In previous recipe we talked about multiple catalogs with same “UriSegment” – which we had a working implementation for incoming URL, i.e. when a customer visit a product url, we know which catalog we should choose from. But we still need to cover the generation of outgoing URL. I.e. when we link a product (For example, from a campaign page), we need to generate an URL which take the “catalog-less” pattern into account.
We need to understand how the outgoing URL is built. The hierarchical router builds the URL by the `RouteSegment` of contents. However, we want to the urls appear to have same catalog, so the `RouteSegment` part for the catalogs must be the same, regardless of the true catalogs. Because all catalogs are on same level, their `RouteSegment` must be unique – and this is enforced from Framework level (which is understandable, otherwise, how can it know which content to choose).