Fabric020 构建一个区块链项目

47.102.201.135:8090_这是本人构建的简单的区块链项目，非常简单的一个项目；比较重要的是写好一个chaincode，看看源码的话10分钟就会了，自己编一个功能强大的chaincode，example_02这个chaincode，init之后不能再申请变量了，你需要再写一个inita用来注册变量；下面是拥有可以申请新变量的chaincode：

peer chaincode invoke -o orderer.qklszzn.com:7050 -C firstchannel -n fab -v 1.1 -c '{"Args":["inita","c","200"]}'

package main

import (
    "fmt"
    "strconv"

    "github.com/hyperledger/fabric/core/chaincode/shim"
    pb "github.com/hyperledger/fabric/protos/peer"
)

// SimpleChaincode example simple Chaincode implementation
type SimpleChaincode struct {
}

func (t *SimpleChaincode) Init(stub shim.ChaincodeStubInterface) pb.Response {
    fmt.Println("ex02 Init")
    _, args := stub.GetFunctionAndParameters()
    var A, B string    // Entities
    var Aval, Bval int // Asset holdings
    var err error

    if len(args) != 4 {
        return shim.Error("Incorrect number of arguments. Expecting 4")
    }

    // Initialize the chaincode
    A = args[0]
    Aval, err = strconv.Atoi(args[1])
    if err != nil {
        return shim.Error("Expecting integer value for asset holding")
    }
    B = args[2]
    Bval, err = strconv.Atoi(args[3])
    if err != nil {
        return shim.Error("Expecting integer value for asset holding")
    }
    fmt.Printf("Aval = %d, Bval = %d\n", Aval, Bval)

    // Write the state to the ledger
    err = stub.PutState(A, []byte(strconv.Itoa(Aval)))
    if err != nil {
        return shim.Error(err.Error())
    }

    err = stub.PutState(B, []byte(strconv.Itoa(Bval)))
    if err != nil {
        return shim.Error(err.Error())
    }

    return shim.Success(nil)
}


func (t *SimpleChaincode) Invoke(stub shim.ChaincodeStubInterface) pb.Response {
    fmt.Println("ex02 Invoke")
    function, args := stub.GetFunctionAndParameters()
    if function == "invoke" {
        // Make payment of X units from A to B
        return t.invoke(stub, args)
    } else if function == "delete" {
        // Deletes an entity from its state
        return t.delete(stub, args)
    } else if function == "query" {
        // the old "Query" is now implemtned in invoke
        return t.query(stub, args)
    } else if function == "inita" {
        return t.inita(stub, args)
    }

    return shim.Error("Invalid invoke function name. Expecting \"invoke\" \"delete\" \"query\" \"inita\"")
}

// Transaction makes payment of X units from A to B
func (t *SimpleChaincode) invoke(stub shim.ChaincodeStubInterface, args []string) pb.Response {
    var A, B string    // Entities
    var Aval, Bval int // Asset holdings
    var X int          // Transaction value
    var err error

    if len(args) != 3 {
        return shim.Error("Incorrect number of arguments. Expecting 3")
    }

    A = args[0]
    B = args[1]

    // Get the state from the ledger
    // TODO: will be nice to have a GetAllState call to ledger
    Avalbytes, err := stub.GetState(A)
    if err != nil {
        return shim.Error("Failed to get state")
    }
    if Avalbytes == nil {
        return shim.Error("Entity not found")
    }
    Aval, _ = strconv.Atoi(string(Avalbytes))

    Bvalbytes, err := stub.GetState(B)
    if err != nil {
        return shim.Error("Failed to get state")
    }
    if Bvalbytes == nil {
        return shim.Error("Entity not found")
    }
    Bval, _ = strconv.Atoi(string(Bvalbytes))

    // Perform the execution
    X, err = strconv.Atoi(args[2])
    if err != nil {
        return shim.Error("Invalid transaction amount, expecting a integer value")
    }
    Aval = Aval - X
    Bval = Bval + X
    fmt.Printf("Aval = %d, Bval = %d\n", Aval, Bval)

    // Write the state back to the ledger
    err = stub.PutState(A, []byte(strconv.Itoa(Aval)))
    if err != nil {
        return shim.Error(err.Error())
    }

    err = stub.PutState(B, []byte(strconv.Itoa(Bval)))
    if err != nil {
        return shim.Error(err.Error())
    }

    return shim.Success(nil)
}

// Deletes an entity from state
func (t *SimpleChaincode) delete(stub shim.ChaincodeStubInterface, args []string) pb.Response {
    if len(args) != 1 {
        return shim.Error("Incorrect number of arguments. Expecting 1")
    }

    A := args[0]

    // Delete the key from the state in ledger
    err := stub.DelState(A)
    if err != nil {
        return shim.Error("Failed to delete state")
    }

    return shim.Success(nil)
}

// query callback representing the query of a chaincode
func (t *SimpleChaincode) query(stub shim.ChaincodeStubInterface, args []string) pb.Response {
    var A string // Entities
    var err error

    if len(args) != 1 {
        return shim.Error("Incorrect number of arguments. Expecting name of the person to query")
    }

    A = args[0]

    // Get the state from the ledger
    Avalbytes, err := stub.GetState(A)
    if err != nil {
        jsonResp := "{\"Error\":\"Failed to get state for " + A + "\"}"
        return shim.Error(jsonResp)
    }

    if Avalbytes == nil {
        jsonResp := "{\"Error\":\"Nil amount for " + A + "\"}"
        return shim.Error(jsonResp)
    }

    jsonResp := "{\"Name\":\"" + A + "\",\"Amount\":\"" + string(Avalbytes) + "\"}"
    fmt.Printf("Query Response:%s\n", jsonResp)
    return shim.Success(Avalbytes)
}


func (t *SimpleChaincode) inita(stub shim.ChaincodeStubInterface, args []string) pb.Response {
    var A string    // Entities
    var Aval int // Asset holdings
    var err error

    if len(args) != 2 {
        return shim.Error("Incorrect number of arguments. Expecting 2")
    }

    A = args[0]

    // Perform the execution
    Aval, err = strconv.Atoi(args[1])
    if err != nil {
        return shim.Error("Invalid transaction amount, expecting a integer value")
    }
    fmt.Printf("Aval = %d\n", Aval)
    // Write the state back to the ledger
    err = stub.PutState(A, []byte(strconv.Itoa(Aval)))
    if err != nil {
        return shim.Error(err.Error())
    }

    return shim.Success(nil)
}

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