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# -*- coding: utf-8 -*-
# Copyright 2014 OpenMarket Ltd
#
# 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.
from synapse.api.errors import SynapseError
from synapse.types import StreamToken
import logging
logger = logging.getLogger(__name__)
class PaginationConfig(object):
"""A configuration object which stores pagination parameters."""
def __init__(self, from_token=None, to_token=None, direction='f',
limit=0):
self.from_token = from_token
self.to_token = to_token
self.direction = 'f' if direction == 'f' else 'b'
self.limit = int(limit)
@classmethod
def from_request(cls, request, raise_invalid_params=True):
def get_param(name, default=None):
lst = request.args.get(name, [])
if len(lst) > 1:
raise SynapseError(
400, "%s must be specified only once" % (name,)
)
elif len(lst) == 1:
return lst[0]
else:
return default
direction = get_param("dir", 'f')
if direction not in ['f', 'b']:
raise SynapseError(400, "'dir' parameter is invalid.")
from_tok = get_param("from")
to_tok = get_param("to")
try:
if from_tok == "END":
from_tok = None # For backwards compat.
elif from_tok:
from_tok = StreamToken.from_string(from_tok)
except:
raise SynapseError(400, "'from' paramater is invalid")
try:
if to_tok:
to_tok = StreamToken.from_string(to_tok)
except:
raise SynapseError(400, "'to' paramater is invalid")
limit = get_param("limit", "0")
if not limit.isdigit():
raise SynapseError(400, "'limit' parameter must be an integer.")
try:
return PaginationConfig(from_tok, to_tok, direction, limit)
except:
logger.exception("Failed to create pagination config")
raise SynapseError(400, "Invalid request.")
def __str__(self):
return (
"<PaginationConfig from_tok=%s, to_tok=%s, "
"direction=%s, limit=%s>"
) % (self.from_token, self.to_token, self.direction, self.limit)
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