def _GetFieldValue(cls, field):
"""Returns the value of a field as the correct type.
Args:
field: The field whose value is extracted. If the given field is None, this
function also returns None. This is to make it easier to chain with
GetFieldInDocument().
Returns:
The value of the field with the correct type (float for number fields,
datetime.datetime for date fields, etc).
Raises:
TypeError: if the type of the field isn't recognized.
"""
if not field:
return None
value_type = field.value().type()
if value_type in search_util.TEXT_DOCUMENT_FIELD_TYPES:
return field.value().string_value()
if value_type == document_pb.FieldValue.DATE:
value = field.value().string_value()
return search_util.DeserializeDate(value)
if value_type == document_pb.FieldValue.NUMBER:
value = field.value().string_value()
return float(value)
if value_type == document_pb.FieldValue.GEO:
value = field.value().geo()
return geo_util.LatLng(value.lat(), value.lng())
raise TypeError('No conversion defined for type %s' % value_type)
def ValueOf(self,
expression,
default_value=None,
return_type=None,
allow_rank=True):
"""Returns the value of an expression on a document.
Args:
expression: The expression string.
default_value: The value to return if the expression cannot be evaluated.
return_type: The type the expression should evaluate to. Used to create
multiple sorts for ambiguous expressions. If None, the expression
evaluates to the inferred type or first type of a field it encounters in
a document.
allow_rank: For expressions that will be used in a sort context,
indicate if rank is allowed.
Returns:
The value of the expression on the evaluator's document, or default_value
if the expression cannot be evaluated on the document.
Raises:
ExpressionEvaluationError: sort expression cannot be evaluated
because the expression or default value is malformed. Callers of
ValueOf should catch and return error to user in response.
QueryExpressionEvaluationError: same as ExpressionEvaluationError but
these errors should return query as error status to users.
"""
expression_tree = Parse(expression)
if not expression_tree.getType() and expression_tree.children:
expression_tree = expression_tree.children[0]
name = query_parser.GetQueryNodeText(expression_tree)
schema = self._inverted_index.GetSchema()
if (expression_tree.getType() == ExpressionParser.NAME
and name in schema):
contains_text_result = False
for field_type in schema[name].type_list():
if field_type in search_util.TEXT_DOCUMENT_FIELD_TYPES:
contains_text_result = True
if (schema.IsType(name, document_pb.FieldValue.DATE)
and not contains_text_result):
if isinstance(default_value, basestring):
try:
default_value = search_util.DeserializeDate(
default_value)
except ValueError:
raise QueryExpressionEvaluationError(
'Default text value is not appropriate for sort expression \''
+ name + '\': failed to parse date \"' +
default_value + '\"')
result = default_value
try:
result = self._Eval(expression_tree,
return_type=return_type,
allow_rank=allow_rank)
except _ExpressionError, e:
logging.debug('Skipping expression %s: %s', expression, e)
def SortKey(scored_doc):
"""Return the sort key for a document based on the request parameters."""
field = search_util.GetFieldInDocument(
scored_doc.document, sort_spec.sort_expression())
if not field:
return default_value
string_val = field.value().string_value()
if field.value().type() in search_util.NUMBER_DOCUMENT_FIELD_TYPES:
return float(string_val)
if field.value().type() is document_pb.FieldValue.DATE:
return search_util.EpochTime(search_util.DeserializeDate(string_val))
return string_val
def ValueOf(self, expression, default_value=None):
"""Returns the value of an expression on a document.
Args:
expression: The expression string.
default_value: The value to return if the expression cannot be evaluated.
Returns:
The value of the expression on the evaluator's document, or default_value
if the expression cannot be evaluated on the document.
Raises:
ExpressionEvaluationError: sort expression cannot be evaluated
because the expression or default value is malformed. Callers of
ValueOf should catch and return error to user in response.
QueryExpressionEvaluationError: same as ExpressionEvaluationError but
these errors should return query as error status to users.
"""
expression_tree = Parse(expression)
if not expression_tree.getType() and expression_tree.children:
expression_tree = expression_tree.children[0]
name = query_parser.GetQueryNodeText(expression_tree)
schema = self._inverted_index.GetSchema()
if (expression_tree.getType() == ExpressionParser.NAME
and schema.IsType(name, document_pb.FieldValue.DATE)):
if isinstance(default_value, basestring):
try:
default_value = search_util.DeserializeDate(default_value)
except ValueError:
raise QueryExpressionEvaluationError(
'failed to parse date \"' + default_value + '\"')
result = default_value
try:
result = self._Eval(expression_tree)
except _ExpressionError, e:
logging.debug('Skipping expression %s: %s', expression, e)
def _DateStrToDays(date_str): date = search_util.DeserializeDate(date_str) return search_util.EpochTime(date) / MSEC_PER_DAY
