text: ﻿#-------------------------------------------------------------------------
  # Copyright (c) Microsoft.  All rights reserved.
  #
  # 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.
  #--------------------------------------------------------------------------
  from contextlib import contextmanager
  from azure.common import (
      AzureHttpError,
  )
  from .._common_conversion import (
      _int_to_str,
      _to_str,
  )
  from .._error import (
      _dont_fail_not_exist,
      _dont_fail_on_exist,
      _validate_not_none,
      _ERROR_STORAGE_MISSING_INFO,
      _validate_access_policies,
  )
  from .._serialization import (
      _get_request_body,
      _update_request,
      _convert_signed_identifiers_to_xml,
      _convert_service_properties_to_xml,
  )
  from .._http import HTTPRequest
  from ..models import (
      Services,
      ListGenerator,
      _OperationContext,
  )
  from .models import TablePayloadFormat
  from .._auth import (
      _StorageSASAuthentication,
      _StorageTableSharedKeyAuthentication,
  )
  from .._connection import _ServiceParameters
  from .._deserialization import (
      _convert_xml_to_service_properties,
      _convert_xml_to_signed_identifiers,
      _convert_xml_to_service_stats,
  )
  from ._serialization import (
      _convert_table_to_json,
      _convert_batch_to_json,
      _update_storage_table_header,
      _get_entity_path,
      _DEFAULT_ACCEPT_HEADER,
      _DEFAULT_CONTENT_TYPE_HEADER,
      _DEFAULT_PREFER_HEADER,
  )
  from ._deserialization import (
      _convert_json_response_to_entity,
      _convert_json_response_to_tables,
      _convert_json_response_to_entities,
      _parse_batch_response,
      _extract_etag,
  )
  from .._constants import (
      SERVICE_HOST_BASE,
      DEFAULT_PROTOCOL,
  )
  from ._request import (
      _get_entity,
      _insert_entity,
      _update_entity,
      _merge_entity,
      _delete_entity,
      _insert_or_replace_entity,
      _insert_or_merge_entity,
  )
  from ..sharedaccesssignature import (
      SharedAccessSignature,
  )
  from ..storageclient import StorageClient
  from .tablebatch import TableBatch
  
  class TableService(StorageClient):
  
      '''
      This is the main class managing Azure Table resources.
  
      The Azure Table service offers structured storage in the form of tables. Tables 
      store data as collections of entities. Entities are similar to rows. An entity 
      has a primary key and a set of properties. A property is a name, typed-value pair, 
      similar to a column. The Table service does not enforce any schema for tables, 
      so two entities in the same table may have different sets of properties. Developers 
      may choose to enforce a schema on the client side. A table may contain any number 
      of entities.
  
      :ivar object key_encryption_key:
          The key-encryption-key optionally provided by the user. If provided, will be used to
          encrypt/decrypt in supported methods.
          For methods requiring decryption, either the key_encryption_key OR the resolver must be provided.
          If both are provided, the resolver will take precedence.
          Must implement the following methods for APIs requiring encryption:
          wrap_key(key)--wraps the specified key (bytes) using an algorithm of the user's choice. Returns the encrypted key as bytes.
          get_key_wrap_algorithm()--returns the algorithm used to wrap the specified symmetric key.
          get_kid()--returns a string key id for this key-encryption-key.
          Must implement the following methods for APIs requiring decryption:
          unwrap_key(key, algorithm)--returns the unwrapped form of the specified symmetric key using the string-specified algorithm.
          get_kid()--returns a string key id for this key-encryption-key.
      :ivar function key_resolver_function(kid):
          A function to resolve keys optionally provided by the user. If provided, will be used to decrypt in supported methods.
          For methods requiring decryption, either the key_encryption_key OR
          the resolver must be provided. If both are provided, the resolver will take precedence.
          It uses the kid string to return a key-encryption-key implementing the interface defined above.
      :ivar function(partition_key, row_key, property_name) encryption_resolver_functions:
          A function that takes in an entity's partition key, row key, and property name and returns 
          a boolean that indicates whether that property should be encrypted.
      :ivar bool require_encryption:
          A flag that may be set to ensure that all messages successfully uploaded to the queue and all those downloaded and
          successfully read from the queue are/were encrypted while on the server. If this flag is set, all required 
          parameters for encryption/decryption must be provided. See the above comments on the key_encryption_key and resolver.
      '''
  
      def __init__(self, account_name=None, account_key=None, sas_token=None, 
                   is_emulated=False, protocol=DEFAULT_PROTOCOL, endpoint_suffix=SERVICE_HOST_BASE,
                   request_session=None, connection_string=None, socket_timeout=None):
          '''
          :param str account_name:
              The storage account name. This is used to authenticate requests 
              signed with an account key and to construct the storage endpoint. It 
              is required unless a connection string is given.
          :param str account_key:
              The storage account key. This is used for shared key authentication. 
          :param str sas_token:
               A shared access signature token to use to authenticate requests 
               instead of the account key. If account key and sas token are both 
               specified, account key will be used to sign.
          :param bool is_emulated:
              Whether to use the emulator. Defaults to False. If specified, will 
              override all other parameters besides connection string and request 
              session.
          :param str protocol:
              The protocol to use for requests. Defaults to https.
          :param str endpoint_suffix:
              The host base component of the url, minus the account name. Defaults 
              to Azure (core.windows.net). Override this to use the China cloud 
              (core.chinacloudapi.cn).
          :param requests.Session request_session:
              The session object to use for http requests.
          :param str connection_string:
              If specified, this will override all other parameters besides 
              request session. See
              http://azure.microsoft.com/en-us/documentation/articles/storage-configure-connection-string/
              for the connection string format.
          :param int socket_timeout:
              If specified, this will override the default socket timeout. The timeout specified is in seconds.
              See DEFAULT_SOCKET_TIMEOUT in _constants.py for the default value.
          '''
          service_params = _ServiceParameters.get_service_parameters(
              'table',
              account_name=account_name, 
              account_key=account_key, 
              sas_token=sas_token, 
              is_emulated=is_emulated, 
              protocol=protocol, 
              endpoint_suffix=endpoint_suffix,
              request_session=request_session,
              connection_string=connection_string,
              socket_timeout=socket_timeout)
              
          super(TableService, self).__init__(service_params)
  
          if self.account_key:
              self.authentication = _StorageTableSharedKeyAuthentication(
                  self.account_name,
                  self.account_key,
              )
          elif self.sas_token:
              self.authentication = _StorageSASAuthentication(self.sas_token)
          else:
              raise ValueError(_ERROR_STORAGE_MISSING_INFO)
  
          self.require_encryption = False
          self.key_encryption_key = None
          self.key_resolver_function = None
          self.encryption_resolver_function = None
  
      def generate_account_shared_access_signature(self, resource_types, permission, 
                                          expiry, start=None, ip=None, protocol=None):
          '''
          Generates a shared access signature for the table service.
          Use the returned signature with the sas_token parameter of TableService.
  
          :param ResourceTypes resource_types:
              Specifies the resource types that are accessible with the account SAS.
          :param AccountPermissions permission:
              The permissions associated with the shared access signature. The 
              user is restricted to operations allowed by the permissions. 
              Required unless an id is given referencing a stored access policy 
              which contains this field. This field must be omitted if it has been 
              specified in an associated stored access policy.
          :param expiry:
              The time at which the shared access signature becomes invalid. 
              Required unless an id is given referencing a stored access policy 
              which contains this field. This field must be omitted if it has 
              been specified in an associated stored access policy. Azure will always 
              convert values to UTC. If a date is passed in without timezone info, it 
              is assumed to be UTC.
          :type expiry: date or str
          :param start:
              The time at which the shared access signature becomes valid. If 
              omitted, start time for this call is assumed to be the time when the 
              storage service receives the request. Azure will always convert values 
              to UTC. If a date is passed in without timezone info, it is assumed to 
              be UTC.
          :type start: date or str
          :param str ip:
              Specifies an IP address or a range of IP addresses from which to accept requests.
              If the IP address from which the request originates does not match the IP address
              or address range specified on the SAS token, the request is not authenticated.
              For example, specifying sip=168.1.5.65 or sip=168.1.5.60-168.1.5.70 on the SAS
              restricts the request to those IP addresses.
          :param str protocol:
              Specifies the protocol permitted for a request made. The default value
              is https,http. See :class:`~azure.storage.models.Protocol` for possible values.
          :return: A Shared Access Signature (sas) token.
          :rtype: str
          '''
          _validate_not_none('self.account_name', self.account_name)
          _validate_not_none('self.account_key', self.account_key)
  
          sas = SharedAccessSignature(self.account_name, self.account_key)
          return sas.generate_account(Services.TABLE, resource_types, permission, 
                                      expiry, start=start, ip=ip, protocol=protocol)
  
  
      def generate_table_shared_access_signature(self, table_name, permission=None, 
                                          expiry=None, start=None, id=None,
                                          ip=None, protocol=None,
                                          start_pk=None, start_rk=None, 
                                          end_pk=None, end_rk=None):
          '''
          Generates a shared access signature for the table.
          Use the returned signature with the sas_token parameter of TableService.
  
          :param str table_name:
              The name of the table to create a SAS token for.
          :param TablePermissions permission:
              The permissions associated with the shared access signature. The 
              user is restricted to operations allowed by the permissions. 
              Required unless an id is given referencing a stored access policy 
              which contains this field. This field must be omitted if it has been 
              specified in an associated stored access policy.
          :param expiry:
              The time at which the shared access signature becomes invalid. 
              Required unless an id is given referencing a stored access policy 
              which contains this field. This field must be omitted if it has 
              been specified in an associated stored access policy. Azure will always 
              convert values to UTC. If a date is passed in without timezone info, it 
              is assumed to be UTC.
          :type expiry: date or str
          :param start:
              The time at which the shared access signature becomes valid. If 
              omitted, start time for this call is assumed to be the time when the 
              storage service receives the request. Azure will always convert values 
              to UTC. If a date is passed in without timezone info, it is assumed to 
              be UTC.
          :type start: date or str
          :param str id:
              A unique value up to 64 characters in length that correlates to a 
              stored access policy. To create a stored access policy, use :func:`~set_table_acl`.
          :param str ip:
              Specifies an IP address or a range of IP addresses from which to accept requests.
              If the IP address from which the request originates does not match the IP address
              or address range specified on the SAS token, the request is not authenticated.
              For example, specifying sip='168.1.5.65' or sip='168.1.5.60-168.1.5.70' on the SAS
              restricts the request to those IP addresses.
          :param str protocol:
              Specifies the protocol permitted for a request made. The default value
              is https,http. See :class:`~azure.storage.models.Protocol` for possible values.
          :param str start_pk:
              The minimum partition key accessible with this shared access 
              signature. startpk must accompany startrk. Key values are inclusive. 
              If omitted, there is no lower bound on the table entities that can 
              be accessed.
          :param str start_rk:
              The minimum row key accessible with this shared access signature. 
              startpk must accompany startrk. Key values are inclusive. If 
              omitted, there is no lower bound on the table entities that can be 
              accessed.
          :param str end_pk:
              The maximum partition key accessible with this shared access 
              signature. endpk must accompany endrk. Key values are inclusive. If 
              omitted, there is no upper bound on the table entities that can be 
              accessed.
          :param str end_rk:
              The maximum row key accessible with this shared access signature. 
              endpk must accompany endrk. Key values are inclusive. If omitted, 
              there is no upper bound on the table entities that can be accessed.
          :return: A Shared Access Signature (sas) token.
          :rtype: str
          '''
          _validate_not_none('table_name', table_name)
          _validate_not_none('self.account_name', self.account_name)
          _validate_not_none('self.account_key', self.account_key)
  
          sas = SharedAccessSignature(self.account_name, self.account_key)
          return sas.generate_table(
              table_name,
              permission=permission, 
              expiry=expiry,
              start=start, 
              id=id,
              ip=ip,
              protocol=protocol,
              start_pk=start_pk,
              start_rk=start_rk,
              end_pk=end_pk,
              end_rk=end_rk,
          )
  
      def get_table_service_stats(self, timeout=None):
          '''
          Retrieves statistics related to replication for the Table service. It is 
          only available when read-access geo-redundant replication is enabled for 
          the storage account.
  
          With geo-redundant replication, Azure Storage maintains your data durable 
          in two locations. In both locations, Azure Storage constantly maintains 
          multiple healthy replicas of your data. The location where you read, 
          create, update, or delete data is the primary storage account location. 
          The primary location exists in the region you choose at the time you 
          create an account via the Azure Management Azure classic portal, for 
          example, North Central US. The location to which your data is replicated 
          is the secondary location. The secondary location is automatically 
          determined based on the location of the primary; it is in a second data 
          center that resides in the same region as the primary location. Read-only 
          access is available from the secondary location, if read-access geo-redundant 
          replication is enabled for your storage account.
  
          :param int timeout:
              The timeout parameter is expressed in seconds.
          :return: The table service stats.
          :rtype: :class:`~azure.storage.models.ServiceStats`
          '''
          request = HTTPRequest()
          request.method = 'GET'
          request.host_locations = self._get_host_locations(primary=False, secondary=True)
          request.path = '/'
          request.query = {
              'restype': 'service',
              'comp': 'stats',
              'timeout': _int_to_str(timeout),
          }
  
          return self._perform_request(request, _convert_xml_to_service_stats)
  
      def get_table_service_properties(self, timeout=None):
          '''
          Gets the properties of a storage account's Table service, including
          logging, analytics and CORS rules.
  
          :param int timeout:
              The server timeout, expressed in seconds.
          :return: The table service properties.
          :rtype: :class:`~azure.storage.models.ServiceProperties`
          '''
          request = HTTPRequest()
          request.method = 'GET'
          request.host_locations = self._get_host_locations(secondary=True)
          request.path = '/'
          request.query = {
              'restype': 'service',
              'comp': 'properties',
              'timeout': _int_to_str(timeout),
          }
  
          return self._perform_request(request, _convert_xml_to_service_properties)
  
      def set_table_service_properties(self, logging=None, hour_metrics=None, 
                                      minute_metrics=None, cors=None, timeout=None):
          '''
          Sets the properties of a storage account's Table service, including
          Azure Storage Analytics. If an element (ex Logging) is left as None, the 
          existing settings on the service for that functionality are preserved. 
          For more information on Azure Storage Analytics, see 
          https://msdn.microsoft.com/en-us/library/azure/hh343270.aspx.
  
          :param Logging logging:
              The logging settings provide request logs.
          :param Metrics hour_metrics:
              The hour metrics settings provide a summary of request 
              statistics grouped by API in hourly aggregates for tables.
          :param Metrics minute_metrics:
              The minute metrics settings provide request statistics 
              for each minute for tables.
          :param cors:
              You can include up to five CorsRule elements in the 
              list. If an empty list is specified, all CORS rules will be deleted, 
              and CORS will be disabled for the service. For detailed information 
              about CORS rules and evaluation logic, see 
              https://msdn.microsoft.com/en-us/library/azure/dn535601.aspx.
          :type cors: list of :class:`~azure.storage.models.CorsRule`
          :param int timeout:
              The server timeout, expressed in seconds.
          '''
          request = HTTPRequest()
          request.method = 'PUT'
          request.host_locations = self._get_host_locations()
          request.path = '/'
          request.query = {
              'restype': 'service',
              'comp': 'properties',
              'timeout': _int_to_str(timeout),
          }
          request.body = _get_request_body(
              _convert_service_properties_to_xml(logging, hour_metrics, minute_metrics, cors))
  
          self._perform_request(request)
  
      def list_tables(self, num_results=None, marker=None, timeout=None):
          '''
          Returns a generator to list the tables. The generator will lazily follow 
          the continuation tokens returned by the service and stop when all tables 
          have been returned or num_results is reached.
  
          If num_results is specified and the account has more than that number of 
          tables, the generator will have a populated next_marker field once it 
          finishes. This marker can be used to create a new generator if more 
          results are desired.
  
          :param int num_results:
              The maximum number of tables to return.
          :param marker:
              An opaque continuation object. This value can be retrieved from the 
              next_marker field of a previous generator object if num_results was 
              specified and that generator has finished enumerating results. If 
              specified, this generator will begin returning results from the point 
              where the previous generator stopped.
          :type marker: obj
          :param int timeout:
              The server timeout, expressed in seconds. This function may make multiple 
              calls to the service in which case the timeout value specified will be 
              applied to each individual call.
          :return: A generator which produces :class:`~azure.storage.models.table.Table` objects.
          :rtype: :class:`~azure.storage.models.ListGenerator`:
          '''
          operation_context = _OperationContext(location_lock=True)
          kwargs = {'max_results': num_results, 'marker': marker, 'timeout': timeout, 
                    '_context': operation_context}
          resp = self._list_tables(**kwargs)
  
          return ListGenerator(resp, self._list_tables, (), kwargs)
  
      def _list_tables(self, max_results=None, marker=None, timeout=None, _context=None):
          '''
          Returns a list of tables under the specified account. Makes a single list 
          request to the service. Used internally by the list_tables method.
  
          :param int max_results:
              The maximum number of tables to return. A single list request may 
              return up to 1000 tables and potentially a continuation token which 
              should be followed to get additional resutls.
          :param marker:
              A dictionary which identifies the portion of the query to be
              returned with the next query operation. The operation returns a
              next_marker element within the response body if the list returned
              was not complete. This value may then be used as a query parameter
              in a subsequent call to request the next portion of the list of
              tables. The marker value is opaque to the client.
          :type marker: obj
          :param int timeout:
              The server timeout, expressed in seconds.
          :return: A list of tables, potentially with a next_marker property.
          :rtype: list of :class:`~azure.storage.models.table.Table`:  
          '''
          request = HTTPRequest()
          request.method = 'GET'
          request.host_locations = self._get_host_locations(secondary=True)
          request.path = '/Tables'
          request.headers = {'Accept': TablePayloadFormat.JSON_NO_METADATA}
          request.query = {
              '$top': _int_to_str(max_results),
              'NextTableName': _to_str(marker),
              'timeout': _int_to_str(timeout),
          }
  
          return self._perform_request(request, _convert_json_response_to_tables, 
                                       operation_context=_context)
  
      def create_table(self, table_name, fail_on_exist=False, timeout=None):
          '''
          Creates a new table in the storage account.
  
          :param str table_name:
              The name of the table to create. The table name may contain only
              alphanumeric characters and cannot begin with a numeric character.
              It is case-insensitive and must be from 3 to 63 characters long.
          :param bool fail_on_exist:
              Specifies whether to throw an exception if the table already exists.
          :param int timeout:
              The server timeout, expressed in seconds.
          :return:
              A boolean indicating whether the table was created. If fail_on_exist 
              was set to True, this will throw instead of returning false.
          :rtype: bool
          '''
          _validate_not_none('table', table_name)
          request = HTTPRequest()
          request.method = 'POST'
          request.host_locations = self._get_host_locations()
          request.path = '/Tables'
          request.query = {'timeout': _int_to_str(timeout)}
          request.headers = {
              _DEFAULT_CONTENT_TYPE_HEADER[0]: _DEFAULT_CONTENT_TYPE_HEADER[1],
              _DEFAULT_PREFER_HEADER[0]: _DEFAULT_PREFER_HEADER[1],
              _DEFAULT_ACCEPT_HEADER[0]: _DEFAULT_ACCEPT_HEADER[1]
          }
          request.body = _get_request_body(_convert_table_to_json(table_name))
  
          if not fail_on_exist:
              try:
                  self._perform_request(request)
                  return True
              except AzureHttpError as ex:
                  _dont_fail_on_exist(ex)
                  return False
          else:
              self._perform_request(request)
              return True
  
      def exists(self, table_name, timeout=None):
          '''
          Returns a boolean indicating whether the table exists.
  
          :param str table_name:
              The name of table to check for existence.
          :param int timeout:
              The server timeout, expressed in seconds.
          :return: A boolean indicating whether the table exists.
          :rtype: bool
          '''
          _validate_not_none('table_name', table_name)
          request = HTTPRequest()
          request.method = 'GET'
          request.host_locations = self._get_host_locations(secondary=True)
          request.path = '/Tables' + "('" + table_name + "')"
          request.headers = {'Accept': TablePayloadFormat.JSON_NO_METADATA}
          request.query = {'timeout': _int_to_str(timeout)}
  
          try:
              self._perform_request(request)
              return True
          except AzureHttpError as ex:
              _dont_fail_not_exist(ex)
              return False
  
      def delete_table(self, table_name, fail_not_exist=False, timeout=None):
          '''
          Deletes the specified table and any data it contains.
  
          When a table is successfully deleted, it is immediately marked for deletion 
          and is no longer accessible to clients. The table is later removed from 
          the Table service during garbage collection.
  
          Note that deleting a table is likely to take at least 40 seconds to complete. 
          If an operation is attempted against the table while it was being deleted, 
          an :class:`AzureConflictHttpError` will be thrown.
  
          :param str table_name:
              The name of the table to delete.
          :param bool fail_not_exist:
              Specifies whether to throw an exception if the table doesn't exist.
          :param int timeout:
              The server timeout, expressed in seconds.
          :return:
              A boolean indicating whether the table was deleted. If fail_not_exist 
              was set to True, this will throw instead of returning false.
          :rtype: bool
          '''
          _validate_not_none('table_name', table_name)
          request = HTTPRequest()
          request.method = 'DELETE'
          request.host_locations = self._get_host_locations()
          request.path = '/Tables(\'' + _to_str(table_name) + '\')'
          request.query = {'timeout': _int_to_str(timeout)}
          request.headers = {_DEFAULT_ACCEPT_HEADER[0]: _DEFAULT_ACCEPT_HEADER[1]}
  
          if not fail_not_exist:
              try:
                  self._perform_request(request)
                  return True
              except AzureHttpError as ex:
                  _dont_fail_not_exist(ex)
                  return False
          else:
              self._perform_request(request)
              return True
  
      def get_table_acl(self, table_name, timeout=None):
          '''
          Returns details about any stored access policies specified on the
          table that may be used with Shared Access Signatures.
  
          :param str table_name:
              The name of an existing table.
          :param int timeout:
              The server timeout, expressed in seconds.
          :return: A dictionary of access policies associated with the table.
          :rtype: dict of str to :class:`~azure.storage.models.AccessPolicy`:
          '''
          _validate_not_none('table_name', table_name)
          request = HTTPRequest()
          request.method = 'GET'
          request.host_locations = self._get_host_locations(secondary=True)
          request.path = '/' + _to_str(table_name)
          request.query = {
              'comp': 'acl',
              'timeout': _int_to_str(timeout),
          }
  
          return self._perform_request(request, _convert_xml_to_signed_identifiers)
  
      def set_table_acl(self, table_name, signed_identifiers=None, timeout=None):
          '''
          Sets stored access policies for the table that may be used with Shared 
          Access Signatures. 
          
          When you set permissions for a table, the existing permissions are replaced. 
          To update the table's permissions, call :func:`~get_table_acl` to fetch 
          all access policies associated with the table, modify the access policy 
          that you wish to change, and then call this function with the complete 
          set of data to perform the update.
  
          When you establish a stored access policy on a table, it may take up to 
          30 seconds to take effect. During this interval, a shared access signature 
          that is associated with the stored access policy will throw an 
          :class:`AzureHttpError` until the access policy becomes active.
  
          :param str table_name:
              The name of an existing table.
          :param signed_identifiers:
              A dictionary of access policies to associate with the table. The 
              dictionary may contain up to 5 elements. An empty dictionary 
              will clear the access policies set on the service. 
          :type signed_identifiers: dict of str to :class:`~azure.storage.models.AccessPolicy`
          :param int timeout:
              The server timeout, expressed in seconds.
          '''
          _validate_not_none('table_name', table_name)
          _validate_access_policies(signed_identifiers)
          request = HTTPRequest()
          request.method = 'PUT'
          request.host_locations = self._get_host_locations()
          request.path = '/' + _to_str(table_name)
          request.query = {
              'comp': 'acl',
              'timeout': _int_to_str(timeout),
          }
          request.body = _get_request_body(
              _convert_signed_identifiers_to_xml(signed_identifiers))
  
          self._perform_request(request)
  
      def query_entities(self, table_name, filter=None, select=None, num_results=None,
                         marker=None, accept=TablePayloadFormat.JSON_MINIMAL_METADATA,
                         property_resolver=None, timeout=None):
          '''
          Returns a generator to list the entities in the table specified. The 
          generator will lazily follow the continuation tokens returned by the 
          service and stop when all entities have been returned or max_results is 
          reached.
  
          If max_results is specified and the account has more than that number of 
          entities, the generator will have a populated next_marker field once it 
          finishes. This marker can be used to create a new generator if more 
          results are desired.
  
          :param str table_name:
              The name of the table to query.
          :param str filter:
              Returns only entities that satisfy the specified filter. Note that 
              no more than 15 discrete comparisons are permitted within a $filter 
              string. See http://msdn.microsoft.com/en-us/library/windowsazure/dd894031.aspx 
              for more information on constructing filters.
          :param str select:
              Returns only the desired properties of an entity from the set.
          :param int num_results:
              The maximum number of entities to return.
          :param marker:
              An opaque continuation object. This value can be retrieved from the 
              next_marker field of a previous generator object if max_results was 
              specified and that generator has finished enumerating results. If 
              specified, this generator will begin returning results from the point 
              where the previous generator stopped.
          :type marker: obj
          :param str accept:
              Specifies the accepted content type of the response payload. See 
              :class:`~azure.storage.table.models.TablePayloadFormat` for possible 
              values.
          :param property_resolver:
              A function which given the partition key, row key, property name, 
              property value, and the property EdmType if returned by the service, 
              returns the EdmType of the property. Generally used if accept is set 
              to JSON_NO_METADATA.
          :type property_resolver: callback function in format of func(pk, rk, prop_name, prop_value, service_edm_type)
          :param int timeout:
              The server timeout, expressed in seconds. This function may make multiple 
              calls to the service in which case the timeout value specified will be 
              applied to each individual call.
          :return: A generator which produces :class:`~azure.storage.table.models.Entity` objects.
          :rtype: :class:`~azure.storage.models.ListGenerator`
          '''
  
          operation_context = _OperationContext(location_lock=True)
          if self.key_encryption_key is not None or self.key_resolver_function is not None:
              # If query already requests all properties, no need to add the metadata columns
              if select is not None and select != '*':
                  select += ',_ClientEncryptionMetadata1,_ClientEncryptionMetadata2'
  
          args = (table_name,)
          kwargs = {'filter': filter, 'select': select, 'max_results': num_results, 'marker': marker, 
                    'accept': accept, 'property_resolver': property_resolver, 'timeout': timeout, 
                    '_context': operation_context}
          resp = self._query_entities(*args, **kwargs)
  
          return ListGenerator(resp, self._query_entities, args, kwargs)
  
      def _query_entities(self, table_name, filter=None, select=None, max_results=None,
                         marker=None, accept=TablePayloadFormat.JSON_MINIMAL_METADATA,
                         property_resolver=None, timeout=None, _context=None):
          '''
          Returns a list of entities under the specified table. Makes a single list 
          request to the service. Used internally by the query_entities method.
  
          :param str table_name:
              The name of the table to query.
          :param str filter:
              Returns only entities that satisfy the specified filter. Note that 
              no more than 15 discrete comparisons are permitted within a $filter 
              string. See http://msdn.microsoft.com/en-us/library/windowsazure/dd894031.aspx 
              for more information on constructing filters.
          :param str select:
              Returns only the desired properties of an entity from the set.
          :param int top:
              The maximum number of entities to return.
          :param marker:
              A dictionary which identifies the portion of the query to be
              returned with the next query operation. The operation returns a
              next_marker element within the response body if the list returned
              was not complete. This value may then be used as a query parameter
              in a subsequent call to request the next portion of the list of
              table. The marker value is opaque to the client.
          :type marker: obj
          :param str accept:
              Specifies the accepted content type of the response payload. See 
              :class:`~azure.storage.table.models.TablePayloadFormat` for possible 
              values.
          :param property_resolver:
              A function which given the partition key, row key, property name, 
              property value, and the property EdmType if returned by the service, 
              returns the EdmType of the property. Generally used if accept is set 
              to JSON_NO_METADATA.
          :type property_resolver: callback function in format of func(pk, rk, prop_name, prop_value, service_edm_type)
          :param int timeout:
              The server timeout, expressed in seconds.
          :return: A list of entities, potentially with a next_marker property.
          :rtype: list of :class:`~azure.storage.table.models.Entity`
          '''
          _validate_not_none('table_name', table_name)
          _validate_not_none('accept', accept)
          next_partition_key = None if marker is None else marker.get('nextpartitionkey')
          next_row_key = None if marker is None else marker.get('nextrowkey')
  
          request = HTTPRequest()
          request.method = 'GET'
          request.host_locations = self._get_host_locations(secondary=True)
          request.path = '/' + _to_str(table_name) + '()'
          request.headers = {'Accept': _to_str(accept)}
          request.query = {
              '$filter': _to_str(filter),
              '$select': _to_str(select),
              '$top': _int_to_str(max_results),
              'NextPartitionKey': _to_str(next_partition_key),
              'NextRowKey': _to_str(next_row_key),
              'timeout': _int_to_str(timeout),
          }
  
          return self._perform_request(request, _convert_json_response_to_entities, 
                                       [property_resolver, self.require_encryption,
                                        self.key_encryption_key, self.key_resolver_function], 
                                        operation_context=_context)
  
      def commit_batch(self, table_name, batch, timeout=None):
          '''
          Commits a :class:`~azure.storage.table.TableBatch` request.
  
          :param str table_name:
              The name of the table to commit the batch to.
          :param TableBatch batch:
              The batch to commit.
          :param int timeout:
              The server timeout, expressed in seconds.
          :return: A list of the batch responses corresponding to the requests in the batch.
          :rtype: list of response objects
          '''
          _validate_not_none('table_name', table_name)
  
          # Construct the batch request
          request = HTTPRequest()
          request.method = 'POST'
          request.host_locations = self._get_host_locations()
          request.path = '/' + '$batch'
          request.query = {'timeout': _int_to_str(timeout)}
  
          # Update the batch operation requests with table and client specific info
          for row_key, batch_request in batch._requests:
              if batch_request.method == 'POST':
                  batch_request.path = '/' + _to_str(table_name)
              else:
                  batch_request.path = _get_entity_path(table_name, batch._partition_key, row_key)
              _update_request(batch_request)
  
          # Construct the batch body
          request.body, boundary = _convert_batch_to_json(batch._requests)
          request.headers = {'Content-Type': boundary}
  
          # Perform the batch request and return the response
          return self._perform_request(request, _parse_batch_response)
  
      @contextmanager
      def batch(self, table_name, timeout=None):
          '''
          Creates a batch object which can be used as a context manager. Commits the batch on exit.
  
          :param str table_name:
              The name of the table to commit the batch to.
          :param int timeout:
              The server timeout, expressed in seconds.
          '''
          batch = TableBatch(self.require_encryption, self.key_encryption_key, self.encryption_resolver_function)
          yield batch
          self.commit_batch(table_name, batch, timeout=timeout)
  
      def get_entity(self, table_name, partition_key, row_key, select=None,
                     accept=TablePayloadFormat.JSON_MINIMAL_METADATA,
                     property_resolver=None, timeout=None):
          '''
          Get an entity from the specified table. Throws if the entity does not exist.
  
          :param str table_name:
              The name of the table to get the entity from.
          :param str partition_key:
              The PartitionKey of the entity.
          :param str row_key:
              The RowKey of the entity.
          :param str select:
              Returns only the desired properties of an entity from the set.
          :param str accept:
              Specifies the accepted content type of the response payload. See 
              :class:`~azure.storage.table.models.TablePayloadFormat` for possible 
              values.
          :param property_resolver:
              A function which given the partition key, row key, property name, 
              property value, and the property EdmType if returned by the service, 
              returns the EdmType of the property. Generally used if accept is set 
              to JSON_NO_METADATA.
          :type property_resolver: callback function in format of func(pk, rk, prop_name, prop_value, service_edm_type)
          :param int timeout:
              The server timeout, expressed in seconds.
          :return: The retrieved entity.
          :rtype: :class:`~azure.storage.table.models.Entity`
          '''
          _validate_not_none('table_name', table_name)
          request = _get_entity(partition_key, row_key, select, accept)
          request.host_locations = self._get_host_locations(secondary=True)
          request.path = _get_entity_path(table_name, partition_key, row_key)
          request.query['timeout'] = _int_to_str(timeout)
  
          return self._perform_request(request, _convert_json_response_to_entity,
                                       [property_resolver, self.require_encryption,
                                        self.key_encryption_key, self.key_resolver_function])
  
      def insert_entity(self, table_name, entity, timeout=None):
          '''
          Inserts a new entity into the table. Throws if an entity with the same 
          PartitionKey and RowKey already exists.
  
          When inserting an entity into a table, you must specify values for the 
          PartitionKey and RowKey system properties. Together, these properties 
          form the primary key and must be unique within the table. Both the 
          PartitionKey and RowKey values must be string values; each key value may 
          be up to 64 KB in size. If you are using an integer value for the key 
          value, you should convert the integer to a fixed-width string, because 
          they are canonically sorted. For example, you should convert the value 
          1 to 0000001 to ensure proper sorting.
  
          :param str table_name:
              The name of the table to insert the entity into.
          :param entity:
              The entity to insert. Could be a dict or an entity object. 
              Must contain a PartitionKey and a RowKey.
          :type entity: a dict or :class:`~azure.storage.table.models.Entity`
          :param int timeout:
              The server timeout, expressed in seconds.
          :return: The etag of the inserted entity.
          :rtype: str
          '''
          _validate_not_none('table_name', table_name)
  
          request = _insert_entity(entity, self.require_encryption, self.key_encryption_key,
                                   self.encryption_resolver_function)
          request.host_locations = self._get_host_locations()
          request.path = '/' + _to_str(table_name)
          request.query['timeout'] = _int_to_str(timeout)
  
          return self._perform_request(request, _extract_etag)
  
      def update_entity(self, table_name, entity, if_match='*', timeout=None):
          '''
          Updates an existing entity in a table. Throws if the entity does not exist. 
          The update_entity operation replaces the entire entity and can be used to 
          remove properties.
  
          :param str table_name:
              The name of the table containing the entity to update.
          :param entity:
              The entity to update. Could be a dict or an entity object. 
              Must contain a PartitionKey and a RowKey.
          :type entity: a dict or :class:`~azure.storage.table.models.Entity`
          :param str if_match:
              The client may specify the ETag for the entity on the 
              request in order to compare to the ETag maintained by the service 
              for the purpose of optimistic concurrency. The update operation 
              will be performed only if the ETag sent by the client matches the 
              value maintained by the server, indicating that the entity has 
              not been modified since it was retrieved by the client. To force 
              an unconditional update, set If-Match to the wildcard character (*).
          :param int timeout:
              The server timeout, expressed in seconds.
          :return: The etag of the entity.
          :rtype: str
          '''
          _validate_not_none('table_name', table_name)
          request = _update_entity(entity, if_match, self.require_encryption, self.key_encryption_key,
                                   self.encryption_resolver_function)        
          request.host_locations = self._get_host_locations()
          request.path = _get_entity_path(table_name, entity['PartitionKey'], entity['RowKey'])
          request.query['timeout'] = _int_to_str(timeout)
  
          return self._perform_request(request, _extract_etag)
  
      def merge_entity(self, table_name, entity, if_match='*', timeout=None):
          '''
          Updates an existing entity by merging the entity's properties. Throws 
          if the entity does not exist. 
          
          This operation does not replace the existing entity as the update_entity
          operation does. A property cannot be removed with merge_entity.
          
          Any properties with null values are ignored. All other properties will be 
          updated or added.
  
          :param str table_name:
              The name of the table containing the entity to merge.
          :param entity:
              The entity to merge. Could be a dict or an entity object. 
              Must contain a PartitionKey and a RowKey.
          :type entity: a dict or :class:`~azure.storage.table.models.Entity`
          :param str if_match:
              The client may specify the ETag for the entity on the 
              request in order to compare to the ETag maintained by the service 
              for the purpose of optimistic concurrency. The merge operation 
              will be performed only if the ETag sent by the client matches the 
              value maintained by the server, indicating that the entity has 
              not been modified since it was retrieved by the client. To force 
              an unconditional merge, set If-Match to the wildcard character (*).
          :param int timeout:
              The server timeout, expressed in seconds.
          :return: The etag of the entity.
          :rtype: str
          '''
  
          _validate_not_none('table_name', table_name)
  
          request = _merge_entity(entity, if_match, self.require_encryption,
                                  self.key_encryption_key)
          request.host_locations = self._get_host_locations()
          request.query['timeout'] = _int_to_str(timeout)
          request.path = _get_entity_path(table_name, entity['PartitionKey'], entity['RowKey'])
  
          return self._perform_request(request, _extract_etag)
  
      def delete_entity(self, table_name, partition_key, row_key,
                        if_match='*', timeout=None):
          '''
          Deletes an existing entity in a table. Throws if the entity does not exist.
  
          When an entity is successfully deleted, the entity is immediately marked 
          for deletion and is no longer accessible to clients. The entity is later 
          removed from the Table service during garbage collection.
  
          :param str table_name:
              The name of the table containing the entity to delete.
          :param str partition_key:
              The PartitionKey of the entity.
          :param str row_key:
              The RowKey of the entity.
          :param str if_match:
              The client may specify the ETag for the entity on the 
              request in order to compare to the ETag maintained by the service 
              for the purpose of optimistic concurrency. The delete operation 
              will be performed only if the ETag sent by the client matches the 
              value maintained by the server, indicating that the entity has 
              not been modified since it was retrieved by the client. To force 
              an unconditional delete, set If-Match to the wildcard character (*).
          :param int timeout:
              The server timeout, expressed in seconds.
          '''
          _validate_not_none('table_name', table_name)
          request = _delete_entity(partition_key, row_key, if_match)
          request.host_locations = self._get_host_locations()
          request.query['timeout'] = _int_to_str(timeout)
          request.path = _get_entity_path(table_name, partition_key, row_key)
  
          self._perform_request(request)
  
      def insert_or_replace_entity(self, table_name, entity, timeout=None):
          '''
          Replaces an existing entity or inserts a new entity if it does not
          exist in the table. Because this operation can insert or update an
          entity, it is also known as an "upsert" operation.
  
          If insert_or_replace_entity is used to replace an entity, any properties 
          from the previous entity will be removed if the new entity does not define 
          them.
  
          :param str table_name:
              The name of the table in which to insert or replace the entity.
          :param entity:
              The entity to insert or replace. Could be a dict or an entity object. 
              Must contain a PartitionKey and a RowKey.
          :type entity: a dict or :class:`~azure.storage.table.models.Entity`
          :param int timeout:
              The server timeout, expressed in seconds.
          :return: The etag of the entity.
          :rtype: str
          '''
          _validate_not_none('table_name', table_name)
          request = _insert_or_replace_entity(entity, self.require_encryption, self.key_encryption_key,
                                   self.encryption_resolver_function)
          request.host_locations = self._get_host_locations()
          request.query['timeout'] = _int_to_str(timeout)
          request.path = _get_entity_path(table_name, entity['PartitionKey'], entity['RowKey'])
  
          return self._perform_request(request, _extract_etag)
  
      def insert_or_merge_entity(self, table_name, entity, timeout=None):
          '''
          Merges an existing entity or inserts a new entity if it does not exist
          in the table. 
  
          If insert_or_merge_entity is used to merge an entity, any properties from 
          the previous entity will be retained if the request does not define or 
          include them.
  
          :param str table_name:
              The name of the table in which to insert or merge the entity.
          :param entity:
              The entity to insert or merge. Could be a dict or an entity object. 
              Must contain a PartitionKey and a RowKey.
          :type entity: a dict or :class:`~azure.storage.table.models.Entity`
          :param int timeout:
              The server timeout, expressed in seconds.
          :return: The etag of the entity.
          :rtype: str
          '''
  
          _validate_not_none('table_name', table_name)
          request = _insert_or_merge_entity(entity, self.require_encryption,
                                            self.key_encryption_key)
          request.host_locations = self._get_host_locations()
          request.query['timeout'] = _int_to_str(timeout)
          request.path = _get_entity_path(table_name, entity['PartitionKey'], entity['RowKey'])
  
          return self._perform_request(request, _extract_etag)
  
      def _perform_request(self, request, parser=None, parser_args=None, operation_context=None):
          _update_storage_table_header(request)
          return super(TableService, self)._perform_request(request, parser, parser_args, operation_context)