如何告诉Golang Gob编码可以序列化包含没有导出字段的结构的结构

Question

I believe this is a legitimate use case for Gob serialization. Yet enc.Encode returns an error because Something has no exported field. Note that I’m not serializing Something directly but only Composed that contains exported fields.

The only workaround I’ve found was to add a Dummy (exported) value to Something. This is ugly. Is there a more elegant solution?

https://play.golang.org/p/0pL6BfBb78m

package main

import (
    "bytes"
    "encoding/gob"
)

type Something struct {
    temp int
}

func (*Something) DoSomething() {}

type Composed struct {
    Something
    DataToSerialize int
}

func main() {
    enc := gob.NewEncoder(&bytes.Buffer{})
    err := enc.Encode(Composed{})
    if err != nil {
        panic(err)
    }
}

Answer 1

Here are some different workarounds from that proposed in the question.

Don't use embedding.

type Composed struct {
    something       Something
    DataToSerialize int
}

func (c *Composed) DoSomething() { c.something.DoSomething() }

playground example

Implement GobDecoder and GobEncoder

func (*Something) GobDecode([]byte) error     { return nil }
func (Something) GobEncode() ([]byte, error) { return nil, nil }

playground example