--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/app/django/core/serializers/xml_serializer.py Fri Jul 18 18:22:23 2008 +0000
@@ -0,0 +1,237 @@
+"""
+XML serializer.
+"""
+
+from django.conf import settings
+from django.core.serializers import base
+from django.db import models
+from django.utils.xmlutils import SimplerXMLGenerator
+from django.utils.encoding import smart_unicode
+from xml.dom import pulldom
+
+class Serializer(base.Serializer):
+ """
+ Serializes a QuerySet to XML.
+ """
+
+ def indent(self, level):
+ if self.options.get('indent', None) is not None:
+ self.xml.ignorableWhitespace('\n' + ' ' * self.options.get('indent', None) * level)
+
+ def start_serialization(self):
+ """
+ Start serialization -- open the XML document and the root element.
+ """
+ self.xml = SimplerXMLGenerator(self.stream, self.options.get("encoding", settings.DEFAULT_CHARSET))
+ self.xml.startDocument()
+ self.xml.startElement("django-objects", {"version" : "1.0"})
+
+ def end_serialization(self):
+ """
+ End serialization -- end the document.
+ """
+ self.indent(0)
+ self.xml.endElement("django-objects")
+ self.xml.endDocument()
+
+ def start_object(self, obj):
+ """
+ Called as each object is handled.
+ """
+ if not hasattr(obj, "_meta"):
+ raise base.SerializationError("Non-model object (%s) encountered during serialization" % type(obj))
+
+ self.indent(1)
+ self.xml.startElement("object", {
+ "pk" : smart_unicode(obj._get_pk_val()),
+ "model" : smart_unicode(obj._meta),
+ })
+
+ def end_object(self, obj):
+ """
+ Called after handling all fields for an object.
+ """
+ self.indent(1)
+ self.xml.endElement("object")
+
+ def handle_field(self, obj, field):
+ """
+ Called to handle each field on an object (except for ForeignKeys and
+ ManyToManyFields)
+ """
+ self.indent(2)
+ self.xml.startElement("field", {
+ "name" : field.name,
+ "type" : field.get_internal_type()
+ })
+
+ # Get a "string version" of the object's data (this is handled by the
+ # serializer base class).
+ if getattr(obj, field.name) is not None:
+ value = self.get_string_value(obj, field)
+ self.xml.characters(smart_unicode(value))
+ else:
+ self.xml.addQuickElement("None")
+
+ self.xml.endElement("field")
+
+ def handle_fk_field(self, obj, field):
+ """
+ Called to handle a ForeignKey (we need to treat them slightly
+ differently from regular fields).
+ """
+ self._start_relational_field(field)
+ related = getattr(obj, field.name)
+ if related is not None:
+ if field.rel.field_name == related._meta.pk.name:
+ # Related to remote object via primary key
+ related = related._get_pk_val()
+ else:
+ # Related to remote object via other field
+ related = getattr(related, field.rel.field_name)
+ self.xml.characters(smart_unicode(related))
+ else:
+ self.xml.addQuickElement("None")
+ self.xml.endElement("field")
+
+ def handle_m2m_field(self, obj, field):
+ """
+ Called to handle a ManyToManyField. Related objects are only
+ serialized as references to the object's PK (i.e. the related *data*
+ is not dumped, just the relation).
+ """
+ self._start_relational_field(field)
+ for relobj in getattr(obj, field.name).iterator():
+ self.xml.addQuickElement("object", attrs={"pk" : smart_unicode(relobj._get_pk_val())})
+ self.xml.endElement("field")
+
+ def _start_relational_field(self, field):
+ """
+ Helper to output the <field> element for relational fields
+ """
+ self.indent(2)
+ self.xml.startElement("field", {
+ "name" : field.name,
+ "rel" : field.rel.__class__.__name__,
+ "to" : smart_unicode(field.rel.to._meta),
+ })
+
+class Deserializer(base.Deserializer):
+ """
+ Deserialize XML.
+ """
+
+ def __init__(self, stream_or_string, **options):
+ super(Deserializer, self).__init__(stream_or_string, **options)
+ self.event_stream = pulldom.parse(self.stream)
+
+ def next(self):
+ for event, node in self.event_stream:
+ if event == "START_ELEMENT" and node.nodeName == "object":
+ self.event_stream.expandNode(node)
+ return self._handle_object(node)
+ raise StopIteration
+
+ def _handle_object(self, node):
+ """
+ Convert an <object> node to a DeserializedObject.
+ """
+ # Look up the model using the model loading mechanism. If this fails,
+ # bail.
+ Model = self._get_model_from_node(node, "model")
+
+ # Start building a data dictionary from the object. If the node is
+ # missing the pk attribute, bail.
+ pk = node.getAttribute("pk")
+ if not pk:
+ raise base.DeserializationError("<object> node is missing the 'pk' attribute")
+
+ data = {Model._meta.pk.attname : Model._meta.pk.to_python(pk)}
+
+ # Also start building a dict of m2m data (this is saved as
+ # {m2m_accessor_attribute : [list_of_related_objects]})
+ m2m_data = {}
+
+ # Deseralize each field.
+ for field_node in node.getElementsByTagName("field"):
+ # If the field is missing the name attribute, bail (are you
+ # sensing a pattern here?)
+ field_name = field_node.getAttribute("name")
+ if not field_name:
+ raise base.DeserializationError("<field> node is missing the 'name' attribute")
+
+ # Get the field from the Model. This will raise a
+ # FieldDoesNotExist if, well, the field doesn't exist, which will
+ # be propagated correctly.
+ field = Model._meta.get_field(field_name)
+
+ # As is usually the case, relation fields get the special treatment.
+ if field.rel and isinstance(field.rel, models.ManyToManyRel):
+ m2m_data[field.name] = self._handle_m2m_field_node(field_node, field)
+ elif field.rel and isinstance(field.rel, models.ManyToOneRel):
+ data[field.attname] = self._handle_fk_field_node(field_node, field)
+ else:
+ if field_node.getElementsByTagName('None'):
+ value = None
+ else:
+ value = field.to_python(getInnerText(field_node).strip())
+ data[field.name] = value
+
+ # Return a DeserializedObject so that the m2m data has a place to live.
+ return base.DeserializedObject(Model(**data), m2m_data)
+
+ def _handle_fk_field_node(self, node, field):
+ """
+ Handle a <field> node for a ForeignKey
+ """
+ # Check if there is a child node named 'None', returning None if so.
+ if node.getElementsByTagName('None'):
+ return None
+ else:
+ return field.rel.to._meta.get_field(field.rel.field_name).to_python(
+ getInnerText(node).strip())
+
+ def _handle_m2m_field_node(self, node, field):
+ """
+ Handle a <field> node for a ManyToManyField.
+ """
+ return [field.rel.to._meta.pk.to_python(
+ c.getAttribute("pk"))
+ for c in node.getElementsByTagName("object")]
+
+ def _get_model_from_node(self, node, attr):
+ """
+ Helper to look up a model from a <object model=...> or a <field
+ rel=... to=...> node.
+ """
+ model_identifier = node.getAttribute(attr)
+ if not model_identifier:
+ raise base.DeserializationError(
+ "<%s> node is missing the required '%s' attribute" \
+ % (node.nodeName, attr))
+ try:
+ Model = models.get_model(*model_identifier.split("."))
+ except TypeError:
+ Model = None
+ if Model is None:
+ raise base.DeserializationError(
+ "<%s> node has invalid model identifier: '%s'" % \
+ (node.nodeName, model_identifier))
+ return Model
+
+
+def getInnerText(node):
+ """
+ Get all the inner text of a DOM node (recursively).
+ """
+ # inspired by http://mail.python.org/pipermail/xml-sig/2005-March/011022.html
+ inner_text = []
+ for child in node.childNodes:
+ if child.nodeType == child.TEXT_NODE or child.nodeType == child.CDATA_SECTION_NODE:
+ inner_text.append(child.data)
+ elif child.nodeType == child.ELEMENT_NODE:
+ inner_text.extend(getInnerText(child))
+ else:
+ pass
+ return u"".join(inner_text)
+