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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
class PaginationConfig(object):
"""A configuration object which stores pagination parameters."""
def __init__(self, from_tok=None, to_tok=None, limit=0):
self.from_tok = from_tok
self.to_tok = to_tok
self.limit = limit
@classmethod
def from_request(cls, request, raise_invalid_params=True):
params = {
"from_tok": PaginationStream.TOK_START,
"to_tok": PaginationStream.TOK_END,
"limit": 0
}
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())
]
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)
return PaginationConfig(**params)
class PaginationStream(object):
""" An interface for streaming data as chunks. """
TOK_START = "START"
TOK_END = "END"
def get_chunk(self, config=None):
""" Return the next chunk in the stream.
Args:
config (PaginationConfig): The config to aid which chunk to get.
Returns:
A dict containing the new start token "start", the new end token
"end" and the data "chunk" as a list.
"""
raise NotImplementedError()
class StreamData(object):
""" An interface for obtaining streaming data from a table. """
def __init__(self, hs):
self.hs = hs
self.store = hs.get_datastore()
def get_rows(self, user_id, from_pkey, to_pkey, limit):
""" Get event stream data between the specified pkeys.
Args:
user_id : The user's ID
from_pkey : The starting pkey.
to_pkey : The end pkey. May be -1 to mean "latest".
limit: The max number of results to return.
Returns:
A tuple containing the list of event stream data and the last pkey.
"""
raise NotImplementedError()
def max_token(self):
""" Get the latest currently-valid token.
Returns:
The latest token."""
raise NotImplementedError()
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