added show amount API to blockchain node

blockchain/blockchain.go

@@ -169,3 +169,15 @@ func (bc *Blockchain) CalculateTotalAmount(blockchainAddress string) float32 {
  }
  return totalAmount
 }
+
+type AmountResponse struct {
+ Amount float32 `json:"amount"`
+}
+
+func (ar *AmountResponse) MarshalJSON() ([]byte, error) {
+ return json.Marshal(struct {
+ Amount float32 `json:"amount"`
+ }{
+ Amount: ar.Amount,
+ })
+}

blockchain_node/blockchain_node.go

@@ -141,11 +141,29 @@ func (bcn *BlockchainNode) StartMine(w http.ResponseWriter, r *http.Request) {
  }
 }
 
+func (bcn *BlockchainNode) Amount(w http.ResponseWriter, r *http.Request) {
+ switch r.Method {
+ case http.MethodGet:
+ blockchainAddress := r.URL.Query().Get("blockchain_address")
+ amount := bcn.GetBlockchain().CalculateTotalAmount(blockchainAddress)
+
+ ar := &block.AmountResponse{Amount: amount}
+ m, _ := ar.MarshalJSON()
+
+ w.Header().Add("Content-Type", "application/json")
+ io.WriteString(w, string(m[:]))
+ default:
+ log.Println("ERROR: Invalid HTTP method")
+ w.WriteHeader(http.StatusBadRequest)
+ }
+}
+
 func (bcn *BlockchainNode) Run() {
  http.HandleFunc("/", bcn.GetChain)
  http.HandleFunc("/transactions", bcn.Transactions)
  http.HandleFunc("/mine", bcn.Mine)
  http.HandleFunc("/mine/start", bcn.StartMine)
+ http.HandleFunc("/amount", bcn.Amount)
 
  log.Fatal(http.ListenAndServe("0.0.0.0:"+strconv.Itoa(int(bcn.Port())), nil))
 }