mod_http_oauth2: Remove authorization codes after use RFC 6749 section 4.1.2 says: > The client MUST NOT use the authorization code more than once. Thus we clear it from the cache after use.

This module blocks configured queries that change server state.

E.g. to make vCard storage read-only:

``` lua
readonly_stores = {
	vcard = { "vcard-temp", "vCard" };
}
```