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# -*- coding: utf-8 -*-
# Copyright 2014-2016 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.
import logging
from typing import Optional
import attr
from synapse.api.errors import SynapseError
from synapse.http.servlet import parse_integer, parse_string
from synapse.http.site import SynapseRequest
from synapse.types import StreamToken
logger = logging.getLogger(__name__)
MAX_LIMIT = 1000
@attr.s(slots=True)
class PaginationConfig:
"""A configuration object which stores pagination parameters."""
from_token = attr.ib(type=Optional[StreamToken])
to_token = attr.ib(type=Optional[StreamToken])
direction = attr.ib(type=str)
limit = attr.ib(type=Optional[int])
@classmethod
def from_request(
cls,
request: SynapseRequest,
raise_invalid_params: bool = True,
default_limit: Optional[int] = None,
) -> "PaginationConfig":
direction = parse_string(request, "dir", default="f", allowed_values=["f", "b"])
from_tok = parse_string(request, "from")
to_tok = parse_string(request, "to")
try:
if from_tok == "END":
from_tok = None # For backwards compat.
elif from_tok:
from_tok = StreamToken.from_string(from_tok)
except Exception:
raise SynapseError(400, "'from' parameter is invalid")
try:
if to_tok:
to_tok = StreamToken.from_string(to_tok)
except Exception:
raise SynapseError(400, "'to' parameter is invalid")
limit = parse_integer(request, "limit", default=default_limit)
if limit:
if limit < 0:
raise SynapseError(400, "Limit must be 0 or above")
limit = min(int(limit), MAX_LIMIT)
try:
return PaginationConfig(from_tok, to_tok, direction, limit)
except Exception:
logger.exception("Failed to create pagination config")
raise SynapseError(400, "Invalid request.")
def __repr__(self) -> str:
return ("PaginationConfig(from_tok=%r, to_tok=%r, direction=%r, limit=%r)") % (
self.from_token,
self.to_token,
self.direction,
self.limit,
)
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