My custom repositories do not show up in the browser or get used for downloads

This is usually caused by an invalid URL in the repository configuration.

The format for a custom repository is file:///<path>, so if the path you want is /tmp/repo, the URL becomes file:////tmp/repo (4 slashes!)

How do the snapshot.update / repo.<repo>.cache.period properties work

If snapshot.update is false, whenever you request a snapshot from maven-proxy, it will just give you whatever it already has.

If snapshot.update is true, whenever you request a snapshot from maven-proxy, it will perform the following logic.

1. Check the snapshot cache (in memory), if I have downloaded this snapshot, check how long ago it was. If it was less than snapshot.update.interval seconds ago, send a 304 NOT MODIFIED response. End Process.

1. For each repository (<repo) see if the snapshot was modified longer ago than repo.<repo>.cache.period, and then check the upstream repository if it is out of date.

1. If something newer is found (in any repository) send that to the user and update the cache. End Process.

1. If nothing newer is found, send a 304 NOT MODIFIED response. End Process.

There are some edge conditions that aren't catered for I suspect.