How It Works¶

Routing Basics¶

As an app developer, you will need to define routes for your app. When the URL changes, the router will look for a matching route. The router will attempt to match routes in the order they are defined.

When a route is found, the router will call the route's before_load method. If the before_load method raises a Redirect, the router will navigate to the redirected URL.

If the route has a load_data method, it will be called, and the return value will be available as the data property on the RoutingContext.

Once the load_data method has been called, the router will call the route's load_form method. A routing_context will be passed to this method. By default, the load_form method will call anvil.open_form on the matching route's form, with routing_context passed as a keyword argument.

Caching¶

There are two types of caching: form caching and data caching.

If a form is cached, instead of creating a new instance, the router will call the route's load_form method with the cached form instance.

If data is cached, the router will only call the load_data method if the data is stale. See the Caching section for more details.

Server vs Client Routing¶

The above process will occur on the server if the user navigates directly to a URL (the initial page request). If the user is navigating from within the app, then routing will happen on the client.