doc: Add RFC documents

1 files changed, 1291 insertions, 0 deletions

diff --git a/doc/rfc/rfc2731.txt b/doc/rfc/rfc2731.txt
new file mode 100644
index 0000000..1d1d194
--- /dev/null
+++ b/doc/rfc/rfc2731.txt
@@ -0,0 +1,1291 @@
+
+
+
+
+
+
+Network Working Group                                           J. Kunze
+Request for Comments: 2731                                   Dublin Core
+Category: Informational                              Metadata Initiative
+                                                           December 1999
+
+
+                 Encoding Dublin Core Metadata in HTML
+
+
+Status of this Memo
+
+   This memo provides information for the Internet community.  It does
+   not specify an Internet standard of any kind.  Distribution of this
+   memo is unlimited.
+
+Copyright Notice
+
+   Copyright (C) The Internet Society (1999).  All Rights Reserved.
+
+1. Abstract
+
+   The Dublin Core [DC1] is a small set of metadata elements for
+   describing information resources.  This document explains how these
+   elements are expressed using the META and LINK tags of HTML
+   [HTML4.0].  A sequence of metadata elements embedded in an HTML file
+   is taken to be a description of that file.  Examples illustrate
+   conventions allowing interoperation with current software that
+   indexes, displays, and manipulates metadata, such as [SWISH-E],
+   [freeWAIS-sf2.0], [GLIMPSE], [HARVEST], [ISEARCH], etc., and the Perl
+   [PERL] scripts in the appendix.
+
+2. HTML, Dublin Core, and Non-Dublin Core Metadata
+
+   The Dublin Core (DC) metadata initiative [DCHOME] has produced a
+   small set of resource description categories [DC1], or elements of
+   metadata (literally, data about data).  Metadata elements are
+   typically small relative to the resource they describe and may, if
+   the resource format permits, be embedded in it.  Two such formats are
+   the Hypertext Markup Language (HTML) and the Extensible Markup
+   Language (XML); HTML is currently in wide use, but once standardized,
+   XML [XML] in conjunction with the Resource Description Framework
+   [RDF] promise a significantly more expressive means of encoding
+   metadata.  The [RDF] specification actually describes a way to use
+   RDF within an HTML document by adhering to an abbreviated syntax.
+
+
+
+
+
+
+
+Kunze                        Informational                      [Page 1]
+
+RFC 2731         Encoding Dublin Core Metadata in HTML     December 1999
+
+
+   This document explains how to encode metadata using HTML 4.0
+   [HTML4.0].  It is not concerned with element semantics, which are
+   defined elsewhere.  For illustrative purposes, some element semantics
+   are alluded to, but in no way should semantics appearing here be
+   considered definitive.
+
+   The HTML encoding allows elements of DC metadata to be interspersed
+   with non-DC elements (provided such mixing is consistent with rules
+   governing use of those non-DC elements).  A DC element is indicated
+   by the prefix "DC", and a non-DC element by another prefix; for
+   example, the prefix "AC" is used with elements from the A-Core [AC].
+
+3. The META Tag
+
+   The META tag of HTML is designed to encode a named metadata element.
+   Each element describes a given aspect of a document or other
+   information resource.  For example, this tagged metadata element,
+
+       <meta name    = "DC.Creator"
+             content = "Simpson, Homer">
+
+   says that Homer Simpson is the Creator, where the element named
+   Creator is defined in the DC element set.  In the more general form,
+
+       <meta name    = "PREFIX.ELEMENT_NAME"
+             content = "ELEMENT_VALUE">
+
+   the capitalized words are meant to be replaced in actual
+   descriptions; thus in the example,
+
+             ELEMENT_NAME   was:  Creator
+             ELEMENT_VALUE  was:  Simpson, Homer
+             and PREFIX     was:  DC
+
+   Within a META tag the first letter of a Dublin Core element name is
+   capitalized.  DC places no restriction on alphabetic case in an
+   element value and any number of META tagged elements may appear
+   together, in any order.  More than one DC element with the same name
+   may appear, and each DC element is optional.  The next example is a
+   book description with two authors, two titles, and no other metadata.
+
+       <meta name    = "DC.Title"
+             content = "The Communist Manifesto">
+       <meta name    = "DC.Creator"
+             content = "Marx, K.">
+
+
+
+
+
+
+Kunze                        Informational                      [Page 2]
+
+RFC 2731         Encoding Dublin Core Metadata in HTML     December 1999
+
+
+       <meta name    = "DC.Creator"
+             content = "Engels, F.">
+       <meta name    = "DC.Title"
+             content = "Capital">
+
+   The prefix "DC" precedes each Dublin Core element encoded with META,
+   and it is separated by a period (.) from the element name following
+   it.  Each non-DC element should be encoded with a prefix that can be
+   used to trace its origin and definition; the linkage between prefix
+   and element definition is made with the LINK tag, as explained in the
+   next section.  Non-DC elements, such as Email from the A-Core [AC],
+   may appear together with DC elements, as in
+
+       <meta name    = "DC.Creator"
+             content = "Da Costa, Jos&eacute;">
+       <meta name    = "AC.Email"
+             content = "dacostaj@peoplesmail.org">
+       <meta name    = "DC.Title"
+             content = "Jesse &#34;The Body&#34; Ventura--A Biography">
+
+   This example also shows how some special characters may be encoded.
+   The author name in the first element contains a diacritic encoded as
+   an HTML character entity reference -- in this case an accented letter
+   E.  Similarly, the last line contains two double-quote characters
+   encoded so as to avoid being interpreted as element content
+   delimiters.
+
+4. The LINK Tag
+
+   The LINK tag of HTML may be used to associate an element name prefix
+   with the reference definition of the element set that it identifies.
+   A sequence of META tags describing a resource is incomplete without
+   one such LINK tag for each different prefix appearing in the
+   sequence.  The previous example could be considered complete with the
+   addition of these two LINK tags:
+
+       <link rel     = "schema.DC"
+             href    = "http://purl.org/DC/elements/1.0/">
+       <link rel     = "schema.AC"
+             href    = "http://metadata.net/ac/2.0/">
+
+   In general, the association takes the form
+
+       <link rel     = "schema.PREFIX"
+             href    = "LOCATION_OF_DEFINITION">
+
+
+
+
+
+
+Kunze                        Informational                      [Page 3]
+
+RFC 2731         Encoding Dublin Core Metadata in HTML     December 1999
+
+
+   where, in actual descriptions, PREFIX is to be replaced by the prefix
+   and LOCATION_OF_DEFINITION by the URL or URN of the defining
+   document.  When embedded in the HEAD part of an HTML file, a sequence
+   of LINK and META tags describes the information in the surrounding
+   HTML file itself.  Here is a complete HTML file with its own embedded
+   description.
+
+       <html>
+       <head>
+       <title> A Dirge </title>
+       <link rel     = "schema.DC"
+             href    = "http://purl.org/DC/elements/1.0/">
+       <meta name    = "DC.Title"
+             content = "A Dirge">
+       <meta name    = "DC.Creator"
+             content = "Shelley, Percy Bysshe">
+       <meta name    = "DC.Type"
+             content = "poem">
+       <meta name    = "DC.Date"
+             content = "1820">
+       <meta name    = "DC.Format"
+             content = "text/html">
+       <meta name    = "DC.Language"
+             content = "en">
+       </head>
+       <body><pre>
+               Rough wind, that moanest loud
+                 Grief too sad for song;
+               Wild wind, when sullen cloud
+                 Knells all the night long;
+               Sad storm, whose tears are vain,
+               Bare woods, whose branches strain,
+               Deep caves and dreary main, -
+                 Wail, for the world's wrong!
+       </pre></body>
+       </html>
+
+5. Encoding Recommendations
+
+   HTML allows more flexibility in principle and in practice than is
+   recommended here for encoding metadata.  Limited flexibility
+   encourages easy development of software for extracting and processing
+   metadata.  At this early evolutionary stage of internet metadata,
+   easy prototyping and experimentation hastens the development of
+   useful standards.
+
+
+
+
+
+
+Kunze                        Informational                      [Page 4]
+
+RFC 2731         Encoding Dublin Core Metadata in HTML     December 1999
+
+
+   Adherence is therefore recommended to the tagging style exemplified
+   in this document as regards prefix and element name capitalization,
+   double-quoting (") of attribute values, and not starting more than
+   one META tag on a line.  There is much room for flexibility, but
+   choosing a style and sticking with it will likely make metadata
+   manipulation and editing easier.  The following META tags adhere to
+   the recommendations and carry identical metadata in three different
+   styles:
+
+       <META NAME="DC.Format"
+             CONTENT="text/html; 12 Kbytes">
+       <meta
+               Content = "text/html; 12 Kbytes"
+               Name = "DC.Format"
+       >
+       <meta name = "DC.Format" content = "text/html; 12 Kbytes">
+
+   Use of these recommendations is known to result in metadata that may
+   be harvested, indexed, and manipulated by popular, freely available
+   software packages such as [SWISH-E], [freeWAIS-sf2.0], [GLIMPSE],
+   [HARVEST], and [ISEARCH], among others.  These conventions also work
+   with the metadata processing scripts appearing in the appendix, as
+   well as with most of the [DCPROJECTS] applications referenced from
+   the [DCHOME] site.  Software support for the LINK tag and qualifier
+   conventions (see the next section) is not currently widespread.
+
+   Ordering of metadata elements is not preserved in general.  Writers
+   of software for metadata indexing and display should try to preserve
+   relative ordering among META tagged elements having the same name
+   (e.g., among multiple authors), however, metadata providers and
+   searchers have no guarantee that ordering will be preserved in
+   metadata that passes through unknown systems.
+
+6. Dublin Core in Real Descriptions
+
+   In actual resource description it is often necessary to qualify
+   Dublin Core elements to add nuances of meaning.  While neither the
+   general principles nor the specific semantics of DC qualifiers are
+   within scope of this document, everyday uses of the qualifier syntax
+   are illustrated to lend realism to later examples.  Without further
+   explanation, the three ways in which the optional qualifier syntax is
+   currently (subject to change) used to supplement the META tag may be
+   summarized as follows:
+
+    <meta lang    = "LANGUAGE_OF_METADATA_CONTENT" ... >
+
+    <meta scheme  = "CONTROLLED_FORMAT_OR_VOCABULARY_OF_METADATA" ... >
+
+
+
+
+Kunze                        Informational                      [Page 5]
+
+RFC 2731         Encoding Dublin Core Metadata in HTML     December 1999
+
+
+    <meta name    = "PREFIX.ELEMENT_NAME.SUBELEMENT_NAME" ... >
+
+   Accordingly, a posthumous work in Spanish might be described with
+
+       <meta name    = "DC.Language"
+             scheme  = "rfc1766"
+             content = "es">
+       <meta name    = "DC.Title"
+             lang    = "es"
+             content = "La Mesa Verde y la Silla Roja">
+       <meta name    = "DC.Title"
+             lang    = "en"
+             content = "The Green Table and the Red Chair">
+       <meta name    = "DC.Date.Created"
+             content = "1935">
+       <meta name    = "DC.Date.Available"
+             content = "1939">
+
+   Note that the qualifier syntax and label suffixes (which follow an
+   element name and a period) used in examples in this document merely
+   reflect current trends in the HTML encoding of qualifiers.  Use of
+   this syntax and these suffixes is neither a standard nor a
+   recommendation.
+
+7. Encoding Dublin Core Elements
+
+   This section consists of very simple Dublin Core encoding examples,
+   arranged by element.
+
+   Title (name given to the resource)
+   -----
+
+    <meta name    = "DC.Title"
+          content = "Polycyclic aromatic hydrocarbon contamination">
+
+    <meta name    = "DC.Title"
+          content = "Crime and Punishment">
+
+    <meta name    = "DC.Title"
+          content = "Methods of Information in Medicine, Vol 32, No 4">
+
+    <meta name    = "DC.Title"
+          content = "Still life #4 with flowers">
+
+    <meta name    = "DC.Title"
+          lang    = "de"
+          content = "Das Wohltemperierte Klavier, Teil I">
+
+
+
+
+Kunze                        Informational                      [Page 6]
+
+RFC 2731         Encoding Dublin Core Metadata in HTML     December 1999
+
+
+   Creator (entity that created the content)
+   -------
+
+    <meta name    = "DC.Creator"
+          content = "Gogh, Vincent van">
+    <meta name    = "DC.Creator"
+          content = "van Gogh, Vincent">
+
+    <meta name    = "DC.Creator"
+          content = "Mao Tse Tung">
+    <meta name    = "DC.Creator"
+          content = "Mao, Tse Tung">
+
+    <meta name    = "DC.Creator"
+          content = "Plato">
+    <meta name    = "DC.Creator"
+          lang    = "fr"
+          content = "Platon">
+
+    <meta name    = "DC.Creator.Director"
+          content = "Sturges, Preston">
+    <meta name    = "DC.Creator.Writer"
+          content = "Hecht, Ben">
+    <meta name    = "DC.Creator.Producer"
+          content = "Chaplin, Charles">
+
+   Subject (topic or keyword)
+   -------
+
+    <meta name    = "DC.Subject"
+          content = "heart attack">
+    <meta name    = "DC.Subject"
+          scheme  = "MESH"
+          content = "Myocardial Infarction; Pericardial Effusion">
+
+    <meta name    = "DC.Subject"
+          content = "vietnam war">
+    <meta name    = "DC.Subject"
+          scheme  = "LCSH"
+          content = "Vietnamese Conflict, 1961-1975">
+
+    <meta name    = "DC.Subject"
+          content = "Friendship">
+    <meta name    = "DC.Subject"
+          scheme  = "ddc"
+          content = "158.25">
+
+
+
+
+
+Kunze                        Informational                      [Page 7]
+
+RFC 2731         Encoding Dublin Core Metadata in HTML     December 1999
+
+
+   Description (account, summary, or abstract of the content)
+   -----------
+
+    <meta name    = "DC.Description"
+          lang    = "en"
+          content = "The Author gives some Account of Himself and Family
+                     -- His First Inducements to Travel -- He is
+                     Shipwrecked, and Swims for his Life -- Gets safe on
+                     Shore in the Country of Lilliput -- Is made a
+                     Prisoner, and carried up the Country">
+
+    <meta name    = "DC.Description"
+          content = "A tutorial and reference manual for Java.">
+
+    <meta name    = "DC.Description"
+          content = "Seated family of five, coconut trees to the left,
+                     sailboats moored off sandy beach to the right,
+                     with volcano in the background.">
+
+   Publisher (entity that made the resource available)
+   ---------
+
+    <meta name    = "DC.Publisher"
+          content = "O'Reilly">
+
+    <meta name    = "DC.Publisher"
+          content = "Digital Equipment Corporation">
+
+    <meta name    = "DC.Publisher"
+          content = "University of California Press">
+
+    <meta name    = "DC.Publisher"
+          content = "State of Florida (USA)">
+
+   Contributor (other entity that made a contribution)
+   -----------
+
+    <meta name    = "DC.Contributor"
+          content = "Curie, Marie">
+
+    <meta name    = "DC.Contributor.Photographer"
+          content = "Adams, Ansel">
+    <meta name    = "DC.Contributor.Artist"
+          content = "Sendak, Maurice">
+    <meta name    = "DC.Contributor.Editor"
+          content = "Starr, Kenneth">
+
+
+
+
+
+Kunze                        Informational                      [Page 8]
+
+RFC 2731         Encoding Dublin Core Metadata in HTML     December 1999
+
+
+   Date (of an event in the life of the resource; [WTN8601] recommended)
+   ----
+
+    <meta name    = "DC.Date"
+          content = "1972">
+
+    <meta name    = "DC.Date"
+          content = "1998-05-14">
+    <meta name    = "DC.Date"
+          scheme  = "WTN8601"
+          content = "1998-05-14">
+
+    <meta name    = "DC.Date.Created"
+          content = "1998-05-14">
+    <meta name    = "DC.Date.Available"
+          content = "1998-05-21">
+    <meta name    = "DC.Date.Valid"
+          content = "1998-05-28">
+
+    <meta name    = "DC.Date.Created"
+          content = "triassic">
+    <meta name    = "DC.Date.Acquired"
+          content = "1957">
+
+    <meta name    = "DC.Date.Accepted"
+          scheme  = "WTN8601"
+          content = "1998-12-02T16:59">
+
+    <meta name    = "DC.Date.DataGathered"
+          scheme  = "ISO8601"
+          content = "98-W49-3T1659">
+
+    <meta name    = "DC.Date.Issued"
+          scheme  = "ANSI.X3.X30-1985"
+          content = "19980514">
+
+   Type (nature, genre, or category; [DCT1] recommended)
+   ----
+
+    <meta name    = "DC.Type"
+          content = "poem">
+
+    <meta name    = "DC.Type"
+          scheme  = "DCT1"
+          content = "software">
+    <meta name    = "DC.Type"
+          content = "software program source code">
+
+
+
+
+Kunze                        Informational                      [Page 9]
+
+RFC 2731         Encoding Dublin Core Metadata in HTML     December 1999
+
+
+    <meta name    = "DC.Type"
+          content = "interactive video game">
+
+    <meta name    = "DC.Type"
+          scheme  = "DCT1"
+          content = "dataset">
+
+    <meta name    = "DC.Type"
+          content = "web home page">
+    <meta name    = "DC.Type"
+          content = "web bibliography">
+
+    <meta name    = "DC.Type"
+          content = "painting">
+    <meta name    = "DC.Type"
+          content = "image; woodblock">
+    <meta name    = "DC.Type"
+          scheme  = "AAT"
+          content = "clipeus (portrait)">
+    <meta name    = "DC.Type"
+          lang    = "en-US"
+          content = "image; advertizement">
+
+    <meta name    = "DC.Type"
+          scheme  = "DCT1"
+          content = "event">
+    <meta name    = "DC.Type"
+          content = "event; periodic">
+
+   Format (physical or digital data format, plus optional dimensions)
+   ------
+
+    <meta name    = "DC.Format"
+          content = "text/xml">
+    <meta name    = "DC.Format"
+          scheme  = "IMT"
+          content = "text/xml">
+
+    <meta name    = "DC.Format"
+          scheme  = "IMT"
+          content = "image/jpeg">
+    <meta name    = "DC.Format"
+          content = "A text file with mono-spaced tables and diagrams.">
+
+    <meta name    = "DC.Format"
+          content = "video/mpeg; 14 minutes">
+
+
+
+
+
+Kunze                        Informational                     [Page 10]
+
+RFC 2731         Encoding Dublin Core Metadata in HTML     December 1999
+
+
+    <meta name    = "DC.Format"
+          content = "unix tar archive, gzip compressed; 1.5 Mbytes">
+
+    <meta name    = "DC.Format"
+          content = "watercolor; 23 cm x 31 cm">
+
+   Identifier (of the resource)
+   ----------
+
+    <meta name    = "DC.Identifier"
+          content = "http://foo.bar.org/zaf/">
+
+    <meta name    = "DC.Identifier"
+          content = "urn:ietf:rfc:1766">
+
+    <meta name    = "DC.Identifier"
+          scheme  = "ISBN"
+          content = "1-56592-149-6">
+
+    <meta name    = "DC.Identifier"
+          scheme  = "LCCN"
+          content = "67-26020">
+
+    <meta name    = "DC.Identifier"
+          scheme  = "DOI"
+          content = "10.12345/33-824688ab">
+
+   Source (reference to the resource's origin)
+   ------
+
+    <meta name    = "DC.Source"
+          content = "Shakespeare's Romeo and Juliet">
+
+    <meta name    = "DC.Source"
+          content = "http://a.b.org/manon/">
+
+   Language (of the content of the resource; [RFC1766] recommended)
+   --------
+
+    <meta name    = "DC.Language"
+          content = "en">
+    <meta name    = "DC.Language"
+          scheme  = "rfc1766"
+          content = "en">
+    <meta name    = "DC.Language"
+          scheme  = "ISO639-2"
+          content = "eng">
+
+
+
+
+Kunze                        Informational                     [Page 11]
+
+RFC 2731         Encoding Dublin Core Metadata in HTML     December 1999
+
+
+    <meta name    = "DC.Language"
+          scheme  = "rfc1766"
+          content = "en-US">
+
+    <meta name    = "DC.Language"
+          content = "zh">
+    <meta name    = "DC.Language"
+          content = "ja">
+    <meta name    = "DC.Language"
+          content = "es">
+    <meta name    = "DC.Language"
+          content = "de">
+
+    <meta name    = "DC.Language"
+          content = "german">
+    <meta name    = "DC.Language"
+          lang    = "fr"
+          content = "allemand">
+
+   Relation (reference to a related resource)
+   --------
+
+    <meta name    = "DC.Relation.IsPartOf"
+          content = "http://foo.bar.org/abc/proceedings/1998/">
+
+    <meta name    = "DC.Relation.IsFormatOf"
+          content = "http://foo.bar.org/cd145.sgml">
+
+    <meta name    = "DC.Relation.IsVersionOf"
+          content = "http://foo.bar.org/draft9.4.4.2">
+
+    <meta name    = "DC.Relation.References"
+          content = "urn:isbn:1-56592-149-6">
+
+    <meta name    = "DC.Relation.IsBasedOn"
+          content = "Shakespeare's Romeo and Juliet">
+
+    <meta name    = "DC.Relation.Requires"
+          content = "LWP::UserAgent; HTML::Parse; URI::URL;
+                     Net::DNS; Tk::Pixmap; Tk::Bitmap; Tk::Photo">
+
+   Coverage (extent or scope of the content)
+   --------
+
+    <meta name    = "DC.Coverage"
+          content = "US civil war era; 1861-1865">
+
+
+
+
+
+Kunze                        Informational                     [Page 12]
+
+RFC 2731         Encoding Dublin Core Metadata in HTML     December 1999
+
+
+    <meta name    = "DC.Coverage"
+          content = "Columbus, Ohio, USA; Lat: 39 57 N Long: 082 59 W">
+
+    <meta name    = "DC.Coverage"
+          scheme  = "TGN"
+          content = "Columbus (C,V)">
+
+    <meta name    = "DC.Coverage.Jurisdiction"
+          content = "Commonwealth of Australia">
+
+   Rights (text or identifier of a rights management statement)
+   ------
+
+    <meta name    = "DC.Rights"
+          lang    = "en"
+          content = "Copyright Acme 1999 - All rights reserved.">
+
+    <meta name    = "DC.Rights"
+          content = "http://foo.bar.org/cgi-bin/terms">
+
+8. Security Considerations
+
+   The syntax rules for encoding Dublin Core metadata in HTML that are
+   documented here pose no direct risk to computers and networks.
+   People can use these rules to encode metadata that is inaccurate or
+   even deliberately misleading (creating mischief in the form of "index
+   spam"), however, this reflects a general pattern of HTML META tag
+   abuse that is not limited to the encoding of metadata from the Dublin
+   Core set.  Even traditional metadata encoding schemes (e.g., [MARC])
+   are not immune to inaccuracy, although they are generally followed in
+   environments where production quality greatly exceeds that of the
+   average Web site.
+
+   Systems that process metadata encoded with META tags need to consider
+   issues related to its accuracy and validity as part of their design
+   and implementation, and users of such systems need to consider the
+   design and implementation assumptions.  Various approaches may be
+   relevant for certain applications, such as adding statements of
+   metadata provenance, signing of metadata with digital signatures, and
+   automating certain aspects of metadata creation; but these are far
+   outside the scope of this document and the underlying META tag syntax
+   that it describes.
+
+
+
+
+
+
+
+
+
+Kunze                        Informational                     [Page 13]
+
+RFC 2731         Encoding Dublin Core Metadata in HTML     December 1999
+
+
+9. Appendix -- Perl Scripts that Manipulate HTML Encoded Metadata
+
+   This section contains two simple programs that work with versions 4
+   and 5 of the Perl [PERL] scripting language interpreter.  They may be
+   taken and freely adapted for local organizational needs, research
+   proposals, venture capital bids, etc.  A variety of applications are
+   within easy reach of implementors that choose to build on these
+   scripts.
+
+   Script 1:  Metadata Format Conversion
+   -------------------------------------
+
+   Here is a simple Perl script that correctly recognizes every example
+   of metadata encoding in this document.  It shows how a modest
+   scripting effort can produce a utility that converts metadata from
+   one format to another.  Minor changes are sufficient to support a
+   number of output formats.
+
+#!/depot/bin/perl
+#
+# This simple perl script extracts metadata embedded in an HTML file
+# and outputs it in an alternate format.  Issues warning about missing
+# element name or value.
+#
+# Handles mixed case tags and attribute values, one per line or spanning
+# several lines.  Also handles a quoted string spanning multiple lines.
+# No error checking.  Does not tolerate more than one "<meta" per line.
+
+print "@(urc;\n";
+while (<>) {
+        next if (! /<meta/i);
+        ($meta) = /(<meta.*$)/i;
+        if (! /<meta.*>/i) {
+                while (<>) {
+                        $meta .= $_;
+                        last if (/>/);
+                }
+        }
+        $name     =    $meta =~ /name\s*=\s*"([^"]*)"/i
+                        ? $1 : "MISSING ELEMENT NAME";
+        $content  = $meta =~ /content\s*=\s*"([^"]*)"/i
+                        ? $1 : "MISSING ELEMENT VALUE";
+        ($scheme) =  $meta =~ /scheme\s*=\s*"([^"]*)"/i;
+        ($lang)   =    $meta =~ /lang\s*=\s*"([^"]*)"/i;
+
+        if ($lang || $scheme) {
+                $mod = " ($lang";
+                if (! $scheme)
+
+
+
+Kunze                        Informational                     [Page 14]
+
+RFC 2731         Encoding Dublin Core Metadata in HTML     December 1999
+
+
+                        { $mod .= ")"; }
+                elsif (! $lang)
+                        { $mod .= "$scheme)" }
+                else
+                        { $mod .= ", $scheme)"; }
+        }
+        else
+                { $mod = ""; }
+
+        print "    @|$name$mod; $content\n";
+}
+print "@)urc;\n";
+# ---- end of Perl script ----
+
+   When the conversion script is run on the metadata file example from
+   the LINK tag section (section 4), it produces the following output.
+
+        @(urc;
+            @|DC.Title; A Dirge
+            @|DC.Creator; Shelley, Percy Bysshe
+            @|DC.Type; poem
+            @|DC.Date; 1820
+            @|DC.Format; text/html
+            @|DC.Language; en
+        @)urc;
+
+   Script 2:  Automated Metadata Creation
+   --------------------------------------
+
+   The creation and maintenance of high-quality metadata can be
+   extremely expensive without automation to assist in processes such as
+   supplying pre-set or computed defaults, validating syntax, verifying
+   value ranges, spell checking, etc.  Considerable relief could be had
+   from a script that reduced an individual provider's metadata burden
+   to just the title of each document.  Below is such a script.  It lets
+   the provider of an HTML document abbreviate an entire embedded
+   resource description using a single HTML comment statement that looks
+   like
+
+       <!--metablock Little Red Riding Hood -->
+
+   Our script processes this statement specially as a kind of "metadata
+   block" declaration with attached title.  The general form is
+
+       <!--metablock TITLE_OF_DOCUMENT -->
+
+
+
+
+
+
+Kunze                        Informational                     [Page 15]
+
+RFC 2731         Encoding Dublin Core Metadata in HTML     December 1999
+
+
+   This statement works much like a "Web server-side include" in that
+   the script replaces it with a fully-specified block of metadata and
+   triggers other replacements.  Once installed, the script can output
+   HTML files suitable for integration into one's production Web server
+   procedures.
+
+   The individual provider keeps a separate "template" file of
+   infrequently changing pre-set values for metadata elements.  If the
+   provider's needs are simple enough, the only element values besides
+   the title that differ from one document to the next may be generated
+   automatically.  Using the script, values may be referenced as
+   variables from within the template or within the document.  Our
+   variable references have the form "(--mbVARNAME)", and here is what
+   they look like inside a template:
+
+       <title> (--mbtitle) </title>
+       <meta name    = "DC.Creator"
+             content = "Simpson, Homer">
+       <meta name    = "DC.Title"
+             content = "(--mbtitle)">
+       <meta name    = "DC.Date.Created"
+             content = "(--mbfilemodtime)">
+       <meta name    = "DC.Identifier"
+             content = "(--mbbaseURL)/(--mbfilename)">
+       <meta name    = "DC.Format"
+             content = "text/html; (--mbfilesize)">
+       <meta name    = "DC.Language"
+             content = "(--mblanguage)-BUREAUCRATESE">
+       <meta name    = "RC.MetadataAuthority"
+             content = "Springfield Nuclear">
+       <link rel     = "schema.DC"
+             href    = "http://purl.org/DC/elements/1.0/">
+       <link rel     = "schema.RC"
+             href    = "http://nukes.org/ReactorCore/rc">
+
+   The above template represents the metadata block that will describe
+   the document once the variable references are replaced with real
+   values.  By the conventions of our script, the following variables
+   will be replaced in both the template and in the document:
+
+       (--mbfilesize)            size of the final output file
+       (--mbtitle)               title of the document
+       (--mblanguage)            language of the document
+       (--mbbaseURL)             beginning part of document identifier
+       (--mbfilename)            last part (minus .html) of identifier
+       (--mbfilemodtime)         last modification date of the document
+
+
+
+
+
+Kunze                        Informational                     [Page 16]
+
+RFC 2731         Encoding Dublin Core Metadata in HTML     December 1999
+
+
+   Here's an example HTML file to run the script on.
+
+       <html>
+       <head>
+       <!--metablock Nutritional Allocation Increase -->
+       <meta name    = "DC.Type"
+             content = "Memorandum">
+       </head>
+       <body>
+       <p>
+       From:  Acting Shift Supervisor
+       To:    Plant Control Personnel
+       RE:    (--mbtitle)
+       Date:  (--mbfilemodtime)
+       <p>
+       Pursuant to directive DOH:10.2001/405aec of article B-2022,
+       subsection 48.2.4.4.1c regarding staff morale and employee
+       productivity standards, the current allocation of doughnut
+       acquisition funds shall be increased effective immediately.
+       </body>
+       </html>
+
+   Note that because replacement occurs throughout the document, the
+   provider need only enter the title once instead of twice (normally
+   the title must be entered once in the HTML head and again in the HTML
+   body).  After running the script, the above file is transformed into
+   this:
+
+       <html>
+       <head>
+           <title> Nutritional Allocation Increase </title>
+       <meta name    = "DC.Creator"
+             content = "Simpson, Homer">
+       <meta name    = "DC.Title"
+             content = "Nutritional Allocation Increase">
+       <meta name    = "DC.Date.Created"
+             content = "1999-03-08">
+       <meta name    = "DC.Identifier"
+             content = "http://moes.bar.com/doh/homer.html">
+       <meta name    = "DC.Format"
+             content = "text/html;    1320  bytes">
+       <meta name    = "DC.Language"
+             content = "en-BUREAUCRATESE">
+       <meta name    = "RC.MetadataAuthority"
+             content = "Springfield Nuclear">
+       <link rel     = "schema.DC"
+             href    = "http://purl.org/DC/elements/1.0/">
+       <link rel     = "schema.RC"
+
+
+
+Kunze                        Informational                     [Page 17]
+
+RFC 2731         Encoding Dublin Core Metadata in HTML     December 1999
+
+
+             href    = "http://nukes.org/ReactorCore/rc">
+       <meta name    = "DC.Type"
+             content = "Memorandum">
+       </head>
+       <body>
+       <p>
+       From:  Acting Shift Supervisor
+       To:    Plant Control Personnel
+       RE:    Nutritional Allocation Increase
+       Date:  1999-03-08
+       <p>
+       Pursuant to directive DOH:10.2001/405aec of article B-2022,
+       subsection 48.2.4.4.1c regarding staff morale and employee
+       productivity standards, the current allocation of doughnut
+       acquisition funds shall be increased effective immediately.
+       </body>
+       </html>
+
+   Here is the script that accomplishes this transformation.
+
+#!/depot/bin/perl
+#
+# This Perl script processes metadata block declarations of the form
+# <!--metablock TITLE_OF_DOCUMENT --> and variable references of the
+# form (--mbVARNAME), replacing them with full metadata blocks and
+# variable values, respectively.  Requires a "template" file.
+# Outputs an HTML file.
+#
+# Invoke this script with a single filename argument, "foo".  It creates
+# an output file "foo.html" using a temporary working file "foo.work".
+# The size of foo.work is measured after variable replacement, and is
+# later inserted into the file in such a way that the file's size does
+# not change in the process.  Has little or no error checking.
+
+$infile = shift;
+open(IN, "< $infile")
+        or die("Could not open input file \"$infile\"");
+$workfile = "$infile.work";
+unlink($workfile);
+open(WORK, "+> $workfile")
+        or die("Could not open work file \"$workfile\"");
+
+@offsets = ();          # records locations for late size replacement
+$title = "";            # gets the title during metablock processing
+$language = "en";       # pre-set language here (not in the template)
+$baseURL = "http://moes.bar.com/doh";   # pre-set base URL here also
+$filename = "$infile.html";             # final output filename
+$filesize = "(--mbfilesize)";           # replaced late (separate pass)
+
+
+
+Kunze                        Informational                     [Page 18]
+
+RFC 2731         Encoding Dublin Core Metadata in HTML     December 1999
+
+
+($year, $month, $day) = (localtime( (stat IN) [9] ))[5, 4, 3];
+$filemodtime = sprintf "%s-%02s-%02s", 1900 + $year, 1 + $month, $day;
+
+sub putout {            # outputs current line with variable replacement
+        if (! /\(--mb/) {
+                print WORK;
+                return;
+        }
+        if (/\(--mbfilesize\)/)                 # remember where it was
+                { push @offsets, tell WORK; }   # but don't replace yet
+        s/\(--mbtitle\)/$title/g;
+        s/\(--mblanguage\)/$language/g;
+        s/\(--mbbaseURL\)/$baseURL/g;
+        s/\(--mbfilename\)/$filename/g;
+        s/\(--mbfilemodtime\)/$filemodtime/g;
+        print WORK;
+}
+
+while (<IN>) {                          # main loop for input file
+        if (! /(.*)<!--metablock\s*(.*)/) {
+                &putout;
+                next;
+        }
+        $title = $2;
+        $_ = $1;
+        &putout;
+        if ($title =~ s/\s*-->(.*)//) {
+                $remainder = $1;
+        }
+        else {
+                while (<IN>) {
+                        $title .= $_;
+                        last if (/(.*)\s*-->(.*)/);
+                }
+                $title .= $1;
+                $remainder = $2;
+        }
+        open(TPLATE, "< template")
+                or die("Could not open template file");
+        while (<TPLATE>)                # subloop for template file
+                { &putout; }
+        close(TPLATE);
+        $_ = $remainder;
+        &putout;
+
+
+
+
+
+
+
+Kunze                        Informational                     [Page 19]
+
+RFC 2731         Encoding Dublin Core Metadata in HTML     December 1999
+
+
+}
+close(IN);
+
+# Now replace filesize variables without altering total byte count.
+select( (select(WORK), $| = 1) [0] );   # first flush output so we
+if (($size = -s WORK) < 100000)         # can get final file size
+        { $scale = 0; }                 # and set scale factor or
+else {                  # compute it, keeping width of size field low
+        for ($scale = 0; $size >= 1000; $scale++)
+                { $size /= 1024; }
+}
+$filesize = sprintf "%7.7s %sbytes",
+        $size, (" ", "K", "M", "G", "T", "P") [$scale];
+
+foreach $pos (@offsets) {       # loop through saved size locations
+        seek WORK, $pos, 0;             # read the line found there
+        $_ = <WORK>;
+        # $filesize must be exactly as wide as "(--mbfilesize)"
+        s/\(--mbfilesize\)/$filesize/g;
+        seek WORK, $pos, 0;             # rewrite it with replacement
+        print WORK;
+}
+
+close(WORK);
+rename($workfile, "$filename")
+        or die("Could not rename \"$workfile\" to \"$filename\"");
+# ---- end of Perl script ----
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Kunze                        Informational                     [Page 20]
+
+RFC 2731         Encoding Dublin Core Metadata in HTML     December 1999
+
+
+10. Author's Address
+
+   John A. Kunze
+   Center for Knowledge Management
+   University of California, San Francisco
+   530 Parnassus Ave, Box 0840
+   San Francisco, CA  94143-0840, USA
+
+   Fax:   +1 415-476-4653
+   EMail: jak@ckm.ucsf.edu
+
+
+11. References
+
+   [AAT]            Art and Architecture Thesaurus, Getty Information
+                    Institute.
+                    http://shiva.pub.getty.edu/aat_browser/
+
+   [AC]             The A-Core: Metadata about Content Metadata, (in
+                    progress)
+                    http://metadata.net/ac/draft-iannella-admin-01.txt
+
+   [DC1]            Weibel, S., Kunze, J., Lagoze, C. and M. Wolf,
+                    "Dublin Core Metadata for Resource Discovery", RFC
+                    2413, September 1998.
+                    ftp://ftp.isi.edu/in-notes/rfc2413.txt
+
+   [DCHOME]         Dublin Core Initiative Home Page.
+                    http://purl.org/DC/
+
+   [DCPROJECTS]     Projects Using Dublin Core Metadata.
+                    http://purl.org/DC/projects/index.htm
+
+   [DCT1]           Dublin Core Type List 1, DC Type Working Group,
+                    March 1999.
+                    http://www.loc.gov/marc/typelist.html
+
+   [freeWAIS-sf2.0] The enhanced freeWAIS distribution, February 1999.
+                    http://ls6-www.cs.uni-
+                    dortmund.de/ir/projects/freeWAIS-sf/
+
+   [GLIMPSE]        Glimpse Home Page.
+                    http://glimpse.cs.arizona.edu/
+
+   [HARVEST]        Harvest Web Indexing.
+                    http://www.tardis.ed.ac.uk/harvest/
+
+
+
+
+
+Kunze                        Informational                     [Page 21]
+
+RFC 2731         Encoding Dublin Core Metadata in HTML     December 1999
+
+
+   [HTML4.0]        Hypertext Markup Language 4.0 Specification, April
+                    1998.
+                    http://www.w3.org/TR/REC-html40/
+
+   [ISEARCH]        Isearch Resources Page.
+                    http://www.etymon.com/Isearch/
+
+   [ISO639-2]       Code for the representation of names of languages,
+                    1996.
+                    http://www.indigo.ie/egt/standards/iso639/iso639-2-
+                    en.html
+
+   [ISO8601]        ISO 8601:1988(E), Data elements and interchange
+                    formats -- Information interchange -- Representation
+                    of dates and times, International Organization for
+                    Standardization, June 1988.
+                    http://www.iso.ch/markete/8601.pdf
+
+   [MARC]           USMARC Format for Bibliographic Data, US Library of
+                    Congress.
+                    http://lcweb.loc.gov/marc/marc.html
+
+   [PERL]           L. Wall, T. Christiansen, R. Schwartz, Programming
+                    Perl, Second Edition, O'Reilly, 1996.
+
+   [RDF]            Resource Description Framework Model and Syntax
+                    Specification, February 1999.
+                    http://www.w3.org/TR/REC-rdf-syntax/
+
+   [RFC1766]        Alvestrand, H., "Tags for the Identification of
+                    Languages", RFC 1766, March 1996.
+                    ftp://ftp.isi.edu/in-notes/rfc1766.txt
+
+   [SWISH-E]        Simple Web Indexing System for Humans - Enhanced.
+                    http://sunsite.Berkeley.EDU/SWISH-E/
+
+   [TGN]            Thesaurus of Geographic Names, Getty Information
+                    Institute.
+                    http://shiva.pub.getty.edu/tgn_browser/
+
+   [WTN8601]        W3C Technical Note - Profile of ISO 8601 Date and
+                    Time Formats.
+                    http://www.w3.org/TR/NOTE-datetime
+
+   [XML]            Extensible Markup Language (XML).
+                    http://www.w3.org/TR/REC-xml
+
+
+
+
+
+Kunze                        Informational                     [Page 22]
+
+RFC 2731         Encoding Dublin Core Metadata in HTML     December 1999
+
+
+12.  Full Copyright Statement
+
+   Copyright (C) The Internet Society (1999).  All Rights Reserved.
+
+   This document and translations of it may be copied and furnished to
+   others, and derivative works that comment on or otherwise explain it
+   or assist in its implementation may be prepared, copied, published
+   and distributed, in whole or in part, without restriction of any
+   kind, provided that the above copyright notice and this paragraph are
+   included on all such copies and derivative works.  However, this
+   document itself may not be modified in any way, such as by removing
+   the copyright notice or references to the Internet Society or other
+   Internet organizations, except as needed for the purpose of
+   developing Internet standards in which case the procedures for
+   copyrights defined in the Internet Standards process must be
+   followed, or as required to translate it into languages other than
+   English.
+
+   The limited permissions granted above are perpetual and will not be
+   revoked by the Internet Society or its successors or assigns.
+
+   This document and the information contained herein is provided on an
+   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
+   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
+   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
+   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
+   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
+
+Acknowledgement
+
+   Funding for the RFC Editor function is currently provided by the
+   Internet Society.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Kunze                        Informational                     [Page 23]
+