512 lines
		
	
	
		
			15 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			512 lines
		
	
	
		
			15 KiB
		
	
	
	
		
			Python
		
	
	
# 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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""" This module contains base REST classes for constructing REST servlets. """
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import logging
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from typing import Dict, Iterable, List, Optional, overload
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from typing_extensions import Literal
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from twisted.web.server import Request
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from synapse.api.errors import Codes, SynapseError
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from synapse.util import json_decoder
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logger = logging.getLogger(__name__)
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def parse_integer(request, name, default=None, required=False):
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    """Parse an integer parameter from the request string
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    Args:
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        request: the twisted HTTP request.
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        name (bytes/unicode): the name of the query parameter.
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        default (int|None): value to use if the parameter is absent, defaults
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            to None.
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        required (bool): whether to raise a 400 SynapseError if the
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            parameter is absent, defaults to False.
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    Returns:
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        int|None: An int value or the default.
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    Raises:
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        SynapseError: if the parameter is absent and required, or if the
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            parameter is present and not an integer.
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    """
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    return parse_integer_from_args(request.args, name, default, required)
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def parse_integer_from_args(args, name, default=None, required=False):
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    if not isinstance(name, bytes):
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        name = name.encode("ascii")
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    if name in args:
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        try:
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            return int(args[name][0])
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        except Exception:
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            message = "Query parameter %r must be an integer" % (name,)
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            raise SynapseError(400, message, errcode=Codes.INVALID_PARAM)
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    else:
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        if required:
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            message = "Missing integer query parameter %r" % (name,)
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            raise SynapseError(400, message, errcode=Codes.MISSING_PARAM)
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        else:
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            return default
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def parse_boolean(request, name, default=None, required=False):
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    """Parse a boolean parameter from the request query string
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    Args:
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        request: the twisted HTTP request.
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        name (bytes/unicode): the name of the query parameter.
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        default (bool|None): value to use if the parameter is absent, defaults
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            to None.
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        required (bool): whether to raise a 400 SynapseError if the
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            parameter is absent, defaults to False.
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    Returns:
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        bool|None: A bool value or the default.
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    Raises:
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        SynapseError: if the parameter is absent and required, or if the
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            parameter is present and not one of "true" or "false".
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    """
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    return parse_boolean_from_args(request.args, name, default, required)
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def parse_boolean_from_args(args, name, default=None, required=False):
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    if not isinstance(name, bytes):
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        name = name.encode("ascii")
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    if name in args:
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        try:
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            return {b"true": True, b"false": False}[args[name][0]]
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        except Exception:
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            message = (
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                "Boolean query parameter %r must be one of ['true', 'false']"
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            ) % (name,)
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            raise SynapseError(400, message)
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    else:
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        if required:
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            message = "Missing boolean query parameter %r" % (name,)
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            raise SynapseError(400, message, errcode=Codes.MISSING_PARAM)
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        else:
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            return default
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@overload
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def parse_bytes_from_args(
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    args: Dict[bytes, List[bytes]],
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    name: str,
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    default: Optional[bytes] = None,
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) -> Optional[bytes]:
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    ...
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@overload
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def parse_bytes_from_args(
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    args: Dict[bytes, List[bytes]],
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    name: str,
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    default: Literal[None] = None,
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    *,
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    required: Literal[True],
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) -> bytes:
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    ...
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@overload
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def parse_bytes_from_args(
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    args: Dict[bytes, List[bytes]],
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    name: str,
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    default: Optional[bytes] = None,
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    required: bool = False,
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) -> Optional[bytes]:
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    ...
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def parse_bytes_from_args(
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    args: Dict[bytes, List[bytes]],
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    name: str,
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    default: Optional[bytes] = None,
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    required: bool = False,
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) -> Optional[bytes]:
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    """
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    Parse a string parameter as bytes from the request query string.
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    Args:
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        args: A mapping of request args as bytes to a list of bytes (e.g. request.args).
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        name: the name of the query parameter.
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        default: value to use if the parameter is absent,
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            defaults to None. Must be bytes if encoding is None.
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        required: whether to raise a 400 SynapseError if the
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            parameter is absent, defaults to False.
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    Returns:
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        Bytes or the default value.
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    Raises:
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        SynapseError if the parameter is absent and required.
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    """
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    name_bytes = name.encode("ascii")
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    if name_bytes in args:
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        return args[name_bytes][0]
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    elif required:
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        message = "Missing string query parameter %s" % (name,)
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        raise SynapseError(400, message, errcode=Codes.MISSING_PARAM)
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    return default
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def parse_string(
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    request: Request,
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    name: str,
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    default: Optional[str] = None,
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    required: bool = False,
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    allowed_values: Optional[Iterable[str]] = None,
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    encoding: str = "ascii",
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):
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    """
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    Parse a string parameter from the request query string.
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    If encoding is not None, the content of the query param will be
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    decoded to Unicode using the encoding, otherwise it will be encoded
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    Args:
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        request: the twisted HTTP request.
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        name: the name of the query parameter.
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        default: value to use if the parameter is absent, defaults to None.
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        required: whether to raise a 400 SynapseError if the
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            parameter is absent, defaults to False.
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        allowed_values: List of allowed values for the
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            string, or None if any value is allowed, defaults to None. Must be
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            the same type as name, if given.
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        encoding: The encoding to decode the string content with.
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    Returns:
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        A string value or the default.
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    Raises:
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        SynapseError if the parameter is absent and required, or if the
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            parameter is present, must be one of a list of allowed values and
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            is not one of those allowed values.
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    """
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    args: Dict[bytes, List[bytes]] = request.args  # type: ignore
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    return parse_string_from_args(
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        args,
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        name,
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        default,
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        required=required,
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        allowed_values=allowed_values,
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        encoding=encoding,
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    )
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def _parse_string_value(
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    value: bytes,
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    allowed_values: Optional[Iterable[str]],
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    name: str,
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    encoding: str,
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) -> str:
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    try:
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        value_str = value.decode(encoding)
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    except ValueError:
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        raise SynapseError(400, "Query parameter %r must be %s" % (name, encoding))
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    if allowed_values is not None and value_str not in allowed_values:
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        message = "Query parameter %r must be one of [%s]" % (
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            name,
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            ", ".join(repr(v) for v in allowed_values),
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        )
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        raise SynapseError(400, message)
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    else:
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        return value_str
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@overload
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def parse_strings_from_args(
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    args: Dict[bytes, List[bytes]],
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    name: str,
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    default: Optional[List[str]] = None,
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    *,
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    allowed_values: Optional[Iterable[str]] = None,
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    encoding: str = "ascii",
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) -> Optional[List[str]]:
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    ...
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@overload
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def parse_strings_from_args(
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    args: Dict[bytes, List[bytes]],
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    name: str,
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    default: Optional[List[str]] = None,
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    *,
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    required: Literal[True],
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    allowed_values: Optional[Iterable[str]] = None,
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    encoding: str = "ascii",
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) -> List[str]:
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    ...
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@overload
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def parse_strings_from_args(
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    args: Dict[bytes, List[bytes]],
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    name: str,
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    default: Optional[List[str]] = None,
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    *,
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    required: bool = False,
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    allowed_values: Optional[Iterable[str]] = None,
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    encoding: str = "ascii",
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) -> Optional[List[str]]:
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    ...
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def parse_strings_from_args(
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    args: Dict[bytes, List[bytes]],
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    name: str,
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    default: Optional[List[str]] = None,
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    required: bool = False,
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    allowed_values: Optional[Iterable[str]] = None,
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    encoding: str = "ascii",
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) -> Optional[List[str]]:
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    """
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    Parse a string parameter from the request query string list.
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    The content of the query param will be decoded to Unicode using the encoding.
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    Args:
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        args: A mapping of request args as bytes to a list of bytes (e.g. request.args).
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        name: the name of the query parameter.
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        default: value to use if the parameter is absent, defaults to None.
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        required: whether to raise a 400 SynapseError if the
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            parameter is absent, defaults to False.
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        allowed_values: List of allowed values for the
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            string, or None if any value is allowed, defaults to None.
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        encoding: The encoding to decode the string content with.
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    Returns:
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        A string value or the default.
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    Raises:
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        SynapseError if the parameter is absent and required, or if the
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            parameter is present, must be one of a list of allowed values and
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            is not one of those allowed values.
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    """
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    name_bytes = name.encode("ascii")
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    if name_bytes in args:
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        values = args[name_bytes]
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        return [
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            _parse_string_value(value, allowed_values, name=name, encoding=encoding)
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            for value in values
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        ]
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    else:
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        if required:
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            message = "Missing string query parameter %r" % (name,)
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            raise SynapseError(400, message, errcode=Codes.MISSING_PARAM)
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        return default
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@overload
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def parse_string_from_args(
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    args: Dict[bytes, List[bytes]],
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    name: str,
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    default: Optional[str] = None,
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    *,
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    allowed_values: Optional[Iterable[str]] = None,
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    encoding: str = "ascii",
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) -> Optional[str]:
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    ...
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@overload
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def parse_string_from_args(
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    args: Dict[bytes, List[bytes]],
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    name: str,
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    default: Optional[str] = None,
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    *,
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    required: Literal[True],
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    allowed_values: Optional[Iterable[str]] = None,
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    encoding: str = "ascii",
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) -> str:
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    ...
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@overload
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def parse_string_from_args(
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    args: Dict[bytes, List[bytes]],
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    name: str,
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    default: Optional[str] = None,
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    required: bool = False,
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    allowed_values: Optional[Iterable[str]] = None,
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    encoding: str = "ascii",
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) -> Optional[str]:
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    ...
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def parse_string_from_args(
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    args: Dict[bytes, List[bytes]],
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    name: str,
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    default: Optional[str] = None,
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    required: bool = False,
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    allowed_values: Optional[Iterable[str]] = None,
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    encoding: str = "ascii",
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) -> Optional[str]:
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    """
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    Parse the string parameter from the request query string list
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    and return the first result.
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    The content of the query param will be decoded to Unicode using the encoding.
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    Args:
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        args: A mapping of request args as bytes to a list of bytes (e.g. request.args).
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        name: the name of the query parameter.
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        default: value to use if the parameter is absent, defaults to None.
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        required: whether to raise a 400 SynapseError if the
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            parameter is absent, defaults to False.
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        allowed_values: List of allowed values for the
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            string, or None if any value is allowed, defaults to None. Must be
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            the same type as name, if given.
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        encoding: The encoding to decode the string content with.
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    Returns:
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        A string value or the default.
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    Raises:
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        SynapseError if the parameter is absent and required, or if the
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            parameter is present, must be one of a list of allowed values and
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            is not one of those allowed values.
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    """
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    strings = parse_strings_from_args(
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        args,
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        name,
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        default=[default] if default is not None else None,
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        required=required,
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        allowed_values=allowed_values,
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        encoding=encoding,
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    )
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    if strings is None:
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        return None
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    return strings[0]
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def parse_json_value_from_request(request, allow_empty_body=False):
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    """Parse a JSON value from the body of a twisted HTTP request.
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    Args:
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        request: the twisted HTTP request.
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        allow_empty_body (bool): if True, an empty body will be accepted and
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            turned into None
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    Returns:
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        The JSON value.
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    Raises:
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        SynapseError if the request body couldn't be decoded as JSON.
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    """
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    try:
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        content_bytes = request.content.read()
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    except Exception:
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        raise SynapseError(400, "Error reading JSON content.")
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    if not content_bytes and allow_empty_body:
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        return None
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    try:
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        content = json_decoder.decode(content_bytes.decode("utf-8"))
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    except Exception as e:
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        logger.warning("Unable to parse JSON: %s (%s)", e, content_bytes)
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        raise SynapseError(400, "Content not JSON.", errcode=Codes.NOT_JSON)
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    return content
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def parse_json_object_from_request(request, allow_empty_body=False):
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    """Parse a JSON object from the body of a twisted HTTP request.
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    Args:
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        request: the twisted HTTP request.
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        allow_empty_body (bool): if True, an empty body will be accepted and
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            turned into an empty dict.
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    Raises:
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        SynapseError if the request body couldn't be decoded as JSON or
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            if it wasn't a JSON object.
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    """
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    content = parse_json_value_from_request(request, allow_empty_body=allow_empty_body)
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    if allow_empty_body and content is None:
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        return {}
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    if type(content) != dict:
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        message = "Content must be a JSON object."
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        raise SynapseError(400, message, errcode=Codes.BAD_JSON)
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    return content
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def assert_params_in_dict(body, required):
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    absent = []
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    for k in required:
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        if k not in body:
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            absent.append(k)
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    if len(absent) > 0:
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        raise SynapseError(400, "Missing params: %r" % absent, Codes.MISSING_PARAM)
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class RestServlet:
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    """A Synapse REST Servlet.
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    An implementing class can either provide its own custom 'register' method,
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    or use the automatic pattern handling provided by the base class.
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    To use this latter, the implementing class instead provides a `PATTERN`
 | 
						|
    class attribute containing a pre-compiled regular expression. The automatic
 | 
						|
    register method will then use this method to register any of the following
 | 
						|
    instance methods associated with the corresponding HTTP method:
 | 
						|
 | 
						|
      on_GET
 | 
						|
      on_PUT
 | 
						|
      on_POST
 | 
						|
      on_DELETE
 | 
						|
 | 
						|
    Automatically handles turning CodeMessageExceptions thrown by these methods
 | 
						|
    into the appropriate HTTP response.
 | 
						|
    """
 | 
						|
 | 
						|
    def register(self, http_server):
 | 
						|
        """Register this servlet with the given HTTP server."""
 | 
						|
        patterns = getattr(self, "PATTERNS", None)
 | 
						|
        if patterns:
 | 
						|
            for method in ("GET", "PUT", "POST", "DELETE"):
 | 
						|
                if hasattr(self, "on_%s" % (method,)):
 | 
						|
                    servlet_classname = self.__class__.__name__
 | 
						|
                    method_handler = getattr(self, "on_%s" % (method,))
 | 
						|
                    http_server.register_paths(
 | 
						|
                        method, patterns, method_handler, servlet_classname
 | 
						|
                    )
 | 
						|
 | 
						|
        else:
 | 
						|
            raise NotImplementedError("RestServlet must register something.")
 |