问题
I am new to Go and I'm building a simple API with it now:
package main
import (
"encoding/json"
"fmt"
"github.com/gorilla/mux"
"github.com/gorilla/handlers"
"log"
"net/http"
)
func main() {
port := ":3000"
var router = mux.NewRouter()
router.HandleFunc("/m/{msg}", handleMessage).Methods("GET")
router.HandleFunc("/n/{num}", handleNumber).Methods("GET")
headersOk := handlers.AllowedHeaders([]string{"Authorization"})
originsOk := handlers.AllowedOrigins([]string{"*"})
methodsOk := handlers.AllowedMethods([]string{"GET", "POST", "OPTIONS"})
fmt.Printf("Server is running at http://localhost%s\n", port)
log.Fatal(http.ListenAndServe(port, handlers.CORS(originsOk, headersOk, methodsOk)(router)))
}
func handleMessage(w http.ResponseWriter, r *http.Request) {
vars := mux.Vars(r)
message := vars["msg"]
response := map[string]string{"message": message}
w.Header().Set("Content-Type", "application/json") // this
json.NewEncoder(w).Encode(response)
}
func handleNumber(w http.ResponseWriter, r *http.Request) {
vars := mux.Vars(r)
number := vars["num"]
response := map[string]string{"number": number}
w.Header().Set("Content-Type", "application/json") // and this
json.NewEncoder(w).Encode(response)
}
I feel like it's not clean to keep repeating w.Header().Set("Content-Type", "application/json")
line in every API function that I have.
So my question here is, does it possible to set that http.ResponseWriter Content-Type header globally for all API functions that I have?
回答1:
You can define middleware
for mux router, here is an example:
func main() {
port := ":3000"
var router = mux.NewRouter()
router.Use(commonMiddleware)
router.HandleFunc("/m/{msg}", handleMessage).Methods("GET")
router.HandleFunc("/n/{num}", handleNumber).Methods("GET")
// rest of code goes here
}
func commonMiddleware(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w.Header().Add("Content-Type", "application/json")
next.ServeHTTP(w, r)
})
}
Read more in the documentation
来源:https://stackoverflow.com/questions/51456253/how-to-set-http-responsewriter-content-type-header-globally-for-all-api-endpoint