hyperledger fabric 测试（六）1.15链码API

1．新建并进入链码存储文件夹：mkdir -p $GOPATH/src/sacc && cd $GOPATH/src/sacc

编写智能合约vim saac.go：

package main                      //go语言主包开始

import (                          // 引入库

    "fmt"                        //第一个为自身的库，作为输出显示

 

    "github.com/hyperledger/fabric/core/chaincode/shim"   //引入shim接口库，fabric专有

    "github.com/hyperledger/fabric/protos/peer"     //引入节点数据流库，处理节点的数据

)

 

// SimpleAsset implements a simple chaincode to manage an asset 定义资产结构

type SimpleAsset struct {

}

 

// Init is called during chaincode instantiation to initialize any

// data. Note that chaincode upgrade also calls this function to reset

// or to migrate data. 实例化时初始化函数。必须有

func (t *SimpleAsset) Init(stub shim.ChaincodeStubInterface) peer.Response { //调用接口，获得参数

    // Get the args from the transaction proposal

    args := stub.GetStringArgs()                //获得API上传的参数

    if len(args) != 2 {                         //如果参数不为两个报错，通过接口显示错误

            return shim.Error("Incorrect arguments. Expecting a key and a value")

    }

 

    // Set up any variables or assets here by calling stub.PutState()

 

    // We store the key and the value on the ledger

    err := stub.PutState(args[0], []byte(args[1]))    //将获得的数据写入账本，同时如果发生错误，则收集发生错误

    if err != nil {                           //如果发生错误就显示错误和参数

            return shim.Error(fmt.Sprintf("Failed to create asset: %s", args[0]))

    }

    return shim.Success(nil)         //返回成功初始化

}

 

// Invoke is called per transaction on the chaincode. Each transaction is

// either a 'get' or a 'set' on the asset created by Init function. The Set

// method may create a new asset by specifying a new key-value pair.

func (t *SimpleAsset) Invoke(stub shim.ChaincodeStubInterface) peer.Response { //通过接口获取参数

    // Extract the function and args from the transaction proposal

    fn, args := stub.GetFunctionAndParameters()  //通过接口，调用getfunc获取参数函数名，具体参数

 

    var result string

    var err error

    if fn == "set" {               //如果函数名为set，调用set函数，上传参数

            result, err = set(stub, args)

    } else { // assume 'get' even if fn is nil  //否则，调用get函数

            result, err = get(stub, args)  

    }

    if err != nil {                            //如果有错误，则发出错误

            return shim.Error(err.Error())

    }

 

    // Return the result as success payload

    return shim.Success([]byte(result))      //返回调用成功

}

 

// Set stores the asset (both key and value) on the ledger. If the key exists,

// it will override the value with the new one

func set(stub shim.ChaincodeStubInterface, args []string) (string, error) { //将2个键值对上传至账本

    if len(args) != 2 {                          //如果参数个数不为2，则报错

            return "", fmt.Errorf("Incorrect arguments. Expecting a key and a value")

    }

 

    err := stub.PutState(args[0], []byte(args[1]))  //键值对上传至账本，如果报错收集错误

    if err != nil {

            return "", fmt.Errorf("Failed to set asset: %s", args[0])

    }

    return args[1], nil

}

 

// Get returns the value of the specified asset key

func get(stub shim.ChaincodeStubInterface, args []string) (string, error) {  //通过接口获得参数

    if len(args) != 1 {

            return "", fmt.Errorf("Incorrect arguments. Expecting a key")

    }

 

    value, err := stub.GetState(args[0])         //账本中寻找数据，同时收集错误

    if err != nil {

            return "", fmt.Errorf("Failed to get asset: %s with error: %s", args[0], err)

    }

    if value == nil {

            return "", fmt.Errorf("Asset not found: %s", args[0])

    }

    return string(value), nil

}

 

// main function starts up the chaincode in the container during instantiate

func main() {                                              //主函数，价值结构完整

    if err := shim.Start(new(SimpleAsset)); err != nil {

            fmt.Printf("Error starting SimpleAsset chaincode: %s", err)

    }

}

2.编译智能合约准备：go get -u --tags nopkcs11 github.com/hyperledger/fabric/core/chaincode/shim

go build --tags nopkcs11

进入编译和测试demo: cd chaincode-docker-devmode

在此目录下新建三个终端

同时T1下载镜像：docker-compose -f docker-compose-simple.yaml up

T2进入测试程序容器：docker exec -it chaincode bash

进入合约文件夹：cd sacc

编译智能合约：go build

对等节点运行链码：CORE_PEER_ADDRESS=peer:7052 CORE_CHAINCODE_ID_NAME=mycc:0 ./sacc

进入cli容器：docker exec -it cli bash

安装程序：peer chaincode install -p chaincodedev/chaincode/sacc -n mycc -v 0

实例化在通道程序：peer chaincode instantiate -n mycc -v 0 -c '{"Args":["a","10"]}' -C myc

3.测试程序

初始化程序：peer chaincode invoke -n mycc -c '{"Args":["set", "a", "20"]}' -C myc

查询函数peer chaincode query -n mycc -c '{"Args":["query","a"]}' -C myc //query时默认的不进行账本改变的查询