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