89 lines
		
	
	
		
			2.8 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			89 lines
		
	
	
		
			2.8 KiB
		
	
	
	
		
			Python
		
	
	
# -*- coding: utf-8 -*-
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# 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)
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class PaginationConfig:
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    """A configuration object which stores pagination parameters."""
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    from_token = attr.ib(type=Optional[StreamToken])
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    to_token = attr.ib(type=Optional[StreamToken])
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    direction = attr.ib(type=str)
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    limit = attr.ib(type=Optional[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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        raise_invalid_params: bool = True,
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        default_limit: Optional[int] = None,
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    ) -> "PaginationConfig":
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        direction = parse_string(request, "dir", default="f", allowed_values=["f", "b"])
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        from_tok = parse_string(request, "from")
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        to_tok = parse_string(request, "to")
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        try:
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            if from_tok == "END":
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                from_tok = None  # For backwards compat.
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            elif from_tok:
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                from_tok = await StreamToken.from_string(store, from_tok)
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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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            if to_tok:
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                to_tok = await StreamToken.from_string(store, to_tok)
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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:
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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(int(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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