Command handler for clients. From https://github.com/AgencyPMG/go-from-scratch

client_handler.go

//Handler is a handler type that understands how to work with Client commands.
type Handler struct {
	//Clients is the Client repository to use within Command handling.
	Clients client.Repo
}

//CreateClient attempts to create a new Client and add it to h.Clients.
//Cmd must be of type *CreateClientCommand.
//The result, if not nil and without error, will be a *client.Client.
func (h *Handler) CreateClient(ctx context.Context, cmd cbus.Command) (interface{}, error) {
	createClient := cmd.(*CreateClientCommand)

	client, err := createClient.newClient()
	if err != nil {
		return nil, err
	}

	err = h.Clients.Add(ctx, *client)

	return client, err
}

//CreateClientCommand is Command that should be used to create a new Client and
//add it to a repository.
type CreateClientCommand struct {
	//Name is the name of the Client to create.
	Name string
}