Best way to add fileSystem to existing http api web server - go

Question

I already have a web server and it work fine, now I want to add the fileSystem module to it.
OverView of the project under below.
// Custom router
type Handler func(ctx context.Context, w http.ResponseWriter, r *http.Request) error
type Middleware func(Handler) Handler
type App struct {
mux *chi.Mux
och *ochttp.Handler
mw []Middleware
}
func NewApp(mw ...Middleware) *App {
app := App{
mux: chi.NewRouter(),
mw: mw,
}
app.och = &ochttp.Handler{
Handler: app.mux,
Propagation: &tracecontext.HTTPFormat{},
}
return &app
}
func (a *App) Handle(verb, path string, handler Handler, mw ...Middleware) {
handler = wrapMiddleware(a.mw, handler)
h := func(w http.ResponseWriter, r *http.Request) {
...
}
a.mux.MethodFunc(verb, path, h)
}
func (a *App) ServeHTTP(w http.ResponseWriter, r *http.Request) {
a.och.ServeHTTP(w, r)
}
// route
func API(...) http.Handler {
app := web.NewApp(mid.Logger(log)...)
s := Something{
...
}
app.Handle("GET", "/v1/somthing", s.DoSomething)
return app
}
// Handler
type Something struct {
...
}
func (s *Something) DoSomething(ctx context.Context, w http.ResponseWriter, r *http.Request) error {
...
}
// main
api := http.Server{
...
Handler: API(...),
}
go func() {
api.ListenAndServe()
}()
The app struct is a custom router, it contains 3rd router, trace library and some middleware. The type Handler is the specific Handler format using for Middleware and any api handler register to this router. Because this project hard code only one Handler, what's the best to add another Handler like fileSystem to it?

Answer 1

http.Handler and Handler conversion through closure.
// http.Handler to Handler
func NewHandler(h http.Handler) Handler {
return func(ctx context.Context, w http.ResponseWriter, r *http.Request) error {
h.ServeHTTP(w, r)
}
}
// Handler to http.Handler
func NewHTTPHandler(h Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
h(context.Background(), w, r)
})
}
// or Handler implement http.Handler
func (fn Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
fn(context.Background(), w, r)
}
app.Handle("ANY","/fs/*", NewHandler(http.FileServer(http.Dir("public"))))
type Handler func (Context) is the best Handler definition. Request the context.Context object through http.Request.Context() or the top-level context.Context is obtained through the http.Server.BaseContext property.
Middleware's best implementation idea has two methods used by the echo or gin framework, but the echo method should not copy the memory allocation waste.
It is recommended to implement the router by yourself. In the mainstream framework and routing inventory, does not have routing priority, such as a large number of libraries such as echo gin httprouter gorilla/mux.
The following is the framework and the simplest implementation that I designed for 22 months.
my web framework: https://github.com/eudore/eudore
simple framework: https://github.com/eudore/eudore/wiki/3.2-frame-mirco-web