blob: d3aefb1e379686509363834f3d8807523f174669 [file] [log] [blame]
#!/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 element_name.startswith('//'):
element_name = '//' + element_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, 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 == 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()