go - 安装链码后尝试查询状态数据库时出现Hyperledger错误

Question

这只是我的chaincod包的一部分，但是我使用ListDoctorPermissions函数查询 Assets 后的状态数据库，在我的情况下是对以下结构的许可:

type Permission struct {
    PermissionId    string `json:"permissionId"`
    DataCategory    string `json:"dataCategory"`
    PatientId       string `json:"patientId"`
    DoctorId        string `json:"doctorId"`
    Right           string `json:"right"`
    From            string `json:"from"`
    To              string `json:"to"`
}

在部署链码的过程中，我在最后运行查询以测试链码，但出现错误:

Error: endorsement failure during query. response: status:500 message:"Error handling success response. Value did not match schema:\n1. return: Invalid type. Expected: array, given: string" 

这就是我调用链码的方式:

peer chaincode query -C mychannel -n permissions -c '{"Args":["ListDoctorPermissions", "doctor1"]}'

在运行查询之前，我在DoctorId为“doctor1”的状态数据库中创建了一个权限，因此在数据库(couchDB)中找到CompositeKey和条目应该没有问题。

// List all Permissions given to a doctor
func (s *SmartContract) ListDoctorPermissions(ctx contractapi.TransactionContextInterface, doctorId string) ([]byte, error) {
    doctorIterator, err := ctx.GetStub().GetStateByPartialCompositeKey("permissionId", []string{doctorId})
    if err != nil {
        return nil, err
    }
    fmt.Printf("the doctor Iterator is: %s", doctorIterator)

    defer doctorIterator.Close()

    var dataCategory string
    var patientId string
    var permissionId string

    var permissions []byte
    bArrayPermissionAlreadyWritten := false

    for doctorIterator.HasNext() {
        responseRange, err := doctorIterator.Next()
        if err != nil {
            return nil, err
        }

        objectType, compositeKeyParts, err := ctx.GetStub().SplitCompositeKey(responseRange.Key)
        if err != nil {
            return nil, err
        }
        fmt.Printf("the objectType is: %s", objectType)

        dataCategory = compositeKeyParts[1]
        patientId = compositeKeyParts[2]
        permissionId = doctorId + dataCategory + patientId
        fmt.Printf("the compositeKeyParts are: %s", compositeKeyParts[0], compositeKeyParts[1], compositeKeyParts[2])

        permissionAsBytes, err := ctx.GetStub().GetState(permissionId)
        if err != nil {
            return nil, err
        }

        if bArrayPermissionAlreadyWritten == true {
            newBytes := append([]byte(","), permissionAsBytes...)
            permissions = append(permissions, newBytes...)
        } else {
            permissions = append(permissions, permissionAsBytes...)
            fmt.Print(permissions)
        }

        fmt.Printf("Found a asset for index : %s asset id : ", objectType, compositeKeyParts[0], compositeKeyParts[1], compositeKeyParts[2])
        bArrayPermissionAlreadyWritten = true

    }

    permissions = append(permissions, []byte("]")...)
    fmt.Print(permissions)
    return permissions, nil
}

Answer 1

我已经运行了上面提供的代码，您的评论正确，该问题似乎源于使用[]byte作为返回类型。我不完全确定为什么会发生这种情况，因为那应该是有效的返回类型。我将对此进行进一步的研究，因为这可能是一个错误。
通过将返回类型转换为string并返回string(permissions)，我能够正确返回数据
在执行此操作时，我注意到您的代码正在基于getState字节构建字节数组。因此，另一个选择是将get状态调用中​​的字节json.Unmarshal到Permission结构中，并将其附加到数组中。然后，您可以将返回类型设为[]Permission。
我现在建议您采用字符串或Permission数组方法，因为我将不得不研究使用[]byte作为返回类型会发生什么情况。
例子:
字符串:

// List all Permissions given to a doctor
func (s *SmartContract) ListDoctorPermissions(ctx contractapi.TransactionContextInterface, doctorId string) (string, error) {
    doctorIterator, err := ctx.GetStub().GetStateByPartialCompositeKey("permissionId", []string{doctorId})
    if err != nil {
        return "", err
    }
    fmt.Printf("the doctor Iterator is: %s", doctorIterator)

    defer doctorIterator.Close()

    var dataCategory string
    var patientId string
    var permissionId string

    var permissions []byte
    bArrayPermissionAlreadyWritten := false

    for doctorIterator.HasNext() {
        responseRange, err := doctorIterator.Next()
        if err != nil {
            return "", err
        }

        objectType, compositeKeyParts, err := ctx.GetStub().SplitCompositeKey(responseRange.Key)
        if err != nil {
            return "", err
        }
        fmt.Printf("the objectType is: %s", objectType)

        dataCategory = compositeKeyParts[1]
        patientId = compositeKeyParts[2]
        permissionId = doctorId + dataCategory + patientId
        fmt.Printf("the compositeKeyParts are: %s", compositeKeyParts[0], compositeKeyParts[1], compositeKeyParts[2])

        permissionAsBytes, err := ctx.GetStub().GetState(permissionId)
        if err != nil {
            return "", err
        }

        if bArrayPermissionAlreadyWritten == true {
            newBytes := append([]byte(","), permissionAsBytes...)
            permissions = append(permissions, newBytes...)
        } else {
            permissions = append(permissions, permissionAsBytes...)
            fmt.Print(permissions)
        }

        fmt.Printf("Found a asset for index : %s asset id : ", objectType, compositeKeyParts[0], compositeKeyParts[1], compositeKeyParts[2])
        bArrayPermissionAlreadyWritten = true

    }

    permissions = append(permissions, []byte("]")...)
    fmt.Print(permissions)
    return string(permissions), nil
}

[]允许:

// List all Permissions given to a doctor
func (s *SmartContract) ListDoctorPermissions(ctx contractapi.TransactionContextInterface, doctorId string) ([]Permission, error) {
    doctorIterator, err := ctx.GetStub().GetStateByPartialCompositeKey("permissionId", []string{doctorId})
    if err != nil {
        return nil, err
    }
    fmt.Printf("the doctor Iterator is: %s", doctorIterator)

    defer doctorIterator.Close()

    var dataCategory string
    var patientId string
    var permissionId string

    var permissions []Permission

    for doctorIterator.HasNext() {
        responseRange, err := doctorIterator.Next()
        if err != nil {
            return nil, err
        }

        objectType, compositeKeyParts, err := ctx.GetStub().SplitCompositeKey(responseRange.Key)
        if err != nil {
            return nil, err
        }
        fmt.Printf("the objectType is: %s", objectType)

        dataCategory = compositeKeyParts[1]
        patientId = compositeKeyParts[2]
        permissionId = doctorId + dataCategory + patientId
        fmt.Printf("the compositeKeyParts are: %s", compositeKeyParts[0], compositeKeyParts[1], compositeKeyParts[2])

        permissionAsBytes, err := ctx.GetStub().GetState(permissionId)
        if err != nil {
            return nil, err
        }

        foundPermission := new(Permission)

        err = json.Unmarshal(permissionAsBytes, foundPermission)

        if err != nil {
            return nil, err
        }

        permissions = append(permissions, *foundPermission)
    }

    fmt.Printf("Permissions %v", permissions)

    return permissions, nil
}