Add options check to Lookup(method, path)

[ntbosscher]

I've built some extras around httprouter which would work much nicer if Lookup(method, path) would include the .HandleOPTIONS functionality that ServeHTTP has.

Use Case

I have user permission based routing. When an options request comes in, it doesn't work the way I'd like it to. Here's an example.

appUsers := httprouter.New()
appUsers.GET("/api/user", someHandler)

adminUsers := httprouter.New()
adminUsers.GET("/api/user", someHandler)
adminUsers.DELETE("/api/user", someHandler) // admin only handler

muxer := Mux({
    appRouter: appUsers,
    adminRouter: adminUsers,
}) 

func (m *Mux) ServeHTTP() {
     if user.IsAppUser && user.IsAdminUser {
              handler, params, _ := m.appRouter.Lookup(r.Method, r.Path)
              if handler != nil {
                     handler.ServeHTTP(w, r, params)
                     return
             }

             m.adminRouter.ServeHTTP(w, r)
            return
     }

     if user.IsAppUser {
          m.appRouter.ServeHTTP(w, r)
          return
     }

     if user.IsAdminUser {
          m.appRouter.ServeHTTP(w, r)
          return
     }

     http.NotFound(w, r)
}

[ntbosscher]

My usage here isn't a very good use case. Please ignore it.

Nevertheless, it seems to me that .Lookup should function almost the same as .ServeHTTP() such that you could implement your own ServeHTTP() with the following code

MyServeHTTP(w, r) {
     handler, params, _ := router.Lookup(r.Method, r.Path)
     handler(w, r, params)
}