8372f48b7a
Change-Id: Ibd4c9811daa6e9e692457ce480a58c964fef7cb9 Signed-off-by: Julien Danjou <julien@danjou.info>
98 lines
3.4 KiB
Python
98 lines
3.4 KiB
Python
# 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.
|
|
#
|
|
|
|
import operator
|
|
|
|
from sqlalchemy import and_
|
|
from sqlalchemy import asc
|
|
from sqlalchemy import desc
|
|
from sqlalchemy import not_
|
|
from sqlalchemy import or_
|
|
|
|
|
|
class QueryTransformer(object):
|
|
operators = {"=": operator.eq,
|
|
"<": operator.lt,
|
|
">": operator.gt,
|
|
"<=": operator.le,
|
|
"=<": operator.le,
|
|
">=": operator.ge,
|
|
"=>": operator.ge,
|
|
"!=": operator.ne,
|
|
"in": lambda field_name, values: field_name.in_(values),
|
|
"=~": lambda field, value: field.op("regexp")(value)}
|
|
|
|
# operators which are differs for different dialects
|
|
dialect_operators = {'postgresql': {'=~': (lambda field, value:
|
|
field.op("~")(value))}}
|
|
|
|
complex_operators = {"or": or_,
|
|
"and": and_,
|
|
"not": not_}
|
|
|
|
ordering_functions = {"asc": asc,
|
|
"desc": desc}
|
|
|
|
def __init__(self, table, query, dialect='mysql'):
|
|
self.table = table
|
|
self.query = query
|
|
self.dialect_name = dialect
|
|
|
|
def _get_operator(self, op):
|
|
return (self.dialect_operators.get(self.dialect_name, {}).get(op)
|
|
or self.operators[op])
|
|
|
|
def _handle_complex_op(self, complex_op, nodes):
|
|
op = self.complex_operators[complex_op]
|
|
if op == not_:
|
|
nodes = [nodes]
|
|
element_list = []
|
|
for node in nodes:
|
|
element = self._transform(node)
|
|
element_list.append(element)
|
|
return op(*element_list)
|
|
|
|
def _handle_simple_op(self, simple_op, nodes):
|
|
op = self._get_operator(simple_op)
|
|
field_name, value = list(nodes.items())[0]
|
|
return op(getattr(self.table, field_name), value)
|
|
|
|
def _transform(self, sub_tree):
|
|
operator, nodes = list(sub_tree.items())[0]
|
|
if operator in self.complex_operators:
|
|
return self._handle_complex_op(operator, nodes)
|
|
else:
|
|
return self._handle_simple_op(operator, nodes)
|
|
|
|
def apply_filter(self, expression_tree):
|
|
condition = self._transform(expression_tree)
|
|
self.query = self.query.filter(condition)
|
|
|
|
def apply_options(self, orderby, limit):
|
|
self._apply_order_by(orderby)
|
|
if limit is not None:
|
|
self.query = self.query.limit(limit)
|
|
|
|
def _apply_order_by(self, orderby):
|
|
if orderby is not None:
|
|
for field in orderby:
|
|
attr, order = list(field.items())[0]
|
|
ordering_function = self.ordering_functions[order]
|
|
self.query = self.query.order_by(ordering_function(
|
|
getattr(self.table, attr)))
|
|
else:
|
|
self.query = self.query.order_by(desc(self.table.timestamp))
|
|
|
|
def get_query(self):
|
|
return self.query
|