#
# This file is licensed under the Affero General Public License (AGPL) version 3.
#
# Copyright (C) 2023 New Vector, Ltd
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# See the GNU Affero General Public License for more details:
# <https://www.gnu.org/licenses/agpl-3.0.html>.
#
# Originally licensed under the Apache License, Version 2.0:
# <http://www.apache.org/licenses/LICENSE-2.0>.
#
# [This file includes modifications made by New Vector Limited]
#
#
import logging
from typing import Optional
import attr
from synapse.api.constants import Direction
from synapse.api.errors import SynapseError
from synapse.http.servlet import parse_enum, parse_integer, parse_string
from synapse.http.site import SynapseRequest
from synapse.storage.databases.main import DataStore
from synapse.types import StreamToken
logger = logging.getLogger(__name__)
MAX_LIMIT = 1000
@attr.s(slots=True, auto_attribs=True)
class PaginationConfig:
"""A configuration object which stores pagination parameters."""
from_token: Optional[StreamToken]
to_token: Optional[StreamToken]
direction: Direction
limit: int
@classmethod
async def from_request(
cls,
store: "DataStore",
request: SynapseRequest,
default_limit: int,
default_dir: Direction = Direction.FORWARDS,
) -> "PaginationConfig":
direction = parse_enum(request, "dir", Direction, default=default_dir)
from_tok_str = parse_string(request, "from")
to_tok_str = parse_string(request, "to")
try:
from_tok = None
if from_tok_str == "END":
from_tok = None # For backwards compat.
elif from_tok_str:
from_tok = await StreamToken.from_string(store, from_tok_str)
except Exception:
raise SynapseError(400, "'from' parameter is invalid")
try:
to_tok = None
if to_tok_str:
to_tok = await StreamToken.from_string(store, to_tok_str)
except Exception:
raise SynapseError(400, "'to' parameter is invalid")
limit = parse_integer(request, "limit", default=default_limit)
if limit < 0:
raise SynapseError(400, "Limit must be 0 or above")
limit = min(limit, MAX_LIMIT)
try:
return PaginationConfig(from_tok, to_tok, direction, limit)
except Exception:
logger.exception("Failed to create pagination config")
raise SynapseError(400, "Invalid request.")
def __repr__(self) -> str:
return "PaginationConfig(from_tok=%r, to_tok=%r, direction=%r, limit=%r)" % (
self.from_token,
self.to_token,
self.direction,
self.limit,
)