Unmarshalling to same struct but different json name - json

Question

I am trying to unmarshal a particular json data, perform some data transformations and then marshal the data and send it. However I want to marshal it with different json variable name.
Can I marshal the data to another json name like have xyz instead of abc
{"abc":1}
to
{"xyz":1}
package main
import (
"fmt"
"encoding/json"
)
type SomeStruct struct {
SomeField int `json:"abc"`
}
func main(){
jsonData := []byte(`{"abc":1}`)
strct := SomeStruct{}
json.Unmarshal([]byte(jsonData), &strct)
fmt.Println(strct)
x, err := json.Marshal(strct)
if err != nil {
fmt.Println("errs", err)
}
finalValue := string(x)
fmt.Println(finalValue)
}

Answer 1

Define two structures, one for your input, one for your output, and convert like this:
package main
import (
"fmt"
"encoding/json"
)
type inStruct struct {
SomeField int `json:"abc"`
}
type outStruct struct {
SomeField int `json:"xyz"`
}
func main(){
jsonData := []byte(`{"abc":1}`)
strct := inStruct{}
if err := json.Unmarshal(jsonData, &strct); err != nil {
log.Fatal(err)
}
// Edit to reflect mkopriva's comment
// outStruct := &outStruct{SomeField: strct.SomeField}
outStruct := outStruct(strct)
x, err := json.Marshal(outStruct)
if err != nil {
log.Fatal(err)
}
finalValue := string(x)
fmt.Println(finalValue)
}

Answer 2

You can potentially implement a custom ToJSON method for the struct, as follows:
package main
import (
"encoding/json"
"fmt"
)
type SomeStruct struct {
SomeField int `json:"abc"`
}
func (s *SomeStruct) ToJSON() string {
return fmt.Sprintf("{\"xyz\":%d}", s.SomeField)
}
func main() {
jsonData := []byte(`{"abc":1}`)
strct := SomeStruct{}
json.Unmarshal([]byte(jsonData), &strct)
fmt.Println(strct)
x, err := json.Marshal(strct)
if err != nil {
fmt.Println("errs", err)
}
finalValue := string(x)
fmt.Println(finalValue)
fmt.Println("custom ToJSON", strct.ToJSON())
}
Playground link: https://play.golang.org/p/mjW0dBPN59Q
It might not be flexible in the long run though. Personally, for requirement like this, I would prefer the solution posted by #Clément