Go - Function vs Method

middleware.go

package main

import (
	"context"
	"net/http"
  
	"github.com/alexedwards/scs/v2"
)

type application struct {
	sessionManager *scs.SessionManager
}

// Function as doesn't have any other dependency
func secureHeaders(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {

		w.Header().Set("Content-Security-Policy",
			"default-src 'self'; style-src 'self' fonts.googleapis.com; font-src fonts.gstatic.com")

		w.Header().Set("Referrer-Policy", "origin-when-cross-origin")
		w.Header().Set("X-Content-Type-Options", "nosniff")
		w.Header().Set("X-Frame-Options", "deny")
		w.Header().Set("X-XSS-Protection", "0")

		next.ServeHTTP(w, r)
	})
}

// Method as it has a 'dependency' (that's how I see it) on my application struct
func (app *application) requireAuthentication(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		profile := app.sessionManager.Get(r.Context(), "profile")

		if profile == nil {
			http.Redirect(w, r, "/", http.StatusTemporaryRedirect)
			return
		}

		w.Header().Add("Cache-Control", "no-store")

		next.ServeHTTP(w, r)
	})
}