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# -*- coding: utf-8 -*-
# Copyright 2014 matrix.org
#
# 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_tok=None, to_tok=None, direction='f', limit=0):
self.from_token = (
StreamToken.from_string(from_tok) if from_tok else None
)
self.to_token = StreamToken.from_string(to_tok) if to_tok else None
self.direction = 'f' if direction == 'f' else 'b'
self.limit = int(limit)
@classmethod
def from_request(cls, request, raise_invalid_params=True):
params = {
"direction": 'f',
}
query_param_mappings = [ # 3-tuple of qp_key, attribute, rules
("from", "from_tok", lambda x: type(x) == str),
("to", "to_tok", lambda x: type(x) == str),
("limit", "limit", lambda x: x.isdigit()),
("dir", "direction", lambda x: x == 'f' or x == 'b'),
]
for qp, attr, is_valid in query_param_mappings:
if qp in request.args:
if is_valid(request.args[qp][0]):
params[attr] = request.args[qp][0]
elif raise_invalid_params:
raise SynapseError(400, "%s parameter is invalid." % qp)
if "from_tok" in params and params["from_tok"] == "END":
# TODO (erikj): This is for compatibility only.
del params["from_tok"]
try:
return PaginationConfig(**params)
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_tok, self.to_tok, self.direction, self.limit)
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