# Each element has a number of properties associated with it: #
# The {@link #ElementTree} class can be used to wrap an element # structure, and convert it from and to XML. ## import sys import re import warnings import io import contextlib from . import ElementPath ## # Parser error. This is a subclass of SyntaxError. #
# In addition to the exception value, an exception instance contains a # specific exception code in the code attribute, and the line and # column of the error in the position attribute. class ParseError(SyntaxError): pass # -------------------------------------------------------------------- ## # Checks if an object appears to be a valid element object. # # @param An element instance. # @return A true value if this is an element object. # @defreturn flag def iselement(element): # FIXME: not sure about this; # isinstance(element, Element) or look for tag/attrib/text attributes return hasattr(element, 'tag') ## # Element class. This class defines the Element interface, and # provides a reference implementation of this interface. #
# The element name, attribute names, and attribute values can be
# either ASCII strings (ordinary Python strings containing only 7-bit
# ASCII characters) or Unicode strings.
#
# @param tag The element name.
# @param attrib An optional dictionary, containing element attributes.
# @param **extra Additional attributes, given as keyword arguments.
# @see Element
# @see SubElement
# @see Comment
# @see ProcessingInstruction
class Element:
#
# 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.
#
# @param tag What tags to look for (default is to return all elements).
# @return An iterator containing all the matching elements.
# @defreturn iterator
def iter(self, tag=None):
if tag == "*":
tag = None
if tag is None or self.tag == tag:
yield self
for e in self._children:
yield from e.iter(tag)
# compatibility
def getiterator(self, tag=None):
# Change for a DeprecationWarning in 1.4
warnings.warn(
"This method will be removed in future versions. "
"Use 'elem.iter()' or 'list(elem.iter())' instead.",
PendingDeprecationWarning, stacklevel=2
)
return list(self.iter(tag))
##
# Creates a text iterator. The iterator loops over this element
# and all subelements, in document order, and returns all inner
# text.
#
# @return An iterator containing all inner text.
# @defreturn iterator
def itertext(self):
tag = self.tag
if not isinstance(tag, str) and tag is not None:
return
if self.text:
yield self.text
for e in self:
yield from e.itertext()
if e.tail:
yield e.tail
# compatibility
_Element = _ElementInterface = Element
##
# Subelement factory. This function creates an element instance, and
# appends it to an existing element.
#
# The element name, attribute names, and attribute values can be
# either 8-bit ASCII strings or Unicode strings.
#
# @param parent The parent element.
# @param tag The subelement name.
# @param attrib An optional dictionary, containing element attributes.
# @param **extra Additional attributes, given as keyword arguments.
# @return An element instance.
# @defreturn Element
def SubElement(parent, tag, attrib={}, **extra):
attrib = attrib.copy()
attrib.update(extra)
element = parent.makeelement(tag, attrib)
parent.append(element)
return element
##
# Comment element factory. This factory function creates a special
# element that will be serialized as an XML comment by the standard
# serializer.
#
# The comment string can be either an 8-bit ASCII string or a Unicode
# string.
#
# @param text A string containing the comment string.
# @return An element instance, representing a comment.
# @defreturn Element
def Comment(text=None):
element = Element(Comment)
element.text = text
return element
##
# PI element factory. This factory function creates a special element
# that will be serialized as an XML processing instruction by the standard
# serializer.
#
# @param target A string containing the PI target.
# @param text A string containing the PI contents, if any.
# @return An element instance, representing a PI.
# @defreturn Element
def ProcessingInstruction(target, text=None):
element = Element(ProcessingInstruction)
element.text = target
if text:
element.text = element.text + " " + text
return element
PI = ProcessingInstruction
##
# QName wrapper. This can be used to wrap a QName attribute value, in
# order to get proper namespace handling on output.
#
# @param text A string containing the QName value, in the form {uri}local,
# or, if the tag argument is given, the URI part of a QName.
# @param tag Optional tag. If given, the first argument is interpreted as
# an URI, and this argument is interpreted as a local name.
# @return An opaque object, representing the QName.
class QName:
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 '
# The exact output format is implementation dependent. In this
# version, it's written as an ordinary XML file.
#
# @param elem An element tree or an individual element.
def dump(elem):
# 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")
# --------------------------------------------------------------------
# parsing
##
# Parses an XML document into an element tree.
#
# @param source A filename or file object containing XML data.
# @param parser An optional parser instance. If not given, the
# standard {@link XMLParser} parser is used.
# @return An ElementTree instance
def parse(source, parser=None):
tree = ElementTree()
tree.parse(source, parser)
return tree
##
# Parses an XML document into an element tree incrementally, and reports
# what's going on to the user.
#
# @param source A filename or file object containing XML data.
# @param events A list of events to report back. If omitted, only "end"
# events are reported.
# @param parser An optional parser instance. If not given, the
# standard {@link XMLParser} parser is used.
# @return A (event, elem) iterator.
def iterparse(source, events=None, parser=None):
close_source = False
if not hasattr(source, "read"):
source = open(source, "rb")
close_source = True
if not parser:
parser = XMLParser(target=TreeBuilder())
return _IterParseIterator(source, events, parser, close_source)
class _IterParseIterator:
def __init__(self, source, events, parser, close_source=False):
self._file = source
self._close_file = close_source
self._events = []
self._index = 0
self._error = None
self.root = self._root = None
self._parser = parser
# wire up the parser for event reporting
parser = self._parser._parser
append = self._events.append
if events is None:
events = ["end"]
for event in events:
if event == "start":
try:
parser.ordered_attributes = 1
parser.specified_attributes = 1
def handler(tag, attrib_in, event=event, append=append,
start=self._parser._start_list):
append((event, start(tag, attrib_in)))
parser.StartElementHandler = handler
except AttributeError:
def handler(tag, attrib_in, event=event, append=append,
start=self._parser._start):
append((event, start(tag, attrib_in)))
parser.StartElementHandler = handler
elif event == "end":
def handler(tag, event=event, append=append,
end=self._parser._end):
append((event, end(tag)))
parser.EndElementHandler = handler
elif event == "start-ns":
def handler(prefix, uri, event=event, append=append):
append((event, (prefix or "", uri or "")))
parser.StartNamespaceDeclHandler = handler
elif event == "end-ns":
def handler(prefix, event=event, append=append):
append((event, None))
parser.EndNamespaceDeclHandler = handler
else:
raise ValueError("unknown event %r" % event)
def __next__(self):
while 1:
try:
item = self._events[self._index]
self._index += 1
return item
except IndexError:
pass
if self._error:
e = self._error
self._error = None
raise e
if self._parser is None:
self.root = self._root
if self._close_file:
self._file.close()
raise StopIteration
# load event buffer
del self._events[:]
self._index = 0
data = self._file.read(16384)
if data:
try:
self._parser.feed(data)
except SyntaxError as exc:
self._error = exc
else:
self._root = self._parser.close()
self._parser = None
def __iter__(self):
return self
##
# Parses an XML document from a string constant. This function can
# be used to embed "XML literals" in Python code.
#
# @param source A string containing XML data.
# @param parser An optional parser instance. If not given, the
# standard {@link XMLParser} parser is used.
# @return An Element instance.
# @defreturn Element
def XML(text, parser=None):
if not parser:
parser = XMLParser(target=TreeBuilder())
parser.feed(text)
return parser.close()
##
# Parses an XML document from a string constant, and also returns
# a dictionary which maps from element id:s to elements.
#
# @param source A string containing XML data.
# @param parser An optional parser instance. If not given, the
# standard {@link XMLParser} parser is used.
# @return A tuple containing an Element instance and a dictionary.
# @defreturn (Element, dictionary)
def XMLID(text, parser=None):
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
##
# Parses an XML document from a string constant. Same as {@link #XML}.
#
# @def fromstring(text)
# @param source A string containing XML data.
# @return An Element instance.
# @defreturn Element
fromstring = XML
##
# Parses an XML document from a sequence of string fragments.
#
# @param sequence A list or other sequence containing XML data fragments.
# @param parser An optional parser instance. If not given, the
# standard {@link XMLParser} parser is used.
# @return An Element instance.
# @defreturn Element
# @since 1.3
def fromstringlist(sequence, parser=None):
if not parser:
parser = XMLParser(target=TreeBuilder())
for text in sequence:
parser.feed(text)
return parser.close()
# --------------------------------------------------------------------
##
# Generic element structure builder. This builder converts a sequence
# of {@link #TreeBuilder.start}, {@link #TreeBuilder.data}, and {@link
# #TreeBuilder.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.
#
# @param element_factory Optional element factory. This factory
# is called to create new Element instances, as necessary.
class TreeBuilder:
def __init__(self, element_factory=None):
self._data = [] # data collector
self._elem = [] # element stack
self._last = None # last element
self._tail = None # true if we're after an end tag
if element_factory is None:
element_factory = Element
self._factory = element_factory
##
# Flushes the builder buffers, and returns the toplevel document
# element.
#
# @return An Element instance.
# @defreturn Element
def close(self):
assert len(self._elem) == 0, "missing end tags"
assert self._last is not None, "missing toplevel element"
return self._last
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 = []
##
# Adds text to the current element.
#
# @param data A string. This should be either an 8-bit string
# containing ASCII text, or a Unicode string.
def data(self, data):
self._data.append(data)
##
# Opens a new element.
#
# @param tag The element name.
# @param attrib A dictionary containing element attributes.
# @return The opened element.
# @defreturn Element
def start(self, tag, attrs):
self._flush()
self._last = elem = self._factory(tag, attrs)
if self._elem:
self._elem[-1].append(elem)
self._elem.append(elem)
self._tail = 0
return elem
##
# Closes the current element.
#
# @param tag The element name.
# @return The closed element.
# @defreturn Element
def end(self, tag):
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
##
# Element structure builder for XML source data, based on the
# expat parser.
#
# @keyparam target Target object. If omitted, the builder uses an
# instance of the standard {@link #TreeBuilder} class.
# @keyparam html Predefine HTML entities. This flag is not supported
# by the current implementation.
# @keyparam encoding Optional encoding. If given, the value overrides
# the encoding specified in the XML file.
# @see #ElementTree
# @see #TreeBuilder
class XMLParser:
def __init__(self, html=0, 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, 'data'):
parser.CharacterDataHandler = target.data
# miscellaneous callbacks
if hasattr(target, 'comment'):
parser.CommentHandler = target.comment
if hasattr(target, 'pi'):
parser.ProcessingInstructionHandler = target.pi
# let expat do the buffering, if supported
try:
parser.buffer_text = 1
except AttributeError:
pass
# use new-style attribute handling, if supported
try:
parser.ordered_attributes = 1
parser.specified_attributes = 1
if hasattr(target, 'start'):
parser.StartElementHandler = self._start_list
except AttributeError:
pass
self._doctype = None
self.entity = {}
try:
self.version = "Expat %d.%d.%d" % expat.version_info
except AttributeError:
pass # unknown
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(self, tag, attrib_in):
fixname = self._fixname
tag = fixname(tag)
attrib = {}
for key, value in attrib_in.items():
attrib[fixname(key)] = value
return self.target.start(tag, attrib)
def _start_list(self, tag, attrib_in):
fixname = self._fixname
tag = fixname(tag)
attrib = {}
if attrib_in:
for i in range(0, len(attrib_in), 2):
attrib[fixname(attrib_in[i])] = attrib_in[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] == "":
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 self.doctype != self._XMLParser__doctype:
# warn about deprecated call
self._XMLParser__doctype(name, pubid, system[1:-1])
self.doctype(name, pubid, system[1:-1])
self._doctype = None
##
# (Deprecated) Handles a doctype declaration.
#
# @param name Doctype name.
# @param pubid Public identifier.
# @param system System identifier.
def doctype(self, name, pubid, system):
"""This method of XMLParser is deprecated."""
warnings.warn(
"This method of XMLParser is deprecated. Define doctype() "
"method on the TreeBuilder target.",
DeprecationWarning,
)
# sentinel, if doctype is redefined in a subclass
__doctype = doctype
##
# Feeds data to the parser.
#
# @param data Encoded data.
def feed(self, data):
try:
self.parser.Parse(data, 0)
except self._error as v:
self._raiseerror(v)
##
# Finishes feeding data to the parser.
#
# @return An element structure.
# @defreturn Element
def close(self):
try:
self.parser.Parse("", 1) # 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
# Import the C accelerators
try:
# Element, SubElement, ParseError, TreeBuilder, XMLParser
from _elementtree import *
except ImportError:
pass
else:
# Overwrite 'ElementTree.parse' and 'iterparse' to use the C XMLParser
class ElementTree(ElementTree):
def parse(self, source, parser=None):
close_source = False
if not hasattr(source, 'read'):
source = open(source, 'rb')
close_source = True
try:
if parser is not None:
while True:
data = source.read(65536)
if not data:
break
parser.feed(data)
self._root = parser.close()
else:
parser = XMLParser()
self._root = parser._parse(source)
return self._root
finally:
if close_source:
source.close()
class iterparse:
"""Parses an XML section into an element tree incrementally.
Reports what’s going on to the user. 'source' is a filename or file
object containing XML data. 'events' is a list of events to report back.
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.
'parser' is an optional parser instance. If not given, the standard
XMLParser parser is used. Returns an iterator providing
(event, elem) pairs.
"""
root = None
def __init__(self, file, events=None, parser=None):
self._close_file = False
if not hasattr(file, 'read'):
file = open(file, 'rb')
self._close_file = True
self._file = file
self._events = []
self._index = 0
self._error = None
self.root = self._root = None
if parser is None:
parser = XMLParser(target=TreeBuilder())
self._parser = parser
self._parser._setevents(self._events, events)
def __next__(self):
while True:
try:
item = self._events[self._index]
self._index += 1
return item
except IndexError:
pass
if self._error:
e = self._error
self._error = None
raise e
if self._parser is None:
self.root = self._root
if self._close_file:
self._file.close()
raise StopIteration
# load event buffer
del self._events[:]
self._index = 0
data = self._file.read(16384)
if data:
try:
self._parser.feed(data)
except SyntaxError as exc:
self._error = exc
else:
self._root = self._parser.close()
self._parser = None
def __iter__(self):
return self
# compatibility
XMLTreeBuilder = XMLParser
# workaround circular import.
try:
from ElementC14N import _serialize_c14n
_serialize["c14n"] = _serialize_c14n
except ImportError:
pass