Thanks Otto - Unfortunately, the service being called doesn’t currently support full HTTP cache semantics at this time. I could add full support, and it is probably the right thing to do in the long run. But for now I was hoping for a solution that didn’t require significant enhancement to the web service.
-Tim > On May 1, 2018, at 5:47 AM, Otto Fowler <ottobackwa...@gmail.com> wrote: > > https://hc.apache.org/httpcomponents-client-ga/tutorial/html/caching.html > <https://hc.apache.org/httpcomponents-client-ga/tutorial/html/caching.html> ? > > > On May 1, 2018 at 00:01:58, Tim Dean (tim.d...@gmail.com > <mailto:tim.d...@gmail.com>) wrote: > >> Hello, >> >> I have a custom NiFi controller service that retrieves data from an external >> web service via HTTP requests. The results from these HTTP requests will be >> needed at various points throughout my process flow. In some situations, I >> could end up needing to access the HTTP response dozens or even hundreds of >> times. >> >> Given that the results of the HTTP request rarely change, I’d like them to >> be cached by my service and returned to my processors when needed. I’d need >> some way to explicitly clear the cache for those occasions when the data in >> the service does change. >> >> I’ve looked at using the DistributedMapCacheClientService implementation to >> cache my web service’s results, but it seems like that connects to a server >> via a socket connection and that doesn’t seem like it would be all that much >> more efficient than calling the web service directly. I’ve also looked at >> using the service’s state manager to store the results as state, but my data >> is a little more complex than what the documentation for state suggests is >> optimal: I don’t think my total map size will get to 1MB in size but it >> could be possible. >> >> Am I overthinking this? Would a simpler solution like creating a simple Java >> HashMap inside my controller service be adequate? I could empty the contents >> of the hash map whenever the controller services is enabled/disabled. Would >> the memory used by this kind of simplified local caching cause problems >> somewhere down the line? >> >> Are there other caching strategies I should be considering? >> >> Thanks >> >> -Tim
