go - 运行 Chaincode 程序时出错

Question

我正在我的 MacOS 上用 GO 编写链码程序。以下是代码:

package main

import (
    "encoding/json"
    "fmt"

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

//Init and Invoke
type SmartContract struct {
}

type SomeDocument struct {
    DocumentID   string `json:"docid"`
    CreatorID    string `json:"uid"`
    DocHolder    string `json:"doc_holder"`
    Location     string `json:"location"`
    DocumentType string `json:"doc_type"`
    Content      string `json:"doc_content"`
}

func (s *SmartContract) Init(APIstub shim.ChaincodeStubInterface) sc.Response {
    return shim.Success(nil)
}

func (s *SmartContract) Invoke(APIstub shim.ChaincodeStubInterface) sc.Response {

    return shim.Success(nil)
}

func main() {
    first_doc := SomeDocument{"1001", "123456789012", "ABCD EFGH", "New Delhi", "School Form", "I want to enroll in this school"}
    theJson, _ := json.Marshal(first_doc) //returns JSON encoding of first_stamp
    fmt.Printf("%+v\n", string(theJson))
    err := shim.Start(new(SmartContract))
    if err != nil {
        fmt.Printf("Error creating new Smart Document: %s", err)
    } else {
        fmt.Println("Success")
    }
}

由于这一行，它显示了以下错误，shim.Start(new(SmartContract)):

{"docid":"1001","uid":"123456789012","doc_holder":"ABCD EFGH","location":"New Delhi","doc_type":"School Form","doc_content":"I want to enroll in this school"}
    2018-04-10 23:34:41.598 IST [shim] SetupChaincodeLogging -> INFO 001 Chaincode log level not provided; defaulting to: INFO
    2018-04-10 23:34:41.598 IST [shim] SetupChaincodeLogging -> INFO 002 Chaincode (build level: ) starting up ...
    Error creating new Smart Document: error chaincode id not provided%

我找不到任何解决方案。

是否可以指定结构属性的长度限制？。例如 DocumentID 的长度应该是 10。

Answer 1

在您查看 the source 时，您会看到它在做什么

chaincodename := viper.GetString("chaincode.id.name")
if chaincodename == "" {
    return errors.New("error chaincode id not provided")
}

我相信你可以做到:

os.Setenv("chaincode.id.name", "whatever")

或

chaincode.id.name=whatever go run main.go

克服它。

至于指定属性的长度，当然可以。您要么使用具有长度的数据结构(例如 [10]byte)，要么将字段设为私有(private)并在 setter 方法中验证长度。

https://play.golang.org/p/WvG-ZWKhrZ7

package main

import (
    "fmt"
    "encoding/json"
)

type SomeDocument struct {
    DocumentID   [10]byte `json:"docid"`
    CreatorID    string `json:"uid"`
    DocHolder    string `json:"doc_holder"`
    Location     string `json:"location"`
    DocumentType string `json:"doc_type"`
    Content      string `json:"doc_content"`
}

func (s *SomeDocument) SetDocumentID(id string) {
    copy(s.DocumentID[:], []byte(id))
}

func (s SomeDocument) MarshalJSON() ([]byte, error) {
    tmp := struct {
    DocumentID   string `json:"docid"`
    CreatorID    string `json:"uid"`
    DocHolder    string `json:"doc_holder"`
    Location     string `json:"location"`
    DocumentType string `json:"doc_type"`
    Content      string `json:"doc_content"`
    }{
    string(s.DocumentID[:]),
    s.CreatorID,
    s.DocHolder,
    s.Location,
    s.DocumentType,
    s.Content,
    }
    return json.Marshal(tmp)
}

func main() {
    s := SomeDocument{}
    s.SetDocumentID("1234567890abcd")
    js, err := json.Marshal(s)
    if err != nil {
        panic(err)
    }
    fmt.Println(string(js))
    // {"docid":"1234567890","uid":"","doc_holder":"","location":"","doc_type":"","doc_content":""}

}