Retry calls using the Retry-After header.

[felipecauefraga]

Hi! I'm testing React Query to enhance the performance of my app. I would like to utilize the Retry-After header (https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Retry-After) to obtain its value and use this time delay for retrying calls. Is there a way to configure React Query to incorporate this header for retry functionality?

[TkDodo]

React Query knows nothing about http headers because it's not tied to http at all. It's a promise based state manager, which means you can do anything as long as your queryFn returns a resolved or rejected promise.

In your case, here's what I would do:

• in the querFn, make your api call with your favourite tool.
• catch errors inside the queryFn
• look at the response headers and read the Retry-After header
• re-throw a custom error that has a property retryAfter you can look at
• implement the retryDelay function to look at the custom error and return a number in millis for how long to wait, something like:

useQuery({
  queryKey,
  queryFn,
  retryDelay: (failureCount, error) => error.retryAfter * 1000
})

[felipecauefraga]

Hey @TkDodo, thanks! I'll give this solution a shot.