Fetch Lifecycle
XMLUI manages the lifecycle of every HTTP request a data-bound component
issues. Requests are deduplicated, cached, and — crucially — cancelled when
they are no longer relevant. You never have to write an AbortController,
a "is component still mounted?" check, or a race-condition guard yourself.
What problems this prevents
- A stale response from an earlier request can no longer overwrite the result of a newer one when a key (such as a query parameter or selected row) changes mid-flight.
- A request that was in flight when the user navigated away does not resolve into a component that no longer exists, eliminating a common source of "Cannot update unmounted component" warnings.
- Two components that ask for the same resource at the same time produce one network request, not two.
- Re-renders triggered by unrelated state changes do not refire requests that have already been satisfied.
How it works
XMLUI's data layer is built on React Query plus the framework's request
proxy. Each DataSource and APICall has a stable key derived from its
URL and parameters; results are cached against that key. When the key
changes or the component unmounts, the framework calls
AbortController.abort() on the in-flight request so the previous fetch
is cancelled before a new one starts. Cached entries are reused across
components that share the same key.
This behaviour is always on. There is no opt-out flag, because returning to manual lifecycle management would re-introduce the very bugs the managed lifecycle prevents.