W3 addresses for WAIS servers

Servers using the WAIS ("Wide Area Information Systems") protocols from Thinking Machines may be accessed as part of the web using addresses of the form (see BNF description)

w a i s : / / hostport / database ...

Access (currently) goes through a gateway which stores the "source" files which contain the descriptions of WAIS servers. This address corresponds to the address of an index. To this may optionally be appended either a search string or a document identifier.

Note that changes have been proposed to WAIS document id format, so this representation of them may have to change with that format. Currently the WAIS document address necessary for retrieval by a client requires the following information, which is orginally provided by the server in the hit list.

Document format

This is normally "TEXT" but other formats such as PS, GIF, exist.

Document length

This is needed by the client who must loop to retrie the whole document in slices.

Document identifier

This is an entity consisting of numerically tagged fields. the binary representation used by WAIS is transformed for readability into a sequence of fields each consisting of a decimal tag, an equals sign (=) , the field value, and a semicolon. Within the field value, hex escaping is used for otherwise illegal characters.

See also: Other W3 address formats, BNF definition.

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Tim BL