95 lines
3.6 KiB
Python
95 lines
3.6 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2014 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 logic for storing HTTP PUT transactions. This is used
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to ensure idempotency when performing PUTs using the REST API."""
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import logging
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logger = logging.getLogger(__name__)
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class HttpTransactionStore(object):
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def __init__(self):
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# { key : (txn_id, response) }
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self.transactions = {}
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def get_response(self, key, txn_id):
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"""Retrieve a response for this request.
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Args:
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key (str): A transaction-independent key for this request. Usually
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this is a combination of the path (without the transaction id)
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and the user's access token.
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txn_id (str): The transaction ID for this request
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Returns:
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A tuple of (HTTP response code, response content) or None.
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"""
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try:
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logger.debug("get_response Key: %s TxnId: %s", key, txn_id)
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(last_txn_id, response) = self.transactions[key]
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if txn_id == last_txn_id:
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logger.info("get_response: Returning a response for %s", key)
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return response
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except KeyError:
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pass
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return None
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def store_response(self, key, txn_id, response):
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"""Stores an HTTP response tuple.
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Args:
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key (str): A transaction-independent key for this request. Usually
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this is a combination of the path (without the transaction id)
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and the user's access token.
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txn_id (str): The transaction ID for this request.
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response (tuple): A tuple of (HTTP response code, response content)
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"""
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logger.debug("store_response Key: %s TxnId: %s", key, txn_id)
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self.transactions[key] = (txn_id, response)
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def store_client_transaction(self, request, txn_id, response):
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"""Stores the request/response pair of an HTTP transaction.
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Args:
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request (twisted.web.http.Request): The twisted HTTP request. This
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request must have the transaction ID as the last path segment.
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response (tuple): A tuple of (response code, response dict)
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txn_id (str): The transaction ID for this request.
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"""
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self.store_response(self._get_key(request), txn_id, response)
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def get_client_transaction(self, request, txn_id):
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"""Retrieves a stored response if there was one.
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Args:
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request (twisted.web.http.Request): The twisted HTTP request. This
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request must have the transaction ID as the last path segment.
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txn_id (str): The transaction ID for this request.
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Returns:
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The response tuple.
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Raises:
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KeyError if the transaction was not found.
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"""
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response = self.get_response(self._get_key(request), txn_id)
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if response is None:
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raise KeyError("Transaction not found.")
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return response
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def _get_key(self, request):
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token = request.args["access_token"][0]
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path_without_txn_id = request.path.rsplit("/", 1)[0]
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return path_without_txn_id + "/" + token
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