Code Json to Struct in Go

Getting Help Code Review
1

Hi friends! I want save the code Json to my struct. The code is:

{
“Dogs”: [
{
“name”: “Alma”,
“year_old”: 2,
“Description”: [“This”, “is”, “Description”, “in”, “a”, “Vector1”]
},
{
“name”: “Tobby”,
“year_old”: 4,
“Description”: [“This”, “is”, “Description”, “in”, “a”, “Vector2”]
}
}

My class is defined as:

type Dog struct {
Name string json:"name"
Year_old float32 json:"year_old"
Description []string json:"description"

}

I try make the next code but the var dogs is nil:

func getDogs(w http.ResponseWriter, r *http.Request) {
reqBody, err := ioutil.ReadAll(r.Body)
if err != nil {
fmt.Fprintf(w, “error”)
return
}

var dogs []Dog
json.Unmarshal(reqBody, &dogs)

The problem is the array “Dogs: []” in the Json. If remove “Dogs: []”, the var dogs conteins the two objetcs.

Thank you.
Bye friends.
Sorry for my basic english.

2

Your JSON does not contain an array but a single object that has a member named Dogs whose value is an array. You will have to represent this in your code.

type Dog struct {
	Name        string   `json:"name"`
	Year_old    float32  `json:"year_old"`
	Description []string `json:"description"`
}

type Dogs struct {
	Dogs []Dog `json:"Dogs"`
}

func main() {
	var dogs Dogs
	json.Unmarshal([]byte(j), &dogs)

	fmt.Println(dogs)
}

See https://play.golang.org/p/Nqxl-S4Pqn9

2 Likes
3

Hi! dogs return nil. I did exactly what you mention, only i replace j for reqBody:

reqBody, err := ioutil.ReadAll(r.Body)
if err != nil {
fmt.Fprintf(w, “error en datos enviados”)
return
}

4

Check the error of unmarschal, what does it say?

In general, for debugging at least, it’s always a good idea to log full returned error and also the data that might lead to that error.

In general, whenever a function or method returns an error value, you should check it, though Lutz left that off in his example.

2 Likes
5

Sorry, I had this:

func main() {

var dogs []Dogs <--------------------  error is Dogs

json.Unmarshal([]byte(j), &dogs)

fmt.Println(dogs)

}

Thank you!!!

6

I’m not sure what you mean by that last post, sorry.

Does it work now?

7

Are you sure that reqBody contains the JSON you expect? If yes, the code I’ve shown above should work. If no, what exactly does the request body contain?

8

Use this online tools which Converts JSON to struct in Go