SPREE-ALLOW(2) SPREE-ALLOW(2)
NAME
Allow - filter client actions
SYNOPSIS
include "spree.m";
include "spree/allow.m";
Clique, Member, Object: import Spree;
allow := load Allow Allow->PATH;
init: fn(m: Spree, c: ref Clique);
add: fn(tag: int, member: ref Member, pattern: string);
del: fn(tag: int, member: ref Member);
action: fn(member: ref Member, cmd: string): (string, int, list of string);
archive: fn(archiveobj: ref Object);
unarchive: fn(archiveobj: ref Object);
DESCRIPTION
A spree(2) client can send arbitrary actions to a running
engine. The Allow module enables an engine to filter
clients' actions, permitting only actions matching certain
provided patterns to get through.
An action is conventionally formatted as a sequence of
space-separated words. A pattern is a string consisting of
a sequence of such words. For a pattern to match a client's
action, each word in the pattern must match each word in the
action. Most pattern words are not special: they must match
literally. The exceptions are:
* An asterisk matches any single word.
& An ampersand matches any set of words. Any words in
the pattern after this are ignored.
%d Matches a decimal integer.
%p Matches a valid player id (decimal integer).
%o Matches any valid object id (decimal integer). The
corresponding word in the list returned by action will
be changed to the local object id from the member's
external representation.
Init must be called first with the spree module, m, and the
current clique, c, to initialise the module.
Add adds the new pattern to the list of allowed actions; tag
is an integer tag that the caller can later use to identify
the action, and I member is the clique member that is
allowed to perform the action (if nil, then any member will
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SPREE-ALLOW(2) SPREE-ALLOW(2)
be allowed to perform the action). Del deletes patterns
tagged with tag from the list of allowed actions. If member
is non-nil, then only patterns specific to that member will
be deleted.
Action matches cmd, an action performed by member, against
the list of all the allowed patterns. It returns a tuple,
say (err, tag, toks). If cmd does not match any pattern,
then err will be non-nil and holds a string describing the
nature of the failure. If a match is made, then tag holds
the matched pattern's tag, as passed to add, and toks holds
the list of words in the action, with object ids matched by
%o changed to their local representation using member.obj.
Archive stores all the allow module's internal state as
attributes on archiveobj (for card game engines, this is
usually the object returned from cardlib->archive (see
cardlib(2))). Unarchive reverses this, restoring the
module's internal state from archiveobj.
SOURCE
/appl/spree/lib/allow.b
SEE ALSO
spree(2), spree-cardlib(2), spree-objstore(2)
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