package main
import (
"bytes"
"fmt"
"github.com/hyperledger/fabric/core/chaincode/shim"
pb "github.com/hyperledger/fabric/protos/peer"
)
//Chaincode implementation
type SimpleChaincode struct {
}
// ===================================================================================
// Main
// ===================================================================================
func main() {
err := shim.Start(new(SimpleChaincode))
if err != nil {
fmt.Printf("Error starting Simple chaincode: %s", err)
}
}
// Init initializes chaincode
// ===========================
func (t *SimpleChaincode) Init(stub shim.ChaincodeStubInterface) pb.Response {
return shim.Success(nil)
}
// Invoke - Our entry point for Invocations
// ========================================
func (t *SimpleChaincode) Invoke(stub shim.ChaincodeStubInterface) pb.Response {
function, args := stub.GetFunctionAndParameters()
fmt.Printf("function: %s,args: %s\n", function, args)
// Handle different functions
if function == "save" { //create a new marble
return t.save(stub, args)
} else if function == "query" { //find Data based on an ad hoc rich query
return t.query(stub, args)
}
fmt.Println("invoke did not find func: " + function) //error
return shim.Error("Received unknown function invocation")
}
// ============================================================
// - create a new data, store into chaincode state
// ============================================================
func (t *SimpleChaincode) save(stub shim.ChaincodeStubInterface, args []string) pb.Response {
if len(args) != 2 {
return shim.Error("Incorrect number of arguments. Expecting 2")
}
err := stub.PutState(args[0], []byte(args[1]))
if err != nil {
return shim.Error(err.Error())
}
fmt.Println("- end save business")
return shim.Success(nil)
}
// ===== Add hoc rich query ========================================================
// query method uses a query string to perform a query for data.
// Query string matching state database syntax is passed in and executed as is.
// Supports ad hoc queries that can be defined at runtime by the client.
// Only available on state databases that support rich query (e.g. CouchDB)
// =========================================================================================
func (t *SimpleChaincode) query(stub shim.ChaincodeStubInterface, args []string) pb.Response {
// 0
// "queryString"
if len(args) < 1 {
return shim.Error("Incorrect number of arguments. Expecting 1")
}
queryString := args[0]
queryResults, err := getQueryResultForQueryString(stub, queryString)
if err != nil {
return shim.Error(err.Error())
}
return shim.Success(queryResults)
}
// =========================================================================================
// getQueryResultForQueryString executes the passed in query string.
// Result set is built and returned as a byte array containing the JSON results.
// =========================================================================================
func getQueryResultForQueryString(stub shim.ChaincodeStubInterface, queryString string) ([]byte, error) {
fmt.Printf("- getQueryResultForQueryString queryString:\n%s\n", queryString)
resultsIterator, err := stub.GetQueryResult(queryString)
if err != nil {
return nil, err
}
defer resultsIterator.Close()
// buffer is a JSON array containing QueryRecords
var buffer bytes.Buffer
buffer.WriteString("[")
bArrayMemberAlreadyWritten := false
for resultsIterator.HasNext() {
queryResponse, err := resultsIterator.Next()
if err != nil {
return nil, err
}
// Add a comma before array members, suppress it for the first array member
if bArrayMemberAlreadyWritten == true {
buffer.WriteString(",")
}
buffer.WriteString("{\"Key\":")
buffer.WriteString("\"")
buffer.WriteString(queryResponse.Key)
buffer.WriteString("\"")
buffer.WriteString(", \"Record\":")
// Record is a JSON object, so we write as-is
buffer.WriteString(string(queryResponse.Value))
buffer.WriteString("}")
bArrayMemberAlreadyWritten = true
}
buffer.WriteString("]")
fmt.Printf("- getQueryResultForQueryString queryResult:\n%s\n", buffer.String())
return buffer.Bytes(), nil
}
现在我们来运行一下这个脚本文件，使用命令