Source code for libcloud.storage.drivers.s3

# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License.  You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import time
import copy
import base64
import hmac
import sys

from hashlib import sha1
from xml.etree.ElementTree import Element, SubElement

from libcloud.utils.py3 import httplib
from libcloud.utils.py3 import urlquote
from libcloud.utils.py3 import urlencode
from libcloud.utils.py3 import b
from libcloud.utils.py3 import tostring

from libcloud.utils.xml import fixxpath, findtext
from libcloud.utils.files import read_in_chunks
from libcloud.common.types import InvalidCredsError, LibcloudError
from libcloud.common.base import ConnectionUserAndKey, RawResponse
from libcloud.common.aws import AWSBaseResponse

from libcloud.storage.base import Object, Container, StorageDriver
from libcloud.storage.types import ContainerIsNotEmptyError
from libcloud.storage.types import InvalidContainerNameError
from libcloud.storage.types import ContainerDoesNotExistError
from libcloud.storage.types import ObjectDoesNotExistError
from libcloud.storage.types import ObjectHashMismatchError


# How long before the token expires
EXPIRATION_SECONDS = 15 * 60

S3_US_STANDARD_HOST = 's3.amazonaws.com'
S3_US_WEST_HOST = 's3-us-west-1.amazonaws.com'
S3_US_WEST_OREGON_HOST = 's3-us-west-2.amazonaws.com'
S3_EU_WEST_HOST = 's3-eu-west-1.amazonaws.com'
S3_AP_SOUTHEAST_HOST = 's3-ap-southeast-1.amazonaws.com'
S3_AP_NORTHEAST_HOST = 's3-ap-northeast-1.amazonaws.com'

API_VERSION = '2006-03-01'
NAMESPACE = 'http://s3.amazonaws.com/doc/%s/' % (API_VERSION)

# AWS multi-part chunks must be minimum 5MB
CHUNK_SIZE = 5 * 1024 * 1024

# Desired number of items in each response inside a paginated request in
# ex_iterate_multipart_uploads.
RESPONSES_PER_REQUEST = 100


class S3Response(AWSBaseResponse):

    valid_response_codes = [httplib.NOT_FOUND, httplib.CONFLICT,
                            httplib.BAD_REQUEST]

    def success(self):
        i = int(self.status)
        return i >= 200 and i <= 299 or i in self.valid_response_codes

    def parse_error(self):
        if self.status in [httplib.UNAUTHORIZED, httplib.FORBIDDEN]:
            raise InvalidCredsError(self.body)
        elif self.status == httplib.MOVED_PERMANENTLY:
            raise LibcloudError('This bucket is located in a different ' +
                                'region. Please use the correct driver.',
                                driver=S3StorageDriver)
        raise LibcloudError('Unknown error. Status code: %d' % (self.status),
                            driver=S3StorageDriver)


class S3RawResponse(S3Response, RawResponse):
    pass


class S3Connection(ConnectionUserAndKey):
    """
    Repersents a single connection to the EC2 Endpoint
    """

    host = 's3.amazonaws.com'
    responseCls = S3Response
    rawResponseCls = S3RawResponse

    def add_default_params(self, params):
        expires = str(int(time.time()) + EXPIRATION_SECONDS)
        params['AWSAccessKeyId'] = self.user_id
        params['Expires'] = expires
        return params

    def pre_connect_hook(self, params, headers):
        params['Signature'] = self._get_aws_auth_param(
            method=self.method, headers=headers, params=params,
            expires=params['Expires'], secret_key=self.key, path=self.action)
        return params, headers

    def _get_aws_auth_param(self, method, headers, params, expires,
                            secret_key, path='/'):
        """
        Signature = URL-Encode( Base64( HMAC-SHA1( YourSecretAccessKeyID,
                                    UTF-8-Encoding-Of( StringToSign ) ) ) );

        StringToSign = HTTP-VERB + "\n" +
            Content-MD5 + "\n" +
            Content-Type + "\n" +
            Expires + "\n" +
            CanonicalizedAmzHeaders +
            CanonicalizedResource;
        """
        special_header_keys = ['content-md5', 'content-type', 'date']
        special_header_values = {'date': ''}
        amz_header_values = {}

        headers_copy = copy.deepcopy(headers)
        for key, value in list(headers_copy.items()):
            key_lower = key.lower()
            if key_lower in special_header_keys:
                special_header_values[key_lower] = value.strip()
            elif key_lower.startswith('x-amz-'):
                amz_header_values[key.lower()] = value.strip()

        if not 'content-md5' in special_header_values:
            special_header_values['content-md5'] = ''

        if not 'content-type' in special_header_values:
            special_header_values['content-type'] = ''

        if expires:
            special_header_values['date'] = str(expires)

        keys_sorted = list(special_header_values.keys())
        keys_sorted.sort()

        buf = [method]
        for key in keys_sorted:
            value = special_header_values[key]
            buf.append(value)
        string_to_sign = '\n'.join(buf)

        keys_sorted = list(amz_header_values.keys())
        keys_sorted.sort()

        amz_header_string = []
        for key in keys_sorted:
            value = amz_header_values[key]
            amz_header_string.append('%s:%s' % (key, value))
        amz_header_string = '\n'.join(amz_header_string)

        values_to_sign = []
        for value in [string_to_sign, amz_header_string, path]:
            if value:
                values_to_sign.append(value)

        string_to_sign = '\n'.join(values_to_sign)
        b64_hmac = base64.b64encode(
            hmac.new(b(secret_key), b(string_to_sign), digestmod=sha1).digest()
        )
        return b64_hmac.decode('utf-8')


class S3MultipartUpload(object):
    """
    Class representing an amazon s3 multipart upload
    """

    def __init__(self, key, id, created_at, initiator, owner):
        """
        Class representing an amazon s3 multipart upload

        :param key: The object/key that was being uploaded
        :type key: ``str``

        :param id: The upload id assigned by amazon
        :type id: ``str``

        :param created_at: The date/time at which the upload was started
        :type created_at: ``str``

        :param initiator: The AWS owner/IAM user who initiated this
        :type initiator: ``str``

        :param owner: The AWS owner/IAM who will own this object
        :type owner: ``str``
        """
        self.key = key
        self.id = id
        self.created_at = created_at
        self.initiator = initiator
        self.owner = owner

    def __repr__(self):
        return ('<S3MultipartUpload: key=%s>' % (self.key))


class S3StorageDriver(StorageDriver):
    name = 'Amazon S3 (standard)'
    website = 'http://aws.amazon.com/s3/'
    connectionCls = S3Connection
    hash_type = 'md5'
    supports_chunked_encoding = False
    supports_s3_multipart_upload = True
    ex_location_name = ''
    namespace = NAMESPACE

    def iterate_containers(self):
        response = self.connection.request('/')
        if response.status == httplib.OK:
            containers = self._to_containers(obj=response.object,
                                             xpath='Buckets/Bucket')
            return containers

        raise LibcloudError('Unexpected status code: %s' % (response.status),
                            driver=self)

    def list_container_objects(self, container, ex_prefix=None):
        """
        Return a list of objects for the given container.

        :param container: Container instance.
        :type container: :class:`Container`

        :param ex_prefix: Only return objects starting with ex_prefix
        :type ex_prefix: ``str``

        :return: A list of Object instances.
        :rtype: ``list`` of :class:`Object`
        """
        return list(self.iterate_container_objects(container,
                    ex_prefix=ex_prefix))

    def iterate_container_objects(self, container, ex_prefix=None):
        """
        Return a generator of objects for the given container.

        :param container: Container instance
        :type container: :class:`Container`

        :param ex_prefix: Only return objects starting with ex_prefix
        :type ex_prefix: ``str``

        :return: A generator of Object instances.
        :rtype: ``generator`` of :class:`Object`
        """
        params = {}
        if ex_prefix:
            params['prefix'] = ex_prefix

        last_key = None
        exhausted = False
        container_path = self._get_container_path(container)

        while not exhausted:
            if last_key:
                params['marker'] = last_key

            response = self.connection.request(container_path,
                                               params=params)

            if response.status != httplib.OK:
                raise LibcloudError('Unexpected status code: %s' %
                                    (response.status), driver=self)

            objects = self._to_objs(obj=response.object,
                                    xpath='Contents', container=container)
            is_truncated = response.object.findtext(fixxpath(
                xpath='IsTruncated', namespace=self.namespace)).lower()
            exhausted = (is_truncated == 'false')

            last_key = None
            for obj in objects:
                last_key = obj.name
                yield obj

    def get_container(self, container_name):
        # This is very inefficient, but afaik it's the only way to do it
        containers = self.list_containers()

        try:
            container = [c for c in containers if c.name == container_name][0]
        except IndexError:
            raise ContainerDoesNotExistError(value=None, driver=self,
                                             container_name=container_name)

        return container

    def get_object(self, container_name, object_name):
        container = self.get_container(container_name=container_name)
        object_path = self._get_object_path(container, object_name)
        response = self.connection.request(object_path, method='HEAD')

        if response.status == httplib.OK:
            obj = self._headers_to_object(object_name=object_name,
                                          container=container,
                                          headers=response.headers)
            return obj

        raise ObjectDoesNotExistError(value=None, driver=self,
                                      object_name=object_name)

    def _get_container_path(self, container):
        """
        Return a container path

        :param container: Container instance
        :type  container: :class:`Container`

        :return: A path for this container.
        :rtype: ``str``
        """
        return '/%s' % (container.name)

    def _get_object_path(self, container, object_name):
        """
        Return an object's CDN path.

        :param container: Container instance
        :type  container: :class:`Container`

        :param object_name: Object name
        :type  object_name: :class:`str`

        :return: A  path for this object.
        :rtype: ``str``
        """
        container_url = self._get_container_path(container)
        object_name_cleaned = self._clean_object_name(object_name)
        object_path = '%s/%s' % (container_url, object_name_cleaned)
        return object_path

    def create_container(self, container_name):
        if self.ex_location_name:
            root = Element('CreateBucketConfiguration')
            child = SubElement(root, 'LocationConstraint')
            child.text = self.ex_location_name

            data = tostring(root)
        else:
            data = ''

        response = self.connection.request('/%s' % (container_name),
                                           data=data,
                                           method='PUT')

        if response.status == httplib.OK:
            container = Container(name=container_name, extra=None, driver=self)
            return container
        elif response.status == httplib.CONFLICT:
            raise InvalidContainerNameError(
                value='Container with this name already exists. The name must '
                      'be unique among all the containers in the system',
                container_name=container_name, driver=self)
        elif response.status == httplib.BAD_REQUEST:
            raise InvalidContainerNameError(value='Container name contains ' +
                                            'invalid characters.',
                                            container_name=container_name,
                                            driver=self)

        raise LibcloudError('Unexpected status code: %s' % (response.status),
                            driver=self)

    def delete_container(self, container):
        # Note: All the objects in the container must be deleted first
        response = self.connection.request('/%s' % (container.name),
                                           method='DELETE')
        if response.status == httplib.NO_CONTENT:
            return True
        elif response.status == httplib.CONFLICT:
            raise ContainerIsNotEmptyError(
                value='Container must be empty before it can be deleted.',
                container_name=container.name, driver=self)
        elif response.status == httplib.NOT_FOUND:
            raise ContainerDoesNotExistError(value=None,
                                             driver=self,
                                             container_name=container.name)

        return False

    def download_object(self, obj, destination_path, overwrite_existing=False,
                        delete_on_failure=True):
        obj_path = self._get_object_path(obj.container, obj.name)

        response = self.connection.request(obj_path, method='GET', raw=True)

        return self._get_object(obj=obj, callback=self._save_object,
                                response=response,
                                callback_kwargs={
                                    'obj': obj,
                                    'response': response.response,
                                    'destination_path': destination_path,
                                    'overwrite_existing': overwrite_existing,
                                    'delete_on_failure': delete_on_failure},
                                success_status_code=httplib.OK)

    def download_object_as_stream(self, obj, chunk_size=None):
        obj_path = self._get_object_path(obj.container, obj.name)
        response = self.connection.request(obj_path, method='GET', raw=True)

        return self._get_object(obj=obj, callback=read_in_chunks,
                                response=response,
                                callback_kwargs={'iterator': response.response,
                                                 'chunk_size': chunk_size},
                                success_status_code=httplib.OK)

    def upload_object(self, file_path, container, object_name, extra=None,
                      verify_hash=True, ex_storage_class=None):
        """
        @inherits: :class:`StorageDriver.upload_object`

        :param ex_storage_class: Storage class
        :type ex_storage_class: ``str``
        """
        upload_func = self._upload_file
        upload_func_kwargs = {'file_path': file_path}

        return self._put_object(container=container, object_name=object_name,
                                upload_func=upload_func,
                                upload_func_kwargs=upload_func_kwargs,
                                extra=extra, file_path=file_path,
                                verify_hash=verify_hash,
                                storage_class=ex_storage_class)

    def _upload_multipart(self, response, data, iterator, container,
                          object_name, calculate_hash=True):
        """
        Callback invoked for uploading data to S3 using Amazon's
        multipart upload mechanism

        :param response: Response object from the initial POST request
        :type response: :class:`S3RawResponse`

        :param data: Any data from the initial POST request
        :type data: ``str``

        :param iterator: The generator for fetching the upload data
        :type iterator: ``generator``

        :param container: The container owning the object to which data is
            being uploaded
        :type container: :class:`Container`

        :param object_name: The name of the object to which we are uploading
        :type object_name: ``str``

        :keyword calculate_hash: Indicates if we must calculate the data hash
        :type calculate_hash: ``bool``

        :return: A tuple of (status, checksum, bytes transferred)
        :rtype: ``tuple``
        """

        object_path = self._get_object_path(container, object_name)

        # Get the upload id from the response xml
        response.body = response.response.read()
        body = response.parse_body()
        upload_id = body.find(fixxpath(xpath='UploadId',
                                       namespace=self.namespace)).text

        try:
            # Upload the data through the iterator
            result = self._upload_from_iterator(iterator, object_path,
                                                upload_id, calculate_hash)
            (chunks, data_hash, bytes_transferred) = result

            # Commit the chunk info and complete the upload
            etag = self._commit_multipart(object_path, upload_id, chunks)
        except Exception:
            exc = sys.exc_info()[1]
            # Amazon provides a mechanism for aborting an upload.
            self._abort_multipart(object_path, upload_id)
            raise exc

        # Modify the response header of the first request. This is used
        # by other functions once the callback is done
        response.headers['etag'] = etag

        return (True, data_hash, bytes_transferred)

    def _upload_from_iterator(self, iterator, object_path, upload_id,
                              calculate_hash=True):
        """
        Uploads data from an interator in fixed sized chunks to S3

        :param iterator: The generator for fetching the upload data
        :type iterator: ``generator``

        :param object_path: The path of the object to which we are uploading
        :type object_name: ``str``

        :param upload_id: The upload id allocated for this multipart upload
        :type upload_id: ``str``

        :keyword calculate_hash: Indicates if we must calculate the data hash
        :type calculate_hash: ``bool``

        :return: A tuple of (chunk info, checksum, bytes transferred)
        :rtype: ``tuple``
        """

        data_hash = None
        if calculate_hash:
            data_hash = self._get_hash_function()

        bytes_transferred = 0
        count = 1
        chunks = []
        params = {'uploadId': upload_id}

        # Read the input data in chunk sizes suitable for AWS
        for data in read_in_chunks(iterator, chunk_size=CHUNK_SIZE,
                                   fill_size=True):
            bytes_transferred += len(data)

            if calculate_hash:
                data_hash.update(data)

            chunk_hash = self._get_hash_function()
            chunk_hash.update(data)
            chunk_hash = base64.b64encode(chunk_hash.digest()).decode('utf-8')

            # This provides an extra level of data check and is recommended
            # by amazon
            headers = {'Content-MD5': chunk_hash}
            params['partNumber'] = count

            request_path = '?'.join((object_path, urlencode(params)))

            resp = self.connection.request(request_path, method='PUT',
                                           data=data, headers=headers)

            if resp.status != httplib.OK:
                raise LibcloudError('Error uploading chunk', driver=self)

            server_hash = resp.headers['etag']

            # Keep this data for a later commit
            chunks.append((count, server_hash))
            count += 1

        if calculate_hash:
            data_hash = data_hash.hexdigest()

        return (chunks, data_hash, bytes_transferred)

    def _commit_multipart(self, object_path, upload_id, chunks):
        """
        Makes a final commit of the data.

        :param object_path: Server side object path.
        :type object_path: ``str``

        :param upload_id: ID of the multipart upload.
        :type upload_id: ``str``

        :param upload_id: A list of (chunk_number, chunk_hash) tuples.
        :type upload_id: ``list``
        """

        root = Element('CompleteMultipartUpload')

        for (count, etag) in chunks:
            part = SubElement(root, 'Part')
            part_no = SubElement(part, 'PartNumber')
            part_no.text = str(count)

            etag_id = SubElement(part, 'ETag')
            etag_id.text = str(etag)

        data = tostring(root)

        params = {'uploadId': upload_id}
        request_path = '?'.join((object_path, urlencode(params)))
        response = self.connection.request(request_path, data=data,
                                           method='POST')

        if response.status != httplib.OK:
            raise LibcloudError('Error in multipart commit', driver=self)

        # Get the server's etag to be passed back to the caller
        body = response.parse_body()
        server_hash = body.find(fixxpath(xpath='ETag',
                                         namespace=self.namespace)).text
        return server_hash

    def _abort_multipart(self, object_path, upload_id):
        """
        Aborts an already initiated multipart upload

        :param object_path: Server side object path.
        :type object_path: ``str``

        :param upload_id: ID of the multipart upload.
        :type upload_id: ``str``
        """

        params = {'uploadId': upload_id}
        request_path = '?'.join((object_path, urlencode(params)))
        resp = self.connection.request(request_path, method='DELETE')

        if resp.status != httplib.NO_CONTENT:
            raise LibcloudError('Error in multipart abort. status_code=%d' %
                                (resp.status), driver=self)

    def upload_object_via_stream(self, iterator, container, object_name,
                                 extra=None, ex_storage_class=None):
        """
        @inherits: :class:`StorageDriver.upload_object_via_stream`

        :param ex_storage_class: Storage class
        :type ex_storage_class: ``str``
        """

        method = 'PUT'
        params = None

        # This driver is used by other S3 API compatible drivers also.
        # Amazon provides a different (complex?) mechanism to do multipart
        # uploads
        if self.supports_s3_multipart_upload:
            # Initiate the multipart request and get an upload id
            upload_func = self._upload_multipart
            upload_func_kwargs = {'iterator': iterator,
                                  'container': container,
                                  'object_name': object_name}
            method = 'POST'
            iterator = iter('')
            params = 'uploads'

        elif self.supports_chunked_encoding:
            upload_func = self._stream_data
            upload_func_kwargs = {'iterator': iterator}
        else:
            # In this case, we have to load the entire object to
            # memory and send it as normal data
            upload_func = self._upload_data
            upload_func_kwargs = {}

        return self._put_object(container=container, object_name=object_name,
                                upload_func=upload_func,
                                upload_func_kwargs=upload_func_kwargs,
                                extra=extra, method=method, query_args=params,
                                iterator=iterator, verify_hash=False,
                                storage_class=ex_storage_class)

    def delete_object(self, obj):
        object_path = self._get_object_path(obj.container, obj.name)
        response = self.connection.request(object_path, method='DELETE')
        if response.status == httplib.NO_CONTENT:
            return True
        elif response.status == httplib.NOT_FOUND:
            raise ObjectDoesNotExistError(value=None, driver=self,
                                          object_name=obj.name)

        return False

    def ex_iterate_multipart_uploads(self, container, prefix=None,
                                     delimiter=None):
        """
        Extension method for listing all in-progress S3 multipart uploads.

        Each multipart upload which has not been committed or aborted is
        considered in-progress.

        :param container: The container holding the uploads
        :type container: :class:`Container`

        :keyword prefix: Print only uploads of objects with this prefix
        :type prefix: ``str``

        :keyword delimiter: The object/key names are grouped based on
            being split by this delimiter
        :type delimiter: ``str``

        :return: A generator of S3MultipartUpload instances.
        :rtype: ``generator`` of :class:`S3MultipartUpload`
        """

        if not self.supports_s3_multipart_upload:
            raise LibcloudError('Feature not supported', driver=self)

        # Get the data for a specific container
        request_path = '%s/?uploads' % (self._get_container_path(container))
        params = {'max-uploads': RESPONSES_PER_REQUEST}

        if prefix:
            params['prefix'] = prefix

        if delimiter:
            params['delimiter'] = delimiter

        finder = lambda node, text: node.findtext(fixxpath(xpath=text,
                                                  namespace=self.namespace))

        while True:
            response = self.connection.request(request_path, params=params)

            if response.status != httplib.OK:
                raise LibcloudError('Error fetching multipart uploads. '
                                    'Got code: %s' % (response.status),
                                    driver=self)

            body = response.parse_body()
            for node in body.findall(fixxpath(xpath='Upload',
                                              namespace=self.namespace)):

                initiator = node.find(fixxpath(xpath='Initiator',
                                               namespace=self.namespace))
                owner = node.find(fixxpath(xpath='Owner',
                                           namespace=self.namespace))

                key = finder(node, 'Key')
                upload_id = finder(node, 'UploadId')
                created_at = finder(node, 'Initiated')
                initiator = finder(initiator, 'DisplayName')
                owner = finder(owner, 'DisplayName')

                yield S3MultipartUpload(key, upload_id, created_at,
                                        initiator, owner)

            # Check if this is the last entry in the listing
            is_truncated = body.findtext(fixxpath(xpath='IsTruncated',
                                                  namespace=self.namespace))

            if is_truncated.lower() == 'false':
                break

            # Provide params for the next request
            upload_marker = body.findtext(fixxpath(xpath='NextUploadIdMarker',
                                                   namespace=self.namespace))
            key_marker = body.findtext(fixxpath(xpath='NextKeyMarker',
                                                namespace=self.namespace))

            params['key-marker'] = key_marker
            params['upload-id-marker'] = upload_marker

    def ex_cleanup_all_multipart_uploads(self, container, prefix=None):
        """
        Extension method for removing all partially completed S3 multipart
        uploads.

        :param container: The container holding the uploads
        :type container: :class:`Container`

        :keyword prefix: Delete only uploads of objects with this prefix
        :type prefix: ``str``
        """

        # Iterate through the container and delete the upload ids
        for upload in self.ex_iterate_multipart_uploads(container, prefix,
                                                        delimiter=None):
            object_path = '/%s/%s' % (container.name, upload.key)
            self._abort_multipart(object_path, upload.id)

    def _clean_object_name(self, name):
        name = urlquote(name)
        return name

    def _put_object(self, container, object_name, upload_func,
                    upload_func_kwargs, method='PUT', query_args=None,
                    extra=None, file_path=None, iterator=None,
                    verify_hash=True, storage_class=None):
        headers = {}
        extra = extra or {}
        storage_class = storage_class or 'standard'
        if storage_class not in ['standard', 'reduced_redundancy']:
            raise ValueError(
                'Invalid storage class value: %s' % (storage_class))

        headers['x-amz-storage-class'] = storage_class.upper()

        content_type = extra.get('content_type', None)
        meta_data = extra.get('meta_data', None)

        if meta_data:
            for key, value in list(meta_data.items()):
                key = 'x-amz-meta-%s' % (key)
                headers[key] = value

        request_path = self._get_object_path(container, object_name)

        if query_args:
            request_path = '?'.join((request_path, query_args))

        # TODO: Let the underlying exceptions bubble up and capture the SIGPIPE
        # here.
        #SIGPIPE is thrown if the provided container does not exist or the user
        # does not have correct permission
        result_dict = self._upload_object(
            object_name=object_name, content_type=content_type,
            upload_func=upload_func, upload_func_kwargs=upload_func_kwargs,
            request_path=request_path, request_method=method,
            headers=headers, file_path=file_path, iterator=iterator)

        response = result_dict['response']
        bytes_transferred = result_dict['bytes_transferred']
        headers = response.headers
        response = response.response
        server_hash = headers['etag'].replace('"', '')

        if (verify_hash and result_dict['data_hash'] != server_hash):
            raise ObjectHashMismatchError(
                value='MD5 hash checksum does not match',
                object_name=object_name, driver=self)
        elif response.status == httplib.OK:
            obj = Object(
                name=object_name, size=bytes_transferred, hash=server_hash,
                extra=None, meta_data=meta_data, container=container,
                driver=self)

            return obj
        else:
            raise LibcloudError(
                'Unexpected status code, status_code=%s' % (response.status),
                driver=self)

    def _to_containers(self, obj, xpath):
        for element in obj.findall(fixxpath(xpath=xpath,
                                   namespace=self.namespace)):
            yield self._to_container(element)

    def _to_objs(self, obj, xpath, container):
        return [self._to_obj(element, container) for element in
                obj.findall(fixxpath(xpath=xpath, namespace=self.namespace))]

    def _to_container(self, element):
        extra = {
            'creation_date': findtext(element=element, xpath='CreationDate',
                                      namespace=self.namespace)
        }

        container = Container(name=findtext(element=element, xpath='Name',
                                            namespace=self.namespace),
                              extra=extra,
                              driver=self
                              )

        return container

    def _headers_to_object(self, object_name, container, headers):
        hash = headers['etag'].replace('"', '')
        extra = {'content_type': headers['content-type'],
                 'etag': headers['etag']}
        meta_data = {}

        if 'last-modified' in headers:
            extra['last_modified'] = headers['last-modified']

        for key, value in headers.items():
            if not key.lower().startswith('x-amz-meta-'):
                continue

            key = key.replace('x-amz-meta-', '')
            meta_data[key] = value

        obj = Object(name=object_name, size=headers['content-length'],
                     hash=hash, extra=extra,
                     meta_data=meta_data,
                     container=container,
                     driver=self)
        return obj

    def _to_obj(self, element, container):
        owner_id = findtext(element=element, xpath='Owner/ID',
                            namespace=self.namespace)
        owner_display_name = findtext(element=element,
                                      xpath='Owner/DisplayName',
                                      namespace=self.namespace)
        meta_data = {'owner': {'id': owner_id,
                               'display_name': owner_display_name}}
        last_modified = findtext(element=element,
                                 xpath='LastModified',
                                 namespace=self.namespace)
        extra = {'last_modified': last_modified}

        obj = Object(name=findtext(element=element, xpath='Key',
                                   namespace=self.namespace),
                     size=int(findtext(element=element, xpath='Size',
                                       namespace=self.namespace)),
                     hash=findtext(element=element, xpath='ETag',
                                   namespace=self.namespace).replace('"', ''),
                     extra=extra,
                     meta_data=meta_data,
                     container=container,
                     driver=self
                     )

        return obj


class S3USWestConnection(S3Connection):
    host = S3_US_WEST_HOST


class S3USWestStorageDriver(S3StorageDriver):
    name = 'Amazon S3 (us-west-1)'
    connectionCls = S3USWestConnection
    ex_location_name = 'us-west-1'


class S3USWestOregonConnection(S3Connection):
    host = S3_US_WEST_OREGON_HOST


class S3USWestOregonStorageDriver(S3StorageDriver):
    name = 'Amazon S3 (us-west-2)'
    connectionCls = S3USWestOregonConnection
    ex_location_name = 'us-west-2'


class S3EUWestConnection(S3Connection):
    host = S3_EU_WEST_HOST


class S3EUWestStorageDriver(S3StorageDriver):
    name = 'Amazon S3 (eu-west-1)'
    connectionCls = S3EUWestConnection
    ex_location_name = 'EU'


class S3APSEConnection(S3Connection):
    host = S3_AP_SOUTHEAST_HOST


class S3APSEStorageDriver(S3StorageDriver):
    name = 'Amazon S3 (ap-southeast-1)'
    connectionCls = S3APSEConnection
    ex_location_name = 'ap-southeast-1'


class S3APNEConnection(S3Connection):
    host = S3_AP_NORTHEAST_HOST


class S3APNEStorageDriver(S3StorageDriver):
    name = 'Amazon S3 (ap-northeast-1)'
    connectionCls = S3APNEConnection
    ex_location_name = 'ap-northeast-1'