#  TAG: refresh_pattern
#       usage: refresh_pattern [-i] regex min percent max [options]
#
#       By default, regular expressions are CASE-SENSITIVE.  To make
#       them case-insensitive, use the -i option.
#
#       'Min' is the time (in minutes) an object without an explicit
#       expiry time should be considered fresh. The recommended
#       value is 0, any higher values may cause dynamic applications
#       to be erroneously cached unless the application designer
#       has taken the appropriate actions.
#
#       'Percent' is a percentage of the objects age (time since last
#       modification age) an object without explicit expiry time
#       will be considered fresh.
#
#       'Max' is an upper limit on how long objects without an explicit
#       expiry time will be considered fresh.
...
#       Basically a cached object is:
#
#               FRESH if expires < now, else STALE
#               STALE if age > max
#               FRESH if lm-factor < percent, else STALE
#               FRESH if age < min
#               else STALE
...
#Suggested default:
refresh_pattern ^ftp:           1440    20%     10080
refresh_pattern ^gopher:        1440    0%      1440
refresh_pattern .               0       20%     4320