90 lines
2.8 KiB
Python
90 lines
2.8 KiB
Python
# Copyright 2014-2016 OpenMarket Ltd
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import logging
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from typing import Optional
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import attr
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from synapse.api.errors import SynapseError
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from synapse.http.servlet import parse_integer, parse_string
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from synapse.http.site import SynapseRequest
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from synapse.storage.databases.main import DataStore
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from synapse.types import StreamToken
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logger = logging.getLogger(__name__)
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MAX_LIMIT = 1000
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@attr.s(slots=True, auto_attribs=True)
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class PaginationConfig:
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"""A configuration object which stores pagination parameters."""
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from_token: Optional[StreamToken]
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to_token: Optional[StreamToken]
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direction: str
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limit: int
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@classmethod
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async def from_request(
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cls,
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store: "DataStore",
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request: SynapseRequest,
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default_limit: int,
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default_dir: str = "f",
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) -> "PaginationConfig":
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direction = parse_string(
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request, "dir", default=default_dir, allowed_values=["f", "b"]
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)
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from_tok_str = parse_string(request, "from")
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to_tok_str = parse_string(request, "to")
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try:
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from_tok = None
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if from_tok_str == "END":
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from_tok = None # For backwards compat.
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elif from_tok_str:
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from_tok = await StreamToken.from_string(store, from_tok_str)
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except Exception:
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raise SynapseError(400, "'from' parameter is invalid")
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try:
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to_tok = None
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if to_tok_str:
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to_tok = await StreamToken.from_string(store, to_tok_str)
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except Exception:
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raise SynapseError(400, "'to' parameter is invalid")
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limit = parse_integer(request, "limit", default=default_limit)
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if limit < 0:
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raise SynapseError(400, "Limit must be 0 or above")
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limit = min(limit, MAX_LIMIT)
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try:
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return PaginationConfig(from_tok, to_tok, direction, limit)
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except Exception:
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logger.exception("Failed to create pagination config")
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raise SynapseError(400, "Invalid request.")
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def __repr__(self) -> str:
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return "PaginationConfig(from_tok=%r, to_tok=%r, direction=%r, limit=%r)" % (
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self.from_token,
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self.to_token,
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self.direction,
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self.limit,
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)
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