252 lines
8.2 KiB
Python
252 lines
8.2 KiB
Python
# -*- coding: utf-8 -*-
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# 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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from synapse.api.errors import SynapseError, Codes
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import logging
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import simplejson
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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 (str): 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 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)
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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 (str): 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 name in args:
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try:
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return {
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"true": True,
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"false": False,
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}[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"
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" ['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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def parse_string(request, name, default=None, required=False,
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allowed_values=None, param_type="string"):
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"""Parse a string 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 (str): the name of the query parameter.
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default (str|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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allowed_values (list[str]): List of allowed values for the string,
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or None if any value is allowed, defaults to None
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Returns:
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str|None: 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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return parse_string_from_args(
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request.args, name, default, required, allowed_values, param_type,
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)
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def parse_string_from_args(args, name, default=None, required=False,
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allowed_values=None, param_type="string"):
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if name in args:
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value = args[name][0]
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if allowed_values is not None and value not in allowed_values:
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message = "Query parameter %r must be one of [%s]" % (
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name, ", ".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
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else:
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if required:
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message = "Missing %s query parameter %r" % (param_type, 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_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 = simplejson.loads(content_bytes)
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except Exception as e:
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logger.warn("Unable to parse JSON: %s", e)
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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(
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request, allow_empty_body=allow_empty_body,
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)
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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_request(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(object):
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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`
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class attribute containing a pre-compiled regular expression. The automatic
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register method will then use this method to register any of the following
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instance methods associated with the corresponding HTTP method:
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on_GET
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on_PUT
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on_POST
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on_DELETE
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on_OPTIONS
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Automatically handles turning CodeMessageExceptions thrown by these methods
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into the appropriate HTTP response.
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"""
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def register(self, http_server):
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""" Register this servlet with the given HTTP server. """
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if hasattr(self, "PATTERNS"):
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patterns = self.PATTERNS
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for method in ("GET", "PUT", "POST", "OPTIONS", "DELETE"):
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if hasattr(self, "on_%s" % (method,)):
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method_handler = getattr(self, "on_%s" % (method,))
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http_server.register_paths(method, patterns, method_handler)
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else:
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raise NotImplementedError("RestServlet must register something.")
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