[NOD-423] Implement get selected tip RPC command (#469)

* [NOD-423] Rename BestBlock to SelectedTip

* [NOD-423] Implement GetSelectedTip RPC command

* [NOD-423] Add help to getSelectedTip command

* [NOD-423] Fix getSelectedTip test

* [NOD-423] Fix tests so they would compile. These tests will need to be rewriten at some point.

* [NOD-423] Make integration test compile. Test need to be revisited

* [NOD-423] Rename variables

* [NOD-423] Change comment s about best block to selected tip.

* [NOD-423] Update comment

* [NOD-423] Change height to bluescore

btcjson/btcdextcmds.go

@@ -72,13 +72,19 @@ func NewGenerateCmd(numBlocks uint32) *GenerateCmd {
 	}
 }
 
-// GetBestBlockCmd defines the getBestBlock JSON-RPC command.
-type GetBestBlockCmd struct{}
+// GetSelectedTipCmd defines the getSelectedTip JSON-RPC command.
+type GetSelectedTipCmd struct {
+	Verbose   *bool `jsonrpcdefault:"true"`
+	VerboseTx *bool `jsonrpcdefault:"false"`
+}
 
-// NewGetBestBlockCmd returns a new instance which can be used to issue a
-// getBestBlock JSON-RPC command.
-func NewGetBestBlockCmd() *GetBestBlockCmd {
-	return &GetBestBlockCmd{}
+// NewGetSelectedTipCmd returns a new instance which can be used to issue a
+// getSelectedTip JSON-RPC command.
+func NewGetSelectedTipCmd(verbose, verboseTx *bool) *GetSelectedTipCmd {
+	return &GetSelectedTipCmd{
+		Verbose:   verbose,
+		VerboseTx: verboseTx,
+	}
 }
 
 // GetCurrentNetCmd defines the getCurrentNet JSON-RPC command.
@@ -144,7 +150,7 @@ func init() {
 	MustRegisterCmd("debugLevel", (*DebugLevelCmd)(nil), flags)
 	MustRegisterCmd("node", (*NodeCmd)(nil), flags)
 	MustRegisterCmd("generate", (*GenerateCmd)(nil), flags)
-	MustRegisterCmd("getBestBlock", (*GetBestBlockCmd)(nil), flags)
+	MustRegisterCmd("getSelectedTip", (*GetSelectedTipCmd)(nil), flags)
 	MustRegisterCmd("getCurrentNet", (*GetCurrentNetCmd)(nil), flags)
 	MustRegisterCmd("getHeaders", (*GetHeadersCmd)(nil), flags)
 	MustRegisterCmd("getTopHeaders", (*GetTopHeadersCmd)(nil), flags)

btcjson/btcdextcmds_test.go

@@ -115,15 +115,18 @@ func TestBtcdExtCmds(t *testing.T) {
 			},
 		},
 		{
-			name: "getBestBlock",
+			name: "getSelectedTip",
 			newCmd: func() (interface{}, error) {
-				return btcjson.NewCmd("getBestBlock")
+				return btcjson.NewCmd("getSelectedTip")
 			},
 			staticCmd: func() interface{} {
-				return btcjson.NewGetBestBlockCmd()
+				return btcjson.NewGetSelectedTipCmd(nil, nil)
+			},
+			marshalled: `{"jsonrpc":"1.0","method":"getSelectedTip","params":[],"id":1}`,
+			unmarshalled: &btcjson.GetSelectedTipCmd{
+				Verbose:   btcjson.Bool(true),
+				VerboseTx: btcjson.Bool(false),
 			},
-			marshalled:   `{"jsonrpc":"1.0","method":"getBestBlock","params":[],"id":1}`,
-			unmarshalled: &btcjson.GetBestBlockCmd{},
 		},
 		{
 			name: "getCurrentNet",

btcjson/dagsvrcmds.go

@@ -124,13 +124,13 @@ func NewGetAllManualNodesInfoCmd(details *bool) *GetAllManualNodesInfoCmd {
 	}
 }
 
-// GetBestBlockHashCmd defines the getBestBlockHash JSON-RPC command.
-type GetBestBlockHashCmd struct{}
+// GetSelectedTipHashCmd defines the getSelectedTipHash JSON-RPC command.
+type GetSelectedTipHashCmd struct{}
 
-// NewGetBestBlockHashCmd returns a new instance which can be used to issue a
-// getBestBlockHash JSON-RPC command.
-func NewGetBestBlockHashCmd() *GetBestBlockHashCmd {
-	return &GetBestBlockHashCmd{}
+// NewGetSelectedTipHashCmd returns a new instance which can be used to issue a
+// getSelectedTipHash JSON-RPC command.
+func NewGetSelectedTipHashCmd() *GetSelectedTipHashCmd {
+	return &GetSelectedTipHashCmd{}
 }
 
 // GetBlockCmd defines the getBlock JSON-RPC command.
@@ -740,7 +740,7 @@ func init() {
 	MustRegisterCmd("decodeRawTransaction", (*DecodeRawTransactionCmd)(nil), flags)
 	MustRegisterCmd("decodeScript", (*DecodeScriptCmd)(nil), flags)
 	MustRegisterCmd("getAllManualNodesInfo", (*GetAllManualNodesInfoCmd)(nil), flags)
-	MustRegisterCmd("getBestBlockHash", (*GetBestBlockHashCmd)(nil), flags)
+	MustRegisterCmd("getSelectedTipHash", (*GetSelectedTipHashCmd)(nil), flags)
 	MustRegisterCmd("getBlock", (*GetBlockCmd)(nil), flags)
 	MustRegisterCmd("getBlocks", (*GetBlocksCmd)(nil), flags)
 	MustRegisterCmd("getBlockDagInfo", (*GetBlockDAGInfoCmd)(nil), flags)

btcjson/dagsvrcmds_test.go

@@ -115,15 +115,15 @@ func TestDAGSvrCmds(t *testing.T) {
 			unmarshalled: &btcjson.GetAllManualNodesInfoCmd{Details: btcjson.Bool(true)},
 		},
 		{
-			name: "getBestBlockHash",
+			name: "getSelectedTipHash",
 			newCmd: func() (interface{}, error) {
-				return btcjson.NewCmd("getBestBlockHash")
+				return btcjson.NewCmd("getSelectedTipHash")
 			},
 			staticCmd: func() interface{} {
-				return btcjson.NewGetBestBlockHashCmd()
+				return btcjson.NewGetSelectedTipHashCmd()
 			},
-			marshalled:   `{"jsonrpc":"1.0","method":"getBestBlockHash","params":[],"id":1}`,
-			unmarshalled: &btcjson.GetBestBlockHashCmd{},
+			marshalled:   `{"jsonrpc":"1.0","method":"getSelectedTipHash","params":[],"id":1}`,
+			unmarshalled: &btcjson.GetSelectedTipHashCmd{},
 		},
 		{
 			name: "getBlock",

btcjson/dagsvrresults.go

@@ -283,7 +283,7 @@ type GetSubnetworkResult struct {
 
 // GetTxOutResult models the data from the gettxout command.
 type GetTxOutResult struct {
-	BestBlock     string             `json:"bestBlock"`
+	SelectedTip   string             `json:"selectedTip"`
 	Confirmations *uint64            `json:"confirmations,omitempty"`
 	IsInMempool   bool               `json:"isInMempool"`
 	Value         float64            `json:"value"`
@@ -485,12 +485,6 @@ type ValidateAddressResult struct {
 	Address string `json:"address,omitempty"`
 }
 
-// GetBestBlockResult models the data from the getbestblock command.
-type GetBestBlockResult struct {
-	Hash   string `json:"hash"`
-	Height uint64 `json:"height"`
-}
-
 // ChainBlock models a block that is part of the selected parent chain.
 type ChainBlock struct {
 	Hash           string          `json:"hash"`

btcjson/jsonrpcerr.go

@@ -54,7 +54,7 @@ const (
 const (
 	ErrRPCBlockNotFound      RPCErrorCode = -5
 	ErrRPCBlockCount         RPCErrorCode = -5
-	ErrRPCBestBlockHash      RPCErrorCode = -5
+	ErrRPCSelectedTipHash    RPCErrorCode = -5
 	ErrRPCDifficulty         RPCErrorCode = -5
 	ErrRPCOutOfRange         RPCErrorCode = -1
 	ErrRPCNoTxInfo           RPCErrorCode = -5

integration/csv_test.go

@@ -435,7 +435,7 @@ func TestBIP0068AndCsv(t *testing.T) {
 
 	// Now mine 10 additional blocks giving the inputs generated above a
 	// age of 11. Space out each block 10 minutes after the previous block.
-	parentBlockHash, err := r.Node.GetBestBlockHash()
+	parentBlockHash, err := r.Node.GetSelectedTipHash()
 	if err != nil {
 		t.Fatalf("unable to get prior block hash: %v", err)
 	}

integration/rpcserver_test.go

@@ -18,10 +18,10 @@ import (
 	"github.com/daglabs/btcd/integration/rpctest"
 )
 
-func testGetBestBlock(r *rpctest.Harness, t *testing.T) {
-	_, prevbestHeight, err := r.Node.GetBestBlock()
+func testGetSelectedTip(r *rpctest.Harness, t *testing.T) {
+	_, prevbestHeight, err := r.Node.GetSelectedTip()
 	if err != nil {
-		t.Fatalf("Call to `getbestblock` failed: %v", err)
+		t.Fatalf("Call to `GetSelectedTip` failed: %v", err)
 	}
 
 	// Create a new block connecting to the current tip.
@@ -30,9 +30,9 @@ func testGetBestBlock(r *rpctest.Harness, t *testing.T) {
 		t.Fatalf("Unable to generate block: %v", err)
 	}
 
-	bestHash, bestHeight, err := r.Node.GetBestBlock()
+	bestHash, bestHeight, err := r.Node.GetSelectedTip()
 	if err != nil {
-		t.Fatalf("Call to `getbestblock` failed: %v", err)
+		t.Fatalf("Call to `GetSelectedTip` failed: %v", err)
 	}
 
 	// Hash should be the same as the newly submitted block.
@@ -95,7 +95,7 @@ func testGetBlockHash(r *rpctest.Harness, t *testing.T) {
 }
 
 var rpcTestCases = []rpctest.HarnessTestCase{
-	testGetBestBlock,
+	testGetSelectedTip,
 	testGetBlockCount,
 	testGetBlockHash,
 }

integration/rpctest/rpc_harness.go

@@ -245,14 +245,15 @@ func (h *Harness) SetUp(createTestChain bool, numMatureOutputs uint32) error {
 
 	// Block until the wallet has fully synced up to the tip of the main
 	// chain.
-	_, height, err := h.Node.GetBestBlock()
+	selectedTip, err := h.Node.GetSelectedTip()
 	if err != nil {
 		return err
 	}
+	blueScore := selectedTip.BlueScore
 	ticker := time.NewTicker(time.Millisecond * 100)
 	for range ticker.C {
 		walletHeight := h.wallet.SyncedHeight()
-		if walletHeight == height {
+		if walletHeight == blueScore {
 			break
 		}
 	}
@@ -429,16 +430,24 @@ func (h *Harness) GenerateAndSubmitBlockWithCustomCoinbaseOutputs(
 		blockVersion = BlockVersion
 	}
 
-	parentBlockHash, parentBlockHeight, err := h.Node.GetBestBlock()
+	selectedTip, err := h.Node.GetSelectedTip()
 	if err != nil {
 		return nil, err
 	}
-	mBlock, err := h.Node.GetBlock(parentBlockHash, nil)
+
+	selectedTipHash, err := daghash.NewHashFromStr(selectedTip.Hash)
 	if err != nil {
 		return nil, err
 	}
+
+	selectedTipBlueScore := selectedTip.BlueScore
+	mBlock, err := h.Node.GetBlock(selectedTipHash, nil)
+	if err != nil {
+		return nil, err
+	}
+
 	parentBlock := util.NewBlock(mBlock)
-	parentBlock.SetChainHeight(parentBlockHeight)
+	parentBlock.SetChainHeight(selectedTipBlueScore)
 
 	// Create a new block including the specified transactions
 	newBlock, err := CreateBlock(parentBlock, txns, blockVersion,

integration/rpctest/utils.go

@@ -81,19 +81,26 @@ func syncBlocks(nodes []*Harness) error {
 retry:
 	for !blocksMatch {
 		var parentHash *daghash.Hash
-		var prevHeight uint64
+		var prevBlueScore uint64
 		for _, node := range nodes {
-			blockHash, blockHeight, err := node.Node.GetBestBlock()
+			selectedTip, err := node.Node.GetSelectedTip()
 			if err != nil {
 				return err
 			}
+
+			blockHash, err := daghash.NewHashFromStr(selectedTip.Hash)
+			if err != nil {
+				return err
+			}
+			blueScore := selectedTip.BlueScore
+
 			if parentHash != nil && (*blockHash != *parentHash ||
-				blockHeight != prevHeight) {
+				blueScore != prevBlueScore) {
 
 				time.Sleep(time.Millisecond * 100)
 				continue retry
 			}
-			parentHash, prevHeight = blockHash, blockHeight
+			parentHash, prevBlueScore = blockHash, blueScore
 		}
 
 		blocksMatch = true

rpcclient/dag.go

@@ -15,13 +15,13 @@ import (
 	"github.com/daglabs/btcd/wire"
 )
 
-// FutureGetBestBlockHashResult is a future promise to deliver the result of a
-// GetBestBlockAsync RPC invocation (or an applicable error).
-type FutureGetBestBlockHashResult chan *response
+// FutureGetSelectedTipHashResult is a future promise to deliver the result of a
+// GetSelectedTipAsync RPC invocation (or an applicable error).
+type FutureGetSelectedTipHashResult chan *response
 
 // Receive waits for the response promised by the future and returns the hash of
 // the best block in the longest block dag.
-func (r FutureGetBestBlockHashResult) Receive() (*daghash.Hash, error) {
+func (r FutureGetSelectedTipHashResult) Receive() (*daghash.Hash, error) {
 	res, err := receiveFuture(r)
 	if err != nil {
 		return nil, err
@@ -36,20 +36,20 @@ func (r FutureGetBestBlockHashResult) Receive() (*daghash.Hash, error) {
 	return daghash.NewHashFromStr(txHashStr)
 }
 
-// GetBestBlockHashAsync returns an instance of a type that can be used to get
+// GetSelectedTipHashAsync returns an instance of a type that can be used to get
 // the result of the RPC at some future time by invoking the Receive function on
 // the returned instance.
 //
-// See GetBestBlockHash for the blocking version and more details.
-func (c *Client) GetBestBlockHashAsync() FutureGetBestBlockHashResult {
-	cmd := btcjson.NewGetBestBlockHashCmd()
+// See GetSelectedTipHash for the blocking version and more details.
+func (c *Client) GetSelectedTipHashAsync() FutureGetSelectedTipHashResult {
+	cmd := btcjson.NewGetSelectedTipHashCmd()
 	return c.sendCmd(cmd)
 }
 
-// GetBestBlockHash returns the hash of the best block in the longest block
-// dag.
-func (c *Client) GetBestBlockHash() (*daghash.Hash, error) {
-	return c.GetBestBlockHashAsync().Receive()
+// GetSelectedTipHash returns the hash of the selected tip of the
+// Block DAG.
+func (c *Client) GetSelectedTipHash() (*daghash.Hash, error) {
+	return c.GetSelectedTipHashAsync().Receive()
 }
 
 // FutureGetBlockResult is a future promise to deliver the result of a

rpcclient/extensions.go

@@ -62,52 +62,87 @@ func (c *Client) DebugLevel(levelSpec string) (string, error) {
 	return c.DebugLevelAsync(levelSpec).Receive()
 }
 
-// FutureGetBestBlockResult is a future promise to deliver the result of a
-// GetBestBlockAsync RPC invocation (or an applicable error).
-type FutureGetBestBlockResult chan *response
+// FutureGetSelectedTipResult is a future promise to deliver the result of a
+// GetSelectedTipAsync RPC invocation (or an applicable error).
+type FutureGetSelectedTipResult chan *response
 
-// Receive waits for the response promised by the future and returns the hash
-// and height of the block in the longest (best) chain.
-func (r FutureGetBestBlockResult) Receive() (*daghash.Hash, uint64, error) {
+// Receive waits for the response promised by the future and returns the
+// selected tip block.
+func (r FutureGetSelectedTipResult) Receive() (*wire.MsgBlock, error) {
 	res, err := receiveFuture(r)
 	if err != nil {
-		return nil, 0, err
+		return nil, err
 	}
 
-	// Unmarshal result as a getbestblock result object.
-	var bestBlock btcjson.GetBestBlockResult
-	err = json.Unmarshal(res, &bestBlock)
+	// Unmarshal result as a string.
+	var blockHex string
+	err = json.Unmarshal(res, &blockHex)
 	if err != nil {
-		return nil, 0, err
+		return nil, err
 	}
 
-	// Convert to hash from string.
-	hash, err := daghash.NewHashFromStr(bestBlock.Hash)
+	// Decode the serialized block hex to raw bytes.
+	serializedBlock, err := hex.DecodeString(blockHex)
 	if err != nil {
-		return nil, 0, err
+		return nil, err
 	}
 
-	return hash, bestBlock.Height, nil
+	// Deserialize the block and return it.
+	var msgBlock wire.MsgBlock
+	err = msgBlock.Deserialize(bytes.NewReader(serializedBlock))
+	if err != nil {
+		return nil, err
+	}
+	return &msgBlock, nil
 }
 
-// GetBestBlockAsync returns an instance of a type that can be used to get the
+// GetSelectedTipAsync returns an instance of a type that can be used to get the
 // result of the RPC at some future time by invoking the Receive function on the
 // returned instance.
 //
-// See GetBestBlock for the blocking version and more details.
+// See GetSelectedTip for the blocking version and more details.
 //
 // NOTE: This is a btcd extension.
-func (c *Client) GetBestBlockAsync() FutureGetBestBlockResult {
-	cmd := btcjson.NewGetBestBlockCmd()
+func (c *Client) GetSelectedTipAsync() FutureGetSelectedTipResult {
+	cmd := btcjson.NewGetSelectedTipCmd(btcjson.Bool(false), btcjson.Bool(false))
 	return c.sendCmd(cmd)
 }
 
-// GetBestBlock returns the hash and height of the block in the longest (best)
-// chain.
-//
+// GetSelectedTip returns the block of the selected DAG tip
 // NOTE: This is a btcd extension.
-func (c *Client) GetBestBlock() (*daghash.Hash, uint64, error) {
-	return c.GetBestBlockAsync().Receive()
+func (c *Client) GetSelectedTip() (*btcjson.GetBlockVerboseResult, error) {
+	return c.GetSelectedTipVerboseAsync().Receive()
+}
+
+// FutureGetSelectedTipVerboseResult is a future promise to deliver the result of a
+// GetSelectedTipVerboseAsync RPC invocation (or an applicable error).
+type FutureGetSelectedTipVerboseResult chan *response
+
+// Receive waits for the response promised by the future and returns the data
+// structure from the server with information about the requested block.
+func (r FutureGetSelectedTipVerboseResult) Receive() (*btcjson.GetBlockVerboseResult, error) {
+	res, err := receiveFuture(r)
+	if err != nil {
+		return nil, err
+	}
+
+	// Unmarshal the raw result into a BlockResult.
+	var blockResult btcjson.GetBlockVerboseResult
+	err = json.Unmarshal(res, &blockResult)
+	if err != nil {
+		return nil, err
+	}
+	return &blockResult, nil
+}
+
+// GetSelectedTipVerboseAsync returns an instance of a type that can be used to get
+// the result of the RPC at some future time by invoking the Receive function on
+// the returned instance.
+//
+// See GeSelectedTipBlockVerbose for the blocking version and more details.
+func (c *Client) GetSelectedTipVerboseAsync() FutureGetSelectedTipVerboseResult {
+	cmd := btcjson.NewGetSelectedTipCmd(btcjson.Bool(true), btcjson.Bool(false))
+	return c.sendCmd(cmd)
 }
 
 // FutureGetCurrentNetResult is a future promise to deliver the result of a

server/rpc/handle_get_best_block.go

@@ -1,15 +0,0 @@
-package rpc
-
-import "github.com/daglabs/btcd/btcjson"
-
-// handleGetBestBlock implements the getBestBlock command.
-func handleGetBestBlock(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
-	// All other "get block" commands give either the height, the
-	// hash, or both but require the block SHA.  This gets both for
-	// the best block.
-	result := &btcjson.GetBestBlockResult{
-		Hash:   s.cfg.DAG.SelectedTipHash().String(),
-		Height: s.cfg.DAG.ChainHeight(), //TODO: (Ori) This is probably wrong. Done only for compilation
-	}
-	return result, nil
-}

server/rpc/handle_get_best_block_hash.go

@@ -1,6 +0,0 @@
-package rpc
-
-// handleGetBestBlockHash implements the getBestBlockHash command.
-func handleGetBestBlockHash(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
-	return s.cfg.DAG.SelectedTipHash().String(), nil
-}

server/rpc/handle_get_block.go

@@ -80,8 +80,8 @@ func handleGetBlock(s *Server, cmd interface{}, closeChan <-chan struct{}) (inte
 		}
 	}
 
-	// When the verbose flag isn't set, simply return the serialized block
-	// as a hex-encoded string.
+	// When the verbose flag is set to false, simply return the serialized block
+	// as a hex-encoded string (verbose flag is on by default).
 	if c.Verbose != nil && !*c.Verbose {
 		return hex.EncodeToString(blkBytes), nil
 	}

server/rpc/handle_get_selected_tip.go

@@ -0,0 +1,46 @@
+package rpc
+
+import (
+	"encoding/hex"
+	"github.com/daglabs/btcd/btcjson"
+	"github.com/daglabs/btcd/database"
+	"github.com/daglabs/btcd/util"
+)
+
+// handleGetSelectedTip implements the getSelectedTip command.
+func handleGetSelectedTip(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
+	getSelectedTipCmd := cmd.(*btcjson.GetSelectedTipCmd)
+	selectedTipHash := s.cfg.DAG.SelectedTipHash()
+
+	var blockBytes []byte
+	err := s.cfg.DB.View(func(dbTx database.Tx) error {
+		var err error
+		blockBytes, err = dbTx.FetchBlock(selectedTipHash)
+		return err
+	})
+	if err != nil {
+		return nil, &btcjson.RPCError{
+			Code:    btcjson.ErrRPCBlockNotFound,
+			Message: "Block not found",
+		}
+	}
+
+	// When the verbose flag is set to false, simply return the serialized block
+	// as a hex-encoded string (verbose flag is on by default).
+	if getSelectedTipCmd.Verbose != nil && !*getSelectedTipCmd.Verbose {
+		return hex.EncodeToString(blockBytes), nil
+	}
+
+	// Deserialize the block.
+	blk, err := util.NewBlockFromBytes(blockBytes)
+	if err != nil {
+		context := "Failed to deserialize block"
+		return nil, internalRPCError(err.Error(), context)
+	}
+
+	blockVerboseResult, err := buildGetBlockVerboseResult(s, blk, getSelectedTipCmd.VerboseTx == nil || !*getSelectedTipCmd.VerboseTx)
+	if err != nil {
+		return nil, err
+	}
+	return blockVerboseResult, nil
+}

server/rpc/handle_get_selected_tip_hash.go

@@ -0,0 +1,6 @@
+package rpc
+
+// handleGetSelectedTipHash implements the getSelectedTipHash command.
+func handleGetSelectedTipHash(s *Server, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
+	return s.cfg.DAG.SelectedTipHash().String(), nil
+}

server/rpc/handle_get_tx_out.go

@@ -22,7 +22,7 @@ func handleGetTxOut(s *Server, cmd interface{}, closeChan <-chan struct{}) (inte
 
 	// If requested and the tx is available in the mempool try to fetch it
 	// from there, otherwise attempt to fetch from the block database.
-	var bestBlockHash string
+	var selectedTipHash string
 	var confirmations *uint64
 	var value uint64
 	var scriptPubKey []byte
@@ -56,7 +56,7 @@ func handleGetTxOut(s *Server, cmd interface{}, closeChan <-chan struct{}) (inte
 			return nil, internalRPCError(errStr, "")
 		}
 
-		bestBlockHash = s.cfg.DAG.SelectedTipHash().String()
+		selectedTipHash = s.cfg.DAG.SelectedTipHash().String()
 		value = txOut.Value
 		scriptPubKey = txOut.ScriptPubKey
 		isCoinbase = mtx.IsCoinBase()
@@ -86,7 +86,7 @@ func handleGetTxOut(s *Server, cmd interface{}, closeChan <-chan struct{}) (inte
 			confirmations = &txConfirmations
 		}
 
-		bestBlockHash = s.cfg.DAG.SelectedTipHash().String()
+		selectedTipHash = s.cfg.DAG.SelectedTipHash().String()
 		value = entry.Amount()
 		scriptPubKey = entry.ScriptPubKey()
 		isCoinbase = entry.IsCoinbase()
@@ -108,7 +108,7 @@ func handleGetTxOut(s *Server, cmd interface{}, closeChan <-chan struct{}) (inte
 	}
 
 	txOutReply := &btcjson.GetTxOutResult{
-		BestBlock:     bestBlockHash,
+		SelectedTip:   selectedTipHash,
 		Confirmations: confirmations,
 		IsInMempool:   isInMempool,
 		Value:         util.Amount(value).ToBTC(),

server/rpc/rpcserver.go

@@ -66,8 +66,8 @@ var rpcHandlersBeforeInit = map[string]commandHandler{
 	"decodeScript":          handleDecodeScript,
 	"generate":              handleGenerate,
 	"getAllManualNodesInfo": handleGetAllManualNodesInfo,
-	"getBestBlock":          handleGetBestBlock,
-	"getBestBlockHash":      handleGetBestBlockHash,
+	"getSelectedTip":        handleGetSelectedTip,
+	"getSelectedTipHash":    handleGetSelectedTipHash,
 	"getBlock":              handleGetBlock,
 	"getBlocks":             handleGetBlocks,
 	"getBlockDagInfo":       handleGetBlockDAGInfo,
@@ -140,8 +140,8 @@ var rpcLimited = map[string]struct{}{
 	"createRawTransaction":  {},
 	"decodeRawTransaction":  {},
 	"decodeScript":          {},
-	"getBestBlock":          {},
-	"getBestBlockHash":      {},
+	"getSelectedTip":        {},
+	"getSelectedTipHash":    {},
 	"getBlock":              {},
 	"getBlocks":             {},
 	"getBlockCount":         {},

server/rpc/rpcserverhelp.go

@@ -149,17 +149,22 @@ var helpDescsEnUS = map[string]string{
 	"getManualNodeInfo--condition1": "details=true",
 	"getManualNodeInfo--result0":    "List of added peers",
 
-	// GetBestBlockResult help.
-	"getBestBlockResult-hash":   "Hex-encoded bytes of the best block hash",
-	"getBestBlockResult-height": "Height of the best block",
+	// GetSelectedTipResult help.
+	"getSelectedTipResult-hash":   "Hex-encoded bytes of the best block hash",
+	"getSelectedTipResult-height": "Height of the best block",
 
-	// GetBestBlockCmd help.
-	"getBestBlock--synopsis": "Get block height and hash of best block in the main chain.",
-	"getBestBlock--result0":  "Get block height and hash of best block in the main chain.",
+	// GetSelectedTipCmd help.
+	"getSelectedTip--synopsis":   "Returns information about the selected tip of the blockDAG.",
+	"getSelectedTip-verbose":     "Specifies the block is returned as a JSON object instead of hex-encoded string",
+	"getSelectedTip-verboseTx":   "Specifies that each transaction is returned as a JSON object and only applies if the verbose flag is true (btcd extension)",
+	"getSelectedTip--condition0": "verbose=false",
+	"getSelectedTip--condition1": "verbose=true",
+	"getSelectedTip-acceptedTx":  "Specifies if the transaction got accepted",
+	"getSelectedTip--result0":    "Hex-encoded bytes of the serialized block",
 
-	// GetBestBlockHashCmd help.
-	"getBestBlockHash--synopsis": "Returns the hash of the of the best (most recent) block in the longest block chain.",
-	"getBestBlockHash--result0":  "The hex-encoded block hash",
+	// GetSelectedTipHashCmd help.
+	"getSelectedTipHash--synopsis": "Returns the hash of the of the selected tip of the blockDAG.",
+	"getSelectedTipHash--result0":  "The hex-encoded block hash",
 
 	// GetBlockCmd help.
 	"getBlock--synopsis":   "Returns information about a block given its hash.",
@@ -519,7 +524,7 @@ var helpDescsEnUS = map[string]string{
 	"getSubnetworkResult-gasLimit": "The gas limit of the subnetwork",
 
 	// GetTxOutResult help.
-	"getTxOutResult-bestBlock":     "The block hash that contains the transaction output",
+	"getTxOutResult-selectedTip":   "The block hash that contains the transaction output",
 	"getTxOutResult-confirmations": "The number of confirmations (Will be 'null' if txindex is not disabled)",
 	"getTxOutResult-isInMempool":   "Whether the transaction is in the mempool",
 	"getTxOutResult-value":         "The transaction amount in BTC",
@@ -675,8 +680,8 @@ var rpcResultTypes = map[string][]interface{}{
 	"decodeScript":          {(*btcjson.DecodeScriptResult)(nil)},
 	"generate":              {(*[]string)(nil)},
 	"getAllManualNodesInfo": {(*[]string)(nil), (*[]btcjson.GetManualNodeInfoResult)(nil)},
-	"getBestBlock":          {(*btcjson.GetBestBlockResult)(nil)},
-	"getBestBlockHash":      {(*string)(nil)},
+	"getSelectedTip":        {(*btcjson.GetBlockVerboseResult)(nil)},
+	"getSelectedTipHash":    {(*string)(nil)},
 	"getBlock":              {(*string)(nil), (*btcjson.GetBlockVerboseResult)(nil)},
 	"getBlocks":             {(*btcjson.GetBlocksResult)(nil)},
 	"getBlockCount":         {(*int64)(nil)},