JSON decoder does not work as expected

[yaa110 (Navid)]

Please consider the following code:

package main

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

func main() {
	j := []byte("{\"bandwidth\":5120}")
	type M struct {
	    rate float64 `json:"bandwidth"`
	}
	r := M{}
	decoder := json.NewDecoder(bytes.NewReader(j))
	err := decoder.Decode(&r)
	fmt.Printf("%+v %+v", r, err)
}

It returns {rate:0} <nil>, what is wrong with it?

[NobbZ (Norbert Melzer)]

The JSON decoder does only work for public fields. You need to make it Rate. Also I’m not sure if it works with function local types at all or if they need to be at the package level.

[nathankerr]

Function local types work just fine. I use them when I need a struct just for the function.

[Yamil_Bracho]

Just change the struct to

type M struct {
	Bandwidth float64 `json:"bandwidth"`
}