# # Copyright (c), 2016-2021, SISSA (International School for Advanced Studies). # All rights reserved. # This file is distributed under the terms of the MIT License. # See the file 'LICENSE' in the root directory of the present # distribution, or http://opensource.org/licenses/MIT. # # @author Davide Brunato # import sys if sys.version_info < (3, 7): from typing import GenericMeta as ABCMeta else: from abc import ABCMeta from itertools import count from typing import TYPE_CHECKING, cast, overload, Any, Dict, List, Iterator, \ Optional, Union, Tuple, Type, MutableMapping, MutableSequence from elementpath import XPathContext, XPath2Parser from .exceptions import XMLSchemaAttributeError, XMLSchemaTypeError, XMLSchemaValueError from .etree import ElementData, etree_tostring from .aliases import ElementType, XMLSourceType, NamespacesType, BaseXsdType, DecodeType from .helpers import get_namespace, get_prefixed_qname, local_name, raw_xml_encode from .converters import XMLSchemaConverter from .resources import XMLResource from . import validators if TYPE_CHECKING: from .validators import XMLSchemaValidationError, XsdElement class DataElement(MutableSequence['DataElement']): """ Data Element, an Element like object with decoded data and schema bindings. :param tag: a string containing a QName in extended format. :param value: the simple typed value of the element. :param attrib: the typed attributes of the element. :param nsmap: an optional map from prefixes to namespaces. :param xsd_element: an optional XSD element association. :param xsd_type: an optional XSD type association. Can be provided \ also if the instance is not bound with an XSD element. """ _children: List['DataElement'] tag: str attrib: Dict[str, Any] nsmap: Dict[str, str] value: Optional[Any] = None tail: Optional[str] = None xsd_element: Optional['XsdElement'] = None xsd_type: Optional[BaseXsdType] = None _encoder: Optional['XsdElement'] = None def __init__(self, tag: str, value: Optional[Any] = None, attrib: Optional[Dict[str, Any]] = None, nsmap: Optional[MutableMapping[str, str]] = None, xsd_element: Optional['XsdElement'] = None, xsd_type: Optional[BaseXsdType] = None) -> None: super(DataElement, self).__init__() self._children = [] self.tag = tag self.attrib = {} self.nsmap = {} if value is not None: self.value = value if attrib is not None: self.attrib.update(attrib) if nsmap is not None: self.nsmap.update(nsmap) if xsd_element is not None: self.xsd_element = xsd_element self.xsd_type = xsd_type or xsd_element.type elif xsd_type is not None: self.xsd_type = xsd_type elif self.xsd_element is not None: self._encoder = self.xsd_element @overload def __getitem__(self, i: int) -> 'DataElement': ... @overload def __getitem__(self, s: slice) -> MutableSequence['DataElement']: ... def __getitem__(self, i: Union[int, slice]) \ -> Union['DataElement', MutableSequence['DataElement']]: return self._children[i] def __setitem__(self, i: Union[int, slice], child: Any) -> None: self._children[i] = child def __delitem__(self, i: Union[int, slice]) -> None: del self._children[i] def __len__(self) -> int: return len(self._children) def insert(self, i: int, child: 'DataElement') -> None: assert isinstance(child, DataElement) self._children.insert(i, child) def __repr__(self) -> str: return '%s(tag=%r)' % (self.__class__.__name__, self.tag) def __iter__(self) -> Iterator['DataElement']: yield from self._children def __setattr__(self, key: str, value: Any) -> None: if key == 'xsd_element': if not isinstance(value, validators.XsdElement): raise XMLSchemaTypeError("invalid type for attribute 'xsd_element'") elif self.xsd_element is value: pass elif self.xsd_element is not None: raise XMLSchemaValueError("the instance is already bound to another XSD element") elif self.xsd_type is not None and self.xsd_type is not value.type: raise XMLSchemaValueError("the instance is already bound to another XSD type") elif key == 'xsd_type': if not isinstance(value, (validators.XsdSimpleType, validators.XsdComplexType)): raise XMLSchemaTypeError("invalid type for attribute 'xsd_type'") elif self.xsd_type is not None and self.xsd_type is not value: raise XMLSchemaValueError("the instance is already bound to another XSD type") elif self.xsd_element is None or value is not self.xsd_element.type: self._encoder = value.schema.create_element( self.tag, parent=value, form='unqualified' ) self._encoder.type = value else: self._encoder = self.xsd_element super(DataElement, self).__setattr__(key, value) @property def text(self) -> Optional[str]: """The string value of the data element.""" return raw_xml_encode(self.value) def get(self, key: str, default: Any = None) -> Any: """Gets a data element attribute.""" return self.attrib.get(key, default) def set(self, key: str, value: Any) -> None: """Sets a data element attribute.""" self.attrib[key] = value @property def xsd_version(self) -> str: return '1.0' if self.xsd_element is None else self.xsd_element.xsd_version @property def namespace(self) -> str: """The element's namespace.""" if self.xsd_element is None: return get_namespace(self.tag) return get_namespace(self.tag) or self.xsd_element.target_namespace @property def name(self) -> str: """The element's name, that matches the tag.""" return self.tag @property def prefixed_name(self) -> str: """The prefixed name, or the tag if no prefix is defined for its namespace.""" return get_prefixed_qname(self.tag, self.nsmap) @property def local_name(self) -> str: """The local part of the tag.""" return local_name(self.tag) def validate(self, use_defaults: bool = True, namespaces: Optional[NamespacesType] = None, max_depth: Optional[int] = None) -> None: """ Validates the XML data object. :param use_defaults: whether to use default values for filling missing data. :param namespaces: is an optional mapping from namespace prefix to URI. \ For default uses the namespace map of the XML data object. :param max_depth: maximum depth for validation, for default there is no limit. :raises: :exc:`XMLSchemaValidationError` if XML data object is not valid. :raises: :exc:`XMLSchemaValueError` if the instance has no schema bindings. """ for error in self.iter_errors(use_defaults, namespaces, max_depth): raise error def is_valid(self, use_defaults: bool = True, namespaces: Optional[NamespacesType] = None, max_depth: Optional[int] = None) -> bool: """ Like :meth:`validate` except it does not raise an exception on validation error but returns ``True`` if the XML data object is valid, ``False`` if it's invalid. :raises: :exc:`XMLSchemaValueError` if the instance has no schema bindings. """ error = next(self.iter_errors(use_defaults, namespaces, max_depth), None) return error is None def iter_errors(self, use_defaults: bool = True, namespaces: Optional[NamespacesType] = None, max_depth: Optional[int] = None) -> Iterator['XMLSchemaValidationError']: """ Generates a sequence of validation errors if the XML data object is invalid. Accepts the same arguments of :meth:`validate`. """ if self._encoder is None: raise XMLSchemaValueError("{!r} has no schema bindings".format(self)) kwargs: Dict[str, Any] = { 'converter': DataElementConverter, 'use_defaults': use_defaults, } if namespaces: kwargs['namespaces'] = namespaces if isinstance(max_depth, int) and max_depth >= 0: kwargs['max_depth'] = max_depth for result in self._encoder.iter_encode(self, **kwargs): if isinstance(result, validators.XMLSchemaValidationError): yield result else: del result def encode(self, validation: str = 'strict', **kwargs: Any) \ -> Union[ElementType, Tuple[ElementType, List['XMLSchemaValidationError']]]: """ Encodes the data object to XML. :param validation: the validation mode. Can be 'lax', 'strict' or 'skip. :param kwargs: optional keyword arguments for the method :func:`iter_encode` \ of :class:`XsdElement`. :return: An ElementTree's Element. If *validation* argument is 'lax' a \ 2-items tuple is returned, where the first item is the encoded object and \ the second item is a list with validation errors. :raises: :exc:`XMLSchemaValidationError` if the object is invalid \ and ``validation='strict'``. """ if 'converter' not in kwargs: kwargs['converter'] = DataElementConverter encoder: Union['XsdElement', BaseXsdType] if self._encoder is not None: encoder = self._encoder elif validation == 'skip': encoder = validators.XMLSchema.builtin_types()['anyType'] else: raise XMLSchemaValueError("{!r} has no schema bindings".format(self)) return encoder.encode(self, validation=validation, **kwargs) to_etree = encode def tostring(self, indent: str = '', max_lines: Optional[int] = None, spaces_for_tab: int = 4) -> Any: """Serializes the data element tree to an XML source string.""" root, errors = self.encode(validation='lax') return etree_tostring(root, self.nsmap, indent, max_lines, spaces_for_tab) def find(self, path: str, namespaces: Optional[NamespacesType] = None) -> Optional['DataElement']: """ Finds the first data element matching the path. :param path: an XPath expression that considers the data element as the root. :param namespaces: an optional mapping from namespace prefix to namespace URI. :return: the first matching data element or ``None`` if there is no match. """ parser = XPath2Parser(namespaces, strict=False) context = XPathContext(cast(Any, self)) result = next(parser.parse(path).select_results(context), None) return result if isinstance(result, DataElement) else None def findall(self, path: str, namespaces: Optional[NamespacesType] = None) -> List['DataElement']: """ Finds all data elements matching the path. :param path: an XPath expression that considers the data element as the root. :param namespaces: an optional mapping from namespace prefix to full name. :return: a list containing all matching data elements in document order, \ an empty list is returned if there is no match. """ parser = XPath2Parser(namespaces, strict=False) context = XPathContext(cast(Any, self)) results = parser.parse(path).get_results(context) if not isinstance(results, list): return [] return [e for e in results if isinstance(e, DataElement)] def iterfind(self, path: str, namespaces: Optional[NamespacesType] = None) -> Iterator['DataElement']: """ Creates and iterator for all XSD subelements matching the path. :param path: an XPath expression that considers the data element as the root. :param namespaces: is an optional mapping from namespace prefix to full name. :return: an iterable yielding all matching data elements in document order. """ parser = XPath2Parser(namespaces, strict=False) context = XPathContext(cast(Any, self)) results = parser.parse(path).select_results(context) yield from filter(lambda x: isinstance(x, DataElement), results) # type: ignore[misc] def iter(self, tag: Optional[str] = None) -> Iterator['DataElement']: """ Creates an iterator for the data element and its subelements. If tag is not `None` or '*', only data elements whose matches tag are returned from the iterator. """ if tag == '*': tag = None if tag is None or tag == self.tag: yield self for child in self._children: yield from child.iter(tag) def iterchildren(self, tag: Optional[str] = None) -> Iterator['DataElement']: """ Creates an iterator for the child data elements. If *tag* is not `None` or '*', only data elements whose name matches tag are returned from the iterator. """ if tag == '*': tag = None for child in self: if tag is None or tag == child.tag: yield child class DataBindingMeta(ABCMeta): """Metaclass for creating classes with bindings to XSD elements.""" xsd_element: 'XsdElement' def __new__(mcs, name: str, bases: Tuple[Type[Any], ...], attrs: Dict[str, Any]) -> 'DataBindingMeta': try: xsd_element = attrs['xsd_element'] except KeyError: msg = "attribute 'xsd_element' is required for an XSD data binding class" raise XMLSchemaAttributeError(msg) from None if not isinstance(xsd_element, validators.XsdElement): raise XMLSchemaTypeError("{!r} is not an XSD element".format(xsd_element)) attrs['__module__'] = None return super(DataBindingMeta, mcs).__new__(mcs, name, bases, attrs) def __init__(cls, name: str, bases: Tuple[Type[Any], ...], attrs: Dict[str, Any]) -> None: super(DataBindingMeta, cls).__init__(name, bases, attrs) cls.xsd_version = cls.xsd_element.xsd_version cls.namespace = cls.xsd_element.target_namespace def fromsource(cls, source: Union[XMLSourceType, XMLResource], allow: str = 'all', defuse: str = 'remote', timeout: int = 300, **kwargs: Any) -> DecodeType[Any]: if not isinstance(source, XMLResource): source = XMLResource(source, allow=allow, defuse=defuse, timeout=timeout) if 'converter' not in kwargs: kwargs['converter'] = DataBindingConverter return cls.xsd_element.schema.decode(source, **kwargs) class DataElementConverter(XMLSchemaConverter): """ XML Schema based converter class for DataElement objects. :param namespaces: a dictionary map from namespace prefixes to URI. :param data_element_class: MutableSequence subclass to use for decoded data. \ Default is `DataElement`. """ __slots__ = 'data_element_class', def __init__(self, namespaces: Optional[NamespacesType] = None, data_element_class: Optional[Type['DataElement']] = None, **kwargs: Any) -> None: if data_element_class is None: self.data_element_class = DataElement else: self.data_element_class = data_element_class kwargs.update(attr_prefix='', text_key='', cdata_prefix='') super(DataElementConverter, self).__init__(namespaces, **kwargs) @property def lossy(self) -> bool: return False @property def losslessly(self) -> bool: return True def copy(self, **kwargs: Any) -> 'DataElementConverter': obj = cast(DataElementConverter, super().copy(**kwargs)) obj.data_element_class = kwargs.get('data_element_class', self.data_element_class) return obj def element_decode(self, data: ElementData, xsd_element: 'XsdElement', xsd_type: Optional[BaseXsdType] = None, level: int = 0) -> 'DataElement': data_element = self.data_element_class( tag=data.tag, value=data.text, nsmap=self.namespaces, xsd_element=xsd_element, xsd_type=xsd_type ) data_element.attrib.update((k, v) for k, v in self.map_attributes(data.attributes)) if (xsd_type or xsd_element.type).model_group is not None: for name, value, _ in self.map_content(data.content): if not name.isdigit(): data_element.append(value) else: try: data_element[-1].tail = value except IndexError: data_element.value = value return data_element def element_encode(self, data_element: 'DataElement', xsd_element: 'XsdElement', level: int = 0) -> ElementData: self.namespaces.update(data_element.nsmap) if not xsd_element.is_matching(data_element.tag, self._namespaces.get('')): raise XMLSchemaValueError("Unmatched tag") attributes = {self.unmap_qname(k, xsd_element.attributes): v for k, v in data_element.attrib.items()} data_len = len(data_element) if not data_len: return ElementData(data_element.tag, data_element.value, None, attributes) content: List[Tuple[Union[str, int], Any]] = [] cdata_num = count(1) if data_element.value is not None: content.append((next(cdata_num), data_element.value)) for e in data_element: content.append((e.tag, e)) if e.tail is not None: content.append((next(cdata_num), e.tail)) return ElementData(data_element.tag, None, content, attributes) class DataBindingConverter(DataElementConverter): """ A :class:`DataElementConverter` that uses XML data binding classes for decoding. Takes the same arguments of its parent class but the argument *data_element_class* is used for define the base for creating the missing XML binding classes. """ __slots__ = () def element_decode(self, data: ElementData, xsd_element: 'XsdElement', xsd_type: Optional[BaseXsdType] = None, level: int = 0) -> 'DataElement': cls = xsd_element.get_binding(self.data_element_class) data_element = cls( tag=data.tag, value=data.text, nsmap=self.namespaces, xsd_type=xsd_type ) data_element.attrib.update((k, v) for k, v in self.map_attributes(data.attributes)) if (xsd_type or xsd_element.type).model_group is not None: for name, value, _ in self.map_content(data.content): if not name.isdigit(): data_element.append(value) else: try: data_element[-1].tail = value except IndexError: data_element.value = value return data_element