226 lines
8.2 KiB
Python
226 lines
8.2 KiB
Python
# Copyright (c) 2017 OpenStack Foundation
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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
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# 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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import json
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import six
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from xml.etree.cElementTree import Element, SubElement, tostring
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from swift.common.constraints import valid_api_version
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from swift.common.http import HTTP_NO_CONTENT
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from swift.common.request_helpers import get_param
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from swift.common.swob import HTTPException, HTTPNotAcceptable, Request, \
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RESPONSE_REASONS, HTTPBadRequest
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#: Mapping of query string ``format=`` values to their corresponding
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#: content-type values.
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FORMAT2CONTENT_TYPE = {'plain': 'text/plain', 'json': 'application/json',
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'xml': 'application/xml'}
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#: Maximum size of a valid JSON container listing body. If we receive
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#: a container listing response larger than this, assume it's a staticweb
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#: response and pass it on to the client.
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# Default max object length is 1024, default container listing limit is 1e4;
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# add a fudge factor for things like hash, last_modified, etc.
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MAX_CONTAINER_LISTING_CONTENT_LENGTH = 1024 * 10000 * 2
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def get_listing_content_type(req):
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"""
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Determine the content type to use for an account or container listing
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response.
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:param req: request object
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:returns: content type as a string (e.g. text/plain, application/json)
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:raises HTTPNotAcceptable: if the requested content type is not acceptable
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:raises HTTPBadRequest: if the 'format' query param is provided and
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not valid UTF-8
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"""
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query_format = get_param(req, 'format')
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if query_format:
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req.accept = FORMAT2CONTENT_TYPE.get(
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query_format.lower(), FORMAT2CONTENT_TYPE['plain'])
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try:
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out_content_type = req.accept.best_match(
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['text/plain', 'application/json', 'application/xml', 'text/xml'])
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except ValueError:
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raise HTTPBadRequest(request=req, body=b'Invalid Accept header')
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if not out_content_type:
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raise HTTPNotAcceptable(request=req)
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return out_content_type
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def to_xml(document_element):
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result = tostring(document_element, encoding='UTF-8').replace(
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b"<?xml version='1.0' encoding='UTF-8'?>",
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b'<?xml version="1.0" encoding="UTF-8"?>', 1)
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if not result.startswith(b'<?xml '):
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# py3 tostring doesn't (necessarily?) include the XML declaration;
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# add it if it's missing.
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result = b'<?xml version="1.0" encoding="UTF-8"?>\n' + result
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return result
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def account_to_xml(listing, account_name):
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if isinstance(account_name, bytes):
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account_name = account_name.decode('utf-8')
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doc = Element('account', name=account_name)
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doc.text = '\n'
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for record in listing:
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if 'subdir' in record:
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name = record.pop('subdir')
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sub = SubElement(doc, 'subdir', name=name)
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else:
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sub = SubElement(doc, 'container')
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for field in ('name', 'count', 'bytes', 'last_modified'):
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SubElement(sub, field).text = six.text_type(
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record.pop(field))
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sub.tail = '\n'
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return to_xml(doc)
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def container_to_xml(listing, base_name):
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if isinstance(base_name, bytes):
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base_name = base_name.decode('utf-8')
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doc = Element('container', name=base_name)
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for record in listing:
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if 'subdir' in record:
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name = record.pop('subdir')
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sub = SubElement(doc, 'subdir', name=name)
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SubElement(sub, 'name').text = name
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else:
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sub = SubElement(doc, 'object')
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for field in ('name', 'hash', 'bytes', 'content_type',
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'last_modified'):
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SubElement(sub, field).text = six.text_type(
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record.pop(field))
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return to_xml(doc)
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def listing_to_text(listing):
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def get_lines():
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for item in listing:
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if 'name' in item:
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yield item['name'].encode('utf-8') + b'\n'
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else:
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yield item['subdir'].encode('utf-8') + b'\n'
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return b''.join(get_lines())
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class ListingFilter(object):
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def __init__(self, app):
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self.app = app
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def __call__(self, env, start_response):
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req = Request(env)
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try:
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# account and container only
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version, acct, cont = req.split_path(2, 3)
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except ValueError:
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return self.app(env, start_response)
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if not valid_api_version(version) or req.method not in ('GET', 'HEAD'):
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return self.app(env, start_response)
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# OK, definitely have an account/container request.
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# Get the desired content-type, then force it to a JSON request.
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try:
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out_content_type = get_listing_content_type(req)
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except HTTPException as err:
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return err(env, start_response)
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params = req.params
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params['format'] = 'json'
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req.params = params
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status, headers, resp_iter = req.call_application(self.app)
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header_to_index = {}
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resp_content_type = resp_length = None
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for i, (header, value) in enumerate(headers):
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header = header.lower()
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if header == 'content-type':
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header_to_index[header] = i
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resp_content_type = value.partition(';')[0]
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elif header == 'content-length':
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header_to_index[header] = i
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resp_length = int(value)
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if not status.startswith('200 '):
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start_response(status, headers)
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return resp_iter
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if resp_content_type != 'application/json':
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start_response(status, headers)
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return resp_iter
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if resp_length is None or \
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resp_length > MAX_CONTAINER_LISTING_CONTENT_LENGTH:
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start_response(status, headers)
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return resp_iter
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def set_header(header, value):
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if value is None:
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del headers[header_to_index[header]]
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else:
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headers[header_to_index[header]] = (
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headers[header_to_index[header]][0], str(value))
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if req.method == 'HEAD':
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set_header('content-type', out_content_type + '; charset=utf-8')
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set_header('content-length', None) # don't know, can't determine
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start_response(status, headers)
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return resp_iter
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body = b''.join(resp_iter)
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try:
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listing = json.loads(body.decode('ascii'))
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# Do a couple sanity checks
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if not isinstance(listing, list):
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raise ValueError
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if not all(isinstance(item, dict) for item in listing):
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raise ValueError
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except ValueError:
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# Static web listing that's returning invalid JSON?
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# Just pass it straight through; that's about all we *can* do.
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start_response(status, headers)
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return [body]
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try:
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if out_content_type.endswith('/xml'):
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if cont:
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body = container_to_xml(listing, cont)
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else:
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body = account_to_xml(listing, acct)
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elif out_content_type == 'text/plain':
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body = listing_to_text(listing)
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# else, json -- we continue down here to be sure we set charset
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except KeyError:
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# listing was in a bad format -- funky static web listing??
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start_response(status, headers)
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return [body]
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if not body:
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status = '%s %s' % (HTTP_NO_CONTENT,
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RESPONSE_REASONS[HTTP_NO_CONTENT][0])
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set_header('content-type', out_content_type + '; charset=utf-8')
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set_header('content-length', len(body))
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start_response(status, headers)
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return [body]
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def filter_factory(global_conf, **local_conf):
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return ListingFilter
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