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ATTRIBUTES option

The ATTRIBUTES option indicates that the attributes associated with the link are to be returned. (If the object is on the same host as the directory, then the server may ignore CACHED attributes of the link and return OBJECT attributes instead. However, the server is never required to return OBJECT attributes for a directory listing. The implementor should use discretion.)

ATTRIBUTES is optionally immediately followed by an argument list, which is a parenthesized +-separated list of attributes to be returned. If the ATTRIBUTES option is specified without any attributes requested, then it is just the same as if one had specified ATTRIBUTES(#INTERESTING). Note that union links do not normally have any interesting attributes attached to them, except for FILTER.

ATTRIBUTES(ID+FILTER) is always implied. For EXTERNAL links, ATTRIBUTES(ACCESS-METHOD) is always implied.gif

There are some special arguments to the ATTRIBUTES option. It is not a good idea for application-defined attributes to have names that conflict with these special arguments; if there are such application-defined attributes, you may have to use the #ALL special argument to look at their values. More than one special argument may be specified, and one may mix special and non-special arguments. Also, note that it is never erroneous for a server to return more attributes than were asked for, nor is it erroneous for a server to return attribute information even if no ATTRIBUTES option was specified to the LIST command. A server that always behaved as if the ATTRIBUTES(#ALL) option were specified would be behaving legally, although it would not be terribly efficient.

#INTERESTING
Return only interesting attributes. What constitutes an ``interesting'' attribute is server-dependent. This allows one to use Prospero for special applications.
#ALL
If this argument is specified, and the object resides on the same host as the link, then the attributes stored with the object referenced by the link will be returned in addition to those stored with the link, and no cached attributes will be returned (they would be irrelevant). If the object resides on a host different from the link, then all attributes stored with the link are returned, but not those stored with the object referenced by the link. This requests everything on the link, except for attributes with the - suffix.gif

#CACHED
Return all attributes of precedence CACHED. If you specify #CACHED with #ALL, the server will return cached attributes in addition to those that would be returned if you'd just specified #ALL. It is not clear how useful this behavior is.
#OBJECT
Return all attributes of type OBJECT. This modifies the rest of the attribute request. It cannot be free-standing; #OBJECT by itself is undefined. Note that this will not work if the object does not reside on the same host as the link.
#ADDITIONAL
Return all attributes of precedence ADDITIONAL.
#REPLACEMENT
Return all attributes of precedence REPLACEMENT.
#LINK
Return all attributes of precedence LINK.
#FIELD
Return all fields (all system-defined standard attributes), except for ones that have already been returned as part of the LINK response, such as HOST, HSONAME, and DEST-EXP.
##FIELD
Return all fields. (This option will be rarely used.)
#APPLICATION
Return all application-defined attributes.


next up previous contents
Next: FILTER option Up: Options Previous: Miscellaneous Options

Padma Indraganti
Thu Jun 20 13:02:20 PDT 1996