Function cacheHeaderMiddleware

src/System/Relay/middleware/cacheHeaderMiddleware.ts:55–94

(props?: CacheHeaderMiddlewareProps)

}

export const cacheHeaderMiddleware = (props?: CacheHeaderMiddlewareProps) => {
  return next => async req => {
    const url = isServer ? props?.url : window.location.pathname

    const cacheControlHeader = (() => {
      const foundRoute = findRoutesByPath({ path: url ?? "" })[0]

      // In a prefetch context, the custom TTL should come from the found route
      // that is being prefetched, and not the current route.
      // During a prefetch, the custom TTL of that found route, if any, is injected into
      // the metadata. Thus, if metadata is present, we should use that TTL (even if undefined).
      const ttl = req.cacheConfig.metadata
        ? req.cacheConfig.metadata.maxAge
        : foundRoute?.route?.serverCacheTTL

      switch (true) {
        case shouldSkipCDNCache(req, props?.user, ttl, url): {
          return { "Cache-Control": "no-cache" }
        }
        case !!ttl: {
          return {
            "Cache-Control": `max-age=${ttl}`,
          }
        }
        default: {
          return {}
        }
      }
    })()

    req.fetchOpts.headers = {
      ...req.fetchOpts.headers,
      ...cacheControlHeader,
    }

    const res = await next(req)

    return res
  }
}