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Edit File: ElementTree.py
# # ElementTree # $Id: ElementTree.py 3440 2008-07-18 14:45:01Z fredrik $ # # light-weight XML support for Python 2.3 and later. # # history (since 1.2.6): # 2005-11-12 fl added tostringlist/fromstringlist helpers # 2006-07-05 fl merged in selected changes from the 1.3 sandbox # 2006-07-05 fl removed support for 2.1 and earlier # 2007-06-21 fl added deprecation/future warnings # 2007-08-25 fl added doctype hook, added parser version attribute etc # 2007-08-26 fl added new serializer code (better namespace handling, etc) # 2007-08-27 fl warn for broken /tag searches on tree level # 2007-09-02 fl added html/text methods to serializer (experimental) # 2007-09-05 fl added method argument to tostring/tostringlist # 2007-09-06 fl improved error handling # 2007-09-13 fl added itertext, iterfind; assorted cleanups # 2007-12-15 fl added C14N hooks, copy method (experimental) # # 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. # -------------------------------------------------------------------- # Licensed to PSF under a Contributor Agreement. # See http://www.python.org/psf/license for licensing details. __all__ = [ # public symbols "Comment", "dump", "Element", "ElementTree", "fromstring", "fromstringlist", "iselement", "iterparse", "parse", "ParseError", "PI", "ProcessingInstruction", "QName", "SubElement", "tostring", "tostringlist", "TreeBuilder", "VERSION", "XML", "XMLParser", "XMLTreeBuilder", ] VERSION = "1.3.0" ## # The <b>Element</b> type is a flexible container object, designed to # store hierarchical data structures in memory. The type can be # described as a cross between a list and a dictionary. # <p> # Each element has a number of properties associated with it: # <ul> # <li>a <i>tag</i>. This is a string identifying what kind of data # this element represents (the element type, in other words).</li> # <li>a number of <i>attributes</i>, stored in a Python dictionary.</li> # <li>a <i>text</i> string.</li> # <li>an optional <i>tail</i> string.</li> # <li>a number of <i>child elements</i>, stored in a Python sequence</li> # </ul> # # To create an element instance, use the {@link #Element} constructor # or the {@link #SubElement} factory function. # <p> # 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 class _SimpleElementPath(object): # emulate pre-1.2 find/findtext/findall behaviour def find(self, element, tag, namespaces=None): for elem in element: if elem.tag == tag: return elem return None def findtext(self, element, tag, default=None, namespaces=None): elem = self.find(element, tag) if elem is None: return default return elem.text or "" def iterfind(self, element, tag, namespaces=None): if tag[:3] == ".//": for elem in element.iter(tag[3:]): yield elem for elem in element: if elem.tag == tag: yield elem def findall(self, element, tag, namespaces=None): return list(self.iterfind(element, tag, namespaces)) try: from . import ElementPath except ImportError: ElementPath = _SimpleElementPath() ## # Parser error. This is a subclass of <b>SyntaxError</b>. # <p> # In addition to the exception value, an exception instance contains a # specific exception code in the <b>code</b> attribute, and the line and # column of the error in the <b>position</b> 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; might be a better idea to look # for tag/attrib/text attributes return isinstance(element, Element) or hasattr(element, "tag") ## # Element class. This class defines the Element interface, and # provides a reference implementation of this interface. # <p> # 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(object): # <tag attrib>text<child/>...</tag>tail ## # (Attribute) Element tag. tag = None ## # (Attribute) Element attribute dictionary. Where possible, use # {@link #Element.get}, # {@link #Element.set}, # {@link #Element.keys}, and # {@link #Element.items} to access # element attributes. attrib = None ## # (Attribute) Text before first subelement. 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. text = None ## # (Attribute) 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. tail = None # text after end tag, if any # constructor def __init__(self, tag, attrib={}, **extra): attrib = attrib.copy() attrib.update(extra) self.tag = tag self.attrib = attrib self._children = [] def __repr__(self): return "<Element %s at 0x%x>" % (repr(self.tag), id(self)) ## # Creates a new element object of the same type as this element. # # @param tag Element tag. # @param attrib Element attributes, given as a dictionary. # @return A new element instance. def makeelement(self, tag, attrib): return self.__class__(tag, attrib) ## # (Experimental) Copies the current element. This creates a # shallow copy; subelements will be shared with the original tree. # # @return A new element instance. def copy(self): elem = self.makeelement(self.tag, self.attrib) elem.text = self.text elem.tail = self.tail elem[:] = self return elem ## # Returns the number of subelements. Note that this only counts # full elements; to check if there's any content in an element, you # have to check both the length and the <b>text</b> attribute. # # @return The number of subelements. def __len__(self): return len(self._children) def __nonzero__(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 ## # Returns the given subelement, by index. # # @param index What subelement to return. # @return The given subelement. # @exception IndexError If the given element does not exist. def __getitem__(self, index): return self._children[index] ## # Replaces the given subelement, by index. # # @param index What subelement to replace. # @param element The new element value. # @exception IndexError If the given element does not exist. def __setitem__(self, index, element): # if isinstance(index, slice): # for elt in element: # assert iselement(elt) # else: # assert iselement(element) self._children[index] = element ## # Deletes the given subelement, by index. # # @param index What subelement to delete. # @exception IndexError If the given element does not exist. def __delitem__(self, index): del self._children[index] ## # Adds a subelement to the end of this element. In document order, # the new element will appear after the last existing subelement (or # directly after the text, if it's the first subelement), but before # the end tag for this element. # # @param element The element to add. def append(self, element): # assert iselement(element) self._children.append(element) ## # Appends subelements from a sequence. # # @param elements A sequence object with zero or more elements. # @since 1.3 def extend(self, elements): # for element in elements: # assert iselement(element) self._children.extend(elements) ## # Inserts a subelement at the given position in this element. # # @param index Where to insert the new subelement. def insert(self, index, element): # assert iselement(element) self._children.insert(index, element) ## # Removes a matching subelement. Unlike the <b>find</b> methods, # this method compares elements based on identity, not on tag # value or contents. To remove subelements by other means, the # easiest way is often to use a list comprehension to select what # elements to keep, and use slice assignment to update the parent # element. # # @param element What element to remove. # @exception ValueError If a matching element could not be found. def remove(self, element): # assert iselement(element) self._children.remove(element) ## # (Deprecated) Returns all subelements. The elements are returned # in document order. # # @return A list of subelements. # @defreturn list of Element instances def getchildren(self): warnings.warn( "This method will be removed in future versions. " "Use 'list(elem)' or iteration over elem instead.", DeprecationWarning, stacklevel=2 ) return self._children ## # Finds the first matching subelement, by tag name or path. # # @param path What element to look for. # @keyparam namespaces Optional namespace prefix map. # @return The first matching element, or None if no element was found. # @defreturn Element or None def find(self, path, namespaces=None): return ElementPath.find(self, path, namespaces) ## # Finds text for the first matching subelement, by tag name or path. # # @param path What element to look for. # @param default What to return if the element was not found. # @keyparam namespaces Optional namespace prefix map. # @return The text content of the first matching element, or the # default value no element was found. Note that if the element # is found, but has no text content, this method returns an # empty string. # @defreturn string def findtext(self, path, default=None, namespaces=None): return ElementPath.findtext(self, path, default, namespaces) ## # Finds all matching subelements, by tag name or path. # # @param path What element to look for. # @keyparam namespaces Optional namespace prefix map. # @return A list or other sequence containing all matching elements, # in document order. # @defreturn list of Element instances def findall(self, path, namespaces=None): return ElementPath.findall(self, path, namespaces) ## # Finds all matching subelements, by tag name or path. # # @param path What element to look for. # @keyparam namespaces Optional namespace prefix map. # @return An iterator or sequence containing all matching elements, # in document order. # @defreturn a generated sequence of Element instances def iterfind(self, path, namespaces=None): return ElementPath.iterfind(self, path, namespaces) ## # Resets an element. This function removes all subelements, clears # all attributes, and sets the <b>text</b> and <b>tail</b> attributes # to None. def clear(self): self.attrib.clear() self._children = [] self.text = self.tail = None ## # Gets an element attribute. Equivalent to <b>attrib.get</b>, but # some implementations may handle this a bit more efficiently. # # @param key What attribute to look for. # @param default What to return if the attribute was not found. # @return The attribute value, or the default value, if the # attribute was not found. # @defreturn string or None def get(self, key, default=None): return self.attrib.get(key, default) ## # Sets an element attribute. Equivalent to <b>attrib[key] = value</b>, # but some implementations may handle this a bit more efficiently. # # @param key What attribute to set. # @param value The attribute value. def set(self, key, value): self.attrib[key] = value ## # Gets a list of attribute names. The names are returned in an # arbitrary order (just like for an ordinary Python dictionary). # Equivalent to <b>attrib.keys()</b>. # # @return A list of element attribute names. # @defreturn list of strings def keys(self): return self.attrib.keys() ## # Gets element attributes, as a sequence. The attributes are # returned in an arbitrary order. Equivalent to <b>attrib.items()</b>. # # @return A list of (name, value) tuples for all attributes. # @defreturn list of (string, string) tuples def items(self): return self.attrib.items() ## # Creates a tree iterator. The iterator loops over this element # and all subelements, in document order, and returns all elements # with a matching tag. # <p> # 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: for e in e.iter(tag): yield e # 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, basestring) and tag is not None: return if self.text: yield self.text for e in self: for s in e.itertext(): yield s 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. # <p> # 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. # <p> # 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 # a URI, and this argument is interpreted as a local name. # @return An opaque object, representing the QName. class QName(object): 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 __hash__(self): return hash(self.text) def __cmp__(self, other): if isinstance(other, QName): return cmp(self.text, other.text) return cmp(self.text, other) # -------------------------------------------------------------------- ## # ElementTree wrapper class. This class represents an entire element # hierarchy, and adds some extra support for serialization to and from # standard XML. # # @param element Optional root element. # @keyparam file Optional file handle or file name. If given, the # tree is initialized with the contents of this XML file. class ElementTree(object): def __init__(self, element=None, file=None): # assert element is None or iselement(element) self._root = element # first node if file: self.parse(file) ## # Gets the root element for this tree. # # @return An element instance. # @defreturn Element def getroot(self): return self._root ## # Replaces the root element for this tree. This discards the # current contents of the tree, and replaces it with the given # element. Use with care. # # @param element An element instance. def _setroot(self, element): # assert iselement(element) self._root = element ## # Loads an external XML document into this element tree. # # @param source A file name or file object. If a file object is # given, it only has to implement a <b>read(n)</b> method. # @keyparam parser An optional parser instance. If not given, the # standard {@link XMLParser} parser is used. # @return The document root element. # @defreturn Element # @exception ParseError If the parser fails to parse the document. def parse(self, source, parser=None): close_source = False if not hasattr(source, "read"): source = open(source, "rb") close_source = True try: if not parser: parser = XMLParser(target=TreeBuilder()) while 1: data = source.read(65536) if not data: break parser.feed(data) self._root = parser.close() return self._root finally: if close_source: source.close() ## # Creates a tree iterator for the root element. The iterator loops # over all elements in this tree, in document order. # # @param tag What tags to look for (default is to return all elements) # @return An iterator. # @defreturn iterator def iter(self, tag=None): # assert self._root is not None return self._root.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 'tree.iter()' or 'list(tree.iter())' instead.", PendingDeprecationWarning, stacklevel=2 ) return list(self.iter(tag)) ## # Same as getroot().find(path), starting at the root of the # tree. # # @param path What element to look for. # @keyparam namespaces Optional namespace prefix map. # @return The first matching element, or None if no element was found. # @defreturn Element or None def find(self, path, namespaces=None): # 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) ## # Same as getroot().findtext(path), starting at the root of the tree. # # @param path What element to look for. # @param default What to return if the element was not found. # @keyparam namespaces Optional namespace prefix map. # @return The text content of the first matching element, or the # default value no element was found. Note that if the element # is found, but has no text content, this method returns an # empty string. # @defreturn string def findtext(self, path, default=None, namespaces=None): # 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) ## # Same as getroot().findall(path), starting at the root of the tree. # # @param path What element to look for. # @keyparam namespaces Optional namespace prefix map. # @return A list or iterator containing all matching elements, # in document order. # @defreturn list of Element instances def findall(self, path, namespaces=None): # 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) ## # Finds all matching subelements, by tag name or path. # Same as getroot().iterfind(path). # # @param path What element to look for. # @keyparam namespaces Optional namespace prefix map. # @return An iterator or sequence containing all matching elements, # in document order. # @defreturn a generated sequence of Element instances def iterfind(self, path, namespaces=None): # 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) ## # Writes the element tree to a file, as XML. # # @def write(file, **options) # @param file A file name, or a file object opened for writing. # @param **options Options, given as keyword arguments. # @keyparam encoding Optional output encoding (default is US-ASCII). # @keyparam xml_declaration Controls if an XML declaration should # be added to the file. Use False for never, True for always, # None for only if not US-ASCII or UTF-8. None is default. # @keyparam default_namespace Sets the default XML namespace (for "xmlns"). # @keyparam method Optional output method ("xml", "html", "text" or # "c14n"; default is "xml"). def write(self, file_or_filename, # keyword arguments encoding=None, xml_declaration=None, default_namespace=None, method=None): # assert self._root is not None if not method: method = "xml" elif method not in _serialize: # FIXME: raise an ImportError for c14n if ElementC14N is missing? raise ValueError("unknown method %r" % method) if hasattr(file_or_filename, "write"): file = file_or_filename else: file = open(file_or_filename, "wb") write = file.write if not encoding: if method == "c14n": encoding = "utf-8" else: encoding = "us-ascii" elif xml_declaration or (xml_declaration is None and encoding not in ("utf-8", "us-ascii")): if method == "xml": write("<?xml version='1.0' encoding='%s'?>\n" % encoding) if method == "text": _serialize_text(write, self._root, encoding) else: qnames, namespaces = _namespaces( self._root, encoding, default_namespace ) serialize = _serialize[method] serialize(write, self._root, encoding, qnames, namespaces) if file_or_filename is not file: file.close() def write_c14n(self, file): # lxml.etree compatibility. use output method instead return self.write(file, method="c14n") # -------------------------------------------------------------------- # serialization support def _namespaces(elem, encoding, 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 encode(text): return text.encode(encoding) 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] = encode("%s:%s" % (prefix, tag)) else: qnames[qname] = encode(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] = encode(qname) except TypeError: _raise_serialization_error(qname) # populate qname and namespaces table try: iterate = elem.iter except AttributeError: iterate = elem.getiterator # cET compatibility for elem in iterate(): tag = elem.tag if isinstance(tag, QName): if tag.text not in qnames: add_qname(tag.text) elif isinstance(tag, basestring): 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, encoding, qnames, namespaces): tag = elem.tag text = elem.text if tag is Comment: write("<!--%s-->" % _encode(text, encoding)) elif tag is ProcessingInstruction: write("<?%s?>" % _encode(text, encoding)) else: tag = qnames[tag] if tag is None: if text: write(_escape_cdata(text, encoding)) for e in elem: _serialize_xml(write, e, encoding, qnames, None) else: write("<" + tag) items = 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.encode(encoding), _escape_attrib(v, encoding) )) for k, v in sorted(items): # lexical order if isinstance(k, QName): k = k.text if isinstance(v, QName): v = qnames[v.text] else: v = _escape_attrib(v, encoding) write(" %s=\"%s\"" % (qnames[k], v)) if text or len(elem): write(">") if text: write(_escape_cdata(text, encoding)) for e in elem: _serialize_xml(write, e, encoding, qnames, None) write("</" + tag + ">") else: write(" />") if elem.tail: write(_escape_cdata(elem.tail, encoding)) HTML_EMPTY = ("area", "base", "basefont", "br", "col", "frame", "hr", "img", "input", "isindex", "link", "meta", "param") try: HTML_EMPTY = set(HTML_EMPTY) except NameError: pass def _serialize_html(write, elem, encoding, qnames, namespaces): tag = elem.tag text = elem.text if tag is Comment: write("<!--%s-->" % _escape_cdata(text, encoding)) elif tag is ProcessingInstruction: write("<?%s?>" % _escape_cdata(text, encoding)) else: tag = qnames[tag] if tag is None: if text: write(_escape_cdata(text, encoding)) for e in elem: _serialize_html(write, e, encoding, qnames, None) else: write("<" + tag) items = 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.encode(encoding), _escape_attrib(v, encoding) )) for k, v in sorted(items): # lexical order if isinstance(k, QName): k = k.text if isinstance(v, QName): v = qnames[v.text] else: v = _escape_attrib_html(v, encoding) # FIXME: handle boolean attributes write(" %s=\"%s\"" % (qnames[k], v)) write(">") ltag = tag.lower() if text: if ltag == "script" or ltag == "style": write(_encode(text, encoding)) else: write(_escape_cdata(text, encoding)) for e in elem: _serialize_html(write, e, encoding, qnames, None) if ltag not in HTML_EMPTY: write("</" + tag + ">") if elem.tail: write(_escape_cdata(elem.tail, encoding)) def _serialize_text(write, elem, encoding): for part in elem.itertext(): write(part.encode(encoding)) if elem.tail: write(elem.tail.encode(encoding)) _serialize = { "xml": _serialize_xml, "html": _serialize_html, "text": _serialize_text, # this optional method is imported at the end of the module # "c14n": _serialize_c14n, } ## # Registers a namespace prefix. The registry is global, and any # existing mapping for either the given prefix or the namespace URI # will be removed. # # @param prefix Namespace prefix. # @param uri Namespace uri. Tags and attributes in this namespace # will be serialized with the given prefix, if at all possible. # @exception ValueError If the prefix is reserved, or is otherwise # invalid. def register_namespace(prefix, uri): if re.match("ns\d+$", prefix): raise ValueError("Prefix format reserved for internal use") for k, v in _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", } def _raise_serialization_error(text): raise TypeError( "cannot serialize %r (type %s)" % (text, type(text).__name__) ) def _encode(text, encoding): try: return text.encode(encoding, "xmlcharrefreplace") except (TypeError, AttributeError): _raise_serialization_error(text) def _escape_cdata(text, encoding): # 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(">", ">") return text.encode(encoding, "xmlcharrefreplace") except (TypeError, AttributeError): _raise_serialization_error(text) def _escape_attrib(text, encoding): # 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("\"", """) if "\n" in text: text = text.replace("\n", " ") return text.encode(encoding, "xmlcharrefreplace") except (TypeError, AttributeError): _raise_serialization_error(text) def _escape_attrib_html(text, encoding): # escape attribute value try: if "&" in text: text = text.replace("&", "&") if ">" in text: text = text.replace(">", ">") if "\"" in text: text = text.replace("\"", """) return text.encode(encoding, "xmlcharrefreplace") except (TypeError, AttributeError): _raise_serialization_error(text) # -------------------------------------------------------------------- ## # Generates a string representation of an XML element, including all # subelements. # # @param element An Element instance. # @keyparam encoding Optional output encoding (default is US-ASCII). # @keyparam method Optional output method ("xml", "html", "text" or # "c14n"; default is "xml"). # @return An encoded string containing the XML data. # @defreturn string def tostring(element, encoding=None, method=None): class dummy: pass data = [] file = dummy() file.write = data.append ElementTree(element).write(file, encoding, method=method) return "".join(data) ## # Generates a string representation of an XML element, including all # subelements. The string is returned as a sequence of string fragments. # # @param element An Element instance. # @keyparam encoding Optional output encoding (default is US-ASCII). # @keyparam method Optional output method ("xml", "html", "text" or # "c14n"; default is "xml"). # @return A sequence object containing the XML data. # @defreturn sequence # @since 1.3 def tostringlist(element, encoding=None, method=None): class dummy: pass data = [] file = dummy() file.write = data.append ElementTree(element).write(file, encoding, method=method) # FIXME: merge small fragments into larger parts return data ## # Writes an element tree or element structure to sys.stdout. This # function should be used for debugging only. # <p> # 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) 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 try: if not parser: parser = XMLParser(target=TreeBuilder()) return _IterParseIterator(source, events, parser, close_source) except: if close_source: source.close() raise class _IterParseIterator(object): 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): try: uri = (uri or "").encode("ascii") except UnicodeError: pass 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): try: 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 break # 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 except: if self._close_file: self._file.close() raise if self._close_file: self._file.close() raise StopIteration 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. # <p> # 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(object): 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 _sentinel = ['sentinel'] ## # Element structure builder for XML source data, based on the # <b>expat</b> 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(object): def __init__(self, html=_sentinel, target=None, encoding=None): if html is not _sentinel: warnings.warnpy3k( "The html argument of XMLParser() is deprecated", DeprecationWarning, stacklevel=2) 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 # callbacks parser.DefaultHandlerExpand = self._default parser.StartElementHandler = self._start parser.EndElementHandler = self._end parser.CharacterDataHandler = self._data # optional callbacks parser.CommentHandler = self._comment parser.ProcessingInstructionHandler = self._pi # let expat do the buffering, if supported try: self._parser.buffer_text = 1 except AttributeError: pass # use new-style attribute handling, if supported try: self._parser.ordered_attributes = 1 self._parser.specified_attributes = 1 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 _fixtext(self, text): # convert text string to ascii, if possible try: return text.encode("ascii") except UnicodeError: return text 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 = self._fixtext(name) return name def _start(self, tag, attrib_in): fixname = self._fixname fixtext = self._fixtext tag = fixname(tag) attrib = {} for key, value in attrib_in.items(): attrib[fixname(key)] = fixtext(value) return self.target.start(tag, attrib) def _start_list(self, tag, attrib_in): fixname = self._fixname fixtext = self._fixtext tag = fixname(tag) attrib = {} if attrib_in: for i in range(0, len(attrib_in), 2): attrib[fixname(attrib_in[i])] = fixtext(attrib_in[i+1]) return self.target.start(tag, attrib) def _data(self, text): return self.target.data(self._fixtext(text)) def _end(self, tag): return self.target.end(self._fixname(tag)) def _comment(self, data): try: comment = self.target.comment except AttributeError: pass else: return comment(self._fixtext(data)) def _pi(self, target, data): try: pi = self.target.pi except AttributeError: pass else: return pi(self._fixtext(target), self._fixtext(data)) def _default(self, text): prefix = text[:1] if prefix == "&": # deal with undefined entities try: self.target.data(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 elif type == "SYSTEM" and n == 3: name, type, system = self._doctype pubid = None else: return if pubid: pubid = pubid[1:-1] 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, 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, v: self._raiseerror(v) tree = self.target.close() del self.target, self._parser # get rid of circular references return tree # compatibility XMLTreeBuilder = XMLParser # workaround circular import. try: from ElementC14N import _serialize_c14n _serialize["c14n"] = _serialize_c14n except ImportError: pass