golang gob interface example

gob.go

package main

import (
	"bytes"
	"encoding/gob"
	"fmt"
)

type MyFace interface {
	A()
}

type Cat struct{}
type Dog struct{}

func (c *Cat) A() {
	fmt.Println("Meow")
}

func (d *Dog) A() {
	fmt.Println("Woof")
}

func init() {
	// This type must match exactly what youre going to be using,
	// down to whether or not its a pointer
	gob.Register(&Cat{})
	gob.Register(&Dog{})
}

func main() {
	network := new(bytes.Buffer)
	enc := gob.NewEncoder(network)

	var inter MyFace
	inter = new(Cat)

	// Note: pointer to the interface
	err := enc.Encode(&inter)
	if err != nil {
		panic(err)
	}

	inter = new(Dog)
	err = enc.Encode(&inter)
	if err != nil {
		panic(err)
	}

	// Now lets get them back out
	dec := gob.NewDecoder(network)

	var get MyFace
	err = dec.Decode(&get)
	if err != nil {
		panic(err)
	}

	// Should meow
	get.A()

	err = dec.Decode(&get)
	if err != nil {
		panic(err)
	}

	// Should woof
	get.A()

}

Hi ad, can you give some advise ?
I would like to send an image through RPC and use GOB package, What should i do ?
Thanks

"//This type must match exactly what youre going to be using,
// down to whether or not its a pointer" - fixed my issue. Thanks a lot

Thanks. This was also helpful to me, since the examples in the standard library's documentation are somewhat deficient.

Thanks. "Type must match exactly" seems an important point as it fixed my issue too.

using gob is still a pain in 2024. I tried the example in the docs, can't decode image.NRGBA into image.Image. and tried some examples from chatGPT as expected failed to solve it. then found this snippet which helped fix 2 issues:

• I need to register &image.NRGBA.
• and encode &image.Image not image.Image variable directly