Question 255123 in Json Question posted in
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How to decode or unmarshal embedded JSON in Golang?

This is the sample in the Playground. The gist of the problem is that I am unable to decode / unmarshal this

    Name := "TestName"
    Desc := "Test Desc"
    Body := []byte(`{"key": "value"}`)//simplest possible JSON but will have multiple levels

    requestJson := fmt.Sprintf(`{"name": "%s","description": "%s","body": "%s"}`, Name, Desc, Body)
    decoder := json.NewDecoder(strings.NewReader(requestJson))
    err := decoder.Decode(&createRpt)
    if err != nil {
        fmt.Println("Report body is expected to be valid JSON", "error", err)
        return
    }

I have also tried to use the unmarshal option as can be seen in the playground .

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2

Answers


  1. 0

    You have a typo in your json, remove the " around body’s value and it will be fixed:

    requestJson := fmt.Sprintf(`{"name": "%s","description": "%s","body": %s}`, Name, Desc, Body)
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  2. 0

    You should avoid, at all cost, formatting your own JSON like this. Just create a struct that you can marshal properly:

    type Foo struct {
    Name        string          `json:"name"`
    Description string          `json:"description"`
    Body        json.RawMessage `json:"body"`
}

func main() {
    name, desc := "Test Name", "Test description, lorum ipsum"
    body := []byte(`{"key": "value"}`)
    jData, err := json.Marshal(Foo{
       Name:        name,
       Description: desc,
       Body:        body,
    })
    if err != nil {
        // handle error
    }
    fmt.Printf("%sn", string(jData))
}

    Demo

    The key here is the json.RawMessage type. This essentially tells json.Marshal that the value should not be unmarshalled, and accordingly it will just be copied over as-is (as a []byte). If you need to later on unmarshal the value of Body elsewhere, you can simply do so like this:

    data := map[string]any{}
if err := json.Unmarshal([]byte(t.Body), &data); err != nil {
    // handle error
}
fmt.Printf("Unmarshalled: %#vn", data)
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