pre-handling-request-in-go-2.go

package main

import (
	"encoding/json"
	"github.com/gorilla/mux"
	"log"
	"net/http"
)

type Response struct {
	Successful bool        `json:"successful"`
	Data       interface{} `json:"data"`
	Err        error       `json:"error"`
}

func main() {
	router := mux.NewRouter()
	router.HandleFunc("/save/something", handle(saveSomething))
	log.Fatal(http.ListenAndServe(":8000", router))
}

func saveSomething(w http.ResponseWriter, r *http.Request) (interface{}, int, error) {
	return "secret token", 200, nil
}

func handle(f func(http.ResponseWriter, *http.Request) (interface{}, int, error)) func(w http.ResponseWriter, r *http.Request) {
	return func(w http.ResponseWriter, r *http.Request) {
		data, status, err := f(w, r)
		w.Header().Add("Content-Type", "application/json")
		w.WriteHeader(status)

		if err != nil {
			json.NewEncoder(w).Encode(Response{
				Successful: false,
				Data:       nil,
				Err:        err,
			})
			return
		}

		log.Println(data, status, err)
		json.NewEncoder(w).Encode(Response{
			Successful: true,
			Data:       data,
			Err:        nil,
		})
	}
}