使用Go（Golang）清除先前的请求RESTFul吗？

Question

I've created a RESTFul API via golang. The Issue is that when I send a /product request I will be given the result in json and when I repeat this request the result will append prevoius. I want to clear the REST data buffer and whenever I send a request, API send me fresh data, not with prevoius. What should I do?

Route Handler

func main() {
    router := mux.NewRouter()

    router.HandleFunc("/product", GetProductInfo).Methods("GET")

    log.Printf("Listenning on Port %s ...
", PORT)
    log.Fatal(http.ListenAndServe(PORT, router))
}

Request Handler

type ProductOut struct {
    ID          int `json:"id,omitempty"`
    Title       string `json:"title,omitempty"`
    Description string `json:"description,omitempty"`
    Price       string `json:"price,omitempty"`
    Location    string `json:"location,omitempty"`
    Created_at  string `json:"created_at,omitempty"`
    Images      []string `json:"images,omitempty"`
}

var product_out []ProductOut

func GetProductInfo(w http.ResponseWriter, r *http.Request) {
    db_select_products := db.SelectProducts() // Gets data from database

    var out ProductOut

    for _, ele := range db_select_products {
        out.ID = contentGetFieldInteger(ele, "out_id") // A method for getting integer from struct field
        out.Title = contentGetFieldString(ele, "out_title") // A method for getting string from struct field
        out.Description = contentGetFieldString(ele, "out_description")
        out.Price = contentGetFieldString(ele, "out_price")
        out.Location = contentGetFieldString(ele, "out_location")
        out.Created_at = contentGetFieldString(ele, "out_created_at")

        db_select_image := db.SelectImages(out.ID) // Gets another data from database

        for _, imele := range db_select_image {
            out.Images = append(out.Images, imageGetFieldString(imele, "out_path"))
            fmt.Println(out.Images)
        }
        product_out = append(product_out, out)

        out.Images = nil
    }
    json.NewEncoder(w).Encode(product_out)
}

Answer 1

You are declaring this as a global variable in your package:

var product_out []ProductOut

That way, the slice is just created once, and you are sharing it between requests.

If you want to declare a new slice for each request, you should move that line inside your GetProductInfo function.