plugins: Use integer config API with interval specification where sensible
Many of these fall into a few categories:
- util.cache size, must be >= 1
- byte or item counts that logically can't be negative
- port numbers that should be in 1..0xffff
The Prosody project is open to contributions (see HACKERS file), but is
maintained daily by:
- Matthew Wild (mail: matthew [at] prosody.im)
- Waqas Hussain (mail: waqas [at] prosody.im)
- Kim Alvefur (mail: zash [at] prosody.im)
You can reach us collectively by email: developers [at] prosody.im
or in realtime in the Prosody chatroom: prosody@conference.prosody.im