Some APIs have resources where a POST is used to send a command that returns
content and doesn't modify state. In this case, it's more like a GET. This
may occur where one might normally GET but the request URI would be too long
for the server to accept. cachedPOST thus behaves more like
GET, checking for a cached response before performing the request and
setting cache if the request is successful. It does no cache dropping, unlike
POST().