Gorilla Mux: doesn't take value in vars := mux.Vars(r) Golang?

Question

go

Good afternoon.

Please tell me, I am writing an Http server that supports the CRUD API. I ran into a problem that the GetPost request - which should search by the Id of the post - does not pull the Id from the URL string. What does it have to do with checking in PostMan, if you enter the line at the end / "Id number", then the request is processed, and if / {Id}, as written in the handler, then the request is not processed. I can't understand what is the reason. The function does not work at all.
Part of the handler code:

type postHandler struct {
Services services.Store
}

func (h *postHandler) NewRouter() *mux.Router {
r := mux.NewRouter()
r.HandleFunc("/post", h.CreatePost). Methods("POST")
r.HandleFunc("/post/{Id}", h.GetPost).Methods("GET")
r.HandleFunc("/posts", h.GetAll).Methods("GET")
r.HandleFunc("/post/{Id}", h.DeletePost).Methods("DELETE")
r.HandleFunc("/ post/{Id}", h.UpdatePost).Methods("PUT")

return r
}

func (h *postHandler) GetPost(w http.ResponseWriter, r *http.Request) {
vars := mux.Vars(r)
key := vars["Id"]
idInt, _ := strconv.Atoi(key)
res, err := h.Services.GetId(idInt)
if err != nil {
w.Write([]byte("could not get post"))
return
}
json.NewEncoder(w).Encode(&res)
}

Accordingly, the rest of Delete and Update have a similar problem.
I will be glad to any advice.

Answer 1

Through mux.Vars you can only extract what's in the URL, i.e. parts of the URL, and the parameters must be retrieved via r.URL.Query().Get("param_name")
Let's look at an example from a real task.
The URL contains the English name of the category (chairs), as well as the width and height filter parameters.

https://domain.com/products/chairs?height=200&width=100

Those. we need to display all products from the category "chairs" (chairs), but not higher than 200 and not wider than 100, respectively, we need to get chairs from the URL and parameters.
The route will be like this in this case

r.HandleFunc("/products/{category_handle}", h.ShowProducts).Methods("GET")

And in the handler it will be like this

// из извлекаем из URL категорию
vars := mux.Vars(r)
categoryHandle := vars["categoryHandle"]

// получаем параметры
height, _ := strconv.Atoi(r.URL.Query().Get("height"))
width, _ := strconv.Atoi(r.URL.Query().Get("width"))