v3: cmdroute: Add Router.Group()

[labi-le]

I expect middleware to run for set and delete commands, but in fact I get this behavior for all commands. How can I concretize the execution of the middleware layer?

        bot.AddInteractionHandler(res)
        
	res.AddFunc("stats", res.Stats)
	res.AddFunc("help", res.Help)
	res.AddFunc("get", res.Get)
	res.AddFunc("search", res.Search)

	res.Use(res.CheckAccess)
	res.AddFunc("set", res.Set)
	res.AddFunc("delete", res.Delete)

[diamondburned]

There's currently no way to make Use only work for certain commands of the same level. Middlewares will always run before the command handler regardless of when they're added.

To do something like this, there should be a Group() function like go-chi:

res.AddFunc("search", res.Search)
res.Group(func(res *cmdroute.Router) {
    res.Use(res.CheckAccess)
    res.AddFunc("set", res.Set)
})

[labi-le]

simple trick

Wrap cmdroute.CommandHandlerFunc in another cmdroute.CommandHandlerFunc

res.AddFunc("set", res.CheckAccessMiddleware(res.Set))

func (r *resource) CheckAccessMiddleware(fn cmdroute.CommandHandlerFunc) cmdroute.CommandHandlerFunc {
	return func(ctx context.Context, data cmdroute.CommandData) *api.InteractionResponseData {
		interaction := data.Event.Data.(*discord.CommandInteraction)

		userID, err := ParseUserID(interaction.Options)
		if err != nil {
			return r.send(err.Error())
		}

		if !checkAccess(r.supportRoleID, data.Event.Member, userID) {
			return r.send(ErrNoAccess.Error())
		}

		return fn(ctx, data)
	}
}