Add DeleteAttribute support to the client

This change adds DeleteAttribute support to the ProxyKmipClient,
leveraging the new generic request capability in the underlying
KMIPProxy client. Going forward all new attribute support will
leverage the new request capability and older supported operations
will be migrated to use it as well, with the ultimate vision
being a final merger of the two client classes into one easy to
use architecture. New unit tests have been added to cover the new
client additions.

Partially implements #547

kmip/services/kmip_client.py

@@ -39,6 +39,8 @@ from kmip.core.enums import ConformanceClause
 from kmip.core.enums import CredentialType
 from kmip.core.enums import Operation as OperationEnum
 
+from kmip.core import exceptions
+
 from kmip.core.factories.credentials import CredentialFactory
 
 from kmip.core import objects
@@ -309,6 +311,86 @@ class KMIPProxy(object):
                 pass
             self.socket = None
 
+    def send_request_payload(self, operation, payload, credential=None):
+        """
+        Send a KMIP request.
+
+        Args:
+            operation (enum): An Operation enumeration specifying the type
+                of operation to be requested. Required.
+            payload (struct): A RequestPayload structure containing the
+                parameters for a specific KMIP operation. Required.
+            credential (struct): A Credential structure containing
+                authentication information for the server. Optional, defaults
+                to None.
+
+        Returns:
+            response (struct): A ResponsePayload structure containing the
+                results of the KMIP operation specified in the request.
+
+        Raises:
+            TypeError: if the payload is not a RequestPayload instance or if
+                the operation and payload type do not match
+            InvalidMessage: if the response message does not have the right
+                number of response payloads, or does not match the request
+                operation
+        """
+        if not isinstance(payload, payloads.RequestPayload):
+            raise TypeError(
+                "The request payload must be a RequestPayload object."
+            )
+
+        # TODO (peterhamilton) For now limit this to the new DeleteAttribute
+        # operation. Migrate over existing operations to use this method
+        # instead.
+        if operation == enums.Operation.DELETE_ATTRIBUTE:
+            if not isinstance(payload, payloads.DeleteAttributeRequestPayload):
+                raise TypeError(
+                    "The request payload for the DeleteAttribute operation "
+                    "must be a DeleteAttributeRequestPayload object."
+                )
+
+        batch_item = messages.RequestBatchItem(
+            operation=operation,
+            request_payload=payload
+        )
+
+        request_message = self._build_request_message(credential, [batch_item])
+        response_message = self._send_and_receive_message(request_message)
+
+        if len(response_message.batch_items) != 1:
+            raise exceptions.InvalidMessage(
+                "The response message does not have the right number of "
+                "requested operation results."
+            )
+
+        batch_item = response_message.batch_items[0]
+
+        if batch_item.result_status.value != enums.ResultStatus.SUCCESS:
+            raise exceptions.OperationFailure(
+                batch_item.result_status.value,
+                batch_item.result_reason.value,
+                batch_item.result_message.value
+            )
+
+        if batch_item.operation.value != operation:
+            raise exceptions.InvalidMessage(
+                "The response message does not match the request operation."
+            )
+
+        # TODO (peterhamilton) Same as above for now.
+        if batch_item.operation.value == enums.Operation.DELETE_ATTRIBUTE:
+            if not isinstance(
+                batch_item.response_payload,
+                payloads.DeleteAttributeResponsePayload
+            ):
+                raise exceptions.InvalidMessage(
+                    "Invalid response payload received for the "
+                    "DeleteAttribute operation."
+                )
+
+        return batch_item.response_payload
+
     def create(self, object_type, template_attribute, credential=None):
         return self._create(object_type=object_type,
                             template_attribute=template_attribute,