offline_mode

Bug 1356 brings up some confusion over what the true meaning of
'offline' is for this option.

As Henrik pointed out fairly early in the discussion there, squids
actual behavior is to 'aggressively cache', not a true
"network-disconnected" mode.

I'm proposing that the option have one or both of two things done to it:

1) simply renamed to something more descriptive ie cache_aggressive on/off.

2) that it be kept as 'offline' but changed to accept a range of flags
indicating which of the external-interface engines inside squid are to
behave as if they were offline. ie "offine cache dns auth"

When any given feature is marked for offline it behaves in a true "not
packet leaves the interface" fashion.
ie
        - 'dns' means no new DNS lookups are performed.
        - 'cache' means no refreshes are performed (RFC 2616 allows for stale
objects already in cache to be used with certain response types)
        - etc.

We may need to exempt localhost traffic from offline mode explicitly.
But will need to be consistent with it.

The existing 'aggressive caching' behaviour may be possible by other
means with cache ACL or refresh_patterns. Or a 'cache=semi' style tag
might be chosen.

Or, we may choose to do both of the above changes.

Amos

-- 
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