interface

必須實作的接口

type Chaincode interface 
{
    //初始化
    Init(stub ChaincodeStubInterface) pb.Response
    //查詢或更新 world state
    Invoke(stub ChaincodeStubInterface) pb.Response
}

撰寫範例

package main
import
(
    "errors"
    "fmt"
    "github.com/hyperledger/fabric/core/chaincode/shim"
)

type SimpleChaincode struct { }

func (t *SimpleChaincode) Init(stub shim.ChaincodeStubInterface, funcGon string, args []string) ([]byte, error) 
{ 
    //… 
}

func (t *SimpleChaincode) Invoke(stub shim.ChaincodeStubInterface, funcGon string, args []string) ([]byte, error) 
{ 
    //… 
}

func main() 
{
    err := shim.Start(new(SimpleChaincode))
    if err != nil 
    {
        fmt.Prinn("Error starGng Simple chaincode: %s", err)
    }
}

開發測試

以 fabric chaincode_example02 為例：

啟動 Orderer 節點

orderer

啟動 peer

CORE_PEER_ID=peer0 peer node start

設置 chaincode
peer chaincode install -p [鏈碼路徑] -n [檔案名稱] -v 1.0

peer chaincode install -p github.com/hyperledger/fabric/examples/chaincode/go/
chaincode_example02/ -n mycc -v 1.0

測試 chaincode：測試模式可以使用 Rest 通訊協定、而正式模式只能使用 Node.js 客戶端

• 初始化

  peer chaincode instanGate -n mycc -v 1.0 -c '{"Args": ["init", "A", "100", "B", "100"]}'
  

• 呼叫

  peer chaincode invoke -n mycc -c '{"Args":["invoke", "A", "B", "10"]}'
  

• 查詢

  peer chaincode query -n mycc -c '{"Args":["query", "A"]}'
  

API 說明

shim.ChaincodeStubInterface

• State

  GetState(key string) ([]byte, error)
  PutState(key string, value []byte) error
  DelState(key string) error
  GetStateByRange(startKey, endKey string) (StateQueryIteratorInterface, error)
  GetStateByPartialCompositeKey(objectType string, keys []string) (StateQueryIteratorInterface, error)
  GetQueryResult(query string) (StateQueryIteratorInterface, error)
  GetHistoryForKey(key string) (StateQueryIteratorInterface, error)
  CreateCompositeKey(objectType string, a,ributes []string) (string, error)
  SplitCompositeKey(compositeKey string) (string, []string, error)
  

• Arg

  GetArgs() [][]byte
  GetStringArgs() []string
  GetFuncGonAndParameters() (string, []string)
  GetArgsSlice() ([]byte, error)
  

• Transaction

  GetCreator() ([]byte, error)
  GetTransient() (map[string][]byte, error)
  GetBinding() ([]byte, error)
  GetTxTimestamp() (*Gmestamp.Timestamp, error)
  GetTxID() string
  

• Event

  SetEvent(name string, payload []byte) error
  

• Chaincode

  Start(cc Chaincode) error	//註冊 Chaincode
  InvokeChaincode(chaincodeName string, args [][]byte, channel string) pb.Response
  

• Log

  NewLogger(name string) *ChaincodeLogger	//建立 Logger
  SetLoggingLevel(level LoggingLevel)		//設定 Log 訊息輸出等級
  

參考資源

API 線上文件：
https://godoc.org/github.com/hyperledger/fabric/core/chaincode/shim

Postman Rest API 測試工具：
https://www.getpostman.com/