Synnefo

# Copyright 2011-2012 GRNET S.A. All rights reserved.

#

# Redistribution and use in source and binary forms, with or

# without modification, are permitted provided that the following

# conditions are met:

#

#   1. Redistributions of source code must retain the above

#      copyright notice, this list of conditions and the following

#      disclaimer.

#

#   2. Redistributions in binary form must reproduce the above

#      copyright notice, this list of conditions and the following

#      disclaimer in the documentation and/or other materials

#      provided with the distribution.

#

# THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS

# OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR

# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF

# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED

# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN

# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

# POSSIBILITY OF SUCH DAMAGE.

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# The views and conclusions contained in the software and

# documentation are those of the authors and should not be

# interpreted as representing official policies, either expressed

# or implied, of GRNET S.A.

from xml.dom import minidom

from django.http import HttpResponse

from django.template.loader import render_to_string

from django.utils import simplejson as json

from django.utils.http import parse_etags

from django.utils.encoding import smart_str

from django.views.decorators.csrf import csrf_exempt

from astakosclient import AstakosClient

from snf_django.lib import api

from snf_django.lib.api import faults

from pithos.api.util import (

    json_encode_decimal, rename_meta_key, format_header_key,

    printable_header_dict, get_account_headers, put_account_headers,

    get_container_headers, put_container_headers, get_object_headers,

    put_object_headers, update_manifest_meta, update_sharing_meta,

    update_public_meta, validate_modification_preconditions,

    validate_matching_preconditions, split_container_object_string,

    copy_or_move_object, get_int_parameter, get_content_length,

    get_content_range, socket_read_iterator, SaveToBackendHandler,

    object_data_response, put_object_block, hashmap_md5, simple_list_response,

    api_method, is_uuid, retrieve_uuid, retrieve_uuids,

    retrieve_displaynames, get_pithos_usage, Checksum, NoChecksum

)

from pithos.api.settings import (UPDATE_MD5, TRANSLATE_UUIDS,

                                 SERVICE_TOKEN, ASTAKOS_AUTH_URL)

from pithos.api import settings

from pithos.backends.base import (

    NotAllowedError, QuotaError, ContainerNotEmpty, ItemNotExists,

    VersionNotExists, ContainerExists, InvalidHash)

from pithos.backends.filter import parse_filters

import logging

logger = logging.getLogger(__name__)

def get_uuids(names):

    try:

        astakos = AstakosClient(SERVICE_TOKEN, ASTAKOS_AUTH_URL,

                                retry=2, use_pool=True, logger=logger)

        uuids = astakos.service_get_uuids(names)

    except Exception, e:

        logger.exception(e)

        return {}

    return uuids

@csrf_exempt

def top_demux(request):

    if request.method == 'GET':

        try:

            request.GET['X-Auth-Token']

        except KeyError:

            try:

                request.META['HTTP_X_AUTH_TOKEN']

            except KeyError:

                return authenticate(request)

        return account_list(request)

    else:

        return api.api_method_not_allowed(request, allowed_methods=['GET'])

@csrf_exempt

def account_demux(request, v_account):

    if TRANSLATE_UUIDS:

        if not is_uuid(v_account):

            uuids = get_uuids([v_account])

            if not uuids or not v_account in uuids:

                return HttpResponse(status=404)

            v_account = uuids[v_account]

    if request.method == 'HEAD':

        return account_meta(request, v_account)

    elif request.method == 'POST':

        return account_update(request, v_account)

    elif request.method == 'GET':

        return container_list(request, v_account)

    else:

        return api.api_method_not_allowed(request,

                                          allowed_methods=['HEAD',

                                                           'POST',

                                                           'GET'])

@csrf_exempt

def container_demux(request, v_account, v_container):

    if TRANSLATE_UUIDS:

        if not is_uuid(v_account):

            uuids = get_uuids([v_account])

            if not uuids or not v_account in uuids:

                return HttpResponse(status=404)

            v_account = uuids[v_account]

    if request.method == 'HEAD':

        return container_meta(request, v_account, v_container)

    elif request.method == 'PUT':

        return container_create(request, v_account, v_container)

    elif request.method == 'POST':

        return container_update(request, v_account, v_container)

    elif request.method == 'DELETE':

        return container_delete(request, v_account, v_container)

    elif request.method == 'GET':

        return object_list(request, v_account, v_container)

    else:

        return api.api_method_not_allowed(request,

                                          allowed_methods=['HEAD',

                                                           'PUT',

                                                           'POST',

                                                           'DELETE',

                                                           'GET'])

@csrf_exempt

def object_demux(request, v_account, v_container, v_object):

    # Helper to avoid placing the token in the URL

    # when loading objects from a browser.

    if TRANSLATE_UUIDS:

        if not is_uuid(v_account):

            uuids = get_uuids([v_account])

            if not uuids or not v_account in uuids:

                return HttpResponse(status=404)

            v_account = uuids[v_account]

    if request.method == 'HEAD':

        return object_meta(request, v_account, v_container, v_object)

    elif request.method == 'GET':

        return object_read(request, v_account, v_container, v_object)

    elif request.method == 'PUT':

        return object_write(request, v_account, v_container, v_object)

    elif request.method == 'COPY':

        return object_copy(request, v_account, v_container, v_object)

    elif request.method == 'MOVE':

        return object_move(request, v_account, v_container, v_object)

    elif request.method == 'POST':

        if request.META.get(

                'CONTENT_TYPE', '').startswith('multipart/form-data'):

            return object_write_form(request, v_account, v_container, v_object)

        return object_update(request, v_account, v_container, v_object)

    elif request.method == 'DELETE':

        return object_delete(request, v_account, v_container, v_object)

    else:

        return api.api_method_not_allowed(request, allowed_methods=['HEAD',

                                                                    'GET',

                                                                    'PUT',

                                                                    'COPY',

                                                                    'MOVE',

                                                                    'POST',

                                                                    'DELETE'])

@api_method('GET', token_required=False, user_required=False, logger=logger)

def authenticate(request):

    # Normal Response Codes: 204

    # Error Response Codes: internalServerError (500),

    #                       forbidden (403),

    #                       badRequest (400)

    x_auth_user = request.META.get('HTTP_X_AUTH_USER')

    x_auth_key = request.META.get('HTTP_X_AUTH_KEY')

    if not x_auth_user or not x_auth_key:

        raise faults.BadRequest('Missing X-Auth-User or X-Auth-Key header')

    response = HttpResponse(status=204)

    uri = request.build_absolute_uri()

    if '?' in uri:

        uri = uri[:uri.find('?')]

    response['X-Auth-Token'] = x_auth_key

    response['X-Storage-Url'] = uri + ('' if uri.endswith('/')

                                       else '/') + x_auth_user

    return response

@api_method('GET', format_allowed=True, user_required=True, logger=logger,

            serializations=["text", "xml", "json"])

def account_list(request):

    # Normal Response Codes: 200, 204

    # Error Response Codes: internalServerError (500),

    #                       badRequest (400)

    response = HttpResponse()

    marker = request.GET.get('marker')

    limit = get_int_parameter(request.GET.get('limit'))

    if not limit:

        limit = settings.API_LIST_LIMIT

    accounts = request.backend.list_accounts(request.user_uniq, marker, limit)

    if request.serialization == 'text':

        if TRANSLATE_UUIDS:

            accounts = retrieve_displaynames(

                getattr(request, 'token', None), accounts)

        if len(accounts) == 0:

            # The cloudfiles python bindings expect 200 if json/xml.

            response.status_code = 204

            return response

        response.status_code = 200

        response.content = '\n'.join(accounts) + '\n'

        return response

    account_meta = []

    for x in accounts:

        if x == request.user_uniq:

            continue

        usage = get_pithos_usage(request.x_auth_token)

        try:

            meta = request.backend.get_account_meta(

                request.user_uniq, x, 'pithos', include_user_defined=False,

                external_quota=usage)

            groups = request.backend.get_account_groups(request.user_uniq, x)

        except NotAllowedError:

            raise faults.Forbidden('Not allowed')

        else:

            rename_meta_key(meta, 'modified', 'last_modified')

            rename_meta_key(

                meta, 'until_timestamp', 'x_account_until_timestamp')

            if groups:

                meta['X-Account-Group'] = printable_header_dict(

                    dict([(k, ','.join(v)) for k, v in groups.iteritems()]))

            account_meta.append(printable_header_dict(meta))

    if TRANSLATE_UUIDS:

        uuids = list(d['name'] for d in account_meta)

        catalog = retrieve_displaynames(

            getattr(request, 'token', None), uuids, return_dict=True)

        for meta in account_meta:

            meta['name'] = catalog.get(meta.get('name'))

    if request.serialization == 'xml':

        data = render_to_string('accounts.xml', {'accounts': account_meta})

    elif request.serialization == 'json':

        data = json.dumps(account_meta)

    response.status_code = 200

    response.content = data

    return response

@api_method('HEAD', user_required=True, logger=logger)

def account_meta(request, v_account):

    # Normal Response Codes: 204

    # Error Response Codes: internalServerError (500),

    #                       forbidden (403),

    #                       badRequest (400)

    until = get_int_parameter(request.GET.get('until'))

    usage = get_pithos_usage(request.x_auth_token)

    try:

        meta = request.backend.get_account_meta(

            request.user_uniq, v_account, 'pithos', until,

            external_quota=usage)

        groups = request.backend.get_account_groups(

            request.user_uniq, v_account)

        if TRANSLATE_UUIDS:

            for k in groups:

                groups[k] = retrieve_displaynames(

                    getattr(request, 'token', None), groups[k])

        policy = request.backend.get_account_policy(

            request.user_uniq, v_account, external_quota=usage)

    except NotAllowedError:

        raise faults.Forbidden('Not allowed')

    validate_modification_preconditions(request, meta)

    response = HttpResponse(status=204)

    put_account_headers(response, meta, groups, policy)

    return response

@api_method('POST', user_required=True, logger=logger)

def account_update(request, v_account):

    # Normal Response Codes: 202

    # Error Response Codes: internalServerError (500),

    #                       forbidden (403),

    #                       badRequest (400)

    meta, groups = get_account_headers(request)

    for k in groups:

        if TRANSLATE_UUIDS:

            try:

                groups[k] = retrieve_uuids(

                    getattr(request, 'token', None),

                    groups[k],

                    fail_silently=False)

            except ItemNotExists, e:

                raise faults.BadRequest(

                    'Bad X-Account-Group header value: %s' % e)

        else:

            try:

                retrieve_displaynames(

                    getattr(request, 'token', None),

                    groups[k],

                    fail_silently=False)

            except ItemNotExists, e:

                raise faults.BadRequest(

                    'Bad X-Account-Group header value: %s' % e)

    replace = True

    if 'update' in request.GET:

        replace = False

    if groups:

        try:

            request.backend.update_account_groups(request.user_uniq, v_account,

                                                  groups, replace)

        except NotAllowedError:

            raise faults.Forbidden('Not allowed')

        except ValueError:

            raise faults.BadRequest('Invalid groups header')

    if meta or replace:

        try:

            request.backend.update_account_meta(request.user_uniq, v_account,

                                                'pithos', meta, replace)

        except NotAllowedError:

            raise faults.Forbidden('Not allowed')

    return HttpResponse(status=202)

@api_method('GET', format_allowed=True, user_required=True, logger=logger,

            serializations=["text", "xml", "json"])

def container_list(request, v_account):

    # Normal Response Codes: 200, 204

    # Error Response Codes: internalServerError (500),

    #                       itemNotFound (404),

    #                       forbidden (403),

    #                       badRequest (400)

    until = get_int_parameter(request.GET.get('until'))

    usage = get_pithos_usage(request.x_auth_token)

    try:

        meta = request.backend.get_account_meta(

            request.user_uniq, v_account, 'pithos', until,

            external_quota=usage)

        groups = request.backend.get_account_groups(

            request.user_uniq, v_account)

        policy = request.backend.get_account_policy(

            request.user_uniq, v_account, external_quota=usage)

    except NotAllowedError:

        raise faults.Forbidden('Not allowed')

    validate_modification_preconditions(request, meta)

    response = HttpResponse()

    put_account_headers(response, meta, groups, policy)

    marker = request.GET.get('marker')

    limit = get_int_parameter(request.GET.get('limit'))

    if not limit:

        limit = settings.API_LIST_LIMIT

    shared = False

    if 'shared' in request.GET:

        shared = True

    public_requested = 'public' in request.GET

    public_granted = public_requested and request.user_uniq == v_account

    if public_requested and not public_granted:

        raise faults.Forbidden(

            'PUblic container listing is not allowed to non path owners')

    try:

        containers = request.backend.list_containers(

            request.user_uniq, v_account,

            marker, limit, shared, until, public_granted)

    except NotAllowedError:

        raise faults.Forbidden('Not allowed')

    except NameError:

        containers = []

    if request.serialization == 'text':

        if len(containers) == 0:

            # The cloudfiles python bindings expect 200 if json/xml.

            response.status_code = 204

            return response

        response.status_code = 200

        response.content = '\n'.join(containers) + '\n'

        return response

    container_meta = []

    for x in containers:

        try:

            meta = request.backend.get_container_meta(

                request.user_uniq, v_account,

                x, 'pithos', until, include_user_defined=False)

            policy = request.backend.get_container_policy(request.user_uniq,

                                                          v_account, x)

        except NotAllowedError:

            raise faults.Forbidden('Not allowed')

        except NameError:

            pass

        else:

            rename_meta_key(meta, 'modified', 'last_modified')

            rename_meta_key(

                meta, 'until_timestamp', 'x_container_until_timestamp')

            if policy:

                meta['X-Container-Policy'] = printable_header_dict(

                    dict([(k, v) for k, v in policy.iteritems()]))

            container_meta.append(printable_header_dict(meta))

    if request.serialization == 'xml':

        data = render_to_string('containers.xml', {'account':

                                v_account, 'containers': container_meta})

    elif request.serialization == 'json':

        data = json.dumps(container_meta)

    response.status_code = 200

    response.content = data

    return response

@api_method('HEAD', user_required=True, logger=logger)

def container_meta(request, v_account, v_container):

    # Normal Response Codes: 204

    # Error Response Codes: internalServerError (500),

    #                       itemNotFound (404),

    #                       forbidden (403),

    #                       badRequest (400)

    until = get_int_parameter(request.GET.get('until'))

    try:

        meta = request.backend.get_container_meta(request.user_uniq, v_account,

                                                  v_container, 'pithos', until)

        meta['object_meta'] = \

            request.backend.list_container_meta(request.user_uniq,

                                                v_account, v_container,

                                                'pithos', until)

        policy = request.backend.get_container_policy(

            request.user_uniq, v_account,

            v_container)

    except NotAllowedError:

        raise faults.Forbidden('Not allowed')

    except ItemNotExists:

        raise faults.ItemNotFound('Container does not exist')

    validate_modification_preconditions(request, meta)

    response = HttpResponse(status=204)

    put_container_headers(request, response, meta, policy)

    return response

@api_method('PUT', user_required=True, logger=logger)

def container_create(request, v_account, v_container):

    # Normal Response Codes: 201, 202

    # Error Response Codes: internalServerError (500),

    #                       itemNotFound (404),

    #                       forbidden (403),

    #                       badRequest (400)

    meta, policy = get_container_headers(request)

    try:

        request.backend.put_container(

            request.user_uniq, v_account, v_container, policy)

        ret = 201

    except NotAllowedError:

        raise faults.Forbidden('Not allowed')

    except ValueError:

        raise faults.BadRequest('Invalid policy header')

    except ContainerExists:

        ret = 202

    if ret == 202 and policy:

        try:

            request.backend.update_container_policy(

                request.user_uniq, v_account,

                v_container, policy, replace=False)

        except NotAllowedError:

            raise faults.Forbidden('Not allowed')

        except ItemNotExists:

            raise faults.ItemNotFound('Container does not exist')

        except ValueError:

            raise faults.BadRequest('Invalid policy header')

    if meta:

        try:

            request.backend.update_container_meta(request.user_uniq, v_account,

                                                  v_container, 'pithos',

                                                  meta, replace=False)

        except NotAllowedError:

            raise faults.Forbidden('Not allowed')

        except ItemNotExists:

            raise faults.ItemNotFound('Container does not exist')

    return HttpResponse(status=ret)

@api_method('POST', format_allowed=True, user_required=True, logger=logger,

            lock_container_path=True)

def container_update(request, v_account, v_container):

    # Normal Response Codes: 202

    # Error Response Codes: internalServerError (500),

    #                       itemNotFound (404),

    #                       forbidden (403),

    #                       badRequest (400)

    meta, policy = get_container_headers(request)

    replace = True

    if 'update' in request.GET:

        replace = False

    if policy:

        try:

            request.backend.update_container_policy(

                request.user_uniq, v_account,

                v_container, policy, replace)

        except NotAllowedError:

            raise faults.Forbidden('Not allowed')

        except ItemNotExists:

            raise faults.ItemNotFound('Container does not exist')

        except ValueError:

            raise faults.BadRequest('Invalid policy header')

    if meta or replace:

        try:

            request.backend.update_container_meta(request.user_uniq, v_account,

                                                  v_container, 'pithos',

                                                  meta, replace)

        except NotAllowedError:

            raise faults.Forbidden('Not allowed')

        except ItemNotExists:

            raise faults.ItemNotFound('Container does not exist')

    content_length = -1

    if request.META.get('HTTP_TRANSFER_ENCODING') != 'chunked':

        content_length = get_int_parameter(

            request.META.get('CONTENT_LENGTH', 0))

    content_type = request.META.get('CONTENT_TYPE')

    hashmap = []

    if (content_type

            and content_type == 'application/octet-stream'

            and content_length != 0):

        for data in socket_read_iterator(request, content_length,

                                         request.backend.block_size):

            # TODO: Raise 408 (Request Timeout) if this takes too long.

            # TODO: Raise 499 (Client Disconnect) if a length is defined

            #       and we stop before getting this much data.

            hashmap.append(request.backend.put_block(data))

    response = HttpResponse(status=202)

    if hashmap:

        response.content = simple_list_response(request, hashmap)

    return response

@api_method('DELETE', user_required=True, logger=logger,

            lock_container_path=True)

def container_delete(request, v_account, v_container):

    # Normal Response Codes: 204

    # Error Response Codes: internalServerError (500),

    #                       conflict (409),

    #                       itemNotFound (404),

    #                       forbidden (403),

    #                       badRequest (400)

    #                       requestentitytoolarge (413)

    until = get_int_parameter(request.GET.get('until'))

    delimiter = request.GET.get('delimiter')

    try:

        request.backend.delete_container(

            request.user_uniq, v_account, v_container,

            until, delimiter=delimiter)

    except NotAllowedError:

        raise faults.Forbidden('Not allowed')

    except ItemNotExists:

        raise faults.ItemNotFound('Container does not exist')

    except ContainerNotEmpty:

        raise faults.Conflict('Container is not empty')

    except QuotaError, e:

        raise faults.RequestEntityTooLarge('Quota error: %s' % e)

    return HttpResponse(status=204)

@api_method('GET', format_allowed=True, user_required=True, logger=logger,

            serializations=["text", "xml", "json"])

def object_list(request, v_account, v_container):

    # Normal Response Codes: 200, 204

    # Error Response Codes: internalServerError (500),

    #                       itemNotFound (404),

    #                       forbidden (403),

    #                       badRequest (400)

    until = get_int_parameter(request.GET.get('until'))

    try:

        meta = request.backend.get_container_meta(request.user_uniq, v_account,

                                                  v_container, 'pithos', until)

        meta['object_meta'] = \

            request.backend.list_container_meta(request.user_uniq,

                                                v_account, v_container,

                                                'pithos', until)

        policy = request.backend.get_container_policy(

            request.user_uniq, v_account,

            v_container)

    except NotAllowedError:

        raise faults.Forbidden('Not allowed')

    except ItemNotExists:

        raise faults.ItemNotFound('Container does not exist')

    validate_modification_preconditions(request, meta)

    response = HttpResponse()

    put_container_headers(request, response, meta, policy)

    path = request.GET.get('path')

    prefix = request.GET.get('prefix')

    delimiter = request.GET.get('delimiter')

    # Path overrides prefix and delimiter.

    virtual = True

    if path:

        prefix = path

        delimiter = '/'

        virtual = False

    # Naming policy.

    if prefix and delimiter and not prefix.endswith(delimiter):

        prefix = prefix + delimiter

    if not prefix:

        prefix = ''

    prefix = prefix.lstrip('/')

    marker = request.GET.get('marker')

    limit = get_int_parameter(request.GET.get('limit'))

    if not limit:

        limit = settings.API_LIST_LIMIT

    keys = request.GET.get('meta')

    if keys:

        keys = [smart_str(x.strip()) for x in keys.split(',')

                if x.strip() != '']

        included, excluded, opers = parse_filters(keys)

        keys = []

        keys += [format_header_key('X-Object-Meta-' + x) for x in included]

        keys += ['!' + format_header_key('X-Object-Meta-' + x)

                 for x in excluded]

        keys += ['%s%s%s' % (format_header_key(

            'X-Object-Meta-' + k), o, v) for k, o, v in opers]

    else:

        keys = []

    shared = False

    if 'shared' in request.GET:

        shared = True

    public_requested = 'public' in request.GET

    public_granted = public_requested and request.user_uniq == v_account

    if public_requested and not public_granted:

        raise faults.Forbidden(

            'PUblic object listing is not allowed to non path owners')

    if request.serialization == 'text':

        try:

            objects = request.backend.list_objects(

                request.user_uniq, v_account,

                v_container, prefix, delimiter, marker,

                limit, virtual, 'pithos', keys, shared,

                until, None, public_granted)

        except NotAllowedError:

            raise faults.Forbidden('Not allowed')

        except ItemNotExists:

            raise faults.ItemNotFound('Container does not exist')

        if len(objects) == 0:

            # The cloudfiles python bindings expect 200 if json/xml.

            response.status_code = 204

            return response

        response.status_code = 200

        response.content = '\n'.join([x[0] for x in objects]) + '\n'

        return response

    try:

        objects = request.backend.list_object_meta(

            request.user_uniq, v_account, v_container, prefix, delimiter,

            marker, limit, virtual, 'pithos', keys, shared, until, None,

            public_granted)

        object_permissions = {}

        object_public = {}

        if until is None:

            name = '/'.join((v_account, v_container, ''))

            name_idx = len(name)

            objects_bulk = []

            for x in request.backend.list_object_permissions(

                    request.user_uniq, v_account, v_container, prefix):

                # filter out objects which are not under the container

                if name != x[:name_idx]:

                    continue

                objects_bulk.append(x[name_idx:])

            if len(objects_bulk) > 0:

                object_permissions = \

                    request.backend.get_object_permissions_bulk(

                        request.user_uniq, v_account, v_container,

                        objects_bulk)

            if request.user_uniq == v_account:

                # Bring public information only if the request user

                # is the object owner

                for k, v in request.backend.list_object_public(

                        request.user_uniq, v_account,

                        v_container, prefix).iteritems():

                    object_public[k[name_idx:]] = v

    except NotAllowedError:

        raise faults.Forbidden('Not allowed')

    except ItemNotExists:

        raise faults.ItemNotFound('Container does not exist')

    object_meta = []

    for meta in objects:

        if TRANSLATE_UUIDS:

            modified_by = meta.get('modified_by')

            if modified_by:

                l = retrieve_displaynames(

                    getattr(request, 'token', None), [meta['modified_by']])

                if l is not None and len(l) == 1:

                    meta['modified_by'] = l[0]

        if len(meta) == 1:

            # Virtual objects/directories.

            object_meta.append(meta)

        else:

            rename_meta_key(

                meta, 'hash', 'x_object_hash')  # Will be replaced by checksum.

            rename_meta_key(meta, 'checksum', 'hash')

            rename_meta_key(meta, 'type', 'content_type')

            rename_meta_key(meta, 'uuid', 'x_object_uuid')

            if until is not None and 'modified' in meta:

                del(meta['modified'])

            else:

                rename_meta_key(meta, 'modified', 'last_modified')

            rename_meta_key(meta, 'modified_by', 'x_object_modified_by')

            rename_meta_key(meta, 'version', 'x_object_version')

            rename_meta_key(

                meta, 'version_timestamp', 'x_object_version_timestamp')