def django_instance_to_entities(connection,
fields,
raw,
instance,
check_null=True,
model=None):
"""
Converts a Django Model instance to an App Engine `Entity`
Arguments:
connection: Djangae appengine connection object
fields: A list of fields to populate in the Entity
raw: raw flag to pass to get_prepared_db_value
instance: The Django model instance to convert
check_null: Whether or not we should enforce NULL during conversion
(throws an error if None is set on a non-nullable field)
model: Model class to use instead of the instance one
Returns:
entity, [entity, entity, ...]
Where the first result in the tuple is the primary entity, and the
remaining entities are optionally descendents of the primary entity. This
is useful for special indexes (e.g. contains)
"""
from gcloudc.db.backends.datastore.indexing import special_indexes_for_column, get_indexer, IgnoreForIndexing
from gcloudc.db.backends.datastore import POLYMODEL_CLASS_ATTRIBUTE
model = model or type(instance)
inheritance_root = get_top_concrete_parent(model)
db_table = get_datastore_kind(inheritance_root)
def value_from_instance(_instance, _field):
value = get_prepared_db_value(connection, _instance, _field, raw)
# If value is None, but there is a default, and the field is not nullable then we should populate it
# Otherwise thing get hairy when you add new fields to models
if value is None and _field.has_default() and not _field.null:
# We need to pass the default through get_db_prep_save to properly do the conversion
# this is how
value = _field.get_db_prep_save(_field.get_default(), connection)
if check_null and (not _field.null
and not _field.primary_key) and value is None:
raise IntegrityError(
"You can't set %s (a non-nullable field) to None!" %
_field.name)
is_primary_key = False
if _field.primary_key and _field.model == inheritance_root:
is_primary_key = True
return value, is_primary_key
field_values = {}
primary_key = None
descendents = []
fields_to_unindex = set()
for field in fields:
value, is_primary_key = value_from_instance(instance, field)
if is_primary_key:
primary_key = value
else:
field_values[field.column] = value
# Add special indexed fields
for index in special_indexes_for_column(model, field.column):
indexer = get_indexer(field, index)
unindex = False
try:
values = indexer.prep_value_for_database(value,
index,
model=model,
column=field.column,
connection=connection)
except IgnoreForIndexing as e:
# We mark this value as being wiped out for indexing
unindex = True
values = e.processed_value
if not hasattr(values, "__iter__") or isinstance(
values, (bytes, str)):
values = [values]
# If the indexer returns additional entities (instead of indexing a special column)
# then just store those entities
if indexer.PREP_VALUE_RETURNS_ENTITIES:
descendents.extend(values)
else:
for i, v in enumerate(values):
column = indexer.indexed_column_name(
field.column, v, index)
if unindex:
fields_to_unindex.add(column)
continue
# If the column already exists in the values, then we convert it to a
# list and append the new value
if column in field_values:
if not isinstance(field_values[column], list):
field_values[column] = [field_values[column], v]
else:
field_values[column].append(v)
else:
# Otherwise we just set the column to the value
field_values[column] = v
args = [db_table]
if primary_key is not None:
args.append(primary_key)
key = Key(*args,
namespace=connection.namespace,
project=connection.gcloud_project)
entity = Entity(key)
entity.update(field_values)
if fields_to_unindex:
entity._properties_to_remove = fields_to_unindex
classes = get_concrete_db_tables(model)
if len(classes) > 1:
entity[POLYMODEL_CLASS_ATTRIBUTE] = list(set(classes))
return entity, descendents
