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#
# Copyright (C) 2006 Google Inc.
#
# 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.
"""Contains extensions to Atom objects used with Google Base."""
__author__ = 'api.jscudder (Jeffrey Scudder)'
try:
from xml.etree import cElementTree as ElementTree
except ImportError:
try:
import cElementTree as ElementTree
except ImportError:
try:
from xml.etree import ElementTree
except ImportError:
from elementtree import ElementTree
import atom
import gdata
# XML namespaces which are often used in Google Base entities.
GBASE_NAMESPACE = 'http://base.google.com/ns/1.0'
GBASE_TEMPLATE = '{http://base.google.com/ns/1.0}%s'
GMETA_NAMESPACE = 'http://base.google.com/ns-metadata/1.0'
GMETA_TEMPLATE = '{http://base.google.com/ns-metadata/1.0}%s'
class ItemAttributeContainer(object):
"""Provides methods for finding Google Base Item attributes.
Google Base item attributes are child nodes in the gbase namespace. Google
Base allows you to define your own item attributes and this class provides
methods to interact with the custom attributes.
"""
def GetItemAttributes(self, name):
"""Returns a list of all item attributes which have the desired name.
Args:
name: str The tag of the desired base attributes. For example, calling
this method with 'rating' would return a list of ItemAttributes
represented by a 'g:rating' tag.
Returns:
A list of matching ItemAttribute objects.
"""
result = []
for attrib in self.item_attributes:
if attrib.name == name:
result.append(attrib)
return result
def FindItemAttribute(self, name):
"""Get the contents of the first Base item attribute which matches name.
This method is deprecated, please use GetItemAttributes instead.
Args:
name: str The tag of the desired base attribute. For example, calling
this method with name = 'rating' would search for a tag rating
in the GBase namespace in the item attributes.
Returns:
The text contents of the item attribute, or none if the attribute was
not found.
"""
for attrib in self.item_attributes:
if attrib.name == name:
return attrib.text
return None
def AddItemAttribute(self, name, value, value_type=None, access=None):
"""Adds a new item attribute tag containing the value.
Creates a new extension element in the GBase namespace to represent a
Google Base item attribute.
Args:
name: str The tag name for the new attribute. This must be a valid xml
tag name. The tag will be placed in the GBase namespace.
value: str Contents for the item attribute
value_type: str (optional) The type of data in the vlaue, Examples: text
float
access: str (optional) Used to hide attributes. The attribute is not
exposed in the snippets feed if access is set to 'private'.
"""
new_attribute = ItemAttribute(name, text=value,
text_type=value_type, access=access)
self.item_attributes.append(new_attribute)
def SetItemAttribute(self, name, value):
"""Changes an existing item attribute's value."""
for attrib in self.item_attributes:
if attrib.name == name:
attrib.text = value
return
def RemoveItemAttribute(self, name):
"""Deletes the first extension element which matches name.
Deletes the first extension element which matches name.
"""
for i in xrange(len(self.item_attributes)):
if self.item_attributes[i].name == name:
del self.item_attributes[i]
return
# We need to overwrite _ConvertElementTreeToMember to add special logic to
# convert custom attributes to members
def _ConvertElementTreeToMember(self, child_tree):
# Find the element's tag in this class's list of child members
if self.__class__._children.has_key(child_tree.tag):
member_name = self.__class__._children[child_tree.tag][0]
member_class = self.__class__._children[child_tree.tag][1]
# If the class member is supposed to contain a list, make sure the
# matching member is set to a list, then append the new member
# instance to the list.
if isinstance(member_class, list):
if getattr(self, member_name) is None:
setattr(self, member_name, [])
getattr(self, member_name).append(atom._CreateClassFromElementTree(
member_class[0], child_tree))
else:
setattr(self, member_name,
atom._CreateClassFromElementTree(member_class, child_tree))
elif child_tree.tag.find('{%s}' % GBASE_NAMESPACE) == 0:
# If this is in the gbase namespace, make it into an extension element.
name = child_tree.tag[child_tree.tag.index('}')+1:]
value = child_tree.text
if child_tree.attrib.has_key('type'):
value_type = child_tree.attrib['type']
else:
value_type = None
self.AddItemAttribute(name, value, value_type)
else:
atom.ExtensionContainer._ConvertElementTreeToMember(self, child_tree)
# We need to overwtite _AddMembersToElementTree to add special logic to
# convert custom members to XML nodes.
def _AddMembersToElementTree(self, tree):
# Convert the members of this class which are XML child nodes.
# This uses the class's _children dictionary to find the members which
# should become XML child nodes.
member_node_names = [values[0] for tag, values in
self.__class__._children.iteritems()]
for member_name in member_node_names:
member = getattr(self, member_name)
if member is None:
pass
elif isinstance(member, list):
for instance in member:
instance._BecomeChildElement(tree)
else:
member._BecomeChildElement(tree)
# Convert the members of this class which are XML attributes.
for xml_attribute, member_name in self.__class__._attributes.iteritems():
member = getattr(self, member_name)
if member is not None:
tree.attrib[xml_attribute] = member
# Convert all special custom item attributes to nodes
for attribute in self.item_attributes:
attribute._BecomeChildElement(tree)
# Lastly, call the ExtensionContainers's _AddMembersToElementTree to
# convert any extension attributes.
atom.ExtensionContainer._AddMembersToElementTree(self, tree)
class ItemAttribute(atom.Text):
"""An optional or user defined attribute for a GBase item.
Google Base allows items to have custom attribute child nodes. These nodes
have contents and a type attribute which tells Google Base whether the
contents are text, a float value with units, etc. The Atom text class has
the same structure, so this class inherits from Text.
"""
_namespace = GBASE_NAMESPACE
_children = atom.Text._children.copy()
_attributes = atom.Text._attributes.copy()
_attributes['access'] = 'access'
def __init__(self, name, text_type=None, access=None, text=None,
extension_elements=None, extension_attributes=None):
"""Constructor for a GBase item attribute
Args:
name: str The name of the attribute. Examples include
price, color, make, model, pages, salary, etc.
text_type: str (optional) The type associated with the text contents
access: str (optional) If the access attribute is set to 'private', the
attribute will not be included in the item's description in the
snippets feed
text: str (optional) The text data in the this element
extension_elements: list (optional) A list of ExtensionElement
instances
extension_attributes: dict (optional) A dictionary of attribute
value string pairs
"""
self.name = name
self.type = text_type
self.access = access
self.text = text
self.extension_elements = extension_elements or []
self.extension_attributes = extension_attributes or {}
def _BecomeChildElement(self, tree):
new_child = ElementTree.Element('')
tree.append(new_child)
new_child.tag = '{%s}%s' % (self.__class__._namespace,
self.name)
self._AddMembersToElementTree(new_child)
def _ToElementTree(self):
new_tree = ElementTree.Element('{%s}%s' % (self.__class__._namespace,
self.name))
self._AddMembersToElementTree(new_tree)
return new_tree
def ItemAttributeFromString(xml_string):
element_tree = ElementTree.fromstring(xml_string)
return _ItemAttributeFromElementTree(element_tree)
def _ItemAttributeFromElementTree(element_tree):
if element_tree.tag.find(GBASE_TEMPLATE % '') == 0:
to_return = ItemAttribute('')
to_return._HarvestElementTree(element_tree)
to_return.name = element_tree.tag[element_tree.tag.index('}')+1:]
if to_return.name and to_return.name != '':
return to_return
return None
class Label(atom.AtomBase):
"""The Google Base label element"""
_tag = 'label'
_namespace = GBASE_NAMESPACE
_children = atom.AtomBase._children.copy()
_attributes = atom.AtomBase._attributes.copy()
def __init__(self, text=None, extension_elements=None,
extension_attributes=None):
self.text = text
self.extension_elements = extension_elements or []
self.extension_attributes = extension_attributes or {}
def LabelFromString(xml_string):
return atom.CreateClassFromXMLString(Label, xml_string)
class Thumbnail(atom.AtomBase):
"""The Google Base thumbnail element"""
_tag = 'thumbnail'
_namespace = GMETA_NAMESPACE
_children = atom.AtomBase._children.copy()
_attributes = atom.AtomBase._attributes.copy()
_attributes['width'] = 'width'
_attributes['height'] = 'height'
def __init__(self, width=None, height=None, text=None, extension_elements=None,
extension_attributes=None):
self.text = text
self.extension_elements = extension_elements or []
self.extension_attributes = extension_attributes or {}
self.width = width
self.height = height
def ThumbnailFromString(xml_string):
return atom.CreateClassFromXMLString(Thumbnail, xml_string)
class ImageLink(atom.Text):
"""The Google Base image_link element"""
_tag = 'image_link'
_namespace = GBASE_NAMESPACE
_children = atom.Text._children.copy()
_attributes = atom.Text._attributes.copy()
_children['{%s}thumbnail' % GMETA_NAMESPACE] = ('thumbnail', [Thumbnail])
def __init__(self, thumbnail=None, text=None, extension_elements=None,
text_type=None, extension_attributes=None):
self.thumbnail = thumbnail or []
self.text = text
self.type = text_type
self.extension_elements = extension_elements or []
self.extension_attributes = extension_attributes or {}
def ImageLinkFromString(xml_string):
return atom.CreateClassFromXMLString(ImageLink, xml_string)
class ItemType(atom.Text):
"""The Google Base item_type element"""
_tag = 'item_type'
_namespace = GBASE_NAMESPACE
_children = atom.Text._children.copy()
_attributes = atom.Text._attributes.copy()
def __init__(self, text=None, extension_elements=None,
text_type=None, extension_attributes=None):
self.text = text
self.type = text_type
self.extension_elements = extension_elements or []
self.extension_attributes = extension_attributes or {}
def ItemTypeFromString(xml_string):
return atom.CreateClassFromXMLString(ItemType, xml_string)
class MetaItemType(ItemType):
"""The Google Base item_type element"""
_tag = 'item_type'
_namespace = GMETA_NAMESPACE
_children = ItemType._children.copy()
_attributes = ItemType._attributes.copy()
def MetaItemTypeFromString(xml_string):
return atom.CreateClassFromXMLString(MetaItemType, xml_string)
class Value(atom.AtomBase):
"""Metadata about common values for a given attribute
A value is a child of an attribute which comes from the attributes feed.
The value's text is a commonly used value paired with an attribute name
and the value's count tells how often this value appears for the given
attribute in the search results.
"""
_tag = 'value'
_namespace = GMETA_NAMESPACE
_children = atom.AtomBase._children.copy()
_attributes = atom.AtomBase._attributes.copy()
_attributes['count'] = 'count'
def __init__(self, count=None, text=None, extension_elements=None,
extension_attributes=None):
"""Constructor for Attribute metadata element
Args:
count: str (optional) The number of times the value in text is given
for the parent attribute.
text: str (optional) The value which appears in the search results.
extension_elements: list (optional) A list of ExtensionElement
instances
extension_attributes: dict (optional) A dictionary of attribute value
string pairs
"""
self.count = count
self.text = text
self.extension_elements = extension_elements or []
self.extension_attributes = extension_attributes or {}
def ValueFromString(xml_string):
return atom.CreateClassFromXMLString(Value, xml_string)
class Attribute(atom.Text):
"""Metadata about an attribute from the attributes feed
An entry from the attributes feed contains a list of attributes. Each
attribute describes the attribute's type and count of the items which
use the attribute.
"""
_tag = 'attribute'
_namespace = GMETA_NAMESPACE
_children = atom.Text._children.copy()
_attributes = atom.Text._attributes.copy()
_children['{%s}value' % GMETA_NAMESPACE] = ('value', [Value])
_attributes['count'] = 'count'
_attributes['name'] = 'name'
def __init__(self, name=None, attribute_type=None, count=None, value=None,
text=None, extension_elements=None, extension_attributes=None):
"""Constructor for Attribute metadata element
Args:
name: str (optional) The name of the attribute
attribute_type: str (optional) The type for the attribute. Examples:
test, float, etc.
count: str (optional) The number of times this attribute appears in
the query results.
value: list (optional) The values which are often used for this
attirbute.
text: str (optional) The text contents of the XML for this attribute.
extension_elements: list (optional) A list of ExtensionElement
instances
extension_attributes: dict (optional) A dictionary of attribute value
string pairs
"""
self.name = name
self.type = attribute_type
self.count = count
self.value = value or []
self.text = text
self.extension_elements = extension_elements or []
self.extension_attributes = extension_attributes or {}
def AttributeFromString(xml_string):
return atom.CreateClassFromXMLString(Attribute, xml_string)
class Attributes(atom.AtomBase):
"""A collection of Google Base metadata attributes"""
_tag = 'attributes'
_namespace = GMETA_NAMESPACE
_children = atom.AtomBase._children.copy()
_attributes = atom.AtomBase._attributes.copy()
_children['{%s}attribute' % GMETA_NAMESPACE] = ('attribute', [Attribute])
def __init__(self, attribute=None, extension_elements=None,
extension_attributes=None, text=None):
self.attribute = attribute or []
self.extension_elements = extension_elements or []
self.extension_attributes = extension_attributes or {}
self.text = text
class GBaseItem(ItemAttributeContainer, gdata.BatchEntry):
"""An Google Base flavor of an Atom Entry.
Google Base items have required attributes, recommended attributes, and user
defined attributes. The required attributes are stored in this class as
members, and other attributes are stored as extension elements. You can
access the recommended and user defined attributes by using
AddItemAttribute, SetItemAttribute, FindItemAttribute, and
RemoveItemAttribute.
The Base Item
"""
_tag = 'entry'
_namespace = atom.ATOM_NAMESPACE
_children = gdata.BatchEntry._children.copy()
_attributes = gdata.BatchEntry._attributes.copy()
_children['{%s}label' % GBASE_NAMESPACE] = ('label', [Label])
_children['{%s}item_type' % GBASE_NAMESPACE] = ('item_type', ItemType)
def __init__(self, author=None, category=None, content=None,
contributor=None, atom_id=None, link=None, published=None, rights=None,
source=None, summary=None, title=None, updated=None, control=None,
label=None, item_type=None, item_attributes=None,
batch_operation=None, batch_id=None, batch_status=None,
text=None, extension_elements=None, extension_attributes=None):
self.author = author or []
self.category = category or []
self.content = content
self.contributor = contributor or []
self.id = atom_id
self.link = link or []
self.published = published
self.rights = rights
self.source = source
self.summary = summary
self.title = title
self.updated = updated
self.control = control
self.label = label or []
self.item_type = item_type
self.item_attributes = item_attributes or []
self.batch_operation = batch_operation
self.batch_id = batch_id
self.batch_status = batch_status
self.text = text
self.extension_elements = extension_elements or []
self.extension_attributes = extension_attributes or {}
def GBaseItemFromString(xml_string):
return atom.CreateClassFromXMLString(GBaseItem, xml_string)
class GBaseSnippet(GBaseItem):
_tag = 'entry'
_namespace = atom.ATOM_NAMESPACE
_children = GBaseItem._children.copy()
_attributes = GBaseItem._attributes.copy()
def GBaseSnippetFromString(xml_string):
return atom.CreateClassFromXMLString(GBaseSnippet, xml_string)
class GBaseAttributeEntry(gdata.GDataEntry):
"""An Atom Entry from the attributes feed"""
_tag = 'entry'
_namespace = atom.ATOM_NAMESPACE
_children = gdata.GDataEntry._children.copy()
_attributes = gdata.GDataEntry._attributes.copy()
_children['{%s}attribute' % GMETA_NAMESPACE] = ('attribute', [Attribute])
def __init__(self, author=None, category=None, content=None,
contributor=None, atom_id=None, link=None, published=None, rights=None,
source=None, summary=None, title=None, updated=None, label=None,
attribute=None, control=None,
text=None, extension_elements=None, extension_attributes=None):
self.author = author or []
self.category = category or []
self.content = content
self.contributor = contributor or []
self.id = atom_id
self.link = link or []
self.published = published
self.rights = rights
self.source = source
self.summary = summary
self.control = control
self.title = title
self.updated = updated
self.label = label or []
self.attribute = attribute or []
self.text = text
self.extension_elements = extension_elements or []
self.extension_attributes = extension_attributes or {}
def GBaseAttributeEntryFromString(xml_string):
return atom.CreateClassFromXMLString(GBaseAttributeEntry, xml_string)
class GBaseItemTypeEntry(gdata.GDataEntry):
"""An Atom entry from the item types feed
These entries contain a list of attributes which are stored in one
XML node called attributes. This class simplifies the data structure
by treating attributes as a list of attribute instances.
Note that the item_type for an item type entry is in the Google Base meta
namespace as opposed to item_types encountered in other feeds.
"""
_tag = 'entry'
_namespace = atom.ATOM_NAMESPACE
_children = gdata.GDataEntry._children.copy()
_attributes = gdata.GDataEntry._attributes.copy()
_children['{%s}attributes' % GMETA_NAMESPACE] = ('attributes', Attributes)
_children['{%s}attribute' % GMETA_NAMESPACE] = ('attribute', [Attribute])
_children['{%s}item_type' % GMETA_NAMESPACE] = ('item_type', MetaItemType)
def __init__(self, author=None, category=None, content=None,
contributor=None, atom_id=None, link=None, published=None, rights=None,
source=None, summary=None, title=None, updated=None, label=None,
item_type=None, control=None, attribute=None, attributes=None,
text=None, extension_elements=None, extension_attributes=None):
self.author = author or []
self.category = category or []
self.content = content
self.contributor = contributor or []
self.id = atom_id
self.link = link or []
self.published = published
self.rights = rights
self.source = source
self.summary = summary
self.title = title
self.updated = updated
self.control = control
self.label = label or []
self.item_type = item_type
self.attributes = attributes
self.attribute = attribute or []
self.text = text
self.extension_elements = extension_elements or []
self.extension_attributes = extension_attributes or {}
def GBaseItemTypeEntryFromString(xml_string):
return atom.CreateClassFromXMLString(GBaseItemTypeEntry, xml_string)
class GBaseItemFeed(gdata.BatchFeed):
"""A feed containing Google Base Items"""
_tag = 'feed'
_namespace = atom.ATOM_NAMESPACE
_children = gdata.BatchFeed._children.copy()
_attributes = gdata.BatchFeed._attributes.copy()
_children['{%s}entry' % atom.ATOM_NAMESPACE] = ('entry', [GBaseItem])
def GBaseItemFeedFromString(xml_string):
return atom.CreateClassFromXMLString(GBaseItemFeed, xml_string)
class GBaseSnippetFeed(gdata.GDataFeed):
"""A feed containing Google Base Snippets"""
_tag = 'feed'
_namespace = atom.ATOM_NAMESPACE
_children = gdata.GDataFeed._children.copy()
_attributes = gdata.GDataFeed._attributes.copy()
_children['{%s}entry' % atom.ATOM_NAMESPACE] = ('entry', [GBaseSnippet])
def GBaseSnippetFeedFromString(xml_string):
return atom.CreateClassFromXMLString(GBaseSnippetFeed, xml_string)
class GBaseAttributesFeed(gdata.GDataFeed):
"""A feed containing Google Base Attributes
A query sent to the attributes feed will return a feed of
attributes which are present in the items that match the
query.
"""
_tag = 'feed'
_namespace = atom.ATOM_NAMESPACE
_children = gdata.GDataFeed._children.copy()
_attributes = gdata.GDataFeed._attributes.copy()
_children['{%s}entry' % atom.ATOM_NAMESPACE] = ('entry',
[GBaseAttributeEntry])
def GBaseAttributesFeedFromString(xml_string):
return atom.CreateClassFromXMLString(GBaseAttributesFeed, xml_string)
class GBaseLocalesFeed(gdata.GDataFeed):
"""The locales feed from Google Base.
This read-only feed defines the permitted locales for Google Base. The
locale value identifies the language, currency, and date formats used in a
feed.
"""
_tag = 'feed'
_namespace = atom.ATOM_NAMESPACE
_children = gdata.GDataFeed._children.copy()
_attributes = gdata.GDataFeed._attributes.copy()
def GBaseLocalesFeedFromString(xml_string):
return atom.CreateClassFromXMLString(GBaseLocalesFeed, xml_string)
class GBaseItemTypesFeed(gdata.GDataFeed):
"""A feed from the Google Base item types feed"""
_tag = 'feed'
_namespace = atom.ATOM_NAMESPACE
_children = gdata.GDataFeed._children.copy()
_attributes = gdata.GDataFeed._attributes.copy()
_children['{%s}entry' % atom.ATOM_NAMESPACE] = ('entry', [GBaseItemTypeEntry])
def GBaseItemTypesFeedFromString(xml_string):
return atom.CreateClassFromXMLString(GBaseItemTypesFeed, xml_string)
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