def remove_invalid_fields(self, queryset, fields, view, request):
"""Remove invalid fields."""
order_fields = []
for field in fields:
# When a dot is present in the order field, treat it as a JSON path.
if '.' not in field:
order_fields.extend(
super(JsonOrderingFilter,
self).remove_invalid_fields(queryset, [field], view,
request))
continue
path = field.split('.')
base_field = path[0]
if len(path) < 2:
continue
if not super(JsonOrderingFilter, self).remove_invalid_fields(
queryset, [base_field], view, request):
continue
reverse = False
if base_field[0] == '-':
base_field = base_field[1:]
reverse = True
# Resolve base field.
try:
quote_name = connection.ops.quote_name
model_meta = queryset.model._meta # pylint: disable=protected-access
base_field = '{}.{}'.format(
quote_name(model_meta.db_table),
quote_name(model_meta.get_field(base_field).column),
)
except FieldDoesNotExist:
continue
placeholders = '->'.join(['%s'] * (len(path) - 2))
# The last placeholder should be accessed via the ->> operator.
if placeholders:
placeholders = '->{}->>%s'.format(placeholders)
else:
placeholders = '->>%s'
expression = RawSQL(
# We can use base_field here directly because we've resolved it via Django ORM.
'{}{}'.format(base_field, placeholders),
params=path[1:],
)
if reverse:
expression = expression.desc()
order_fields.append(expression)
return order_fields
def order_by_json_path(self, json_path, language_code=None, order='asc'):
"""
Orders a queryset by the value of the specified `json_path`.
More about the `#>>` operator and the `json_path` arg syntax:
https://www.postgresql.org/docs/current/static/functions-json.html
More about Raw SQL expressions:
https://docs.djangoproject.com/en/dev/ref/models/expressions/#raw-sql-expressions
Usage example:
MyModel.objects.language('en_us').filter(is_active=True).order_by_json_path('title')
"""
language_code = (language_code or self._language_code
or self.get_language_key(language_code))
json_path = '{%s,%s}' % (language_code, json_path)
# Our jsonb field is named `translations`.
raw_sql_expression = RawSQL("translations#>>%s", (json_path, ))
if order == 'desc':
raw_sql_expression = raw_sql_expression.desc()
return self.order_by(raw_sql_expression)
