# Copyright (c) 2010-2012 OpenStack, LLC.
#
# Licensed 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.

"""
OpenStack Swift client library used internally
"""

import socket
import sys
import logging
import warnings
from functools import wraps

from urllib import quote as _quote
from urlparse import urlparse, urlunparse
from httplib import HTTPException, HTTPConnection, HTTPSConnection
from time import sleep, time

from swiftclient.exceptions import ClientException, InvalidHeadersException
from swiftclient.utils import get_environ_proxies

try:
    from swiftclient.https_connection import HTTPSConnectionNoSSLComp
except ImportError:
    HTTPSConnectionNoSSLComp = HTTPSConnection


try:
    from logging import NullHandler
except ImportError:
    class NullHandler(logging.Handler):
        def handle(self, record):
            pass

        def emit(self, record):
            pass

        def createLock(self):
            self.lock = None

logger = logging.getLogger("swiftclient")
logger.addHandler(NullHandler())


def http_log(args, kwargs, resp, body):
    if not logger.isEnabledFor(logging.INFO):
        return

    # create and log equivalent curl command
    string_parts = ['curl -i']
    for element in args:
        if element == 'HEAD':
            string_parts.append(' -I')
        elif element in ('GET', 'POST', 'PUT'):
            string_parts.append(' -X %s' % element)
        else:
            string_parts.append(' %s' % element)
    if 'headers' in kwargs:
        for element in kwargs['headers']:
            header = ' -H "%s: %s"' % (element, kwargs['headers'][element])
            string_parts.append(header)

    # log response as debug if good, or info if error
    if resp.status < 300:
        log_method = logger.debug
    else:
        log_method = logger.info

    log_method("REQ: %s" % "".join(string_parts))
    log_method("RESP STATUS: %s %s" % (resp.status, resp.reason))
    log_method("RESP HEADERS: %s", resp.getheaders())
    if body:
        log_method("RESP BODY: %s", body)


def quote(value, safe='/'):
    """
    Patched version of urllib.quote that encodes utf8 strings before quoting
    """
    value = encode_utf8(value)
    if isinstance(value, str):
        return _quote(value, safe)
    else:
        return value


def validate_headers(headers):
    if headers:
        for key, raw_value in headers.iteritems():
            value = str(encode_utf8(raw_value))

            if '\n' in value:
                raise InvalidHeadersException("%r header contained a "
                                              "newline" % key)
            if '\r' in value:
                raise InvalidHeadersException("%r header contained a "
                                              "carriage return" % key)


def encode_utf8(value):
    if isinstance(value, unicode):
        value = value.encode('utf8')
    return value


# look for a real json parser first
try:
    # simplejson is popular and pretty good
    from simplejson import loads as json_loads
except ImportError:
    # 2.6 will have a json module in the stdlib
    from json import loads as json_loads


def http_connection(url, proxy=None, ssl_compression=True):
    """
    Make an HTTPConnection or HTTPSConnection

    :param url: url to connect to
    :param proxy: proxy to connect through, if any; None by default; str of the
                  format 'http://127.0.0.1:8888' to set one
    :param ssl_compression: Whether to enable compression at the SSL layer.
                            If set to 'False' and the pyOpenSSL library is
                            present an attempt to disable SSL compression
                            will be made. This may provide a performance
                            increase for https upload/download operations.
    :returns: tuple of (parsed url, connection object)
    :raises ClientException: Unable to handle protocol scheme
    """
    url = encode_utf8(url)
    parsed = urlparse(url)
    if proxy:
        proxy_parsed = urlparse(proxy)
    else:
        proxies = get_environ_proxies(parsed.netloc)
        proxy = proxies.get(parsed.scheme, None)
        proxy_parsed = urlparse(proxy) if proxy else None
    host = proxy_parsed.netloc if proxy else parsed.netloc
    if parsed.scheme == 'http':
        conn = HTTPConnection(host)
    elif parsed.scheme == 'https':
        if ssl_compression is True:
            conn = HTTPSConnection(host)
        else:
            conn = HTTPSConnectionNoSSLComp(host)
    else:
        raise ClientException('Cannot handle protocol scheme %s for url %s' %
                              (parsed.scheme, repr(url)))

    def putheader_wrapper(func):

        @wraps(func)
        def putheader_escaped(key, value):
            func(encode_utf8(key), encode_utf8(value))
        return putheader_escaped
    conn.putheader = putheader_wrapper(conn.putheader)

    def request_wrapper(func):

        @wraps(func)
        def request_escaped(method, url, body=None, headers=None):
            validate_headers(headers)
            url = encode_utf8(url)
            if body:
                body = encode_utf8(body)
            func(method, url, body=body, headers=headers or {})
        return request_escaped
    conn.request = request_wrapper(conn.request)
    if proxy:
        try:
            # python 2.6 method
            conn._set_tunnel(parsed.hostname, parsed.port)
        except AttributeError:
            # python 2.7 method
            conn.set_tunnel(parsed.hostname, parsed.port)
    return parsed, conn


def get_auth_1_0(url, user, key, snet):
    parsed, conn = http_connection(url)
    method = 'GET'
    conn.request(method, parsed.path, '',
                 {'X-Auth-User': user, 'X-Auth-Key': key})
    resp = conn.getresponse()
    body = resp.read()
    http_log((url, method,), {}, resp, body)
    url = resp.getheader('x-storage-url')

    # There is a side-effect on current Rackspace 1.0 server where a
    # bad URL would get you that document page and a 200. We error out
    # if we don't have a x-storage-url header and if we get a body.
    if resp.status < 200 or resp.status >= 300 or (body and not url):
        raise ClientException('Auth GET failed', http_scheme=parsed.scheme,
                              http_host=conn.host, http_port=conn.port,
                              http_path=parsed.path, http_status=resp.status,
                              http_reason=resp.reason)
    if snet:
        parsed = list(urlparse(url))
        # Second item in the list is the netloc
        netloc = parsed[1]
        parsed[1] = 'snet-' + netloc
        url = urlunparse(parsed)
    return url, resp.getheader('x-storage-token',
                               resp.getheader('x-auth-token'))


def get_keystoneclient_2_0(auth_url, user, key, os_options, **kwargs):
    """
    Authenticate against a auth 2.0 server.

    We are using the keystoneclient library for our 2.0 authentication.
    """

    insecure = kwargs.get('insecure', False)
    debug = logger.isEnabledFor(logging.DEBUG) and True or False

    try:
        from keystoneclient.v2_0 import client as ksclient
        from keystoneclient import exceptions
    except ImportError:
        sys.exit('''
Auth version 2.0 requires python-keystoneclient, install it or use Auth
version 1.0 which requires ST_AUTH, ST_USER, and ST_KEY environment
variables to be set or overridden with -A, -U, or -K.''')

    try:
        _ksclient = ksclient.Client(username=user,
                                    password=key,
                                    tenant_name=os_options.get('tenant_name'),
                                    tenant_id=os_options.get('tenant_id'),
                                    debug=debug,
                                    cacert=kwargs.get('cacert'),
                                    auth_url=auth_url, insecure=insecure)
    except exceptions.Unauthorized:
        raise ClientException('Unauthorised. Check username, password'
                              ' and tenant name/id')
    except exceptions.AuthorizationFailure as err:
        raise ClientException('Authorization Failure. %s' % err)
    service_type = os_options.get('service_type') or 'object-store'
    endpoint_type = os_options.get('endpoint_type') or 'publicURL'
    try:
        endpoint = _ksclient.service_catalog.url_for(
            attr='region',
            filter_value=os_options.get('region_name'),
            service_type=service_type,
            endpoint_type=endpoint_type)
    except exceptions.EndpointNotFound:
        raise ClientException('Endpoint for %s not found - '
                              'have you specified a region?' % service_type)
    return (endpoint, _ksclient.auth_token)


def get_auth(auth_url, user, key, **kwargs):
    """
    Get authentication/authorization credentials.

    The snet parameter is used for Rackspace's ServiceNet internal network
    implementation. In this function, it simply adds *snet-* to the beginning
    of the host name for the returned storage URL. With Rackspace Cloud Files,
    use of this network path causes no bandwidth charges but requires the
    client to be running on Rackspace's ServiceNet network.
    """
    auth_version = kwargs.get('auth_version', '1')
    os_options = kwargs.get('os_options', {})

    storage_url, token = None, None
    if auth_version in ['1.0', '1', 1]:
        storage_url, token = get_auth_1_0(auth_url,
                                          user,
                                          key,
                                          kwargs.get('snet'))
    elif auth_version in ['2.0', '2', 2]:
        # We are allowing to specify a token/storage-url to re-use
        # without having to re-authenticate.
        if (os_options.get('object_storage_url') and
                os_options.get('auth_token')):
            return (os_options.get('object_storage_url'),
                    os_options.get('auth_token'))

        # We are handling a special use case here when we were
        # allowing specifying the account/tenant_name with the -U
        # argument
        if not kwargs.get('tenant_name') and ':' in user:
            (os_options['tenant_name'],
             user) = user.split(':')

        # We are allowing to have an tenant_name argument in get_auth
        # directly without having os_options
        if kwargs.get('tenant_name'):
            os_options['tenant_name'] = kwargs['tenant_name']

        if (not 'tenant_name' in os_options):
            raise ClientException('No tenant specified')

        insecure = kwargs.get('insecure', False)
        cacert = kwargs.get('cacert', None)
        storage_url, token = get_keystoneclient_2_0(auth_url, user,
                                                    key, os_options,
                                                    cacert=cacert,
                                                    insecure=insecure)
    else:
        raise ClientException('Unknown auth_version %s specified.'
                              % auth_version)

    # Override storage url, if necessary
    if os_options.get('object_storage_url'):
        return os_options['object_storage_url'], token
    else:
        return storage_url, token


def store_response(resp, response_dict):
    """
    store information about an operation into a dict

    :param resp: an http response object containing the response
                 headers
    :param response_dict: a dict into which are placed the
       status, reason and a dict of lower-cased headers
    """
    if response_dict is not None:
        resp_headers = {}
        for header, value in resp.getheaders():
            resp_headers[header.lower()] = value

        response_dict['status'] = resp.status
        response_dict['reason'] = resp.reason
        response_dict['headers'] = resp_headers


def get_account(url, token, marker=None, limit=None, prefix=None,
                end_marker=None, http_conn=None, full_listing=False):
    """
    Get a listing of containers for the account.

    :param url: storage URL
    :param token: auth token
    :param marker: marker query
    :param limit: limit query
    :param prefix: prefix query
    :param end_marker: end_marker query
    :param http_conn: HTTP connection object (If None, it will create the
                      conn object)
    :param full_listing: if True, return a full listing, else returns a max
                         of 10000 listings
    :returns: a tuple of (response headers, a list of containers) The response
              headers will be a dict and all header names will be lowercase.
    :raises ClientException: HTTP GET request failed
    """
    if not http_conn:
        http_conn = http_connection(url)
    if full_listing:
        rv = get_account(url, token, marker, limit, prefix,
                         end_marker, http_conn)
        listing = rv[1]
        while listing:
            marker = listing[-1]['name']
            listing = \
                get_account(url, token, marker, limit, prefix,
                            end_marker, http_conn)[1]
            if listing:
                rv[1].extend(listing)
        return rv
    parsed, conn = http_conn
    qs = 'format=json'
    if marker:
        qs += '&marker=%s' % quote(marker)
    if limit:
        qs += '&limit=%d' % limit
    if prefix:
        qs += '&prefix=%s' % quote(prefix)
    if end_marker:
        qs += '&end_marker=%s' % quote(end_marker)
    full_path = '%s?%s' % (parsed.path, qs)
    headers = {'X-Auth-Token': token}
    method = 'GET'
    conn.request(method, full_path, '', headers)
    resp = conn.getresponse()
    body = resp.read()
    http_log(("%s?%s" % (url, qs), method,), {'headers': headers}, resp, body)

    resp_headers = {}
    for header, value in resp.getheaders():
        resp_headers[header.lower()] = value
    if resp.status < 200 or resp.status >= 300:
        raise ClientException('Account GET failed', http_scheme=parsed.scheme,
                              http_host=conn.host, http_port=conn.port,
                              http_path=parsed.path, http_query=qs,
                              http_status=resp.status, http_reason=resp.reason,
                              http_response_content=body)
    if resp.status == 204:
        body
        return resp_headers, []
    return resp_headers, json_loads(body)


def head_account(url, token, http_conn=None):
    """
    Get account stats.

    :param url: storage URL
    :param token: auth token
    :param http_conn: HTTP connection object (If None, it will create the
                      conn object)
    :returns: a dict containing the response's headers (all header names will
              be lowercase)
    :raises ClientException: HTTP HEAD request failed
    """
    if http_conn:
        parsed, conn = http_conn
    else:
        parsed, conn = http_connection(url)
    method = "HEAD"
    headers = {'X-Auth-Token': token}
    conn.request(method, parsed.path, '', headers)
    resp = conn.getresponse()
    body = resp.read()
    http_log((url, method,), {'headers': headers}, resp, body)
    if resp.status < 200 or resp.status >= 300:
        raise ClientException('Account HEAD failed', http_scheme=parsed.scheme,
                              http_host=conn.host, http_port=conn.port,
                              http_path=parsed.path, http_status=resp.status,
                              http_reason=resp.reason,
                              http_response_content=body)
    resp_headers = {}
    for header, value in resp.getheaders():
        resp_headers[header.lower()] = value
    return resp_headers


def post_account(url, token, headers, http_conn=None, response_dict=None):
    """
    Update an account's metadata.

    :param url: storage URL
    :param token: auth token
    :param headers: additional headers to include in the request
    :param http_conn: HTTP connection object (If None, it will create the
                      conn object)
    :param response_dict: an optional dictionary into which to place
                     the response - status, reason and headers
    :raises ClientException: HTTP POST request failed
    """
    if http_conn:
        parsed, conn = http_conn
    else:
        parsed, conn = http_connection(url)
    method = 'POST'
    headers['X-Auth-Token'] = token
    conn.request(method, parsed.path, '', headers)
    resp = conn.getresponse()
    body = resp.read()
    http_log((url, method,), {'headers': headers}, resp, body)

    store_response(resp, response_dict)

    if resp.status < 200 or resp.status >= 300:
        raise ClientException('Account POST failed',
                              http_scheme=parsed.scheme,
                              http_host=conn.host,
                              http_port=conn.port,
                              http_path=parsed.path,
                              http_status=resp.status,
                              http_reason=resp.reason,
                              http_response_content=body)


def get_container(url, token, container, marker=None, limit=None,
                  prefix=None, delimiter=None, end_marker=None,
                  path=None, http_conn=None,
                  full_listing=False):
    """
    Get a listing of objects for the container.

    :param url: storage URL
    :param token: auth token
    :param container: container name to get a listing for
    :param marker: marker query
    :param limit: limit query
    :param prefix: prefix query
    :param delimiter: string to delimit the queries on
    :param end_marker: marker query
    :param path: path query (equivalent: "delimiter=/" and "prefix=path/")
    :param http_conn: HTTP connection object (If None, it will create the
                      conn object)
    :param full_listing: if True, return a full listing, else returns a max
                         of 10000 listings
    :returns: a tuple of (response headers, a list of objects) The response
              headers will be a dict and all header names will be lowercase.
    :raises ClientException: HTTP GET request failed
    """
    if not http_conn:
        http_conn = http_connection(url)
    if full_listing:
        rv = get_container(url, token, container, marker, limit, prefix,
                           delimiter, end_marker, path, http_conn)
        listing = rv[1]
        while listing:
            if not delimiter:
                marker = listing[-1]['name']
            else:
                marker = listing[-1].get('name', listing[-1].get('subdir'))
            listing = get_container(url, token, container, marker, limit,
                                    prefix, delimiter, end_marker, path,
                                    http_conn)[1]
            if listing:
                rv[1].extend(listing)
        return rv
    parsed, conn = http_conn
    cont_path = '%s/%s' % (parsed.path, quote(container))
    qs = 'format=json'
    if marker:
        qs += '&marker=%s' % quote(marker)
    if limit:
        qs += '&limit=%d' % limit
    if prefix:
        qs += '&prefix=%s' % quote(prefix)
    if delimiter:
        qs += '&delimiter=%s' % quote(delimiter)
    if end_marker:
        qs += '&end_marker=%s' % quote(end_marker)
    if path:
        qs += '&path=%s' % quote(path)
    headers = {'X-Auth-Token': token}
    method = 'GET'
    conn.request(method, '%s?%s' % (cont_path, qs), '', headers)
    resp = conn.getresponse()
    body = resp.read()
    http_log(('%s%s?%s' % (url.replace(parsed.path, ''), cont_path, qs),
              method,), {'headers': headers}, resp, body)

    if resp.status < 200 or resp.status >= 300:
        raise ClientException('Container GET failed',
                              http_scheme=parsed.scheme, http_host=conn.host,
                              http_port=conn.port, http_path=cont_path,
                              http_query=qs, http_status=resp.status,
                              http_reason=resp.reason,
                              http_response_content=body)
    resp_headers = {}
    for header, value in resp.getheaders():
        resp_headers[header.lower()] = value
    if resp.status == 204:
        return resp_headers, []
    return resp_headers, json_loads(body)


def head_container(url, token, container, http_conn=None, headers=None):
    """
    Get container stats.

    :param url: storage URL
    :param token: auth token
    :param container: container name to get stats for
    :param http_conn: HTTP connection object (If None, it will create the
                      conn object)
    :returns: a dict containing the response's headers (all header names will
              be lowercase)
    :raises ClientException: HTTP HEAD request failed
    """
    if http_conn:
        parsed, conn = http_conn
    else:
        parsed, conn = http_connection(url)
    path = '%s/%s' % (parsed.path, quote(container))
    method = 'HEAD'
    req_headers = {'X-Auth-Token': token}
    if headers:
        req_headers.update(headers)
    conn.request(method, path, '', req_headers)
    resp = conn.getresponse()
    body = resp.read()
    http_log(('%s%s' % (url.replace(parsed.path, ''), path), method,),
             {'headers': req_headers}, resp, body)

    if resp.status < 200 or resp.status >= 300:
        raise ClientException('Container HEAD failed',
                              http_scheme=parsed.scheme, http_host=conn.host,
                              http_port=conn.port, http_path=path,
                              http_status=resp.status, http_reason=resp.reason,
                              http_response_content=body)
    resp_headers = {}
    for header, value in resp.getheaders():
        resp_headers[header.lower()] = value
    return resp_headers


def put_container(url, token, container, headers=None, http_conn=None,
                  response_dict=None):
    """
    Create a container

    :param url: storage URL
    :param token: auth token
    :param container: container name to create
    :param headers: additional headers to include in the request
    :param http_conn: HTTP connection object (If None, it will create the
                      conn object)
    :param response_dict: an optional dictionary into which to place
                     the response - status, reason and headers
    :raises ClientException: HTTP PUT request failed
    """
    if http_conn:
        parsed, conn = http_conn
    else:
        parsed, conn = http_connection(url)
    path = '%s/%s' % (parsed.path, quote(container))
    method = 'PUT'
    if not headers:
        headers = {}
    headers['X-Auth-Token'] = token
    if not 'content-length' in (k.lower() for k in headers):
        headers['Content-Length'] = '0'
    conn.request(method, path, '', headers)
    resp = conn.getresponse()
    body = resp.read()

    store_response(resp, response_dict)

    http_log(('%s%s' % (url.replace(parsed.path, ''), path), method,),
             {'headers': headers}, resp, body)
    if resp.status < 200 or resp.status >= 300:
        raise ClientException('Container PUT failed',
                              http_scheme=parsed.scheme, http_host=conn.host,
                              http_port=conn.port, http_path=path,
                              http_status=resp.status, http_reason=resp.reason,
                              http_response_content=body)


def post_container(url, token, container, headers, http_conn=None,
                   response_dict=None):
    """
    Update a container's metadata.

    :param url: storage URL
    :param token: auth token
    :param container: container name to update
    :param headers: additional headers to include in the request
    :param http_conn: HTTP connection object (If None, it will create the
                      conn object)
    :param response_dict: an optional dictionary into which to place
                     the response - status, reason and headers
    :raises ClientException: HTTP POST request failed
    """
    if http_conn:
        parsed, conn = http_conn
    else:
        parsed, conn = http_connection(url)
    path = '%s/%s' % (parsed.path, quote(container))
    method = 'POST'
    headers['X-Auth-Token'] = token
    if not 'content-length' in (k.lower() for k in headers):
        headers['Content-Length'] = '0'
    conn.request(method, path, '', headers)
    resp = conn.getresponse()
    body = resp.read()
    http_log(('%s%s' % (url.replace(parsed.path, ''), path), method,),
             {'headers': headers}, resp, body)

    store_response(resp, response_dict)

    if resp.status < 200 or resp.status >= 300:
        raise ClientException('Container POST failed',
                              http_scheme=parsed.scheme, http_host=conn.host,
                              http_port=conn.port, http_path=path,
                              http_status=resp.status, http_reason=resp.reason,
                              http_response_content=body)


def delete_container(url, token, container, http_conn=None,
                     response_dict=None):
    """
    Delete a container

    :param url: storage URL
    :param token: auth token
    :param container: container name to delete
    :param http_conn: HTTP connection object (If None, it will create the
                      conn object)
    :param response_dict: an optional dictionary into which to place
                     the response - status, reason and headers
    :raises ClientException: HTTP DELETE request failed
    """
    if http_conn:
        parsed, conn = http_conn
    else:
        parsed, conn = http_connection(url)
    path = '%s/%s' % (parsed.path, quote(container))
    headers = {'X-Auth-Token': token}
    method = 'DELETE'
    conn.request(method, path, '', headers)
    resp = conn.getresponse()
    body = resp.read()
    http_log(('%s%s' % (url.replace(parsed.path, ''), path), method,),
             {'headers': headers}, resp, body)

    store_response(resp, response_dict)

    if resp.status < 200 or resp.status >= 300:
        raise ClientException('Container DELETE failed',
                              http_scheme=parsed.scheme, http_host=conn.host,
                              http_port=conn.port, http_path=path,
                              http_status=resp.status, http_reason=resp.reason,
                              http_response_content=body)


def get_object(url, token, container, name, http_conn=None,
               resp_chunk_size=None, query_string=None,
               response_dict=None, headers=None):
    """
    Get an object

    :param url: storage URL
    :param token: auth token
    :param container: container name that the object is in
    :param name: object name to get
    :param http_conn: HTTP connection object (If None, it will create the
                      conn object)
    :param resp_chunk_size: if defined, chunk size of data to read. NOTE: If
                            you specify a resp_chunk_size you must fully read
                            the object's contents before making another
                            request.
    :param query_string: if set will be appended with '?' to generated path
    :param response_dict: an optional dictionary into which to place
                     the response - status, reason and headers
    :param headers: an optional dictionary with additional headers to include
                    in the request
    :returns: a tuple of (response headers, the object's contents) The response
              headers will be a dict and all header names will be lowercase.
    :raises ClientException: HTTP GET request failed
    """
    if http_conn:
        parsed, conn = http_conn
    else:
        parsed, conn = http_connection(url)
    path = '%s/%s/%s' % (parsed.path, quote(container), quote(name))
    if query_string:
        path += '?' + query_string
    method = 'GET'
    headers = headers.copy() if headers else {}
    headers['X-Auth-Token'] = token
    conn.request(method, path, '', headers)
    resp = conn.getresponse()

    parsed_response = {}
    store_response(resp, parsed_response)
    if response_dict is not None:
        response_dict.update(parsed_response)

    if resp.status < 200 or resp.status >= 300:
        body = resp.read()
        http_log(('%s%s' % (url.replace(parsed.path, ''), path), method,),
                 {'headers': headers}, resp, body)
        raise ClientException('Object GET failed', http_scheme=parsed.scheme,
                              http_host=conn.host, http_port=conn.port,
                              http_path=path, http_status=resp.status,
                              http_reason=resp.reason,
                              http_response_content=body)
    if resp_chunk_size:

        def _object_body():
            buf = resp.read(resp_chunk_size)
            while buf:
                yield buf
                buf = resp.read(resp_chunk_size)
        object_body = _object_body()
    else:
        object_body = resp.read()
    http_log(('%s%s' % (url.replace(parsed.path, ''), path), method,),
             {'headers': headers}, resp, None)

    return parsed_response['headers'], object_body


def head_object(url, token, container, name, http_conn=None):
    """
    Get object info

    :param url: storage URL
    :param token: auth token
    :param container: container name that the object is in
    :param name: object name to get info for
    :param http_conn: HTTP connection object (If None, it will create the
                      conn object)
    :returns: a dict containing the response's headers (all header names will
              be lowercase)
    :raises ClientException: HTTP HEAD request failed
    """
    if http_conn:
        parsed, conn = http_conn
    else:
        parsed, conn = http_connection(url)
    path = '%s/%s/%s' % (parsed.path, quote(container), quote(name))
    method = 'HEAD'
    headers = {'X-Auth-Token': token}
    conn.request(method, path, '', headers)
    resp = conn.getresponse()
    body = resp.read()
    http_log(('%s%s' % (url.replace(parsed.path, ''), path), method,),
             {'headers': headers}, resp, body)
    if resp.status < 200 or resp.status >= 300:
        raise ClientException('Object HEAD failed', http_scheme=parsed.scheme,
                              http_host=conn.host, http_port=conn.port,
                              http_path=path, http_status=resp.status,
                              http_reason=resp.reason,
                              http_response_content=body)
    resp_headers = {}
    for header, value in resp.getheaders():
        resp_headers[header.lower()] = value
    return resp_headers


def put_object(url, token=None, container=None, name=None, contents=None,
               content_length=None, etag=None, chunk_size=None,
               content_type=None, headers=None, http_conn=None, proxy=None,
               query_string=None, response_dict=None):
    """
    Put an object

    :param url: storage URL
    :param token: auth token; if None, no token will be sent
    :param container: container name that the object is in; if None, the
                      container name is expected to be part of the url
    :param name: object name to put; if None, the object name is expected to be
                 part of the url
    :param contents: a string or a file like object to read object data from;
                     if None, a zero-byte put will be done
    :param content_length: value to send as content-length header; also limits
                           the amount read from contents; if None, it will be
                           computed via the contents or chunked transfer
                           encoding will be used
    :param etag: etag of contents; if None, no etag will be sent
    :param chunk_size: chunk size of data to write; it defaults to 65536;
                       used only if the the contents object has a 'read'
                       method, eg. file-like objects, ignored otherwise
    :param content_type: value to send as content-type header; if None, no
                         content-type will be set (remote end will likely try
                         to auto-detect it)
    :param headers: additional headers to include in the request, if any
    :param http_conn: HTTP connection object (If None, it will create the
                      conn object)
    :param proxy: proxy to connect through, if any; None by default; str of the
                  format 'http://127.0.0.1:8888' to set one
    :param query_string: if set will be appended with '?' to generated path
    :param response_dict: an optional dictionary into which to place
                     the response - status, reason and headers
    :returns: etag
    :raises ClientException: HTTP PUT request failed
    """
    if http_conn:
        parsed, conn = http_conn
    else:
        parsed, conn = http_connection(url, proxy=proxy)
    path = parsed.path
    if container:
        path = '%s/%s' % (path.rstrip('/'), quote(container))
    if name:
        path = '%s/%s' % (path.rstrip('/'), quote(name))
    if query_string:
        path += '?' + query_string
    if headers:
        headers = dict(headers)
    else:
        headers = {}
    if token:
        headers['X-Auth-Token'] = token
    if etag:
        headers['ETag'] = etag.strip('"')
    if content_length is not None:
        headers['Content-Length'] = str(content_length)
    else:
        for n, v in headers.iteritems():
            if n.lower() == 'content-length':
                content_length = int(v)
    if content_type is not None:
        headers['Content-Type'] = content_type
    if not contents:
        headers['Content-Length'] = '0'
    if hasattr(contents, 'read'):
        if chunk_size is None:
            chunk_size = 65536
        conn.putrequest('PUT', path)
        for header, value in headers.iteritems():
            conn.putheader(header, value)
        if content_length is None:
            conn.putheader('Transfer-Encoding', 'chunked')
            conn.endheaders()
            chunk = contents.read(chunk_size)
            while chunk:
                conn.send('%x\r\n%s\r\n' % (len(chunk), chunk))
                chunk = contents.read(chunk_size)
            conn.send('0\r\n\r\n')
        else:
            conn.endheaders()
            left = content_length
            while left > 0:
                size = chunk_size
                if size > left:
                    size = left
                chunk = contents.read(size)
                conn.send(chunk)
                left -= len(chunk)
    else:
        if chunk_size is not None:
            warn_msg = '%s object has no \"read\" method, ignoring chunk_size'\
                % type(contents).__name__
            warnings.warn(warn_msg, stacklevel=2)
        conn.request('PUT', path, contents, headers)
    resp = conn.getresponse()
    body = resp.read()
    headers = {'X-Auth-Token': token}
    http_log(('%s%s' % (url.replace(parsed.path, ''), path), 'PUT',),
             {'headers': headers}, resp, body)

    store_response(resp, response_dict)

    if resp.status < 200 or resp.status >= 300:
        raise ClientException('Object PUT failed', http_scheme=parsed.scheme,
                              http_host=conn.host, http_port=conn.port,
                              http_path=path, http_status=resp.status,
                              http_reason=resp.reason,
                              http_response_content=body)

    return resp.getheader('etag', '').strip('"')


def post_object(url, token, container, name, headers, http_conn=None,
                response_dict=None):
    """
    Update object metadata

    :param url: storage URL
    :param token: auth token
    :param container: container name that the object is in
    :param name: name of the object to update
    :param headers: additional headers to include in the request
    :param http_conn: HTTP connection object (If None, it will create the
                      conn object)
    :param response_dict: an optional dictionary into which to place
                     the response - status, reason and headers
    :raises ClientException: HTTP POST request failed
    """
    if http_conn:
        parsed, conn = http_conn
    else:
        parsed, conn = http_connection(url)
    path = '%s/%s/%s' % (parsed.path, quote(container), quote(name))
    headers['X-Auth-Token'] = token
    conn.request('POST', path, '', headers)
    resp = conn.getresponse()
    body = resp.read()
    http_log(('%s%s' % (url.replace(parsed.path, ''), path), 'POST',),
             {'headers': headers}, resp, body)

    store_response(resp, response_dict)

    if resp.status < 200 or resp.status >= 300:
        raise ClientException('Object POST failed', http_scheme=parsed.scheme,
                              http_host=conn.host, http_port=conn.port,
                              http_path=path, http_status=resp.status,
                              http_reason=resp.reason,
                              http_response_content=body)


def delete_object(url, token=None, container=None, name=None, http_conn=None,
                  headers=None, proxy=None, query_string=None,
                  response_dict=None):
    """
    Delete object

    :param url: storage URL
    :param token: auth token; if None, no token will be sent
    :param container: container name that the object is in; if None, the
                      container name is expected to be part of the url
    :param name: object name to delete; if None, the object name is expected to
                 be part of the url
    :param http_conn: HTTP connection object (If None, it will create the
                      conn object)
    :param headers: additional headers to include in the request
    :param proxy: proxy to connect through, if any; None by default; str of the
                  format 'http://127.0.0.1:8888' to set one
    :param query_string: if set will be appended with '?' to generated path
    :param response_dict: an optional dictionary into which to place
                     the response - status, reason and headers
    :raises ClientException: HTTP DELETE request failed
    """
    if http_conn:
        parsed, conn = http_conn
    else:
        parsed, conn = http_connection(url, proxy=proxy)
    path = parsed.path
    if container:
        path = '%s/%s' % (path.rstrip('/'), quote(container))
    if name:
        path = '%s/%s' % (path.rstrip('/'), quote(name))
    if query_string:
        path += '?' + query_string
    if headers:
        headers = dict(headers)
    else:
        headers = {}
    if token:
        headers['X-Auth-Token'] = token
    conn.request('DELETE', path, '', headers)
    resp = conn.getresponse()
    body = resp.read()
    http_log(('%s%s' % (url.replace(parsed.path, ''), path), 'DELETE',),
             {'headers': headers}, resp, body)

    store_response(resp, response_dict)

    if resp.status < 200 or resp.status >= 300:
        raise ClientException('Object DELETE failed',
                              http_scheme=parsed.scheme, http_host=conn.host,
                              http_port=conn.port, http_path=path,
                              http_status=resp.status, http_reason=resp.reason,
                              http_response_content=body)


def get_capabilities(http_conn):
    """
    Get cluster capability infos.

    :param http_conn: HTTP connection
    :returns: a dict containing the cluster capabilities
    :raises ClientException: HTTP Capabilities GET failed
    """
    parsed, conn = http_conn
    conn.request('GET', parsed.path, '')
    resp = conn.getresponse()
    body = resp.read()
    http_log((parsed.geturl(), 'GET',), {'headers': {}}, resp, body)
    if resp.status < 200 or resp.status >= 300:
        raise ClientException('Capabilities GET failed',
                              http_scheme=parsed.scheme,
                              http_host=conn.host, http_port=conn.port,
                              http_path=parsed.path, http_status=resp.status,
                              http_reason=resp.reason,
                              http_response_content=body)
    return json_loads(body)


class Connection(object):
    """Convenience class to make requests that will also retry the request"""

    def __init__(self, authurl=None, user=None, key=None, retries=5,
                 preauthurl=None, preauthtoken=None, snet=False,
                 starting_backoff=1, max_backoff=64, tenant_name=None,
                 os_options=None, auth_version="1", cacert=None,
                 insecure=False, ssl_compression=True):
        """
        :param authurl: authentication URL
        :param user: user name to authenticate as
        :param key: key/password to authenticate with
        :param retries: Number of times to retry the request before failing
        :param preauthurl: storage URL (if you have already authenticated)
        :param preauthtoken: authentication token (if you have already
                             authenticated) note authurl/user/key/tenant_name
                             are not required when specifying preauthtoken
        :param snet: use SERVICENET internal network default is False
        :param starting_backoff: initial delay between retries (seconds)
        :param max_backoff: maximum delay between retries (seconds)
        :param auth_version: OpenStack auth version, default is 1.0
        :param tenant_name: The tenant/account name, required when connecting
                            to a auth 2.0 system.
        :param os_options: The OpenStack options which can have tenant_id,
                           auth_token, service_type, endpoint_type,
                           tenant_name, object_storage_url, region_name
        :param insecure: Allow to access insecure keystone server.
                         The keystone's certificate will not be verified.
        :param ssl_compression: Whether to enable compression at the SSL layer.
                                If set to 'False' and the pyOpenSSL library is
                                present an attempt to disable SSL compression
                                will be made. This may provide a performance
                                increase for https upload/download operations.
        """
        self.authurl = authurl
        self.user = user
        self.key = key
        self.retries = retries
        self.http_conn = None
        self.url = preauthurl
        self.token = preauthtoken
        self.attempts = 0
        self.snet = snet
        self.starting_backoff = starting_backoff
        self.max_backoff = max_backoff
        self.auth_version = auth_version
        self.os_options = os_options or {}
        if tenant_name:
            self.os_options['tenant_name'] = tenant_name
        self.cacert = cacert
        self.insecure = insecure
        self.ssl_compression = ssl_compression
        self.auth_end_time = 0

    def close(self):
        if self.http_conn and type(self.http_conn) is tuple\
                and len(self.http_conn) > 1:
            conn = self.http_conn[1]
            if hasattr(conn, 'close') and callable(conn.close):
                conn.close()
                self.http_conn = None

    def get_auth(self):
        return get_auth(self.authurl, self.user, self.key,
                        snet=self.snet,
                        auth_version=self.auth_version,
                        os_options=self.os_options,
                        cacert=self.cacert,
                        insecure=self.insecure)

    def http_connection(self):
        return http_connection(self.url,
                               ssl_compression=self.ssl_compression)

    def _add_response_dict(self, target_dict, kwargs):
        if target_dict is not None:
            response_dict = kwargs['response_dict']
            if 'response_dicts' in target_dict:
                target_dict['response_dicts'].append(response_dict)
            else:
                target_dict['response_dicts'] = [response_dict]
            target_dict.update(response_dict)

    def _retry(self, reset_func, func, *args, **kwargs):
        self.attempts = 0
        retried_auth = False
        backoff = self.starting_backoff
        caller_response_dict = kwargs.pop('response_dict', None)
        while self.attempts <= self.retries:
            self.attempts += 1
            try:
                if not self.url or not self.token:
                    self.url, self.token = self.get_auth()
                    self.http_conn = None
                self.auth_end_time = time()
                if not self.http_conn:
                    self.http_conn = self.http_connection()
                kwargs['http_conn'] = self.http_conn
                if caller_response_dict is not None:
                    kwargs['response_dict'] = {}
                rv = func(self.url, self.token, *args, **kwargs)
                self._add_response_dict(caller_response_dict, kwargs)
                return rv
            except (socket.error, HTTPException) as e:
                self._add_response_dict(caller_response_dict, kwargs)
                if self.attempts > self.retries:
                    logger.exception(e)
                    raise
                self.http_conn = None
            except ClientException as err:
                self._add_response_dict(caller_response_dict, kwargs)
                if self.attempts > self.retries:
                    logger.exception(err)
                    raise
                if err.http_status == 401:
                    self.url = self.token = None
                    if retried_auth or not all((self.authurl,
                                                self.user,
                                                self.key)):
                        logger.exception(err)
                        raise
                    retried_auth = True
                elif err.http_status == 408:
                    self.http_conn = None
                elif 500 <= err.http_status <= 599:
                    pass
                else:
                    logger.exception(err)
                    raise
            sleep(backoff)
            backoff = min(backoff * 2, self.max_backoff)
            if reset_func:
                reset_func(func, *args, **kwargs)

    def head_account(self):
        """Wrapper for :func:`head_account`"""
        return self._retry(None, head_account)

    def get_account(self, marker=None, limit=None, prefix=None,
                    end_marker=None, full_listing=False):
        """Wrapper for :func:`get_account`"""
        # TODO(unknown): With full_listing=True this will restart the entire
        # listing with each retry. Need to make a better version that just
        # retries where it left off.
        return self._retry(None, get_account, marker=marker, limit=limit,
                           prefix=prefix, end_marker=end_marker,
                           full_listing=full_listing)

    def post_account(self, headers, response_dict=None):
        """Wrapper for :func:`post_account`"""
        return self._retry(None, post_account, headers,
                           response_dict=response_dict)

    def head_container(self, container):
        """Wrapper for :func:`head_container`"""
        return self._retry(None, head_container, container)

    def get_container(self, container, marker=None, limit=None, prefix=None,
                      delimiter=None, end_marker=None, path=None,
                      full_listing=False):
        """Wrapper for :func:`get_container`"""
        # TODO(unknown): With full_listing=True this will restart the entire
        # listing with each retry. Need to make a better version that just
        # retries where it left off.
        return self._retry(None, get_container, container, marker=marker,
                           limit=limit, prefix=prefix, delimiter=delimiter,
                           end_marker=end_marker, path=path,
                           full_listing=full_listing)

    def put_container(self, container, headers=None, response_dict=None):
        """Wrapper for :func:`put_container`"""
        return self._retry(None, put_container, container, headers=headers,
                           response_dict=response_dict)

    def post_container(self, container, headers, response_dict=None):
        """Wrapper for :func:`post_container`"""
        return self._retry(None, post_container, container, headers,
                           response_dict=response_dict)

    def delete_container(self, container, response_dict=None):
        """Wrapper for :func:`delete_container`"""
        return self._retry(None, delete_container, container,
                           response_dict=response_dict)

    def head_object(self, container, obj):
        """Wrapper for :func:`head_object`"""
        return self._retry(None, head_object, container, obj)

    def get_object(self, container, obj, resp_chunk_size=None,
                   query_string=None, response_dict=None, headers=None):
        """Wrapper for :func:`get_object`"""
        return self._retry(None, get_object, container, obj,
                           resp_chunk_size=resp_chunk_size,
                           query_string=query_string,
                           response_dict=response_dict, headers=headers)

    def put_object(self, container, obj, contents, content_length=None,
                   etag=None, chunk_size=None, content_type=None,
                   headers=None, query_string=None, response_dict=None):
        """Wrapper for :func:`put_object`"""

        def _default_reset(*args, **kwargs):
            raise ClientException('put_object(%r, %r, ...) failure and no '
                                  'ability to reset contents for reupload.'
                                  % (container, obj))

        if isinstance(contents, str) or not contents:
            # if its a str or None then you can retry as much as you want
            reset_func = None
        else:
            reset_func = _default_reset
            if self.retries > 0:
                tell = getattr(contents, 'tell', None)
                seek = getattr(contents, 'seek', None)
                if tell and seek:
                    orig_pos = tell()
                    reset_func = lambda *a, **k: seek(orig_pos)

        return self._retry(reset_func, put_object, container, obj, contents,
                           content_length=content_length, etag=etag,
                           chunk_size=chunk_size, content_type=content_type,
                           headers=headers, query_string=query_string,
                           response_dict=response_dict)

    def post_object(self, container, obj, headers, response_dict=None):
        """Wrapper for :func:`post_object`"""
        return self._retry(None, post_object, container, obj, headers,
                           response_dict=response_dict)

    def delete_object(self, container, obj, query_string=None,
                      response_dict=None):
        """Wrapper for :func:`delete_object`"""
        return self._retry(None, delete_object, container, obj,
                           query_string=query_string,
                           response_dict=response_dict)

    def get_capabilities(self, url=None):
        if not url:
            url, _ = self.get_auth()
        scheme = urlparse(url).scheme
        netloc = urlparse(url).netloc
        url = scheme + '://' + netloc + '/info'
        http_conn = http_connection(url, ssl_compression=self.ssl_compression)
        return get_capabilities(http_conn)