e5d92994b1
Using the lazy gettext functionality from oslo gettextutils, it is possible to use the Accept-Language header to translate an exception message to the user requested locale and return that translation from the API. Implements bp user-locale-api Change-Id: I48de5e681827305eef60c7a77e8d3091f9d64be0 Co-authored-by: Mathew Odden <mrodden@us.ibm.com> Co-authored-by: Ben Nemec <openstack@nemebean.com>
125 lines
5.2 KiB
Python
125 lines
5.2 KiB
Python
# -*- encoding: utf-8 -*-
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#
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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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# Author: Doug Hellmann <doug.hellmann@dreamhost.com>
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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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import webob
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from xml import etree as et
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try:
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from xml.etree.ElementTree import ParseError
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except ImportError:
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from xml.parsers.expat import ExpatError as ParseError
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from ceilometer.api import hooks
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from ceilometer.openstack.common import gettextutils
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from ceilometer.openstack.common import log
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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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"""
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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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"""
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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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# Find the first TranslationHook in the array of hooks and use the
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# translatable_error object from it
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error = None
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for hook in self.app.hooks:
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if isinstance(hook, hooks.TranslationHook):
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error = hook.local_error.translatable_error
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break
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user_locale = req.accept_language.best_match(
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gettextutils.get_available_languages('ceilometer'),
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default_match='en_US')
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if (req.accept.best_match(['application/json', 'application/xml'])
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== 'application/xml'):
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try:
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# simple check xml is valid
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fault = et.ElementTree.fromstring('\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 = (
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gettextutils.get_localized_message(
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error, user_locale))
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body = [et.ElementTree.tostring(
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et.ElementTree.fromstring(
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'<error_message>'
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+ et.ElementTree.tostring(fault)
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+ '</error_message>'))]
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except ParseError as err:
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LOG.error('Error parsing HTTP response: %s' % err)
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body = ['<error_message>%s' % state['status_code']
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+ '</error_message>']
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state['headers'].append(('Content-Type', 'application/xml'))
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else:
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try:
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fault = json.loads('\n'.join(app_iter))
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if error is not None and 'faultstring' in fault:
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fault['faultstring'] = (
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gettextutils.get_localized_message(
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error, user_locale))
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body = [json.dumps({'error_message': json.dumps(fault)})]
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except ValueError as err:
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body = [json.dumps({'error_message': '\n'.join(app_iter)})]
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state['headers'].append(('Content-Type', 'application/json'))
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state['headers'].append(('Content-Length', len(body[0])))
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else:
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body = app_iter
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return body
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