CODEWITHSUNDEEP
jsongodecode
Mariodiar
Mariodiar

Reputation: 80

Golang unmarshal json that starts as an array

I'm trying to unmarshal this json https://www.reddit.com/r/videos/comments/3vgdsb/recruitment_2016.json

It starts as an array of two different objects, and I only need data on the second object.

I want to retrieve the comments body, it doesn't give me any error when i'm trying to decode it, but it doesn't capture the data I want.

This is the output I get from running this:

//Response struct when initialized: []
//Response struct decoded: [{{{[]}}} {{{[]}}}]

////

type Response []struct {
    Parent struct {
        Data struct {
            Children []struct {
                Com Comment
            }
        }
    }
}

type Comment struct {
    Name string `json:"body"`
}

func init() {
    http.HandleFunc("/api/getcomments", getComments)
}

func getComments(w http.ResponseWriter, r *http.Request) {

    url := "https://www.reddit.com/r/videos/comments/3vgdsb/recruitment_2016.json"
    c := appengine.NewContext(r)
    client := urlfetch.Client(c)
    resp, err := client.Get(url)
    if err != nil { fmt.Fprint(w, "Error client.Get(): ", err) }

    re := new(Response)
    fmt.Fprint(w, "Response struct: ", re, "\n")

    errTwo := json.NewDecoder(resp.Body).Decode(&re)
    if errTwo != nil {  fmt.Fprint(w, "Error decoding: ", errTwo, "\n") }

    fmt.Fprint(w, "Response struct: ", re)
}

Upvotes: 1

Views: 908

Answers (2)

pierre.zemb
pierre.zemb

Reputation: 98

For everyone that is struggling to create the right structure for JSON unmarshalling, here's a cool website that convert any JSON to the right Go struct: JSON-to-Go

Upvotes: 8

Not_a_Golfer
Not_a_Golfer

Reputation: 49187

The json data you are unmarshaling does not conform with your data, and if the names of the fields are not like in your struct, you should use struct tags as well. It should be more like this:

type Response []struct {
        Kind string `json:"kind"`
        Data struct {
            Children []struct {
                Data struct {
                    Replies []struct {
                       // whatever...
                    } `json:"replies"`
                } `json:"data"`
            } `json:"children"`
        } `json:"data"`
    }
}

Of course I'd replace the inline types with real, named types, but I'm just making a point here in regards to the data hierarchy.

Goddamn, that's some ugly bloated JSON BTW.

Upvotes: 3

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