Tapestry 5 - decouple page class name from URL

Question

Is there any baked-in way, or established Tapestry pattern, to decouple the name of a page Class from the URL which renders it?

My specific problem is that I have a page class in an English codebase but I want the URLs to be in another language.

For example, the Hello.java page should be accessible from www.example.com/hola rather than the standard www.example.com/hello - though it's fine if both of these URLs work.

Ideally I want something like an annotation to configure a different URL name in-place for each individual page class.

Off the top of my head I could solve this myself with a map of URLs to page class names and a custom RequestFilter to do the mapping on each request - but I don't want to reinvent the wheel if there's a baked-in way to do this or a better pattern that anyone can suggest?

Answer 1

Tapestry has a LinkTransformer but I've always found the API lacking since you don't have access to the default behaviour. Igor has written a blog post about the LinkTransformer API here

I've always found it necessary to decorate the ComponentEventLinkEncoder so that I can access the default behaviour and tweak it. See ModeComponentEventLinkEncoder.java and AppModule.java for an example which tweaks the default behaviour and does some string manipulation on the URL.

Thiago has created a url rewriter api here but I've never used it myself. I'm pretty sure his solution is based on decorating the ComponentEventLinkEncoder for outbound URLs and a RequestFilter for inbound URLs.

Answer 2

Tynamo's tapestry-routing could help you. It depends on how do you want to generate the links to www.example.com/hola and www.example.com/hello

The @At annotation only allows one route per page, but you can contribute all the routes you want via your AppModule, like this:

@Primary
@Contribute(RouteProvider.class)
public static void addRoutes(OrderedConfiguration<Route> configuration, ComponentClassResolver componentClassResolver) {
    String pageName = componentClassResolver.resolvePageClassNameToPageName(Home.class.getName());
    String canonicalized = componentClassResolver.canonicalizePageName(pageName);
    configuration.add("home1", new Route("/home1", canonicalized));
    configuration.add("home2", new Route("/home2", canonicalized));
    configuration.add("home3", new Route("/home3", canonicalized));
    configuration.add("home4", new Route("/home4", canonicalized));
    configuration.add("hola", new Route("/hola", canonicalized)); // the last one is going to be use by default to create links to the page
}

The routes are ordered and by default the last one is going to be used to generate the links. Currently there is no way to avoid using the default route to generate the links.