72 lines
3.5 KiB
Plaintext
72 lines
3.5 KiB
Plaintext
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gWAIS LINK FORMAT
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This document describes Prospero links to files accessible through
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WAIS; we have not yet determined a format for WAIS directory & index
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lookups. This format works for both external WAIS links and native
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WAIS links (that is, links to WAIS files stored on a server running
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Prospero).
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The WAIS record locator string has a port # and hostname encoded into
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it. We treat the record locator as an impenetrable object that we
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just give to the WAIS server at a particular wais server (WAIS servers
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are uniquely identified by a hostname port # pair); Prospero itself
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doesn't worry about extracting this information from the WAIS record
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locator string. The person or computer program creating a link to a
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WAIS object is responsible for obtaining the WAIS port # and hostname.
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The HOSTNAME on the VLINK is the hostname of the prospero server which
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stores information about that file. If the server is running on a
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non-standard port, this hostname will be followed by a port number in
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parentheses.
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The HSONAME on the VLINK for a file which is usually accessed through
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WAIS begins with the sequence WAIS/OBJECT/ and then finishes with the
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WAIS record locator string.
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Not all files which can be retrieved via the WAIS access method will
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have an HSONAME on the VLINK in this format. This is because the
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server may send a WAIS access method even for a file that is primarily
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accessed through NFS, Anonymous FTP, or some other access method. In
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this case, the ACCESS-METHOD attribute for the file will usually have
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the six-token format (described below).
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The ACCESS-METHOD attribute for WAIS files consists of 5 [sometimes 6] tokens:
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WAIS INTERNET-D <hostname> ASCII <hsoname>
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[optional record locator string]
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WAIS, INTERNET-D, and ASCII are literals.
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The <hostname> token in the ACCESS-METHOD attribute is the name of the
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host whose WAIS server must be contacted to retrieve the object (same
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as the hostname encoded into the record locator). If the WAIS server
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is running on the default WAIS port (210), this <hostname> token may be the
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normal Internet hostname or it may be followed by the port # in
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parentheses. The <hostname> token must always include the port # in
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parentheses if the WAIS server is running on a non-default port.
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If a sixth token is present in the WAIS access-method attribute, then
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this is the WAIS record locator string which will be sent to the WAIS
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server to retrieve the object. If the sixth token is not present,
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then the <hsoname> token of the ACCESS-METHOD attribute must begin with
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the sequence WAIS/OBJECT/ and then finish off with the WAIS record
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locator string. The WAIS/OBJECT/ prefix will be stripped off and the
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resulting string will be sent to the WAIS server.
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The most common case for the WAIS access method is on a link whose
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target is FILE (not EXTERNAL) to an object which can be retrieved from
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a wais server running on the default WAIS port on the same host as the
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PROSPERO server which indexes it, and with the PROSPERO server running
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on the default PROSPERO port. In this case, the HOST and HOSNAME
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tokens in the ACCESS-METHOD attribute are the same and those for the
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link. Therefore, using the defaults that apply to all access methods,
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the ACCESS-METHOD attribute can be sent across the network as:
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WAIS '' '' '' ''
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In the case of an EXTERNAL link to a WAIS object, the HOST and HSONAME
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tokens in the vlink are customarially (although this is not strictly
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enforced) the same as those for the access method, and the access
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method is sent across the network using the defaulting mechanism.
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