| # Copyright 2017-present Open Networking Foundation |
| # |
| # Licensed under the Apache License, Version 2.0 (the "License"); |
| # you may not use this file except in compliance with the License. |
| # You may obtain a copy of the License at |
| # |
| # http://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, software |
| # distributed under the License is distributed on an "AS IS" BASIS, |
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| # See the License for the specific language governing permissions and |
| # limitations under the License. |
| |
| |
| #!/usr/bin/env python |
| from types import StringTypes |
| from lxml import etree |
| from StringIO import StringIO |
| |
| # helper functions to help build xpaths |
| |
| |
| class XpathFilter: |
| @staticmethod |
| def filter_value(key, value): |
| xpath = "" |
| if isinstance(value, str): |
| if "*" in value: |
| value = value.replace("*", "") |
| xpath = 'contains(%s, "%s")' % (key, value) |
| else: |
| xpath = '%s="%s"' % (key, value) |
| return xpath |
| |
| @staticmethod |
| def xpath(filter={}): |
| xpath = "" |
| if filter: |
| filter_list = [] |
| for (key, value) in filter.items(): |
| if key == "text": |
| key = "text()" |
| else: |
| key = "@" + key |
| if isinstance(value, str): |
| filter_list.append(XpathFilter.filter_value(key, value)) |
| elif isinstance(value, list): |
| stmt = " or ".join( |
| [XpathFilter.filter_value(key, str(val)) for val in value] |
| ) |
| filter_list.append(stmt) |
| if filter_list: |
| xpath = " and ".join(filter_list) |
| xpath = "[" + xpath + "]" |
| return xpath |
| |
| |
| # a wrapper class around lxml.etree._Element |
| # the reason why we need this one is because of the limitations |
| # we've found in xpath to address documents with multiple namespaces defined |
| # in a nutshell, we deal with xml documents that have |
| # a default namespace defined (xmlns="http://default.com/") and specific prefixes defined |
| # (xmlns:foo="http://foo.com") |
| # according to the documentation instead of writing |
| # element.xpath ( "//node/foo:subnode" ) |
| # we'd then need to write xpaths like |
| # element.xpath ( "//{http://default.com/}node/{http://foo.com}subnode" ) |
| # which is a real pain.. |
| # So just so we can keep some reasonable programming style we need to manage the |
| # namespace map that goes with the _Element (its internal .nsmap being unmutable) |
| class XmlElement: |
| def __init__(self, element, namespaces): |
| self.element = element |
| self.namespaces = namespaces |
| |
| # redefine as few methods as possible |
| def xpath(self, xpath, namespaces=None): |
| if not namespaces: |
| namespaces = self.namespaces |
| elems = self.element.xpath(xpath, namespaces=namespaces) |
| return [XmlElement(elem, namespaces) for elem in elems] |
| |
| def add_element(self, tagname, **kwds): |
| element = etree.SubElement(self.element, tagname, **kwds) |
| return XmlElement(element, self.namespaces) |
| |
| def append(self, elem): |
| if isinstance(elem, XmlElement): |
| self.element.append(elem.element) |
| else: |
| self.element.append(elem) |
| |
| def getparent(self): |
| return XmlElement(self.element.getparent(), self.namespaces) |
| |
| def get_instance(self, instance_class=None, fields=[]): |
| """ |
| Returns an instance (dict) of this xml element. The instance |
| holds a reference to this xml element. |
| """ |
| if not instance_class: |
| instance_class = Object |
| if not fields and hasattr(instance_class, "fields"): |
| fields = instance_class.fields |
| |
| if not fields: |
| instance = instance_class(self.attrib, self) |
| else: |
| instance = instance_class({}, self) |
| for field in fields: |
| if field in self.attrib: |
| instance[field] = self.attrib[field] |
| return instance |
| |
| def add_instance(self, name, instance, fields=[]): |
| """ |
| Adds the specifed instance(s) as a child element of this xml |
| element. |
| """ |
| if not fields and hasattr(instance, "keys"): |
| fields = instance.keys() |
| elem = self.add_element(name) |
| for field in fields: |
| if field in instance and instance[field]: |
| elem.set(field, unicode(instance[field])) |
| return elem |
| |
| def remove_elements(self, name): |
| """ |
| Removes all occurences of an element from the tree. Start at |
| specified root_node if specified, otherwise start at tree's root. |
| """ |
| |
| if not name.startswith("//"): |
| name = "//" + name |
| elements = self.element.xpath("%s " % name, namespaces=self.namespaces) |
| for element in elements: |
| parent = element.getparent() |
| parent.remove(element) |
| |
| def delete(self): |
| parent = self.getparent() |
| parent.remove(self) |
| |
| def remove(self, element): |
| if isinstance(element, XmlElement): |
| self.element.remove(element.element) |
| else: |
| self.element.remove(element) |
| |
| def set_text(self, text): |
| self.element.text = text |
| |
| # Element does not have unset ?!? |
| def unset(self, key): |
| del self.element.attrib[key] |
| |
| def toxml(self): |
| return etree.tostring(self.element, encoding="UTF-8", pretty_print=True) |
| |
| def __str__(self): |
| return self.toxml() |
| |
| # are redirected on self.element |
| def __getattr__(self, name): |
| if not hasattr(self.element, name): |
| raise AttributeError(name) |
| return getattr(self.element, name) |
| |
| |
| class Xml: |
| def __init__(self, xml=None, namespaces=None): |
| self.root = None |
| self.namespaces = namespaces |
| self.default_namespace = None |
| self.schema = None |
| if isinstance(xml, basestring): |
| self.parse_xml(xml) |
| if isinstance(xml, XmlElement): |
| self.root = xml |
| self.namespaces = xml.namespaces |
| elif isinstance(xml, etree._ElementTree) or isinstance(xml, etree._Element): |
| self.parse_xml(etree.tostring(xml)) |
| |
| def parse_xml(self, xml): |
| """ |
| parse rspec into etree |
| """ |
| parser = etree.XMLParser(remove_blank_text=True) |
| try: |
| tree = etree.parse(xml, parser) |
| except IOError: |
| # 'rspec' file doesnt exist. 'rspec' is proably an xml string |
| try: |
| tree = etree.parse(StringIO(xml), parser) |
| except Exception as e: |
| raise Exception(str(e)) |
| root = tree.getroot() |
| self.namespaces = dict(root.nsmap) |
| # set namespaces map |
| if "default" not in self.namespaces and None in self.namespaces: |
| # If the 'None' exist, then it's pointing to the default namespace. This makes |
| # it hard for us to write xpath queries for the default naemspace because lxml |
| # wont understand a None prefix. We will just associate the default namespeace |
| # with a key named 'default'. |
| self.namespaces["default"] = self.namespaces.pop(None) |
| |
| else: |
| self.namespaces["default"] = "default" |
| |
| self.root = XmlElement(root, self.namespaces) |
| # set schema |
| for key in self.root.attrib.keys(): |
| if key.endswith("schemaLocation"): |
| # schemaLocation should be at the end of the list. |
| # Use list comprehension to filter out empty strings |
| schema_parts = [x for x in self.root.attrib[key].split(" ") if x] |
| self.schema = schema_parts[1] |
| namespace, schema = schema_parts[0], schema_parts[1] |
| break |
| |
| def parse_dict(self, d, root_tag_name="xml", element=None): |
| if element is None: |
| if self.root is None: |
| self.parse_xml("<%s/>" % root_tag_name) |
| element = self.root.element |
| |
| if "text" in d: |
| text = d.pop("text") |
| element.text = text |
| |
| # handle repeating fields |
| for (key, value) in d.items(): |
| if isinstance(value, list): |
| value = d.pop(key) |
| for val in value: |
| if isinstance(val, dict): |
| child_element = etree.SubElement(element, key) |
| self.parse_dict(val, key, child_element) |
| elif isinstance(val, basestring): |
| child_element = etree.SubElement(element, key).text = val |
| |
| elif isinstance(value, int): |
| d[key] = unicode(d[key]) |
| elif value is None: |
| d.pop(key) |
| |
| # element.attrib.update will explode if DateTimes are in the |
| # dcitionary. |
| d = d.copy() |
| # looks like iteritems won't stand side-effects |
| for k in d.keys(): |
| if not isinstance(d[k], StringTypes): |
| del d[k] |
| |
| element.attrib.update(d) |
| |
| def validate(self, schema): |
| """ |
| Validate against rng schema |
| """ |
| relaxng_doc = etree.parse(schema) |
| relaxng = etree.RelaxNG(relaxng_doc) |
| if not relaxng(self.root): |
| error = relaxng.error_log.last_error |
| message = "%s (line %s)" % (error.message, error.line) |
| raise Exception(message) |
| return True |
| |
| def xpath(self, xpath, namespaces=None): |
| if not namespaces: |
| namespaces = self.namespaces |
| return self.root.xpath(xpath, namespaces=namespaces) |
| |
| def set(self, key, value): |
| return self.root.set(key, value) |
| |
| def remove_attribute(self, name, element=None): |
| if not element: |
| element = self.root |
| element.remove_attribute(name) |
| |
| def add_element(self, *args, **kwds): |
| """ |
| Wrapper around etree.SubElement(). Adds an element to |
| specified parent node. Adds element to root node is parent is |
| not specified. |
| """ |
| return self.root.add_element(*args, **kwds) |
| |
| def remove_elements(self, name, element=None): |
| """ |
| Removes all occurences of an element from the tree. Start at |
| specified root_node if specified, otherwise start at tree's root. |
| """ |
| if not element: |
| element = self.root |
| |
| element.remove_elements(name) |
| |
| def add_instance(self, *args, **kwds): |
| return self.root.add_instance(*args, **kwds) |
| |
| def get_instance(self, *args, **kwds): |
| return self.root.get_instnace(*args, **kwds) |
| |
| def get_element_attributes(self, elem=None, depth=0): |
| if elem is None: |
| elem = self.root |
| if not hasattr(elem, "attrib"): |
| # this is probably not an element node with attribute. could be just and an |
| # attribute, return it |
| return elem |
| attrs = dict(elem.attrib) |
| attrs["text"] = str(elem.text).strip() |
| attrs["parent"] = elem.getparent() |
| if isinstance(depth, int) and depth > 0: |
| for child_elem in list(elem): |
| key = str(child_elem.tag) |
| if key not in attrs: |
| attrs[key] = [self.get_element_attributes(child_elem, depth - 1)] |
| else: |
| attrs[key].append( |
| self.get_element_attributes(child_elem, depth - 1) |
| ) |
| else: |
| attrs["child_nodes"] = list(elem) |
| return attrs |
| |
| def append(self, elem): |
| return self.root.append(elem) |
| |
| def iterchildren(self): |
| return self.root.iterchildren() |
| |
| def merge(self, in_xml): |
| pass |
| |
| def __str__(self): |
| return self.toxml() |
| |
| def toxml(self): |
| return etree.tostring(self.root.element, encoding="UTF-8", pretty_print=True) |
| |
| # XXX smbaker, for record.load_from_string |
| def todict(self, elem=None): |
| if elem is None: |
| elem = self.root |
| d = {} |
| d.update(elem.attrib) |
| d["text"] = elem.text |
| for child in elem.iterchildren(): |
| if child.tag not in d: |
| d[child.tag] = [] |
| d[child.tag].append(self.todict(child)) |
| |
| if len(d) == 1 and ("text" in d): |
| d = d["text"] |
| |
| return d |
| |
| def save(self, filename): |
| f = open(filename, "w") |
| f.write(self.toxml()) |
| f.close() |