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