rpc/client: support getstateheight RPC

pkg/rpc/client/rpc_test.go

@@ -620,6 +620,21 @@ var rpcClientTestCases = map[string][]rpcClientTestCase{
 			},
 		},
 	},
+	"getstateheight": {
+		{
+			name: "positive",
+			invoke: func(c *Client) (interface{}, error) {
+				return c.GetStateHeight()
+			},
+			serverResponse: `{"id":1,"jsonrpc":"2.0","result":{"blockHeight":208,"stateHeight":200}}`,
+			result: func(c *Client) interface{} {
+				return &result.StateHeight{
+					BlockHeight: 208,
+					StateHeight: 200,
+				}
+			},
+		},
+	},
 	"getstateroot": {
 		{
 			name: "positive",

pkg/rpc/client/state.go

@@ -3,6 +3,7 @@ package client
 import (
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
 	"github.com/nspcc-dev/neo-go/pkg/rpc/request"
+	"github.com/nspcc-dev/neo-go/pkg/rpc/response/result"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 )
 
@@ -24,3 +25,13 @@ func (c *Client) getStateRoot(p request.RawParams) (*state.MPTRootState, error)
 	}
 	return &resp, nil
 }
+
+// GetStateHeight returns current block and state height.
+func (c *Client) GetStateHeight() (*result.StateHeight, error) {
+	resp := new(result.StateHeight)
+	err := c.performRequest("getstateheight", request.NewRawParams(), resp)
+	if err != nil {
+		return nil, err
+	}
+	return resp, nil
+}