使用通用类型参数在Go中创建函数

Question

I am trying to create a generic function that can accept a key string and a reference to an object.

The function reads a key's content, which is a serialized byte array out of an original object of the same type and it should assign that (deserializing) to an empty structure of that same type. The function wants to be generic, so it can serialize a type A as well as B or []C

Here is what I tried to do:

func GetObject(key string, thing interface{}) error {
    var buf bytes.Buffer        
    dec := gob.NewDecoder(&buf)
    err := dec.Decode(thing)
    if err != nil {
        log.Errorf(cs.ctx, "cloud store - GetObject - decode error:", err)
        return err
    }
    return nil
}

This is how I try to invoke the above function:

newThing := MyStruct{}
err := GetObject("a123", &newThing)

The last lines about cause a runtime error:

decode error:%!(EXTRA *errors.errorString=EOF)

the question:

• is the interface approach correct for this purpose (allow the function be used generically) ?
• The serialization error ( using Gob ) seems to be problematic. Any suggestions on how to rectify that ?

Answer 1

The concept of interfaces is correct. The issue was related to a missing getter from the persistence store and how to create a buffer out of its []byte content:

func GetObject(key string, thing interface{}) error {
    content, _ := SomePersistanceStoreGet(fileName)
    buffer := bytes.NewBuffer(content)
    dec := gob.NewDecoder(buffer)
   err := dec.Decode(thing)
    if err != nil {
        log.Errorf("decode error: %v", err)
        return err
    }
    return nil
}