Detect RBF transactions in explorer and API #237

api/types.go

@@ -191,6 +191,7 @@ type Tx struct {
 	ValueInSat       *Amount           `json:"valueIn,omitempty"`
 	FeesSat          *Amount           `json:"fees,omitempty"`
 	Hex              string            `json:"hex,omitempty"`
+	Rbf              bool              `json:"rbf,omitempty"`
 	CoinSpecificData interface{}       `json:"-"`
 	CoinSpecificJSON json.RawMessage   `json:"-"`
 	TokenTransfers   []TokenTransfer   `json:"tokenTransfers,omitempty"`

api/worker.go

@@ -142,6 +142,7 @@ func (w *Worker) GetTransactionFromBchainTx(bchainTx *bchain.Tx, height uint32,
 	var valInSat, valOutSat, feesSat big.Int
 	var pValInSat *big.Int
 	vins := make([]Vin, len(bchainTx.Vin))
+	rbf := false
 	for i := range bchainTx.Vin {
 		bchainVin := &bchainTx.Vin[i]
 		vin := &vins[i]
@@ -149,6 +150,10 @@ func (w *Worker) GetTransactionFromBchainTx(bchainTx *bchain.Tx, height uint32,
 		vin.N = i
 		vin.Vout = bchainVin.Vout
 		vin.Sequence = int64(bchainVin.Sequence)
+		// detect explicit Replace-by-Fee transactions as defined by BIP125
+		if bchainTx.Confirmations == 0 && bchainVin.Sequence < 0xffffffff-1 {
+			rbf = true
+		}
 		vin.Hex = bchainVin.ScriptSig.Hex
 		vin.Coinbase = bchainVin.Coinbase
 		if w.chainType == bchain.ChainBitcoinType {
@@ -317,6 +322,7 @@ func (w *Worker) GetTransactionFromBchainTx(bchainTx *bchain.Tx, height uint32,
 		ValueOutSat:      (*Amount)(&valOutSat),
 		Version:          bchainTx.Version,
 		Hex:              bchainTx.Hex,
+		Rbf:              rbf,
 		Vin:              vins,
 		Vout:             vouts,
 		CoinSpecificData: bchainTx.CoinSpecificData,

static/templates/txdetail.html

@@ -3,6 +3,7 @@
     <div class="row line-bot">
         <div class="col-xs-7 col-md-8 ellipsis">
             <a href="/tx/{{$tx.Txid}}">{{$tx.Txid}}</a>
+            {{- if $tx.Rbf}}<span title="Replace-by-Fee (RBF) transaction, could be overriden"> ⚠️</span>{{end -}}
         </div>
         {{- if $tx.Blocktime}}<div class="col-xs-5 col-md-4 text-muted text-right">{{if $tx.Confirmations}}mined{{else}}first seen{{end}} {{formatUnixTime $tx.Blocktime}}</div>{{end -}}
     </div>