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# encoding: utf-8
"""
Temporary stand-in for main oxml module that came across with the
PackageReader transplant. Probably much will get replaced with objects from
the pptx.oxml.core and then this module will either get deleted or only hold
the package related custom element classes.
"""
from __future__ import absolute_import, print_function, unicode_literals
from lxml import etree
from .constants import NAMESPACE as NS, RELATIONSHIP_TARGET_MODE as RTM
# configure XML parser
element_class_lookup = etree.ElementNamespaceClassLookup()
oxml_parser = etree.XMLParser(remove_blank_text=True, resolve_entities=False)
oxml_parser.set_element_class_lookup(element_class_lookup)
nsmap = {
'ct': NS.OPC_CONTENT_TYPES,
'pr': NS.OPC_RELATIONSHIPS,
'r': NS.OFC_RELATIONSHIPS,
}
# ===========================================================================
# functions
# ===========================================================================
def parse_xml(text):
"""
``etree.fromstring()`` replacement that uses oxml parser
"""
return etree.fromstring(text, oxml_parser)
def qn(tag):
"""
Stands for "qualified name", a utility function to turn a namespace
prefixed tag name into a Clark-notation qualified tag name for lxml. For
example, ``qn('p:cSld')`` returns ``'{http://schemas.../main}cSld'``.
"""
prefix, tagroot = tag.split(':')
uri = nsmap[prefix]
return '{%s}%s' % (uri, tagroot)
def serialize_part_xml(part_elm):
"""
Serialize *part_elm* etree element to XML suitable for storage as an XML
part. That is to say, no insignificant whitespace added for readability,
and an appropriate XML declaration added with UTF-8 encoding specified.
"""
return etree.tostring(part_elm, encoding='UTF-8', standalone=True)
def serialize_for_reading(element):
"""
Serialize *element* to human-readable XML suitable for tests. No XML
declaration.
"""
return etree.tostring(element, encoding='unicode', pretty_print=True)
# ===========================================================================
# Custom element classes
# ===========================================================================
class BaseOxmlElement(etree.ElementBase):
"""
Base class for all custom element classes, to add standardized behavior
to all classes in one place.
"""
@property
def xml(self):
"""
Return XML string for this element, suitable for testing purposes.
Pretty printed for readability and without an XML declaration at the
top.
"""
return serialize_for_reading(self)
class CT_Default(BaseOxmlElement):
"""
``<Default>`` element, specifying the default content type to be applied
to a part with the specified extension.
"""
@property
def content_type(self):
"""
String held in the ``ContentType`` attribute of this ``<Default>``
element.
"""
return self.get('ContentType')
@property
def extension(self):
"""
String held in the ``Extension`` attribute of this ``<Default>``
element.
"""
return self.get('Extension')
@staticmethod
def new(ext, content_type):
"""
Return a new ``<Default>`` element with attributes set to parameter
values.
"""
xml = '<Default xmlns="%s"/>' % nsmap['ct']
default = parse_xml(xml)
default.set('Extension', ext)
default.set('ContentType', content_type)
return default
class CT_Override(BaseOxmlElement):
"""
``<Override>`` element, specifying the content type to be applied for a
part with the specified partname.
"""
@property
def content_type(self):
"""
String held in the ``ContentType`` attribute of this ``<Override>``
element.
"""
return self.get('ContentType')
@staticmethod
def new(partname, content_type):
"""
Return a new ``<Override>`` element with attributes set to parameter
values.
"""
xml = '<Override xmlns="%s"/>' % nsmap['ct']
override = parse_xml(xml)
override.set('PartName', partname)
override.set('ContentType', content_type)
return override
@property
def partname(self):
"""
String held in the ``PartName`` attribute of this ``<Override>``
element.
"""
return self.get('PartName')
class CT_Relationship(BaseOxmlElement):
"""
``<Relationship>`` element, representing a single relationship from a
source to a target part.
"""
@staticmethod
def new(rId, reltype, target, target_mode=RTM.INTERNAL):
"""
Return a new ``<Relationship>`` element.
"""
xml = '<Relationship xmlns="%s"/>' % nsmap['pr']
relationship = parse_xml(xml)
relationship.set('Id', rId)
relationship.set('Type', reltype)
relationship.set('Target', target)
if target_mode == RTM.EXTERNAL:
relationship.set('TargetMode', RTM.EXTERNAL)
return relationship
@property
def rId(self):
"""
String held in the ``Id`` attribute of this ``<Relationship>``
element.
"""
return self.get('Id')
@property
def reltype(self):
"""
String held in the ``Type`` attribute of this ``<Relationship>``
element.
"""
return self.get('Type')
@property
def target_ref(self):
"""
String held in the ``Target`` attribute of this ``<Relationship>``
element.
"""
return self.get('Target')
@property
def target_mode(self):
"""
String held in the ``TargetMode`` attribute of this
``<Relationship>`` element, either ``Internal`` or ``External``.
Defaults to ``Internal``.
"""
return self.get('TargetMode', RTM.INTERNAL)
class CT_Relationships(BaseOxmlElement):
"""
``<Relationships>`` element, the root element in a .rels file.
"""
def add_rel(self, rId, reltype, target, is_external=False):
"""
Add a child ``<Relationship>`` element with attributes set according
to parameter values.
"""
target_mode = RTM.EXTERNAL if is_external else RTM.INTERNAL
relationship = CT_Relationship.new(rId, reltype, target, target_mode)
self.append(relationship)
@staticmethod
def new():
"""
Return a new ``<Relationships>`` element.
"""
xml = '<Relationships xmlns="%s"/>' % nsmap['pr']
relationships = parse_xml(xml)
return relationships
@property
def Relationship_lst(self):
"""
Return a list containing all the ``<Relationship>`` child elements.
"""
return self.findall(qn('pr:Relationship'))
@property
def xml(self):
"""
Return XML string for this element, suitable for saving in a .rels
stream, not pretty printed and with an XML declaration at the top.
"""
return serialize_part_xml(self)
class CT_Types(BaseOxmlElement):
"""
``<Types>`` element, the container element for Default and Override
elements in [Content_Types].xml.
"""
def add_default(self, ext, content_type):
"""
Add a child ``<Default>`` element with attributes set to parameter
values.
"""
default = CT_Default.new(ext, content_type)
self.append(default)
def add_override(self, partname, content_type):
"""
Add a child ``<Override>`` element with attributes set to parameter
values.
"""
override = CT_Override.new(partname, content_type)
self.append(override)
@property
def defaults(self):
return self.findall(qn('ct:Default'))
@staticmethod
def new():
"""
Return a new ``<Types>`` element.
"""
xml = '<Types xmlns="%s"/>' % nsmap['ct']
types = parse_xml(xml)
return types
@property
def overrides(self):
return self.findall(qn('ct:Override'))
ct_namespace = element_class_lookup.get_namespace(nsmap['ct'])
ct_namespace['Default'] = CT_Default
ct_namespace['Override'] = CT_Override
ct_namespace['Types'] = CT_Types
pr_namespace = element_class_lookup.get_namespace(nsmap['pr'])
pr_namespace['Relationship'] = CT_Relationship
pr_namespace['Relationships'] = CT_Relationships