
)
return self.__copy__()
def __copy__(self):
elem = self.makeelement(self.tag, self.attrib)
elem.text = self.text
elem.tail = self.tail
elem[:] = self
return elem
def __len__(self):
return len(self._children)
def __bool__(self):
warnings.warn(
"The behavior of this method will change in future versions. "
"Use specific 'len(elem)' or 'elem is not None' test instead.",
FutureWarning, stacklevel=2
)
return len(self._children) != 0 # emulate old behaviour, for now
def __getitem__(self, index):
return self._children[index]
def __setitem__(self, index, element):
if isinstance(index, slice):
for elt in element:
self._assert_is_element(elt)
else:
self._assert_is_element(element)
self._children[index] = element
def __delitem__(self, index):
del self._children[index]
def append(self, subelement):
"""Add *subelement* to the end of this element.
The new element will appear in document order after the last existing
subelement (or directly after the text, if it's the first subelement),
but before the end tag for this element.
"""
self._assert_is_element(subelement)
self._children.append(subelement)
def extend(self, elements):
"""Append subelements from a sequence.
*elements* is a sequence with zero or more elements.
"""
for element in elements:
self._assert_is_element(element)
self._children.append(element)
def insert(self, index, subelement):
"""Insert *subelement* at position *index*."""
self._assert_is_element(subelement)
self._children.insert(index, subelement)
def _assert_is_element(self, e):
# Need to refer to the actual Python implementation, not the
# shadowing C implementation.
if not isinstance(e, _Element_Py):
raise TypeError('expected an Element, not %s' % type(e).__name__)
def remove(self, subelement):
"""Remove matching subelement.
Unlike the find methods, this method compares elements based on
identity, NOT ON tag value or contents. To remove subelements by
other means, the easiest way is to use a list comprehension to
select what elements to keep, and then use slice assignment to update
the parent element.
ValueError is raised if a matching element could not be found.
"""
# assert iselement(element)
self._children.remove(subelement)
def find(self, path, namespaces=None):
"""Find first matching element by tag name or path.
*path* is a string having either an element tag or an XPath,
*namespaces* is an optional mapping from namespace prefix to full name.
Return the first matching element, or None if no element was found.
"""
return ElementPath.find(self, path, namespaces)
def findtext(self, path, default=None, namespaces=None):
"""Find text for first matching element by tag name or path.
*path* is a string having either an element tag or an XPath,
*default* is the value to return if the element was not found,
*namespaces* is an optional mapping from namespace prefix to full name.
Return text content of first matching element, or default value if
none was found. Note that if an element is found having no text
content, the empty string is returned.
"""
return ElementPath.findtext(self, path, default, namespaces)
def findall(self, path, namespaces=None):
"""Find all matching subelements by tag name or path.
*path* is a string having either an element tag or an XPath,
*namespaces* is an optional mapping from namespace prefix to full name.
Returns list containing all matching elements in document order.
"""
return ElementPath.findall(self, path, namespaces)
def iterfind(self, path, namespaces=None):
"""Find all matching subelements by tag name or path.
*path* is a string having either an element tag or an XPath,
*namespaces* is an optional mapping from namespace prefix to full name.
Return an iterable yielding all matching elements in document order.
"""
return ElementPath.iterfind(self, path, namespaces)
def clear(self):
"""Reset element.
This function removes all subelements, clears all attributes, and sets
the text and tail attributes to None.
"""
self.attrib.clear()
self._children = []
self.text = self.tail = None
def get(self, key, default=None):
"""Get element attribute.
Equivalent to attrib.get, but some implementations may handle this a
bit more efficiently. *key* is what attribute to look for, and
*default* is what to return if the attribute was not found.
Returns a string containing the attribute value, or the default if
attribute was not found.
"""
return self.attrib.get(key, default)
def set(self, key, value):
"""Set element attribute.
Equivalent to attrib[key] = value, but some implementations may handle
this a bit more efficiently. *key* is what attribute to set, and
*value* is the attribute value to set it to.
"""
self.attrib[key] = value
def keys(self):
"""Get list of attribute names.
Names are returned in an arbitrary order, just like an ordinary
Python dict. Equivalent to attrib.keys()
"""
return self.attrib.keys()
def items(self):
"""Get element attributes as a sequence.
The attributes are returned in arbitrary order. Equivalent to
attrib.items().
Return a list of (name, value) tuples.
"""
return self.attrib.items()
def iter(self, tag=None):
"""Create tree iterator.
The iterator loops over the element and all subelements in document
order, returning all elements with a matching tag.
If the tree structure is modified during iteration, new or removed
elements may or may not be included. To get a stable set, use the
list() function on the iterator, and loop over the resulting list.
*tag* is what tags to look for (default is to return all elements)
Return an iterator containing all the matching elements.
"""
if tag == "*":
tag = None
if tag is None or self.tag == tag:
yield self
for e in self._children:
yield from e.iter(tag)
def itertext(self):
"""Create text iterator.
The iterator loops over the element and all subelements in document
order, returning all inner text.
"""
tag = self.tag
if not isinstance(tag, str) and tag is not None:
return
t = self.text
if t:
yield t
for e in self:
yield from e.itertext()
t = e.tail
if t:
yield t
def SubElement(parent, tag, attrib={}, **extra):
"""Subelement factory which creates an element instance, and appends it
to an existing parent.
The element tag, attribute names, and attribute values can be either
bytes or Unicode strings.
*parent* is the parent element, *tag* is the subelements name, *attrib* is
an optional directory containing element attributes, *extra* are
additional attributes given as keyword arguments.
"""
attrib = {**attrib, **extra}
element = parent.makeelement(tag, attrib)
parent.append(element)
return element
def Comment(text=None):
"""Comment element factory.
This function creates a special element which the standard serializer
serializes as an XML comment.
*text* is a string containing the comment string.
"""
element = Element(Comment)
element.text = text
return element
def ProcessingInstruction(target, text=None):
"""Processing Instruction element factory.
This function creates a special element which the standard serializer
serializes as an XML comment.
*target* is a string containing the processing instruction, *text* is a
string containing the processing instruction contents, if any.
"""
element = Element(ProcessingInstruction)
element.text = target
if text:
element.text = element.text + " " + text
return element
PI = ProcessingInstruction
class QName:
"""Qualified name wrapper.
This class can be used to wrap a QName attribute value in order to get
proper namespace handing on output.
*text_or_uri* is a string containing the QName value either in the form
{uri}local, or if the tag argument is given, the URI part of a QName.
*tag* is an optional argument which if given, will make the first
argument (text_or_uri) be interpreted as a URI, and this argument (tag)
be interpreted as a local name.
"""
def __init__(self, text_or_uri, tag=None):
if tag:
text_or_uri = "{%s}%s" % (text_or_uri, tag)
self.text = text_or_uri
def __str__(self):
return self.text
def __repr__(self):
return '<%s %r>' % (self.__class__.__name__, self.text)
def __hash__(self):
return hash(self.text)
def __le__(self, other):
if isinstance(other, QName):
return self.text <= other.text
return self.text <= other
def __lt__(self, other):
if isinstance(other, QName):
return self.text < other.text
return self.text < other
def __ge__(self, other):
if isinstance(other, QName):
return self.text >= other.text
return self.text >= other
def __gt__(self, other):
if isinstance(other, QName):
return self.text > other.text
return self.text > other
def __eq__(self, other):
if isinstance(other, QName):
return self.text == other.text
return self.text == other
# --------------------------------------------------------------------
class ElementTree:
"""An XML element hierarchy.
This class also provides support for serialization to and from
standard XML.
*element* is an optional root element node,
*file* is an optional file handle or file name of an XML file whose
contents will be used to initialize the tree with.
"""
def __init__(self, element=None, file=None):
# assert element is None or iselement(element)
self._root = element # first node
if file:
self.parse(file)
def getroot(self):
"""Return root element of this tree."""
return self._root
def _setroot(self, element):
"""Replace root element of this tree.
This will discard the current contents of the tree and replace it
with the given element. Use with care!
"""
# assert iselement(element)
self._root = element
def parse(self, source, parser=None):
"""Load external XML document into element tree.
*source* is a file name or file object, *parser* is an optional parser
instance that defaults to XMLParser.
ParseError is raised if the parser fails to parse the document.
Returns the root element of the given source document.
"""
close_source = False
if not hasattr(source, "read"):
source = open(source, "rb")
close_source = True
try:
if parser is None:
# If no parser was specified, create a default XMLParser
parser = XMLParser()
if hasattr(parser, '_parse_whole'):
# The default XMLParser, when it comes from an accelerator,
# can define an internal _parse_whole API for efficiency.
# It can be used to parse the whole source without feeding
# it with chunks.
self._root = parser._parse_whole(source)
return self._root
while True:
data = source.read(65536)
if not data:
break
parser.feed(data)
self._root = parser.close()
return self._root
finally:
if close_source:
source.close()
def iter(self, tag=None):
"""Create and return tree iterator for the root element.
The iterator loops over all elements in this tree, in document order.
*tag* is a string with the tag name to iterate over
(default is to return all elements).
"""
# assert self._root is not None
return self._root.iter(tag)
def find(self, path, namespaces=None):
"""Find first matching element by tag name or path.
Same as getroot().find(path), which is Element.find()
*path* is a string having either an element tag or an XPath,
*namespaces* is an optional mapping from namespace prefix to full name.
Return the first matching element, or None if no element was found.
"""
# assert self._root is not None
if path[:1] == "/":
path = "." + path
warnings.warn(
"This search is broken in 1.3 and earlier, and will be "
"fixed in a future version. If you rely on the current "
"behaviour, change it to %r" % path,
FutureWarning, stacklevel=2
)
return self._root.find(path, namespaces)
def findtext(self, path, default=None, namespaces=None):
"""Find first matching element by tag name or path.
Same as getroot().findtext(path), which is Element.findtext()
*path* is a string having either an element tag or an XPath,
*namespaces* is an optional mapping from namespace prefix to full name.
Return the first matching element, or None if no element was found.
"""
# assert self._root is not None
if path[:1] == "/":
path = "." + path
warnings.warn(
"This search is broken in 1.3 and earlier, and will be "
"fixed in a future version. If you rely on the current "
"behaviour, change it to %r" % path,
FutureWarning, stacklevel=2
)
return self._root.findtext(path, default, namespaces)
def findall(self, path, namespaces=None):
"""Find all matching subelements by tag name or path.
Same as getroot().findall(path), which is Element.findall().
*path* is a string having either an element tag or an XPath,
*namespaces* is an optional mapping from namespace prefix to full name.
Return list containing all matching elements in document order.
"""
# assert self._root is not None
if path[:1] == "/":
path = "." + path
warnings.warn(
"This search is broken in 1.3 and earlier, and will be "
"fixed in a future version. If you rely on the current "
"behaviour, change it to %r" % path,
FutureWarning, stacklevel=2
)
return self._root.findall(path, namespaces)
def iterfind(self, path, namespaces=None):
"""Find all matching subelements by tag name or path.
Same as getroot().iterfind(path), which is element.iterfind()
*path* is a string having either an element tag or an XPath,
*namespaces* is an optional mapping from namespace prefix to full name.
Return an iterable yielding all matching elements in document order.
"""
# assert self._root is not None
if path[:1] == "/":
path = "." + path
warnings.warn(
"This search is broken in 1.3 and earlier, and will be "
"fixed in a future version. If you rely on the current "
"behaviour, change it to %r" % path,
FutureWarning, stacklevel=2
)
return self._root.iterfind(path, namespaces)
def write(self, file_or_filename,
encoding=None,
xml_declaration=None,
default_namespace=None,
method=None, *,
short_empty_elements=True):
"""Write element tree to a file as XML.
Arguments:
*file_or_filename* -- file name or a file object opened for writing
*encoding* -- the output encoding (default: US-ASCII)
*xml_declaration* -- bool indicating if an XML declaration should be
added to the output. If None, an XML declaration
is added if encoding IS NOT either of:
US-ASCII, UTF-8, or Unicode
*default_namespace* -- sets the default XML namespace (for "xmlns")
*method* -- either "xml" (default), "html, "text", or "c14n"
*short_empty_elements* -- controls the formatting of elements
that contain no content. If True (default)
they are emitted as a single self-closed
tag, otherwise they are emitted as a pair
of start/end tags
"""
if not method:
method = "xml"
elif method not in _serialize:
raise ValueError("unknown method %r" % method)
if not encoding:
if method == "c14n":
encoding = "utf-8"
else:
encoding = "us-ascii"
with _get_writer(file_or_filename, encoding) as (write, declared_encoding):
if method == "xml" and (xml_declaration or
(xml_declaration is None and
encoding.lower() != "unicode" and
declared_encoding.lower() not in ("utf-8", "us-ascii"))):
write("<?xml version='1.0' encoding='%s'?>\n" % (
declared_encoding,))
if method == "text":
_serialize_text(write, self._root)
else:
qnames, namespaces = _namespaces(self._root, default_namespace)
serialize = _serialize[method]
serialize(write, self._root, qnames, namespaces,
short_empty_elements=short_empty_elements)
def write_c14n(self, file):
# lxml.etree compatibility. use output method instead
return self.write(file, method="c14n")
# --------------------------------------------------------------------
# serialization support
@contextlib.contextmanager
def _get_writer(file_or_filename, encoding):
# returns text write method and release all resources after using
try:
write = file_or_filename.write
except AttributeError:
# file_or_filename is a file name
if encoding.lower() == "unicode":
encoding="utf-8"
with open(file_or_filename, "w", encoding=encoding,
errors="xmlcharrefreplace") as file:
yield file.write, encoding
else:
# file_or_filename is a file-like object
# encoding determines if it is a text or binary writer
if encoding.lower() == "unicode":
# use a text writer as is
yield write, getattr(file_or_filename, "encoding", None) or "utf-8"
else:
# wrap a binary writer with TextIOWrapper
with contextlib.ExitStack() as stack:
if isinstance(file_or_filename, io.BufferedIOBase):
file = file_or_filename
elif isinstance(file_or_filename, io.RawIOBase):
file = io.BufferedWriter(file_or_filename)
# Keep the original file open when the BufferedWriter is
# destroyed
stack.callback(file.detach)
else:
# This is to handle passed objects that aren't in the
# IOBase hierarchy, but just have a write method
file = io.BufferedIOBase()
file.writable = lambda: True
file.write = write
try:
# TextIOWrapper uses this methods to determine
# if BOM (for UTF-16, etc) should be added
file.seekable = file_or_filename.seekable
file.tell = file_or_filename.tell
except AttributeError:
pass
file = io.TextIOWrapper(file,
encoding=encoding,
errors="xmlcharrefreplace",
newline="\n")
# Keep the original file open when the TextIOWrapper is
# destroyed
stack.callback(file.detach)
yield file.write, encoding
def _namespaces(elem, default_namespace=None):
# identify namespaces used in this tree
# maps qnames to *encoded* prefix:local names
qnames = {None: None}
# maps uri:s to prefixes
namespaces = {}
if default_namespace:
namespaces[default_namespace] = ""
def add_qname(qname):
# calculate serialized qname representation
try:
if qname[:1] == "{":
uri, tag = qname[1:].rsplit("}", 1)
prefix = namespaces.get(uri)
if prefix is None:
prefix = _namespace_map.get(uri)
if prefix is None:
prefix = "ns%d" % len(namespaces)
if prefix != "xml":
namespaces[uri] = prefix
if prefix:
qnames[qname] = "%s:%s" % (prefix, tag)
else:
qnames[qname] = tag # default element
else:
if default_namespace:
# FIXME: can this be handled in XML 1.0?
raise ValueError(
"cannot use non-qualified names with "
"default_namespace option"
)
qnames[qname] = qname
except TypeError:
_raise_serialization_error(qname)
# populate qname and namespaces table
for elem in elem.iter():
tag = elem.tag
if isinstance(tag, QName):
if tag.text not in qnames:
add_qname(tag.text)
elif isinstance(tag, str):
if tag not in qnames:
add_qname(tag)
elif tag is not None and tag is not Comment and tag is not PI:
_raise_serialization_error(tag)
for key, value in elem.items():
if isinstance(key, QName):
key = key.text
if key not in qnames:
add_qname(key)
if isinstance(value, QName) and value.text not in qnames:
add_qname(value.text)
text = elem.text
if isinstance(text, QName) and text.text not in qnames:
add_qname(text.text)
return qnames, namespaces
def _serialize_xml(write, elem, qnames, namespaces,
short_empty_elements, **kwargs):
tag = elem.tag
text = elem.text
if tag is Comment:
write("<!--%s-->" % text)
elif tag is ProcessingInstruction:
write("<?%s?>" % text)
else:
tag = qnames[tag]
if tag is None:
if text:
write(_escape_cdata(text))
for e in elem:
_serialize_xml(write, e, qnames, None,
short_empty_elements=short_empty_elements)
else:
write("<" + tag)
items = list(elem.items())
if items or namespaces:
if namespaces:
for v, k in sorted(namespaces.items(),
key=lambda x: x[1]): # sort on prefix
if k:
k = ":" + k
write(" xmlns%s=\"%s\"" % (
k,
_escape_attrib(v)
))
for k, v in items:
if isinstance(k, QName):
k = k.text
if isinstance(v, QName):
v = qnames[v.text]
else:
v = _escape_attrib(v)
write(" %s=\"%s\"" % (qnames[k], v))
if text or len(elem) or not short_empty_elements:
write(">")
if text:
write(_escape_cdata(text))
for e in elem:
_serialize_xml(write, e, qnames, None,
short_empty_elements=short_empty_elements)
write("</" + tag + ">")
else:
write(" />")
if elem.tail:
write(_escape_cdata(elem.tail))
HTML_EMPTY = {"area", "base", "basefont", "br", "col", "embed", "frame", "hr",
"img", "input", "isindex", "link", "meta", "param", "source",
"track", "wbr"}
def _serialize_html(write, elem, qnames, namespaces, **kwargs):
tag = elem.tag
text = elem.text
if tag is Comment:
write("<!--%s-->" % _escape_cdata(text))
elif tag is ProcessingInstruction:
write("<?%s?>" % _escape_cdata(text))
else:
tag = qnames[tag]
if tag is None:
if text:
write(_escape_cdata(text))
for e in elem:
_serialize_html(write, e, qnames, None)
else:
write("<" + tag)
items = list(elem.items())
if items or namespaces:
if namespaces:
for v, k in sorted(namespaces.items(),
key=lambda x: x[1]): # sort on prefix
if k:
k = ":" + k
write(" xmlns%s=\"%s\"" % (
k,
_escape_attrib(v)
))
for k, v in items:
if isinstance(k, QName):
k = k.text
if isinstance(v, QName):
v = qnames[v.text]
else:
v = _escape_attrib_html(v)
# FIXME: handle boolean attributes
write(" %s=\"%s\"" % (qnames[k], v))
write(">")
ltag = tag.lower()
if text:
if ltag == "script" or ltag == "style":
write(text)
else:
write(_escape_cdata(text))
for e in elem:
_serialize_html(write, e, qnames, None)
if ltag not in HTML_EMPTY:
write("</" + tag + ">")
if elem.tail:
write(_escape_cdata(elem.tail))
def _serialize_text(write, elem):
for part in elem.itertext():
write(part)
if elem.tail:
write(elem.tail)
_serialize = {
"xml": _serialize_xml,
"html": _serialize_html,
"text": _serialize_text,
# this optional method is imported at the end of the module
# "c14n": _serialize_c14n,
}
def register_namespace(prefix, uri):
"""Register a namespace prefix.
The registry is global, and any existing mapping for either the
given prefix or the namespace URI will be removed.
*prefix* is the namespace prefix, *uri* is a namespace uri. Tags and
attributes in this namespace will be serialized with prefix if possible.
ValueError is raised if prefix is reserved or is invalid.
"""
if re.match(r"ns\d+$", prefix):
raise ValueError("Prefix format reserved for internal use")
for k, v in list(_namespace_map.items()):
if k == uri or v == prefix:
del _namespace_map[k]
_namespace_map[uri] = prefix
_namespace_map = {
# "well-known" namespace prefixes
"http://www.w3.org/XML/1998/namespace": "xml",
"http://www.w3.org/1999/xhtml": "html",
"http://www.w3.org/1999/02/22-rdf-syntax-ns#": "rdf",
"http://schemas.xmlsoap.org/wsdl/": "wsdl",
# xml schema
"http://www.w3.org/2001/XMLSchema": "xs",
"http://www.w3.org/2001/XMLSchema-instance": "xsi",
# dublin core
"http://purl.org/dc/elements/1.1/": "dc",
}
# For tests and troubleshooting
register_namespace._namespace_map = _namespace_map
def _raise_serialization_error(text):
raise TypeError(
"cannot serialize %r (type %s)" % (text, type(text).__name__)
)
def _escape_cdata(text):
# escape character data
try:
# it's worth avoiding do-nothing calls for strings that are
# shorter than 500 characters, or so. assume that's, by far,
# the most common case in most applications.
if "&" in text:
text = text.replace("&", "&")
if "<" in text:
text = text.replace("<", "<")
if ">" in text:
text = text.replace(">", ">")
return text
except (TypeError, AttributeError):
_raise_serialization_error(text)
def _escape_attrib(text):
# escape attribute value
try:
if "&" in text:
text = text.replace("&", "&")
if "<" in text:
text = text.replace("<", "<")
if ">" in text:
text = text.replace(">", ">")
if "\"" in text:
text = text.replace("\"", """)
# Although section 2.11 of the XML specification states that CR or
# CR LN should be replaced with just LN, it applies only to EOLNs
# which take part of organizing file into lines. Within attributes,
# we are replacing these with entity numbers, so they do not count.
# http://www.w3.org/TR/REC-xml/#sec-line-ends
# The current solution, contained in following six lines, was
# discussed in issue 17582 and 39011.
if "\r" in text:
text = text.replace("\r", " ")
if "\n" in text:
text = text.replace("\n", " ")
if "\t" in text:
text = text.replace("\t", "	")
return text
except (TypeError, AttributeError):
_raise_serialization_error(text)
def _escape_attrib_html(text):
# escape attribute value
try:
if "&" in text:
text = text.replace("&", "&")
if ">" in text:
text = text.replace(">", ">")
if "\"" in text:
text = text.replace("\"", """)
return text
except (TypeError, AttributeError):
_raise_serialization_error(text)
# --------------------------------------------------------------------
def tostring(element, encoding=None, method=None, *,
xml_declaration=None, default_namespace=None,
short_empty_elements=True):
"""Generate string representation of XML element.
All subelements are included. If encoding is "unicode", a string
is returned. Otherwise a bytestring is returned.
*element* is an Element instance, *encoding* is an optional output
encoding defaulting to US-ASCII, *method* is an optional output which can
be one of "xml" (default), "html", "text" or "c14n", *default_namespace*
sets the default XML namespace (for "xmlns").
Returns an (optionally) encoded string containing the XML data.
"""
stream = io.StringIO() if encoding == 'unicode' else io.BytesIO()
ElementTree(element).write(stream, encoding,
xml_declaration=xml_declaration,
default_namespace=default_namespace,
method=method,
short_empty_elements=short_empty_elements)
return stream.getvalue()
class _ListDataStream(io.BufferedIOBase):
"""An auxiliary stream accumulating into a list reference."""
def __init__(self, lst):
self.lst = lst
def writable(self):
return True
def seekable(self):
return True
def write(self, b):
self.lst.append(b)
def tell(self):
return len(self.lst)
def tostringlist(element, encoding=None, method=None, *,
xml_declaration=None, default_namespace=None,
short_empty_elements=True):
lst = []
stream = _ListDataStream(lst)
ElementTree(element).write(stream, encoding,
xml_declaration=xml_declaration,
default_namespace=default_namespace,
method=method,
short_empty_elements=short_empty_elements)
return lst
def dump(elem):
"""Write element tree or element structure to sys.stdout.
This function should be used for debugging only.
*elem* is either an ElementTree, or a single Element. The exact output
format is implementation dependent. In this version, it's written as an
ordinary XML file.
"""
# debugging
if not isinstance(elem, ElementTree):
elem = ElementTree(elem)
elem.write(sys.stdout, encoding="unicode")
tail = elem.getroot().tail
if not tail or tail[-1] != "\n":
sys.stdout.write("\n")
def indent(tree, space=" ", level=0):
"""Indent an XML document by inserting newlines and indentation space
after elements.
*tree* is the ElementTree or Element to modify. The (root) element
itself will not be changed, but the tail text of all elements in its
subtree will be adapted.
*space* is the whitespace to insert for each indentation level, two
space characters by default.
*level* is the initial indentation level. Setting this to a higher
value than 0 can be used for indenting subtrees that are more deeply
nested inside of a document.
"""
if isinstance(tree, ElementTree):
tree = tree.getroot()
if level < 0:
raise ValueError(f"Initial indentation level must be >= 0, got {level}")
if not len(tree):
return
# Reduce the memory consumption by reusing indentation strings.
indentations = ["\n" + level * space]
def _indent_children(elem, level):
# Start a new indentation level for the first child.
child_level = level + 1
try:
child_indentation = indentations[child_level]
except IndexError:
child_indentation = indentations[level] + space
indentations.append(child_indentation)
if not elem.text or not elem.text.strip():
elem.text = child_indentation
for child in elem:
if len(child):
_indent_children(child, child_level)
if not child.tail or not child.tail.strip():
child.tail = child_indentation
# Dedent after the last child by overwriting the previous indentation.
if not child.tail.strip():
child.tail = indentations[level]
_indent_children(tree, 0)
# --------------------------------------------------------------------
# parsing
def parse(source, parser=None):
"""Parse XML document into element tree.
*source* is a filename or file object containing XML data,
*parser* is an optional parser instance defaulting to XMLParser.
Return an ElementTree instance.
"""
tree = ElementTree()
tree.parse(source, parser)
return tree
def iterparse(source, events=None, parser=None):
"""Incrementally parse XML document into ElementTree.
This class also reports what's going on to the user based on the
*events* it is initialized with. The supported events are the strings
"start", "end", "start-ns" and "end-ns" (the "ns" events are used to get
detailed namespace information). If *events* is omitted, only
"end" events are reported.
*source* is a filename or file object containing XML data, *events* is
a list of events to report back, *parser* is an optional parser instance.
Returns an iterator providing (event, elem) pairs.
"""
# Use the internal, undocumented _parser argument for now; When the
# parser argument of iterparse is removed, this can be killed.
pullparser = XMLPullParser(events=events, _parser=parser)
if not hasattr(source, "read"):
source = open(source, "rb")
close_source = True
else:
close_source = False
def iterator(source):
try:
while True:
yield from pullparser.read_events()
# load event buffer
data = source.read(16 * 1024)
if not data:
break
pullparser.feed(data)
root = pullparser._close_and_return_root()
yield from pullparser.read_events()
it = wr()
if it is not None:
it.root = root
finally:
if close_source:
source.close()
class IterParseIterator(collections.abc.Iterator):
__next__ = iterator(source).__next__
def __del__(self):
if close_source:
source.close()
it = IterParseIterator()
it.root = None
wr = weakref.ref(it)
return it
class XMLPullParser:
def __init__(self, events=None, *, _parser=None):
# The _parser argument is for internal use only and must not be relied
# upon in user code. It will be removed in a future release.
# See https://bugs.python.org/issue17741 for more details.
self._events_queue = collections.deque()
self._parser = _parser or XMLParser(target=TreeBuilder())
# wire up the parser for event reporting
if events is None:
events = ("end",)
self._parser._setevents(self._events_queue, events)
def feed(self, data):
"""Feed encoded data to parser."""
if self._parser is None:
raise ValueError("feed() called after end of stream")
if data:
try:
self._parser.feed(data)
except SyntaxError as exc:
self._events_queue.append(exc)
def _close_and_return_root(self):
# iterparse needs this to set its root attribute properly :(
root = self._parser.close()
self._parser = None
return root
def close(self):
"""Finish feeding data to parser.
Unlike XMLParser, does not return the root element. Use
read_events() to consume elements from XMLPullParser.
"""
self._close_and_return_root()
def read_events(self):
"""Return an iterator over currently available (event, elem) pairs.
Events are consumed from the internal event queue as they are
retrieved from the iterator.
"""
events = self._events_queue
while events:
event = events.popleft()
if isinstance(event, Exception):
raise event
else:
yield event
def flush(self):
if self._parser is None:
raise ValueError("flush() called after end of stream")
self._parser.flush()
def XML(text, parser=None):
"""Parse XML document from string constant.
This function can be used to embed "XML Literals" in Python code.
*text* is a string containing XML data, *parser* is an
optional parser instance, defaulting to the standard XMLParser.
Returns an Element instance.
"""
if not parser:
parser = XMLParser(target=TreeBuilder())
parser.feed(text)
return parser.close()
def XMLID(text, parser=None):
"""Parse XML document from string constant for its IDs.
*text* is a string containing XML data, *parser* is an
optional parser instance, defaulting to the standard XMLParser.
Returns an (Element, dict) tuple, in which the
dict maps element id:s to elements.
"""
if not parser:
parser = XMLParser(target=TreeBuilder())
parser.feed(text)
tree = parser.close()
ids = {}
for elem in tree.iter():
id = elem.get("id")
if id:
ids[id] = elem
return tree, ids
# Parse XML document from string constant. Alias for XML().
fromstring = XML
def fromstringlist(sequence, parser=None):
"""Parse XML document from sequence of string fragments.
*sequence* is a list of other sequence, *parser* is an optional parser
instance, defaulting to the standard XMLParser.
Returns an Element instance.
"""
if not parser:
parser = XMLParser(target=TreeBuilder())
for text in sequence:
parser.feed(text)
return parser.close()
# --------------------------------------------------------------------
class TreeBuilder:
"""Generic element structure builder.
This builder converts a sequence of start, data, and end method
calls to a well-formed element structure.
You can use this class to build an element structure using a custom XML
parser, or a parser for some other XML-like format.
*element_factory* is an optional element factory which is called
to create new Element instances, as necessary.
*comment_factory* is a factory to create comments to be used instead of
the standard factory. If *insert_comments* is false (the default),
comments will not be inserted into the tree.
*pi_factory* is a factory to create processing instructions to be used
instead of the standard factory. If *insert_pis* is false (the default),
processing instructions will not be inserted into the tree.
"""
def __init__(self, element_factory=None, *,
comment_factory=None, pi_factory=None,
insert_comments=False, insert_pis=False):
self._data = [] # data collector
self._elem = [] # element stack
self._last = None # last element
self._root = None # root element
self._tail = None # true if we're after an end tag
if comment_factory is None:
comment_factory = Comment
self._comment_factory = comment_factory
self.insert_comments = insert_comments
if pi_factory is None:
pi_factory = ProcessingInstruction
self._pi_factory = pi_factory
self.insert_pis = insert_pis
if element_factory is None:
element_factory = Element
self._factory = element_factory
def close(self):
"""Flush builder buffers and return toplevel document Element."""
assert len(self._elem) == 0, "missing end tags"
assert self._root is not None, "missing toplevel element"
return self._root
def _flush(self):
if self._data:
if self._last is not None:
text = "".join(self._data)
if self._tail:
assert self._last.tail is None, "internal error (tail)"
self._last.tail = text
else:
assert self._last.text is None, "internal error (text)"
self._last.text = text
self._data = []
def data(self, data):
"""Add text to current element."""
self._data.append(data)
def start(self, tag, attrs):
"""Open new element and return it.
*tag* is the element name, *attrs* is a dict containing element
attributes.
"""
self._flush()
self._last = elem = self._factory(tag, attrs)
if self._elem:
self._elem[-1].append(elem)
elif self._root is None:
self._root = elem
self._elem.append(elem)
self._tail = 0
return elem
def end(self, tag):
"""Close and return current Element.
*tag* is the element name.
"""
self._flush()
self._last = self._elem.pop()
assert self._last.tag == tag,\
"end tag mismatch (expected %s, got %s)" % (
self._last.tag, tag)
self._tail = 1
return self._last
def comment(self, text):
"""Create a comment using the comment_factory.
*text* is the text of the comment.
"""
return self._handle_single(
self._comment_factory, self.insert_comments, text)
def pi(self, target, text=None):
"""Create a processing instruction using the pi_factory.
*target* is the target name of the processing instruction.
*text* is the data of the processing instruction, or ''.
"""
return self._handle_single(
self._pi_factory, self.insert_pis, target, text)
def _handle_single(self, factory, insert, *args):
elem = factory(*args)
if insert:
self._flush()
self._last = elem
if self._elem:
self._elem[-1].append(elem)
self._tail = 1
return elem
# also see ElementTree and TreeBuilder
class XMLParser:
"""Element structure builder for XML source data based on the expat parser.
*target* is an optional target object which defaults to an instance of the
standard TreeBuilder class, *encoding* is an optional encoding string
which if given, overrides the encoding specified in the XML file:
http://www.iana.org/assignments/character-sets
"""
def __init__(self, *, target=None, encoding=None):
try:
from xml.parsers import expat
except ImportError:
try:
import pyexpat as expat
except ImportError:
raise ImportError(
"No module named expat; use SimpleXMLTreeBuilder instead"
)
parser = expat.ParserCreate(encoding, "}")
if target is None:
target = TreeBuilder()
# underscored names are provided for compatibility only
self.parser = self._parser = parser
self.target = self._target = target
self._error = expat.error
self._names = {} # name memo cache
# main callbacks
parser.DefaultHandlerExpand = self._default
if hasattr(target, 'start'):
parser.StartElementHandler = self._start
if hasattr(target, 'end'):
parser.EndElementHandler = self._end
if hasattr(target, 'start_ns'):
parser.StartNamespaceDeclHandler = self._start_ns
if hasattr(target, 'end_ns'):
parser.EndNamespaceDeclHandler = self._end_ns
if hasattr(target, 'data'):
parser.CharacterDataHandler = target.data
# miscellaneous callbacks
if hasattr(target, 'comment'):
parser.CommentHandler = target.comment
if hasattr(target, 'pi'):
parser.ProcessingInstructionHandler = target.pi
# Configure pyexpat: buffering, new-style attribute handling.
parser.buffer_text = 1
parser.ordered_attributes = 1
self._doctype = None
self.entity = {}
try:
self.version = "Expat %d.%d.%d" % expat.version_info
except AttributeError:
pass # unknown
def _setevents(self, events_queue, events_to_report):
# Internal API for XMLPullParser
# events_to_report: a list of events to report during parsing (same as
# the *events* of XMLPullParser's constructor.
# events_queue: a list of actual parsing events that will be populated
# by the underlying parser.
#
parser = self._parser
append = events_queue.append
for event_name in events_to_report:
if event_name == "start":
parser.ordered_attributes = 1
def handler(tag, attrib_in, event=event_name, append=append,
start=self._start):
append((event, start(tag, attrib_in)))
parser.StartElementHandler = handler
elif event_name == "end":
def handler(tag, event=event_name, append=append,
end=self._end):
append((event, end(tag)))
parser.EndElementHandler = handler
elif event_name == "start-ns":
# TreeBuilder does not implement .start_ns()
if hasattr(self.target, "start_ns"):
def handler(prefix, uri, event=event_name, append=append,
start_ns=self._start_ns):
append((event, start_ns(prefix, uri)))
else:
def handler(prefix, uri, event=event_name, append=append):
append((event, (prefix or '', uri or '')))
parser.StartNamespaceDeclHandler = handler
elif event_name == "end-ns":
# TreeBuilder does not implement .end_ns()
if hasattr(self.target, "end_ns"):
def handler(prefix, event=event_name, append=append,
end_ns=self._end_ns):
append((event, end_ns(prefix)))
else:
def handler(prefix, event=event_name, append=append):
append((event, None))
parser.EndNamespaceDeclHandler = handler
elif event_name == 'comment':
def handler(text, event=event_name, append=append, self=self):
append((event, self.target.comment(text)))
parser.CommentHandler = handler
elif event_name == 'pi':
def handler(pi_target, data, event=event_name, append=append,
self=self):
append((event, self.target.pi(pi_target, data)))
parser.ProcessingInstructionHandler = handler
else:
raise ValueError("unknown event %r" % event_name)
def _raiseerror(self, value):
err = ParseError(value)
err.code = value.code
err.position = value.lineno, value.offset
raise err
def _fixname(self, key):
# expand qname, and convert name string to ascii, if possible
try:
name = self._names[key]
except KeyError:
name = key
if "}" in name:
name = "{" + name
self._names[key] = name
return name
def _start_ns(self, prefix, uri):
return self.target.start_ns(prefix or '', uri or '')
def _end_ns(self, prefix):
return self.target.end_ns(prefix or '')
def _start(self, tag, attr_list):
# Handler for expat's StartElementHandler. Since ordered_attributes
# is set, the attributes are reported as a list of alternating
# attribute name,value.
fixname = self._fixname
tag = fixname(tag)
attrib = {}
if attr_list:
for i in range(0, len(attr_list), 2):
attrib[fixname(attr_list[i])] = attr_list[i+1]
return self.target.start(tag, attrib)
def _end(self, tag):
return self.target.end(self._fixname(tag))
def _default(self, text):
prefix = text[:1]
if prefix == "&":
# deal with undefined entities
try:
data_handler = self.target.data
except AttributeError:
return
try:
data_handler(self.entity[text[1:-1]])
except KeyError:
from xml.parsers import expat
err = expat.error(
"undefined entity %s: line %d, column %d" %
(text, self.parser.ErrorLineNumber,
self.parser.ErrorColumnNumber)
)
err.code = 11 # XML_ERROR_UNDEFINED_ENTITY
err.lineno = self.parser.ErrorLineNumber
err.offset = self.parser.ErrorColumnNumber
raise err
elif prefix == "<" and text[:9] == "<!DOCTYPE":
self._doctype = [] # inside a doctype declaration
elif self._doctype is not None:
# parse doctype contents
if prefix == ">":
self._doctype = None
return
text = text.strip()
if not text:
return
self._doctype.append(text)
n = len(self._doctype)
if n > 2:
type = self._doctype[1]
if type == "PUBLIC" and n == 4:
name, type, pubid, system = self._doctype
if pubid:
pubid = pubid[1:-1]
elif type == "SYSTEM" and n == 3:
name, type, system = self._doctype
pubid = None
else:
return
if hasattr(self.target, "doctype"):
self.target.doctype(name, pubid, system[1:-1])
elif hasattr(self, "doctype"):
warnings.warn(
"The doctype() method of XMLParser is ignored. "
"Define doctype() method on the TreeBuilder target.",
RuntimeWarning)
self._doctype = None
def feed(self, data):
"""Feed encoded data to parser."""
try:
self.parser.Parse(data, False)
except self._error as v:
self._raiseerror(v)
def close(self):
"""Finish feeding data to parser and return element structure."""
try:
self.parser.Parse(b"", True) # end of data
except self._error as v:
self._raiseerror(v)
try:
close_handler = self.target.close
except AttributeError:
pass
else:
return close_handler()
finally:
# get rid of circular references
del self.parser, self._parser
del self.target, self._target
def flush(self):
was_enabled = self.parser.GetReparseDeferralEnabled()
try:
self.parser.SetReparseDeferralEnabled(False)
self.parser.Parse(b"", False)
except self._error as v:
self._raiseerror(v)
finally:
self.parser.SetReparseDeferralEnabled(was_enabled)
# --------------------------------------------------------------------
# C14N 2.0
def canonicalize(xml_data=None, *, out=None, from_file=None, **options):
"""Convert XML to its C14N 2.0 serialised form.
If *out* is provided, it must be a file or file-like object that receives
the serialised canonical XML output (text, not bytes) through its ``.write()``
method. To write to a file, open it in text mode with encoding "utf-8".
If *out* is not provided, this function returns the output as text string.
Either *xml_data* (an XML string) or *from_file* (a file path or
file-like object) must be provided as input.
The configuration options are the same as for the ``C14NWriterTarget``.
"""
if xml_data is None and from_file is None:
raise ValueError("Either 'xml_data' or 'from_file' must be provided as input")
sio = None
if out is None:
sio = out = io.StringIO()
parser = XMLParser(target=C14NWriterTarget(out.write, **options))
if xml_data is not None:
parser.feed(xml_data)
parser.close()
elif from_file is not None:
parse(from_file, parser=parser)
return sio.getvalue() if sio is not None else None
_looks_like_prefix_name = re.compile(r'^\w+:\w+$', re.UNICODE).match
class C14NWriterTarget:
"""
Canonicalization writer target for the XMLParser.
Serialises parse events to XML C14N 2.0.
The *write* function is used for writing out the resulting data stream
as text (not bytes). To write to a file, open it in text mode with encoding
"utf-8" and pass its ``.write`` method.
Configuration options:
- *with_comments*: set to true to include comments
- *strip_text*: set to true to strip whitespace before and after text content
- *rewrite_prefixes*: set to true to replace namespace prefixes by "n{number}"
- *qname_aware_tags*: a set of qname aware tag names in which prefixes
should be replaced in text content
- *qname_aware_attrs*: a set of qname aware attribute names in which prefixes
should be replaced in text content
- *exclude_attrs*: a set of attribute names that should not be serialised
- *exclude_tags*: a set of tag names that should not be serialised
"""
def __init__(self, write, *,
with_comments=False, strip_text=False, rewrite_prefixes=False,
qname_aware_tags=None, qname_aware_attrs=None,
exclude_attrs=None, exclude_tags=None):
self._write = write
self._data = []
self._with_comments = with_comments
self._strip_text = strip_text
self._exclude_attrs = set(exclude_attrs) if exclude_attrs else None
self._exclude_tags = set(exclude_tags) if exclude_tags else None
self._rewrite_prefixes = rewrite_prefixes
if qname_aware_tags:
self._qname_aware_tags = set(qname_aware_tags)
else:
self._qname_aware_tags = None
if qname_aware_attrs:
self._find_qname_aware_attrs = set(qname_aware_attrs).intersection
else:
self._find_qname_aware_attrs = None
# Stack with globally and newly declared namespaces as (uri, prefix) pairs.
self._declared_ns_stack = [[
("http://www.w3.org/XML/1998/namespace", "xml"),
]]
# Stack with user declared namespace prefixes as (uri, prefix) pairs.
self._ns_stack = []
if not rewrite_prefixes:
self._ns_stack.append(list(_namespace_map.items()))
self._ns_stack.append([])
self._prefix_map = {}
self._preserve_space = [False]
self._pending_start = None
self._root_seen = False
self._root_done = False
self._ignored_depth = 0
def _iter_namespaces(self, ns_stack, _reversed=reversed):
for namespaces in _reversed(ns_stack):
if namespaces: # almost no element declares new namespaces
yield from namespaces
def _resolve_prefix_name(self, prefixed_name):
prefix, name = prefixed_name.split(':', 1)
for uri, p in self._iter_namespaces(self._ns_stack):
if p == prefix:
return f'{{{uri}}}{name}'
raise ValueError(f'Prefix {prefix} of QName "{prefixed_name}" is not declared in scope')
def _qname(self, qname, uri=None):
if uri is None:
uri, tag = qname[1:].rsplit('}', 1) if qname[:1] == '{' else ('', qname)
else:
tag = qname
prefixes_seen = set()
for u, prefix in self._iter_namespaces(self._declared_ns_stack):
if u == uri and prefix not in prefixes_seen:
return f'{prefix}:{tag}' if prefix else tag, tag, uri
prefixes_seen.add(prefix)
# Not declared yet => add new declaration.
if self._rewrite_prefixes:
if uri in self._prefix_map:
prefix = self._prefix_map[uri]
else:
prefix = self._prefix_map[uri] = f'n{len(self._prefix_map)}'
self._declared_ns_stack[-1].append((uri, prefix))
return f'{prefix}:{tag}', tag, uri
if not uri and '' not in prefixes_seen:
# No default namespace declared => no prefix needed.
return tag, tag, uri
for u, prefix in self._iter_namespaces(self._ns_stack):
if u == uri:
self._declared_ns_stack[-1].append((uri, prefix))
return f'{prefix}:{tag}' if prefix else tag, tag, uri
if not uri:
# As soon as a default namespace is defined,
# anything that has no namespace (and thus, no prefix) goes there.
return tag, tag, uri
raise ValueError(f'Namespace "{uri}" is not declared in scope')
def data(self, data):
if not self._ignored_depth:
self._data.append(data)
def _flush(self, _join_text=''.join):
data = _join_text(self._data)
del self._data[:]
if self._strip_text and not self._preserve_space[-1]:
data = data.strip()
if self._pending_start is not None:
args, self._pending_start = self._pending_start, None
qname_text = data if data and _looks_like_prefix_name(data) else None
self._start(*args, qname_text)
if qname_text is not None:
return
if data and self._root_seen:
self._write(_escape_cdata_c14n(data))
def start_ns(self, prefix, uri):
if self._ignored_depth:
return
# we may have to resolve qnames in text content
if self._data:
self._flush()
self._ns_stack[-1].append((uri, prefix))
def start(self, tag, attrs):
if self._exclude_tags is not None and (
self._ignored_depth or tag in self._exclude_tags):
self._ignored_depth += 1
return
if self._data:
self._flush()
new_namespaces = []
self._declared_ns_stack.append(new_namespaces)
if self._qname_aware_tags is not None and tag in self._qname_aware_tags:
# Need to parse text first to see if it requires a prefix declaration.
self._pending_start = (tag, attrs, new_namespaces)
return
self._start(tag, attrs, new_namespaces)
def _start(self, tag, attrs, new_namespaces, qname_text=None):
if self._exclude_attrs is not None and attrs:
attrs = {k: v for k, v in attrs.items() if k not in self._exclude_attrs}
qnames = {tag, *attrs}
resolved_names = {}
# Resolve prefixes in attribute and tag text.
if qname_text is not None:
qname = resolved_names[qname_text] = self._resolve_prefix_name(qname_text)
qnames.add(qname)
if self._find_qname_aware_attrs is not None and attrs:
qattrs = self._find_qname_aware_attrs(attrs)
if qattrs:
for attr_name in qattrs:
value = attrs[attr_name]
if _looks_like_prefix_name(value):
qname = resolved_names[value] = self._resolve_prefix_name(value)
qnames.add(qname)
else:
qattrs = None
else:
qattrs = None
# Assign prefixes in lexicographical order of used URIs.
parse_qname = self._qname
parsed_qnames = {n: parse_qname(n) for n in sorted(
qnames, key=lambda n: n.split('}', 1))}
# Write namespace declarations in prefix order ...
if new_namespaces:
attr_list = [
('xmlns:' + prefix if prefix else 'xmlns', uri)
for uri, prefix in new_namespaces
]
attr_list.sort()
else:
# almost always empty
attr_list = []
# ... followed by attributes in URI+name order
if attrs:
for k, v in sorted(attrs.items()):
if qattrs is not None and k in qattrs and v in resolved_names:
v = parsed_qnames[resolved_names[v]][0]
attr_qname, attr_name, uri = parsed_qnames[k]
# No prefix for attributes in default ('') namespace.
attr_list.append((attr_qname if uri else attr_name, v))
# Honour xml:space attributes.
space_behaviour = attrs.get('{http://www.w3.org/XML/1998/namespace}space')
self._preserve_space.append(
space_behaviour == 'preserve' if space_behaviour
else self._preserve_space[-1])
# Write the tag.
write = self._write
write('<' + parsed_qnames[tag][0])
if attr_list:
write(''.join([f' {k}="{_escape_attrib_c14n(v)}"' for k, v in attr_list]))
write('>')
# Write the resolved qname text content.
if qname_text is not None:
write(_escape_cdata_c14n(parsed_qnames[resolved_names[qname_text]][0]))
self._root_seen = True
self._ns_stack.append([])
def end(self, tag):
if self._ignored_depth:
self._ignored_depth -= 1
return
if self._data:
self._flush()
self._write(f'</{self._qname(tag)[0]}>')
self._preserve_space.pop()
self._root_done = len(self._preserve_space) == 1
self._declared_ns_stack.pop()
self._ns_stack.pop()
def comment(self, text):
if not self._with_comments:
return
if self._ignored_depth:
return
if self._root_done:
self._write('\n')
elif self._root_seen and self._data:
self._flush()
self._write(f'<!--{_escape_cdata_c14n(text)}-->')
if not self._root_seen:
self._write('\n')
def pi(self, target, data):
if self._ignored_depth:
return
if self._root_done:
self._write('\n')
elif self._root_seen and self._data:
self._flush()
self._write(
f'<?{target} {_escape_cdata_c14n(data)}?>' if data else f'<?{target}?>')
if not self._root_seen:
self._write('\n')
def _escape_cdata_c14n(text):
# escape character data
try:
# it's worth avoiding do-nothing calls for strings that are
# shorter than 500 character, or so. assume that's, by far,
# the most common case in most applications.
if '&' in text:
text = text.replace('&', '&')
if '<' in text:
text = text.replace('<', '<')
if '>' in text:
text = text.replace('>', '>')
if '\r' in text:
text = text.replace('\r', '
')
return text
except (TypeError, AttributeError):
_raise_serialization_error(text)
def _escape_attrib_c14n(text):
# escape attribute value
try:
if '&' in text:
text = text.replace('&', '&')
if '<' in text:
text = text.replace('<', '<')
if '"' in text:
text = text.replace('"', '"')
if '\t' in text:
text = text.replace('\t', '	')
if '\n' in text:
text = text.replace('\n', '
')
if '\r' in text:
text = text.replace('\r', '
')
return text
except (TypeError, AttributeError):
_raise_serialization_error(text)
# --------------------------------------------------------------------
# Import the C accelerators
try:
# Element is going to be shadowed by the C implementation. We need to keep
# the Python version of it accessible for some "creative" by external code
# (see tests)
_Element_Py = Element
# Element, SubElement, ParseError, TreeBuilder, XMLParser, _set_factories
from _elementtree import *
from _elementtree import _set_factories
except ImportError:
pass
else:
_set_factories(Comment, ProcessingInstruction)