Example: RewriteMap user-to-host txt:conf/u2h
Since: Apache 1.2
The RewriteMap directive defines a rewriting map that
can be used inside rule substitution strings by the mapping
functions so as to insert/substitute fields through a
key lookup. Various types of sources of this lookup can
be used. The map-name is used to specify a mapping
function for the substitution strings of a rewriting rule
via ${map-name:lookup-key[default-value]}
constructs. When such a construct occurs the map, map-name
is consulted and the key lookup-key is looked up. If the key
is found, the looked-up value is substituted for the construct.
If the key is not found, then the default-value or the empty
string (if no default-value was specified) is used.
The following combinations for map-type and map-source
can be used: Standard Plain Text (map-type: txt,
map-source: UNIX file path to valid regular text file);
Randomized Plain Text (map-type: rnd, map-source:
UNIX file path to valid regular text file); Hash File
(map-type: dbm, map-source: UNIX file system path
to valid regular NDBM file); Internal Function (map-type:
int, map-source: toupper, tolower, esca==pe, or
unescape); and External Rewriting Program (map-type:
prg, map-source: UNIX file system path to valid regular
executable).
The RewriteMap directive can occur multiple times. Keep
in mind that while you cannot declare a rewriting map in
a per-directory context, it is possible to use it in a
per-directory context.