在Go中验证HTTP请求的惯用方式

Question

I need to validate that my http request has two parameters, Start and End. Currently, I set a default value that should not appear as either of the parameters and check for it along with other invalid values. However, this feels like a hack. What should be the proper way to do this?

Here is my code:

type Request struct {
    Start int `json: "start"`
    End int `json: "end"`
}


func HandlePost(w http.ResponseWriter, r *http.Request) {
    body , _ := ioutil.ReadAll(r.Body)
    reqData := Request{Start: -1, End: -1} // < whats the correct way to do this
    json.Unmarshal(body, &reqData)  

    if reqData.Start < 0 && reqData.End < 0 {
        w.WriteHeader(http.StatusBadRequest)
        return
    }
    // rest of the logic
}