xmlbuilder.py
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"""Implementation of the DOM Level 3 'LS-Load' feature.""" import copy import warnings import xml.dom from xml.dom.NodeFilter import NodeFilter __all__ = ["DOMBuilder", "DOMEntityResolver", "DOMInputSource"] class Options: """Features object that has variables set for each DOMBuilder feature. The DOMBuilder class uses an instance of this class to pass settings to the ExpatBuilder class. """ # Note that the DOMBuilder class in LoadSave constrains which of these # values can be set using the DOM Level 3 LoadSave feature. namespaces = 1 namespace_declarations = True validation = False external_parameter_entities = True external_general_entities = True external_dtd_subset = True validate_if_schema = False validate = False datatype_normalization = False create_entity_ref_nodes = True entities = True whitespace_in_element_content = True cdata_sections = True comments = True charset_overrides_xml_encoding = True infoset = False supported_mediatypes_only = False errorHandler = None filter = None class DOMBuilder: entityResolver = None errorHandler = None filter = None ACTION_REPLACE = 1 ACTION_APPEND_AS_CHILDREN = 2 ACTION_INSERT_AFTER = 3 ACTION_INSERT_BEFORE = 4 _legal_actions = (ACTION_REPLACE, ACTION_APPEND_AS_CHILDREN, ACTION_INSERT_AFTER, ACTION_INSERT_BEFORE) def __init__(self): self._options = Options() def _get_entityResolver(self): return self.entityResolver def _set_entityResolver(self, entityResolver): self.entityResolver = entityResolver def _get_errorHandler(self): return self.errorHandler def _set_errorHandler(self, errorHandler): self.errorHandler = errorHandler def _get_filter(self): return self.filter def _set_filter(self, filter): self.filter = filter def setFeature(self, name, state): if self.supportsFeature(name): state = state and 1 or 0 try: settings = self._settings[(_name_xform(name), state)] except KeyError: raise xml.dom.NotSupportedErr( "unsupported feature: %r" % (name,)) else: for name, value in settings: setattr(self._options, name, value) else: raise xml.dom.NotFoundErr("unknown feature: " + repr(name)) def supportsFeature(self, name): return hasattr(self._options, _name_xform(name)) def canSetFeature(self, name, state): key = (_name_xform(name), state and 1 or 0) return key in self._settings # This dictionary maps from (feature,value) to a list of # (option,value) pairs that should be set on the Options object. # If a (feature,value) setting is not in this dictionary, it is # not supported by the DOMBuilder. # _settings = { ("namespace_declarations", 0): [ ("namespace_declarations", 0)], ("namespace_declarations", 1): [ ("namespace_declarations", 1)], ("validation", 0): [ ("validation", 0)], ("external_general_entities", 0): [ ("external_general_entities", 0)], ("external_general_entities", 1): [ ("external_general_entities", 1)], ("external_parameter_entities", 0): [ ("external_parameter_entities", 0)], ("external_parameter_entities", 1): [ ("external_parameter_entities", 1)], ("validate_if_schema", 0): [ ("validate_if_schema", 0)], ("create_entity_ref_nodes", 0): [ ("create_entity_ref_nodes", 0)], ("create_entity_ref_nodes", 1): [ ("create_entity_ref_nodes", 1)], ("entities", 0): [ ("create_entity_ref_nodes", 0), ("entities", 0)], ("entities", 1): [ ("entities", 1)], ("whitespace_in_element_content", 0): [ ("whitespace_in_element_content", 0)], ("whitespace_in_element_content", 1): [ ("whitespace_in_element_content", 1)], ("cdata_sections", 0): [ ("cdata_sections", 0)], ("cdata_sections", 1): [ ("cdata_sections", 1)], ("comments", 0): [ ("comments", 0)], ("comments", 1): [ ("comments", 1)], ("charset_overrides_xml_encoding", 0): [ ("charset_overrides_xml_encoding", 0)], ("charset_overrides_xml_encoding", 1): [ ("charset_overrides_xml_encoding", 1)], ("infoset", 0): [], ("infoset", 1): [ ("namespace_declarations", 0), ("validate_if_schema", 0), ("create_entity_ref_nodes", 0), ("entities", 0), ("cdata_sections", 0), ("datatype_normalization", 1), ("whitespace_in_element_content", 1), ("comments", 1), ("charset_overrides_xml_encoding", 1)], ("supported_mediatypes_only", 0): [ ("supported_mediatypes_only", 0)], ("namespaces", 0): [ ("namespaces", 0)], ("namespaces", 1): [ ("namespaces", 1)], } def getFeature(self, name): xname = _name_xform(name) try: return getattr(self._options, xname) except AttributeError: if name == "infoset": options = self._options return (options.datatype_normalization and options.whitespace_in_element_content and options.comments and options.charset_overrides_xml_encoding and not (options.namespace_declarations or options.validate_if_schema or options.create_entity_ref_nodes or options.entities or options.cdata_sections)) raise xml.dom.NotFoundErr("feature %s not known" % repr(name)) def parseURI(self, uri): if self.entityResolver: input = self.entityResolver.resolveEntity(None, uri) else: input = DOMEntityResolver().resolveEntity(None, uri) return self.parse(input) def parse(self, input): options = copy.copy(self._options) options.filter = self.filter options.errorHandler = self.errorHandler fp = input.byteStream if fp is None and options.systemId: import urllib.request fp = urllib.request.urlopen(input.systemId) return self._parse_bytestream(fp, options) def parseWithContext(self, input, cnode, action): if action not in self._legal_actions: raise ValueError("not a legal action") raise NotImplementedError("Haven't written this yet...") def _parse_bytestream(self, stream, options): import xml.dom.expatbuilder builder = xml.dom.expatbuilder.makeBuilder(options) return builder.parseFile(stream) def _name_xform(name): return name.lower().replace('-', '_') class DOMEntityResolver(object): __slots__ = '_opener', def resolveEntity(self, publicId, systemId): assert systemId is not None source = DOMInputSource() source.publicId = publicId source.systemId = systemId source.byteStream = self._get_opener().open(systemId) # determine the encoding if the transport provided it source.encoding = self._guess_media_encoding(source) # determine the base URI is we can import posixpath, urllib.parse parts = urllib.parse.urlparse(systemId) scheme, netloc, path, params, query, fragment = parts # XXX should we check the scheme here as well? if path and not path.endswith("/"): path = posixpath.dirname(path) + "/" parts = scheme, netloc, path, params, query, fragment source.baseURI = urllib.parse.urlunparse(parts) return source def _get_opener(self): try: return self._opener except AttributeError: self._opener = self._create_opener() return self._opener def _create_opener(self): import urllib.request return urllib.request.build_opener() def _guess_media_encoding(self, source): info = source.byteStream.info() if "Content-Type" in info: for param in info.getplist(): if param.startswith("charset="): return param.split("=", 1)[1].lower() class DOMInputSource(object): __slots__ = ('byteStream', 'characterStream', 'stringData', 'encoding', 'publicId', 'systemId', 'baseURI') def __init__(self): self.byteStream = None self.characterStream = None self.stringData = None self.encoding = None self.publicId = None self.systemId = None self.baseURI = None def _get_byteStream(self): return self.byteStream def _set_byteStream(self, byteStream): self.byteStream = byteStream def _get_characterStream(self): return self.characterStream def _set_characterStream(self, characterStream): self.characterStream = characterStream def _get_stringData(self): return self.stringData def _set_stringData(self, data): self.stringData = data def _get_encoding(self): return self.encoding def _set_encoding(self, encoding): self.encoding = encoding def _get_publicId(self): return self.publicId def _set_publicId(self, publicId): self.publicId = publicId def _get_systemId(self): return self.systemId def _set_systemId(self, systemId): self.systemId = systemId def _get_baseURI(self): return self.baseURI def _set_baseURI(self, uri): self.baseURI = uri class DOMBuilderFilter: """Element filter which can be used to tailor construction of a DOM instance. """ # There's really no need for this class; concrete implementations # should just implement the endElement() and startElement() # methods as appropriate. Using this makes it easy to only # implement one of them. FILTER_ACCEPT = 1 FILTER_REJECT = 2 FILTER_SKIP = 3 FILTER_INTERRUPT = 4 whatToShow = NodeFilter.SHOW_ALL def _get_whatToShow(self): return self.whatToShow def acceptNode(self, element): return self.FILTER_ACCEPT def startContainer(self, element): return self.FILTER_ACCEPT del NodeFilter class _AsyncDeprecatedProperty: def warn(self, cls): clsname = cls.__name__ warnings.warn( "{cls}.async is deprecated; use {cls}.async_".format(cls=clsname), DeprecationWarning) def __get__(self, instance, cls): self.warn(cls) if instance is not None: return instance.async_ return False def __set__(self, instance, value): self.warn(type(instance)) setattr(instance, 'async_', value) class DocumentLS: """Mixin to create documents that conform to the load/save spec.""" async_ = False locals()['async'] = _AsyncDeprecatedProperty() # Avoid DeprecationWarning def _get_async(self): return False def _set_async(self, flag): if flag: raise xml.dom.NotSupportedErr( "asynchronous document loading is not supported") def abort(self): # What does it mean to "clear" a document? Does the # documentElement disappear? raise NotImplementedError( "haven't figured out what this means yet") def load(self, uri): raise NotImplementedError("haven't written this yet") def loadXML(self, source): raise NotImplementedError("haven't written this yet") def saveXML(self, snode): if snode is None: snode = self elif snode.ownerDocument is not self: raise xml.dom.WrongDocumentErr() return snode.toxml() del _AsyncDeprecatedProperty class DOMImplementationLS: MODE_SYNCHRONOUS = 1 MODE_ASYNCHRONOUS = 2 def createDOMBuilder(self, mode, schemaType): if schemaType is not None: raise xml.dom.NotSupportedErr( "schemaType not yet supported") if mode == self.MODE_SYNCHRONOUS: return DOMBuilder() if mode == self.MODE_ASYNCHRONOUS: raise xml.dom.NotSupportedErr( "asynchronous builders are not supported") raise ValueError("unknown value for mode") def createDOMWriter(self): raise NotImplementedError( "the writer interface hasn't been written yet!") def createDOMInputSource(self): return DOMInputSource()
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