9e07e7d971
TranslationHook was using a threading.local() to store an error message however the threading.local() was being created in __init__ of the Hook. Hooks are not per request, so this wasn't really working as planned. Now, instead of using threading.local() at all, we just modify the environ held by pecan (and later used by the ParsableErrorMiddleware). environ is request-local. This change feels a bit crufty because it is but because of the way Exceptions are managed in the app there's not really any good way to do it. We could consider changing the way Exceptions related to error messages, but that would be a very large change. Change-Id: I463059df28f291cea0644b1a9908a907f146ba1f Closes-Bug: #1481244
129 lines
5.2 KiB
Python
129 lines
5.2 KiB
Python
#
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# Copyright 2013 IBM Corp.
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# Copyright 2012 New Dream Network, LLC (DreamHost)
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# 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, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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"""Middleware to replace the plain text message body of an error
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response with one formatted so the client can parse it.
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Based on pecan.middleware.errordocument
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"""
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import json
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from lxml import etree
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from oslo_log import log
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import six
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import webob
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from aodh import i18n
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from aodh.i18n import _
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LOG = log.getLogger(__name__)
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class ParsableErrorMiddleware(object):
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"""Replace error body with something the client can parse."""
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@staticmethod
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def best_match_language(accept_language):
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"""Determines best available locale from the Accept-Language header.
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:returns: the best language match or None if the 'Accept-Language'
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header was not available in the request.
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"""
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if not accept_language:
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return None
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all_languages = i18n.get_available_languages()
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return accept_language.best_match(all_languages)
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def __init__(self, app):
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self.app = app
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def __call__(self, environ, start_response):
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# Request for this state, modified by replace_start_response()
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# and used when an error is being reported.
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state = {}
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def replacement_start_response(status, headers, exc_info=None):
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"""Overrides the default response to make errors parsable."""
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try:
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status_code = int(status.split(' ')[0])
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state['status_code'] = status_code
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except (ValueError, TypeError): # pragma: nocover
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raise Exception((
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'ErrorDocumentMiddleware received an invalid '
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'status %s' % status
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))
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else:
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if (state['status_code'] // 100) not in (2, 3):
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# Remove some headers so we can replace them later
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# when we have the full error message and can
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# compute the length.
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headers = [(h, v)
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for (h, v) in headers
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if h not in ('Content-Length', 'Content-Type')
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]
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# Save the headers in case we need to modify them.
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state['headers'] = headers
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return start_response(status, headers, exc_info)
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app_iter = self.app(environ, replacement_start_response)
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if (state['status_code'] // 100) not in (2, 3):
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req = webob.Request(environ)
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error = environ.get('translatable_error')
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user_locale = self.best_match_language(req.accept_language)
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if (req.accept.best_match(['application/json', 'application/xml'])
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== 'application/xml'):
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content_type = 'application/xml'
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try:
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# simple check xml is valid
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fault = etree.fromstring(b'\n'.join(app_iter))
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# Add the translated error to the xml data
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if error is not None:
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for fault_string in fault.findall('faultstring'):
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fault_string.text = i18n.translate(error,
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user_locale)
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error_message = etree.tostring(fault)
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body = b''.join((b'<error_message>',
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error_message,
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b'</error_message>'))
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except etree.XMLSyntaxError as err:
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LOG.error(_('Error parsing HTTP response: %s'), err)
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error_message = state['status_code']
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body = '<error_message>%s</error_message>' % error_message
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if six.PY3:
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body = body.encode('utf-8')
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else:
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content_type = 'application/json'
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app_data = b'\n'.join(app_iter)
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if six.PY3:
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app_data = app_data.decode('utf-8')
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try:
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fault = json.loads(app_data)
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if error is not None and 'faultstring' in fault:
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fault['faultstring'] = i18n.translate(error,
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user_locale)
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except ValueError as err:
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fault = app_data
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body = json.dumps({'error_message': fault})
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if six.PY3:
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body = body.encode('utf-8')
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state['headers'].append(('Content-Length', str(len(body))))
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state['headers'].append(('Content-Type', content_type))
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body = [body]
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else:
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body = app_iter
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return body
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