Hyperledger Fabric 2.x 中链码如何获取区块高度？

Question

我正在 Hyperledger Fabric 2.4 中进行编码。我需要查询链码中当前的块高度，但我没有找到这样的函数。我怎样才能实现这个目标？

Answer 1

Chaincode 可以使用

system chaincode

获取有关通道的信息。当区块链网络启动时，

system chaincode

是“内置”的

通道信息（包括区块高度）可以通过

QSCC

系统链码获取。

查询系统链码（QSCC）在所有节点中运行，提供账本 API，包括区块查询、交易查询等

import (
    "fmt"
    "github.com/hyperledger/fabric-chaincode-go/shim"
    pb "github.com/hyperledger/fabric-protos-go/peer"
    "github.com/golang/protobuf/proto"
    commonProto "github.com/hyperledger/fabric-protos-go/common"
)

func (t *MyChaincode) Invoke(stub shim.ChaincodeStubInterface) pb.Response {
    // ... your chaincode logic ...

    // Define the system chaincode you want to call and the arguments.
    // In this example, we'll query the block height using the "qscc" system chaincode.
    sysCC := "qscc"
    fcn := "GetChainInfo"
    channelID := "mychannel"

    // Call the system chaincode
    response := stub.InvokeChaincode(sysCC, [][]byte{[]byte(fcn), []byte(channelID)}, channelID)

    // Check the response for errors
    if response.Status != shim.OK {
        errMsg := fmt.Sprintf("Error invoking '%s' chaincode: %s", sysCC, response.Message)
        return shim.Error(errMsg)
    }

    // Process the response payload
    result := response.Payload

    // Unmarshal the response payload
    chainInfo := &commonProto.BlockchainInfo{}
    err := proto.Unmarshal(result, chainInfo)
    if err != nil {
        errMsg := fmt.Sprintf("Error unmarshaling BlockchainInfo: %s", err)
        return shim.Error(errMsg)
    }

    // Get the block height
    blockHeight := chainInfo.GetHeight()

    // ... do something with the block height

    // ... continue with your chaincode logic and return the appropriate response
}

Answer 2

感谢您的回答！我总是得到0。

线路是否正确，channelID出现了两次。

response := stub.InvokeChaincode(sysCC, [][]byte{[]byte(fcn), []byte(channelID)}, channelID)

应该是吗

response := stub.InvokeChaincode(sysCC, [][]byte{[]byte(fcn)}, channelID)