Network Working Group                                           R. Moats
Request for Comments: 2648                                          AT&T
Category: Informational                                      August 1999


                  A URN Namespace for IETF Documents

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.

Abstract

  A system for Uniform Resource Names (URNs) must be capable of
  supporting new naming systems.  As an example of proposing a new
  namespace, this document proposes the "ietf" namespace.  This
  namespace consists of the RFC family of documents (RFCs, STDs, FYIs,
  and BCPs) developed by the IETF and published by the RFC Editor, the
  minutes of working groups (WG) and birds of a feather (BOF) meetings
  that occur during IETF conferences, and the Internet Drafts published
  by the Internet Drafts Editor.  Both the current URN framework and
  URN syntax support this namespace.

1. Introduction

  This document proposes the "ietf" namespace, which consists of the
  RFC family of documents (RFCs, STDs, FYIs, and BCPs) developed by the
  IETF and published by the RFC editor and the minutes of working
  groups (WG) and birds of a feather (BOF) meetings that occur during
  IETF conferences.

  The namespace specification is for a formal namespace.

2. Specification Template

     Namespace ID:

           "ietf" requested.







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     Registration Information:

           Registration version number: 1
           Registration date: 1999-04-22

     Declared registrant of the namespace:

           Ryan Moats
           [email protected]
           AT&T
           15621 Drexel Circle
           Omaha, NE 68135-2358

     Declaration of structure:

           The identifier has the following ABNF [2] specification:

           NSS = rfc-nss / fyi-nss / std-nss / bcp-nss /
                 draft-nss / mtg-nss / other-nss

           rfc-nss = "rfc:" 1*DIGIT
           fyi-nss = "fyi:" 1*DIGIT
           std-nss = "std:" 1*DIGIT
           bcp-nss = "bcp:" 1*DIGIT
           draft-nss = "id:" string
           mtg-nss = "mtg:" string
           other-nss = string
             ; beginning with a prefix other than one of those
             ; above for future expansion

           string = 1*(DIGIT / ALPHA / "-")

           If the IESG (or it successor) adds a new document series,
           this ABNF specification will need to be updated.  Further,
           if a working group or BOF is created that used characters
           outside the range of this ABNF specification, this
           specification will need to be updated.  Any system intended
           to resolve names for this namespace should be written with
           the awareness that this could occur at any time.

     Relevant ancillary documentation:

           Relevant documentation is in RFC 2648.








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     Identifier uniqueness considerations:

           Because the rfc-editor assigns the RFC number uniquely these
           URNs are unique.  Since the mapping between RFCs and other
           rfc-editor document series (STDs, FYIs or BCPs) is not
           necessarily one-to-one, uniqueness of STDs, FYIs and BCPs
           are defined based on the document mappings maintained by the
           RFC Editor (the index files "rfc-index.txt", "fyi-
           index.txt", "bcp-index.txt", "std-index.txt") are defined to
           be the definitive statement of the assignment of RFC Family
           URNs in this namespace.  The meeting minutes portion of the
           namespace is guaranteed unique because the URN includes the
           sequence number of the IETF conference.  The document
           mapping maintained by the Internet Drafts editor ("1id-
           abstracts.txt") is defined as the definitive statement of
           the assignment of URNs for the internet draft portion of
           this namespace.

     Identifier persistence considerations:

           Persistence of the URNs of this namespace is independent of
           the mutability of the underlying documents.  A URN once
           assigned will never be reassigned to a different resource;
           the assignment is persistent and immutable.  Immutability of
           RFCs, STDs, FYIs and BCPs is at the discretion of the RFC
           Editor.  They may be composites of one or more RFCs and the
           set of RFCs that includes them may change with time.  It is
           important to note that this mutability of some resources is
           independent of the immutability of URN assignment to a
           resource.

     Process of identifier assignment:

           Assignment of URNs from this namespace occurs in three ways.
           The first is through publication of a new RFC, FYI, STD or
           BCP is by the RFC Editor. This new document will have a new
           series number and will therefore define a new URN.  The
           document mappings maintained by the RFC Editor (the index
           files "rfc-index.txt", "fyi-index.txt", "bcp-index.txt" and
           "std-index.txt") are defined to be the definitive statement
           of the assignment of RFC Family URNs in this namespace.

           The second way a URN is assigned is through the filing of
           meeting minutes by a working group or birds of a feather as
           part of an IETF conference.  The list of minutes maintained
           by the IETF for each working group and conference in the
           subtree pointed at by the URL ftp://ietf.org/ietf/ is
           considered the definitive assignment of URNs for working



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           group or birds of a feather minutes.

           The third way a URN is assigned is through the publication
           of a new internet-draft by the Internet Draft Editor.  This
           draft will have a distinct name (and version number) and
           therefore defined a new URN.  The document mapping
           maintained by the Internet Drafts editor ("1id-
           abstracts.txt") is defined as the definitive statement of
           the assignment of URNs for this portion of the namespace.

     Process of identifier resolution:

           A mirrored copy of the underlying documentation is required
           to resolve these URNs.  Resolution via HTTP is done by a set
           of simple Perl cgi-bin scripts presented in Appendix A.

     Rules for Lexical Equivalence:

           The entire URN is case-insensitive.

     Conformance with URN Syntax:

           There are no additional characters reserved.

     Validation mechanism:

           None additional to resolution specified

     Scope:

           Global.

3. Examples

  The following are examples of URNs that a resolver for this namespace
  can resolve:

        urn:ietf:rfc:2141
        urn:ietf:std:50
        urn:ietf:id:ietf-urn-ietf-06
        urn:ietf:mtg:41-urn










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4. Security Considerations

  Because this namespace defines no additional reserved characters, it
  does not add any security considerations beyond those inherent from
  the existence of the reserved characters from [1].  Further, none of
  the reserved characters from [1] are used in the definition of the
  NSS. This means that resolvers for this namespace may be considered
  "secure" in the sense that any escaping of characters in the NSS MUST
  result in the resolver indicating that the URN has incorrect syntax.

5. Acknowledgments

  Thanks to various members of the URN working group for comments on
  earlier drafts of this document.  The work described in this document
  is partially supported by the National Science Foundation,
  Cooperative Agreement NCR-9218179.

6. References

  Request For Comments (RFC) and Internet Draft documents are available
  from numerous mirror sites.

  [1]  Moats, R., "URN Syntax", RFC 2141, May 1997.

  [2]  Crocker, D. and P. Overell, "Augmented BNF for Syntax
       Specifications: ABNF", RFC 2234, November 1997.

7. Author's Address

  Ryan Moats
  AT&T
  15621 Drexel Circle
  Omaha, NE 68135-2358
  USA

  EMail:  [email protected]















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Appendix A.  Example Resolution Scripts

  The following scripts are examples that can be used for resolving
  URNs in this namespace.

A.1 I2C

#!/usr/local/bin/perl

use strict;

#
# this is a URN 2 URC resolver for the ietf namespace
#

my(%cite) = (
 bcp => "/ftp/rfc/bcp-index.txt",
 fyi => "/ftp/fyi/fyi-index.txt",
 id => "/ftp/internet-drafts/1id-abstracts.txt",
 rfc => "/ftp/rfc/rfc-index.txt",
 std => "/ftp/std/std-index.txt"
);
my(%number2date) = (
 44 => "99mar",
 43 => "98dec", 42 => "98aug", 41 => "98apr",
 40 => "97dec", 39 => "97aug", 38 => "97apr",
 37 => "96dec", 36 => "96jun", 35 => "96mar",
 34 => "95dec", 33 => "95jul", 32 => "95apr",
 31 => "94dec", 30 => "94jul", 29 => "94mar",
 28 => "93nov", 27 => "93jul", 26 => "93mar",
 25 => "92nov", 24 => "92jul", 23 => "92mar",
 22 => "91nov", 21 => "91jul", 20 => "91mar",
 19 => "90dec" );

my($wgpath) = "/ftp/ietf";
my($urn) = $ENV{'QUERY_STRING'};
my($host) = $ENV{'SERVER_NAME'}; #get my host name for ftp: URLs
my($accept) = $ENV{'HTTP_ACCEPT'}; #this is the "Accept:" HTTP header

(&resolveid($1), exit) if ($urn =~ /urn:ietf:id:(\S+)/i);
(&resolverfc($1, $2), exit) if ($urn =~ /urn:ietf:(\w*):(\d*)/i);
(&resolvemtg($1, $2), exit) if ($urn =~ /urn:ietf:mtg:(\d*)-(\w*)/i);
&urn_error("400 Bad Request\n");

sub resolvemtg {
 my($ietfnum, $sesnam) = @_;
 &urn_error("404 Not Found\n") if (!defined $number2date{$ietfnum});
 my($date)=$number2date{$ietfnum};



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 my($link)="$wgpath/$sesnam/$sesnam-minutes-$date.txt";
 if (-f $link) {
   print "Status:  200 OK\r\n";
   print "Content-type: text/html\r\n\r\n";
   print "<HTML>\n<TITLE>Citation for $urn</TITLE>\n";
   print "<BODY>\n";
   print "<H1><A HREF=\"$link\">$urn</A>:</H1>\n";
   print "Minutes of the $sesnam working group from the "
         . &end($ietfnum) . " IETF";
   print "</BODY>\n</HTML>\n";
   return;
 }
 my($link)="$wgpath/$date/$sesnam-minutes-$date.txt";
 if (-f $link) {
   print "Status:  200 OK\r\n";
   print "Content-type: text/html\r\n\r\n";
   print "<HTML>\n<TITLE>Citation for $urn</TITLE>\n";
   print "<BODY>\n";
   print "<H1><A HREF=\"$link\">$urn</A>:</H1>\n";
   print "Minutes of the $sesnam working group from the "
          . &end($ietfnum) . " IETF";
   print "</BODY>\n</HTML>\n";
   return;
 }
 &urn_error("404 Not Found\n");
}

sub end {
 my($inarg)=@_;
 return $inarg . "st" if ($inarg =~ /1$/);
 return $inarg . "nd" if ($inarg =~ /2$/);
 return $inarg . "rd" if ($inarg =~ /3$/);
 return $inarg . "th";
}

sub resolverfc {
 my($flag,@bib,$i,$k,$j,$done,@ref);
 my($l,$link);
 my($scheme, $value) = @_;
 $scheme =~ tr/A-Z/a-z/;
 if (!defined $cite{$scheme}) {
   &urn_error("404 Not Found\n");
 }

 $flag = 0;
 open(INPUT, "$cite{$scheme}");
 while (<INPUT>) {
   $flag = 1 if (/^0*$value /);



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   if ($flag == 1) {
     last if (/^$/);
     chop;
     push @bib,$_;
   }
 }

 if ($scheme ne "rfc") {
   print "Status:  200 OK\r\n";
   print "Content-type: text/html\r\n\r\n";
   $bib[0] =~ s/^[0-9]*\s*/<B>/;
   for ($i=0; $i<=$#bib; $i+=1) {
     last if ($bib[$i] =~ s/\./.<\/B>/);
   }
   for ($i=0;$i<=$#bib;$i+=1) {
     $k=$bib[$i];
     while ($k =~ /(fyi|std|rfc|bcp)([0-9]+)(.*)/i) {
       push @ref,"$1$2";
       $k=$3;
     }
     $done="";
     foreach $j (@ref) {
       next if ($done =~ $j);
       $done .= "$j ";
       $l = $j;
       $l =~ tr/A-Z/a-z/;
       $link=&make_link("$l");
       $bib[$i] =~ s/$j/<A HREF="$link">$j<\/A>/g;
     }
   }
   print "<HTML>\n<TITLE>Citation for $urn</TITLE>\n";
   print "<BODY>\n";
   $link=&make_link("$scheme$value");
   print "<H1><A HREF=\"$link\">$scheme$value</A>:</H1>\n";
   foreach $i (@bib) {
     print "$i\n";
   }
   print "</BODY>\n</HTML>\n";
 } else {
   print "Status:  200 OK\r\n";
   print "Content-type: text/html\r\n\r\n";
   $bib[0] =~ s/^[0-9]*\s*//;
   $j=0;
   for ($i=0; $i<=$#bib; $i+=1) {
     $j += ($bib[$i] =~ s/, "/, <B>"/);
     $j += ($bib[$i] =~ s/",/"<\/B>,/);
   }
   for ($i=0;$i<=$#bib;$i+=1) {



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     $k=$bib[$i];
     while ($k =~ /(fyi\s|std\s|rfc|bcp)([0-9]+)(.*)/i) {
       push @ref,"$1$2";
       $k=$3;
     }
     $done="";
     foreach $j (@ref) {
       next if ($done =~ $j);
       $done .= "$j ";
       $l = $j;
       $l =~ s/\s//g;
       $l =~ tr/A-Z/a-z/;
       $link=&make_link("$l");
       $bib[$i] =~ s/$j/<A HREF="$link">$j<\/A>/g;
     }
   }
   print "<HTML>\n<TITLE>Citation for $urn</TITLE>\n";
   print "<BODY>\n";
   $link=&make_link("$scheme$value");
   print "<H1><A HREF=\"$link\">$scheme$value</A>:</H1>\n";
   foreach $i (@bib) {
     print "$i\n";
   }
   print "</BODY>\n</HTML>\n";
 }
}

sub make_link {
 my($sc);
 my($inarg)=@_;
 ($sc=$1) if ($inarg =~ /([a-z]*)/);
 return "/$sc/$inarg.ps" if (-e "/ftp/$sc/$inarg.ps");
 return "/$sc/$inarg.html" if (-e "/ftp/$sc/$inarg.html");
 return "/$sc/$inarg.txt";
}

sub urn_error {
 my($code) = @_; #store failure code here...

 print "Status:  $code";
 print "Content-type: text/html\n\n<HTML>\n";
 print "<head><title>URN Resolution: I2C $code</title></head>\n";
 print "<BODY>\n";
 print "<h1>URN to URC resolution failed for the URN:</h1>\n";
 print "<hr><h3>$urn</h3>\n";
 print "</body>\n";
 print "</html>\n";
 exit;



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};

sub resolveid {
 my($flag,@bib,$i,$k,$j,$count,@ref);
 my($l,$link, $hdr, $done);
 my($value) = @_;
 my($scheme) = "id";

 open(INPUT, "$cite{$scheme}");
 while (<INPUT>) {
#
# capture record
#
   if ($flag == 1 || /^\s+\"/) {
     push @bib,$_;
     ($hdr = -1, $count = 0, $flag = 1) if (/^\s+\"/);
     $count++ if (/^\s+$/);
   }
   if ($count == 1) {
     $hdr = $#bib if ($hdr == -1);
   }
   if ($count == 2) {
     for ($i=0; $i<=$hdr; $i+=1) {
           if ($bib[$i] =~ /<(.*)>/) {
             $l = $1;
             if ($l eq "draft-$value.txt" || $l eq "draft-$value.ps") {
               print "Status:  200 OK\r\n";
               print "Content-type: text/html\r\n\r\n";
               print "<HTML>\n<TITLE>Citation for $urn</TITLE>\n";
               print "<BODY>\n";
               print "<a
href=\"http://blackhole.vip.att.net/internet-drafts/$l\">$l</a>:\n";
               print "<pre>\n";
               foreach $i (@bib) {
                 print "$i";
               }
               print "</pre>\n";
               print "</BODY>\n</HTML>\n";
               exit;
             }
           }
     }
     $flag = 0;
     @bib = ();
   }
 }
 &urn_error("404 Not Found\n");
}



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A.2 I2L

#!/usr/local/bin/perl

use strict;

#
# this is a URN 2 URL resolver for the ietf namespace
#

my(%pathbase) = (
 rfc => "rfc/rfc",
 fyi => "fyi/fyi",
 std => "std/std",
 bcp => "bcp/bcp",
 id => "internet-drafts/draft-"
);

my(%number2date) = (
 44 => "99mar",
 43 => "98dec", 42 => "98aug", 41 => "98apr",
 40 => "97dec", 39 => "97aug", 38 => "97apr",
 37 => "96dec", 36 => "96jun", 35 => "96mar",
 34 => "95dec", 33 => "95jul", 32 => "95apr",
 31 => "94dec", 30 => "94jul", 29 => "94mar",
 28 => "93nov", 27 => "93jul", 26 => "93mar",
 25 => "92nov", 24 => "92jul", 23 => "92mar",
 22 => "91nov", 21 => "91jul", 20 => "91mar",
 19 => "90dec" );

my($wgpath) = "/ftp/ietf";
my($urn) = $ENV{'QUERY_STRING'};
my($host) = $ENV{'SERVER_NAME'}; #get my host name for ftp: URLs
my($accept) = $ENV{'HTTP_ACCEPT'}; #this is the "Accept:" HTTP header

(&resolveid($1), exit) if ($urn =~ /urn:ietf:id:(\S+)/i);
(&resolverfc($1, $2), exit) if ($urn =~ /urn:ietf:(\w*):(\d*)/i);
(&resolvemtg($1, $2), exit) if ($urn =~ /urn:ietf:mtg:(\d*)-(\w*)/i);
&urn_error("400 Bad Request\n");

sub resolvemtg {
 my($ietfnum, $sesnam) = @_;
 &urn_error("404 Not Found\n") if (!defined $number2date{$ietfnum});
 my($date)=$number2date{$ietfnum};
 my($link)="$wgpath/$sesnam/$sesnam-minutes-$date.txt";
 if (-f $link) {
   print "Status:  302 Moved temporarily\n";
   print "Location: $link\n";



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   return;
 }
 my($link)="$wgpath/$date/$sesnam-minutes-$date.txt";
 if (-f $link) {
   print "Status:  302 Moved temporarily\n";
   print "Location: $link\n";
   return;
 }
 &urn_error("404 Not Found\n");
}

sub end {
 my($inarg)=@_;
 return $inarg . "st" if ($inarg =~ /1$/);
 return $inarg . "nd" if ($inarg =~ /2$/);
 return $inarg . "rd" if ($inarg =~ /3$/);
 return $inarg . "th";
}

sub resolverfc {
 my($flag,@bib,$i,$k,$j,$done,@ref);
 my($l,$link);
 my($scheme, $value) = @_;
 $scheme =~ tr/A-Z/a-z/;
 &urn_error("404 Not Found\n")if (!defined $pathbase{$scheme});
 my($txttry)="/ftp/$pathbase{$scheme}$value.txt";
 my($pstry)="/ftp/$pathbase{$scheme}$value.ps";
 my($htmltry)="/ftp/$pathbase{$scheme}$value.html";
MIME_SWITCH: {
   if ($accept =~ /application\/postscript/ && -f $pstry) {
     print "Status:  302 Moved temporarily\n";
     print "Location: http://$host/$pathbase{$scheme}$value.ps\n\n";
     last MIME_SWITCH;
   }
   if ($accept =~ /text\/html/ && -f $htmltry) {
     print "Status:  302 Moved temporarily0;
     print "Location: http://$host/$pathbase{$scheme}$value.html\n\n";
     last MIME_SWITCH;
   }
   if ($accept =~ /\*\/\*|text\/plain/ && -f $txttry) {
     print "Status:  302 Moved temporarily\n";
     print "Location: http://$host/$pathbase{$scheme}$value.txt\n\n";
     last MIME_SWITCH;
   }
   &urn_error("404 Not Found\n");
 }
}




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sub urn_error {
 my($code) = @_; #store failure code here...

 print "Status:  $code";
 print "Content-type: text/html\n\n<HTML>\n";
 print "<head><title>URN Resolution: I2L $code</title></head>\n";
 print "<BODY>\n";
 print "<h1>URN to URL resolution failed for the URN:</h1>\n";
 print "<hr><h3>$urn</h3>\n";
 print "</body>\n";
 print "</html>\n";
 exit;
}

sub resolveid {
 my($flag,@bib,$i,$k,$j,$done,@ref);
 my($l,$link);
 my($scheme) = "id";
 my($value) = @_;
 $scheme =~ tr/A-Z/a-z/;
 &urn_error("404 Not Found\n")if (!defined $pathbase{$scheme});
 my($txttry)="/ftp/$pathbase{$scheme}$value.txt";
 my($pstry)="/ftp/$pathbase{$scheme}$value.ps";
 my($htmltry)="/ftp/$pathbase{$scheme}$value.html";
MIME_SWITCH: {
   if ($accept =~ /application\/postscript/ && -f $pstry) {
     print "Status:  302 Moved temporarily\n";
     print "Location: http://$host/$pathbase{$scheme}$value.ps\n\n";
     last MIME_SWITCH;
   }
   if ($accept =~ /text\/html/ && -f $htmltry) {
     print "Status:  302 Moved temporarily\n";
     print "Location: http://$host/$pathbase{$scheme}$value.html\n\n";
     last MIME_SWITCH;
   }
   if ($accept =~ /\*\/\*|text\/plain/ && -f $txttry) {
     print "Status:  302 Moved temporarily\n";
     print "Location: http://$host/$pathbase{$scheme}$value.txt\n\n";
     last MIME_SWITCH;
   }
   &urn_error("404 Not Found\n");
 }
}








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A.3 I2Ls

#!/usr/local/bin/perl

use strict;

#
# this is a URN 2 URLs resolver for the ietf namespace
#

my(@urls);

my(%pathbase) = (
 rfc => "rfc/rfc",
 fyi => "fyi/fyi",
 std => "std/std",
 bcp => "bcp/bcp",
 id => "internet-drafts/draft-"
);

my(%number2date) = (
 44 => "99mar",
 43 => "98dec", 42 => "98aug", 41 => "98apr",
 40 => "97dec", 39 => "97aug", 38 => "97apr",
 37 => "96dec", 36 => "96jun", 35 => "96mar",
 34 => "95dec", 33 => "95jul", 32 => "95apr",
 31 => "94dec", 30 => "94jul", 29 => "94mar",
 28 => "93nov", 27 => "93jul", 26 => "93mar",
 25 => "92nov", 24 => "92jul", 23 => "92mar",
 22 => "91nov", 21 => "91jul", 20 => "91mar",
 19 => "90dec" );

my($wgpath) = "/ftp/ietf";
my($urn) = $ENV{'QUERY_STRING'};
my($host) = $ENV{'SERVER_NAME'}; #get my host name for ftp: URLs
my($accept) = $ENV{'HTTP_ACCEPT'}; #this is the "Accept:" HTTP header

(&resolveid($1), exit) if ($urn =~ /urn:ietf:id:(\S+)/i);
(&resolve1($1, $2), exit) if ($urn =~ /urn:ietf:(\w*):(\d*)/i);
(&resolve2($1, $2), exit) if ($urn =~ /urn:ietf:mtg:(\d*)-(\w*)/i);
&urn_error("400 Bad Request\n");

sub resolve2 {
 my($ietfnum, $sesnam) = @_;
 &urn_error("404 Not Found\n") if (!defined $number2date{$ietfnum});
 my($date)=$number2date{$ietfnum};
 my($link)="$wgpath/$sesnam/$sesnam-minutes-$date.txt";
 if (-f $link) {



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   $link=~s/^\/ftp\///;
   my($ftplink)="ftp://$host/$link";
   my($httplink)="http://$host/$link";
   my($glink)="gopher://$host:70/0/$link";

   if ($accept =~ /text\/uri-list/) { #look for text/uri-list,
       otherwise text/html
     print "Status: 200 OK\n";
     print "Content-type: text/uri-list\n\n\n";
     print "#$urn\n";
     print "$ftplink\n";
     print "$httplink\n";
     print "$glink\n";
   }
   if ($accept =~ /\*\/\*|text\/html/) {
     print "Status: 200 OK\n";
     print "Content-type: text/html\n\n<HTML>\n";
     print "<head><title>URN Resolution: I2Ls</title></head>\n";
     print "<BODY>\n";
     print "<h1>URN $urn resolves to the following URLs:</h1>\n";
     print "<hr><ul>\n";
     print "<a href=\"$ftplink\">$ftplink</a>\n";
     print "<a href=\"$httplink\">$httplink</a>\n";
     print "<a href=\"$glink\">$glink</a>\n";
     print "</UL>\n</body>\n</HTML>\n";
   }
   return;
 }
 my($link)="$wgpath/$date/$sesnam-minutes-$date.txt";
 if (-f $link) {
   $link=~s/^\/ftp\///;
   my($ftplink)="ftp://$host/$link";
   my($httplink)="http://$host/$link";
   my($glink)="gopher://$host:70/0/$link";
   if ($accept =~ /text\/uri-list/) { #look for text/uri-list,
       otherwise text/html
     print "Status: 200 OK\n";
     print "Content-type: text/uri-list\n\n\n";
     print "#$urn\n";
     print "$ftplink\n";
     print "$httplink\n";
     print "$glink\n";
   }
   if ($accept =~ /\*\/\*|text\/html/) {
     print "Status: 200 OK\n";
     print "Content-type: text/html\n\n<HTML>\n";
     print "<head><title>URN Resolution: I2Ls</title></head>\n";
     print "<BODY>\n";



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     print "<h1>URN $urn resolves to the following URLs:</h1>\n";
     print "<hr><ul>\n";
     print "<a href=\"$ftplink\">$ftplink</a>\n";
     print "<a href=\"$httplink\">$httplink</a>\n";
     print "<a href=\"$glink\">$glink</a>\n";
     print "</UL>\n</body>\n</HTML>\n";
   }

   return;
 }
 &urn_error("404 Not Found\n");
}

sub resolve1 {
 my($flag,@bib,$i,$k,$j,$done,@ref);
 my($l,$link);
 my($scheme, $value) = @_;
 $scheme =~ tr/A-Z/a-z/;
 &urn_error("404 Not Found\n")if (!defined $pathbase{$scheme});
 my($try)="/ftp/$pathbase{$scheme}$value.txt";
 if (-f $try) {
   push(@urls, "http://$host/$pathbase{$scheme}$value.txt");
   push(@urls, "ftp://$host/$pathbase{$scheme}$value.txt");
   push(@urls, "gopher://$host:70/0/$pathbase{$scheme}$value.txt");
 }
 $try="/ftp/$pathbase{$scheme}$value.ps";
 if (-f $try) {
   push(@urls, "http://$host/$pathbase{$scheme}$value.ps");
   push(@urls, "ftp://$host/$pathbase{$scheme}$value.ps");
   push(@urls, "gopher://$host:70/0/$pathbase{$scheme}$value.ps");
 }
 $try="/ftp/$pathbase{$scheme}$value.html";
 if (-f $try) {
   push(@urls, "http://$host/$pathbase{$scheme}$value.html");
   push(@urls, "ftp://$host/$pathbase{$scheme}$value.html");
 }

 &urn_error("404 Not Found\n") if ($#urls == -1);

MIME_SWITCH: {
   if ($accept =~ /text\/uri-list/) { #look for text/uri-list,
       otherwise text/html
     print "Status: 200 OK\n";
     print "Content-type: text/uri-list\n\n\n";
     print "#$urn\n";
     foreach $i (@urls) {
       print "$i\n";
     }



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     last MIME_SWITCH;
   }
   if ($accept =~ /\*\/\*|text\/html/) {
     print "Status: 200 OK\n";
     print "Content-type: text/html\n\n<HTML>\n";
     print "<head><title>URN Resolution: I2Ls</title></head>\n";
     print "<BODY>\n";
     print "<h1>URN $urn resolves to the following URLs:</h1>\n";
     print "<hr><ul>\n";
     foreach $i (@urls) {
       print "<LI><A HREF=\"$i\">$i</A>\n";
     }
     print "</UL>\n</body>\n</HTML>\n";
     last MIME_SWITCH;
   }
 }
}

sub urn_error {
 my($code) = @_; #store failure code here...

 print "Status: $code";
 print "Content-type: text/html\n\n<HTML>\n";
 print "<head><title>URN Resolution: I2L $code</title></head>\n";
 print "<BODY>\n";
 print "<h1>URN to URL resolution failed for the URN:</h1>\n";
 print "<hr><h3>$urn</h3>\n";
 print "</body>\n";
 print "</html>\n";
 exit;
}

sub resolveid {
 my($flag,@bib,$i,$k,$j,$done,@ref);
 my($l,$link);
 my($value) = @_;
 my($scheme) = "id";
 $scheme =~ tr/A-Z/a-z/;
 &urn_error("404 Not Found\n")if (!defined $pathbase{$scheme});
 my($try)="/ftp/$pathbase{$scheme}$value.txt";
 if (-f $try) {
   push(@urls, "http://$host/$pathbase{$scheme}$value.txt");
   push(@urls, "ftp://$host/$pathbase{$scheme}$value.txt");
   push(@urls, "gopher://$host:70/0/$pathbase{$scheme}$value.txt");
 }
 $try="/ftp/$pathbase{$scheme}$value.ps";
 if (-f $try) {
   push(@urls, "http://$host/$pathbase{$scheme}$value.ps");



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   push(@urls, "ftp://$host/$pathbase{$scheme}$value.ps");
   push(@urls, "gopher://$host:70/0/$pathbase{$scheme}$value.ps");
 }
 $try="/ftp/$pathbase{$scheme}$value.html";
 if (-f $try) {
   push(@urls, "http://$host/$pathbase{$scheme}$value.html");
   push(@urls, "ftp://$host/$pathbase{$scheme}$value.html");
 }

 &urn_error("404 Not Found\n") if ($#urls == -1);

MIME_SWITCH: {
   if ($accept =~ /text\/uri-list/) { #look for text/uri-list,
       otherwise text/html
     print "Status: 200 OK\n";
     print "Content-type: text/uri-list\n\n\n";
     print "#$urn\n";
     foreach $i (@urls) {
       print "$i\n";
     }
     last MIME_SWITCH;
   }
   if ($accept =~ /\*\/\*|text\/html/) {
     print "Status: 200 OK\n";
     print "Content-type: text/html\n\n<HTML>\n";
     print "<head><title>URN Resolution: I2Ls</title></head>\n";
     print "<BODY>\n";
     print "<h1>URN $urn resolves to the following URLs:</h1>\n";
     print "<hr><ul>\n";
     foreach $i (@urls) {
       print "<LI><A HREF=\"$i\">$i</A>\n";
     }
     print "</UL>\n</body>\n</HTML>\n";
     last MIME_SWITCH;
   }
 }
}

A.4 I2Ns

#!/usr/local/bin/perl

use strict;

#
# this is a URN 2 URNs resolver for the ietf namespace
#




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my(%cite) = (
 rfc => "/ftp/rfc/rfc-index.txt",
 fyi => "/ftp/fyi/fyi-index.txt",
 std => "/ftp/std/std-index.txt",
 bcp => "/ftp/rfc/bcp-index.txt"
);

my(%number2date) = (
 44 => "99mar",
 43 => "98dec", 42 => "98aug", 41 => "98apr",
 40 => "97dec", 39 => "97aug", 38 => "97apr",
 37 => "96dec", 36 => "96jun", 35 => "96mar",
 34 => "95dec", 33 => "95jul", 32 => "95apr",
 31 => "94dec", 30 => "94jul", 29 => "94mar",
 28 => "93nov", 27 => "93jul", 26 => "93mar",
 25 => "92nov", 24 => "92jul", 23 => "92mar",
 22 => "91nov", 21 => "91jul", 20 => "91mar",
 19 => "90dec" );

my($wgpath) = "/ftp/ietf";
my($urn) = $ENV{'QUERY_STRING'};
my($host) = $ENV{'SERVER_NAME'}; #get my host name for ftp: URLs
my($port) = $ENV={'SERVER_PORT'};
my($accept) = $ENV{'HTTP_ACCEPT'}; #this is the "Accept:" HTTP header

(&resolve1($1, $2), exit) if ($urn =~ /urn:ietf:(\w*):(\d*)/i);
(&resolve2($1, $2), exit) if ($urn =~ /urn:ietf:mtg:(\d*)-(\w*)/i);
&urn_error("400 Bad Request\n");

sub resolve2 {
 my($ietfnum, $sesnam) = @_;
 &urn_error("404 Not Found\n") if (!defined $number2date{$ietfnum});
 my($date)=$number2date{$ietfnum};
 my($link)="$wgpath/$sesnam/$sesnam-minutes-$date.txt";
 if (-f $link) {
   if ($accept =~ /text\/uri-list/) {
       print "Status: 200 OK\n";
       print "Content-type: text/uri-list\n\n\n";
       print "#$urn\n";
       return;
   }
   if ($accept =~ /\*\/\*|text]\/html/) {
     print "Status: 200 OK\n";
     print "Content-type: text/html\n\n<HTML>\n";
     print "<head><title>URN Resolution: I2Ns</title></head>\n";
     print "<BODY>\n";
     print "<h1>URN $urn resolves to the following URNs:</h1>\n";
     print "<hr><ul>\n";



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     print "</UL>\n</body>\n</HTML>\n";
     return;
   }
 }
 my($link)="$wgpath/$date/$sesnam-minutes-$date.txt";
 if (-f $link) {
   if ($accept =~ /text\/uri-list/) {
       print "Status: 200 OK\n";
       print "Content-type: text/uri-list\n\n\n";
       print "#$urn\n";
       return;
   }
   if ($accept =~ /\*\/\*|text\/html/) {
       print "Status: 200 OK\n";
       print "Content-type: text/html\n\n<HTML>\n";
       print "<head><title>URN Resolution: I2Ns</title></head>\n";
       print "<BODY>\n";
       print "<h1>URN $urn resolves to the following URNs:</h1>\n";
       print "<hr><ul>\n";
       print "</UL>\n</body>\n</HTML>\n";
       return;
   }
 }
 &urn_error("404 Not Found\n");
}

sub end {
 my($inarg)=@_;
 return $inarg . "st" if ($inarg =~ /1$/);
 return $inarg . "nd" if ($inarg =~ /2$/);
 return $inarg . "rd" if ($inarg =~ /3$/);
 return $inarg . "th";
}

sub resolve1 {
 my($flag,@bib,$i,$k,$j,$done,@ref);
 my($l,$link);
 my($scheme, $value) = @_;
 $scheme =~ tr/A-Z/a-z/;
 if (!defined $cite{$scheme}) {
   &urn_error("404 Not Found\n");
 }

 $flag = 0;
 open(INPUT, "$cite{$scheme}");
 while (<INPUT>) {
   $flag = 1 if (/^0*$value /);
   if ($flag == 1) {



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     last if (/^$/);
     chop;
     push @bib,$_;
   }
 }

 $k=join " ",@bib;
 while ($k =~ /(\S*)\s*(fyi|std|rfc|bcp)\s*([0-9]+)(.*)/i) {
   $k=$4;
   $a=$2; $b=$3;
   if (($a ne $scheme || $b ne $value) && ($1 !~ /obso/i)){
     $a =~ tr/A-Z/a-z/;
     $b =~ s/^0*//;
     push @ref,"urn:ietf:$a:$b";
   }
 }

MIME_SWITCH: {
   if ($accept =~ /text\/uri-list/) {
       print "Status: 200 OK\n";
       print "Content-type: text/uri-list\n\n\n";
       print "#$urn\n";
       foreach $i (@ref) {
           print "$i\n";
       }
       last MIME_SWITCH;
   }
 if ($accept =~ /\*\/\*|text\/html/) {
   print "Status: 200 OK\n";
   print "Content-type: text/html\n\n<HTML>\n";
   print "<head><title>URN Resolution: I2Ns</title></head>\n";
   print "<BODY>\n";
   print "<h1>URN $urn resolves to the following URNs:</h1>\n";
   print "<hr><ul>\n";
       foreach $i (@ref) {
           print "<li>$i: Click to resolve using\n";
           print "<a
href=\"http://$host:$port/uri-res/I2C?$i\">I2C</a>,\n";
           print "<a
href=\"http://$host:$port/uri-res/I2L?$i\">I2L</a>,\n";
           print "<a
href=\"http://$host:$port/uri-res/I2Ls?$i\">I2Ls</a>,\n";
           print "<a
href=\"http://$host:$port/uri-res/I2R?$i\">I2R</a>,\n";
           print "<a
href=\"http://$host:$port/uri-res/I2Rs?$i\">I2Rs</a>\n";
       }
   print "</UL>\n</body>\n</HTML>\n";



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 }
}
}

sub make_link {
 my($sc);
 my($inarg)=@_;
 ($sc=$1) if ($inarg =~ /([a-z]*)/);
 return "/$sc/$inarg.ps" if (-e "/ftp/$sc/$inarg.ps");
 return "/$sc/$inarg.html" if (-e "/ftp/$sc/$inarg.html");
 return "/$sc/$inarg.txt";
}

sub urn_error {
 my($code) = @_; #store failure code here...

 print "Status: $code";
 print "Content-type: text/html\n\n<HTML>\n";
 print "<head><title>URN Resolution: I2Ns $code</title></head>\n";
 print "<BODY>\n";
 print "<h1>URN to URN resolution failed for the URN:</h1>\n";
 print "<hr><h3>$urn</h3>\n";
 print "</body>\n";
 print "</html>\n";
 exit;
};

A.5 I2R

#!/usr/local/bin/perl

use strict;

#
# this is a URN 2 resource resolver for the ietf namespace
#

my(%pathbase) = (
 rfc => "rfc/rfc",
 fyi => "fyi/fyi",
 std => "std/std",
 bcp => "bcp/bcp",
 id => "internet-drafts/draft-"
);

my(%number2date) = (
 44 => "99mar",
 43 => "98dec", 42 => "98aug", 41 => "98apr",



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 40 => "97dec", 39 => "97aug", 38 => "97apr",
 37 => "96dec", 36 => "96jun", 35 => "96mar",
 34 => "95dec", 33 => "95jul", 32 => "95apr",
 31 => "94dec", 30 => "94jul", 29 => "94mar",
 28 => "93nov", 27 => "93jul", 26 => "93mar",
 25 => "92nov", 24 => "92jul", 23 => "92mar",
 22 => "91nov", 21 => "91jul", 20 => "91mar",
 19 => "90dec" );

my($wgpath) = "/ftp/ietf";
my($urn) = $ENV{'QUERY_STRING'};
my($host) = $ENV{'SERVER_NAME'}; #get my host name for ftp: URLs
my($accept) = $ENV{'HTTP_ACCEPT'}; #this is the "Accept:" HTTP header

print "$urn\n";
(&resolveid($1), exit) if ($urn =~ /urn:ietf:id:(\S+)/i);
(&resolve1($1, $2), exit) if ($urn =~ /urn:ietf:(\w*):(\d*)/i);
(&resolve2($1, $2), exit) if ($urn =~ /urn:ietf:mtg:(\d*)-(\w*)/i);
&urn_error("400 Bad Request\n");

sub resolve2 {
 my($ietfnum, $sesnam) = @_;
 &urn_error("404 Not Found\n") if (!defined $number2date{$ietfnum});
 my($date)=$number2date{$ietfnum};
 my($link)="$wgpath/$sesnam/$sesnam-minutes-$date.txt";
 if (-f $link) {
     print "Status:  200 OK\n";
     print "Content-type: text/plain\n\n";
     open(FILE, "$link");
     while (<FILE>) {
         print $_;
     }
     close FILE;
   return;
 }
 my($link)="$wgpath/$date/$sesnam-minutes-$date.txt";
 if (-f $link) {
     print "Status:  200 OK\n";
     print "Content-type: text/plain\n\n";
     open(FILE, "$link");
     while (<FILE>) {
         print $_;
     }
     close FILE;
   return;
 }
 &urn_error("404 Not Found\n");
}



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sub end {
 my($inarg)=@_;
 return $inarg . "st" if ($inarg =~ /1$/);
 return $inarg . "nd" if ($inarg =~ /2$/);
 return $inarg . "rd" if ($inarg =~ /3$/);
 return $inarg . "th";
}

sub resolve1 {
 my($flag,@bib,$i,$k,$j,$done,@ref);
 my($l,$link);
 my($scheme, $value) = @_;
 $scheme =~ tr/A-Z/a-z/;
 &urn_error("404 Not Found\n")if (!defined $pathbase{$scheme});
 my($txttry)="/ftp/$pathbase{$scheme}$value.txt";
 my($pstry)="/ftp/$pathbase{$scheme}$value.ps";
 my($htmltry)="/ftp/$pathbase{$scheme}$value.html";
MIME_SWITCH: {
   if ($accept =~ /application\/postscript/ && -f $pstry) {
     print "Status:  200 OK\n";
     print "Content-type: application/postscript\n\n";
     open(FILE, "$pstry");
     while (<FILE>) {
         print $_;
     }
     close FILE;
     last MIME_SWITCH;
   }
   if ($accept =~ /text\/html/ && -f $htmltry) {
       print "Status:  200 OK\n";
       print "Content-type: text/html\n\n";
       open(FILE, "$htmltry");
       while (<FILE>) {
           print $_;
       }
       close FILE;
       last MIME_SWITCH;
   }
   if ($accept =~ /\*\/\*|text\/plain/ && -f $txttry) {
       print "Status:  200 OK\n";
       print "Content-type: text/plain\n\n";
       open(FILE, "$txttry");
       while (<FILE>) {
           print $_;
       }
       close FILE;
       last MIME_SWITCH;
   }



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   &urn_error("404 Not Found\n");
 }
}

sub resolveid {
 my($flag,@bib,$i,$k,$j,$done,@ref);
 my($l,$link);
 my($scheme) = "id";
 my($value) = @_;
 $scheme =~ tr/A-Z/a-z/;
 &urn_error("404 Not Found\n")if (!defined $pathbase{$scheme});
 my($txttry)="/ftp/$pathbase{$scheme}$value.txt";
 my($pstry)="/ftp/$pathbase{$scheme}$value.ps";
 my($htmltry)="/ftp/$pathbase{$scheme}$value.html";
MIME_SWITCH: {
   if ($accept =~ /application\/postscript/ && -f $pstry) {
     print "Status:  200 OK\n";
     print "Content-type: application/postscript\n\n";
     open(FILE, "$pstry");
     while (<FILE>) {
         print $_;
     }
     close FILE;
     last MIME_SWITCH;
   }
   if ($accept =~ /text\/html/ && -f $htmltry) {
       print "Status:  200 OK\n";
       print "Content-type: text/html\n\n";
       open(FILE, "$htmltry");
       while (<FILE>) {
           print $_;
       }
       close FILE;
       last MIME_SWITCH;
   }
   if ($accept =~ /\*\/\*|text\/plain/ && -f $txttry) {
       print "Status:  200 OK\n";
       print "Content-type: text/plain\n\n";
       open(FILE, "$txttry");
       while (<FILE>) {
           print $_;
       }
       close FILE;
       last MIME_SWITCH;
   }
   &urn_error("404 Not Found\n");
 }
}



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RFC 2648           A URN Namespace for IETF Documents        August 1999


sub urn_error {
 my($code) = @_; #store failure code here...

 print "Status:  $code";
 print "Content-type: text/html\n\n<HTML>\n";
 print "<head><title>URN Resolution: I2R $code</title></head>\n";
 print "<BODY>\n";
 print "<h1>URN to URL resolution failed for the URN:</h1>\n";
 print "<hr><h3>$urn</h3>\n";
 print "</body>\n";
 print "</html>\n";
 exit;
}

A.6 I2Rs

#!/usr/local/bin/perl

use strict;

#
# this is a URN 2 resources resolver for the ietf namespace
#

my(@urls);

my(%pathbase) = (
 rfc => "rfc/rfc",
 fyi => "fyi/fyi",
 std => "std/std",
 bcp => "bcp/bcp",
 id => "internet-drafts/draft-"
);

my(%number2date) = (
 44 => "99mar",
 43 => "98dec", 42 => "98aug", 41 => "98apr",
 40 => "97dec", 39 => "97aug", 38 => "97apr",
 37 => "96dec", 36 => "96jun", 35 => "96mar",
 34 => "95dec", 33 => "95jul", 32 => "95apr",
 31 => "94dec", 30 => "94jul", 29 => "94mar",
 28 => "93nov", 27 => "93jul", 26 => "93mar",
 25 => "92nov", 24 => "92jul", 23 => "92mar",
 22 => "91nov", 21 => "91jul", 20 => "91mar",
 19 => "90dec" );

my($wgpath) = "/ftp/ietf";
my($urn) = $ENV{'QUERY_STRING'};



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RFC 2648           A URN Namespace for IETF Documents        August 1999


my($host) = $ENV{'SERVER_NAME'}; #get my host name for ftp: URLs
my($accept) = $ENV{'HTTP_ACCEPT'}; #this is the "Accept:" HTTP header

(&resolveid($1), exit) if ($urn =~ /urn:ietf:id:(\s*)/i);
(&resolve1($1, $2), exit) if ($urn =~ /urn:ietf:(\w*):(\d*)/i);
(&resolve2($1, $2), exit) if ($urn =~ /urn:ietf:mtg:(\d*)-(\w*)/i);
&urn_error("400 Bad Request\n");

sub resolve2 {
 my($ietfnum, $sesnam) = @_;
 my(@vers,$i);
 &urn_error("404 Not Found\n") if (!defined $number2date{$ietfnum});
 my($date)=$number2date{$ietfnum};
 my($link)="$wgpath/$sesnam/$sesnam-minutes-$date.txt";

 if (-f $link) {
     push(@vers,$link);
 }
 $link="$wgpath/$date/$sesnam-minutes-$date.txt";
 if (-f $link) {
     push(@vers,$link);
 }
 &urn_error("404 Not Found\n") if ($#vers==-1);

 print "Status: 200 OK\n";
 print "Content-type: multipart/alternative; boundary=endpart\n\n";
 foreach $i (@vers) {
     print "--endpart\n";
     if ($i =~ /html$/) {
         print "Content-Type: text/html\n\n";
     }
     if ($i =~ /txt$/) {
         print "Content-Type: text/plain\n\n";
     }
     if ($i =~ /ps$/) {
         print "Content-Type: application/postscript\n\n";
     }
     open(FILE, "$i");
     while (<FILE>) {
         print "$_";
     }
     close FILE;
 }
 print "--endpart\n";
}

sub resolve1 {
 my($flag,@bib,$i,$k,$j,$done,@ref);



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RFC 2648           A URN Namespace for IETF Documents        August 1999


 my($l,$link,@vers);
 my($scheme, $value) = @_;
 $scheme =~ tr/A-Z/a-z/;
 &urn_error("404 Not Found\n")if (!defined $pathbase{$scheme});
 my($try)="/ftp/$pathbase{$scheme}$value.txt";
 if (-f $try) {
     push(@vers, $try);
 }
 $try="/ftp/$pathbase{$scheme}$value.ps";
 if (-f $try) {
     push(@vers, $try);
 }
 $try="/ftp/$pathbase{$scheme}$value.html";
 if (-f $try) {
     push(@vers, $try);

 }
 print "Status: 200 OK\n";
 print "Content-type: multipart/alternative; boundary=endpart\n\n";
 foreach $i (@vers) {
     print "--endpart\n";
     if ($i =~ /html$/) {
         print "Content-Type: text/html\n\n";
     }
     if ($i =~ /txt$/) {
         print "Content-Type: text/plain\n\n";
     }
     if ($i =~ /ps$/) {
         print "Content-Type: application/postscript\n\n";
     }
     open(FILE, "$i");
     while (<FILE>) {
         print "$_";
     }
     close FILE;
 }
 print "--endpart\n";
}

sub resolveid {
 my($flag,@bib,$i,$k,$j,$done,@ref);
 my($l,$link,@vers);
 my($scheme) = "id";
 my($value) = @_;
 $scheme =~ tr/A-Z/a-z/;
 &urn_error("404 Not Found\n")if (!defined $pathbase{$scheme});
 my($try)="/ftp/$pathbase{$scheme}$value.txt";
 if (-f $try) {



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RFC 2648           A URN Namespace for IETF Documents        August 1999


     push(@vers, $try);
 }
 $try="/ftp/$pathbase{$scheme}$value.ps";
 if (-f $try) {
     push(@vers, $try);
 }
 $try="/ftp/$pathbase{$scheme}$value.html";
 if (-f $try) {
     push(@vers, $try);
 }
 print "Status: 200 OK\n";
 print "Content-type: multipart/alternative; boundary=endpart\n\n";
 foreach $i (@vers) {
     print "--endpart\n";
     if ($i =~ /html$/) {
         print "Content-Type: text/html\n\n";

     }
     if ($i =~ /txt$/) {
         print "Content-Type: text/plain\n\n";
     }
     if ($i =~ /ps$/) {
         print "Content-Type: application/postscript\n\n";
     }
     open(FILE, "$i");
     while (<FILE>) {
         print "$_";
     }
     close FILE;
 }
 print "--endpart\n";
}
sub urn_error {
 my($code) = @_; #store failure code here...

 print "Status: $code";
 print "Content-type: text/html\n\n<HTML>\n";
 print "<head><title>URN Resolution: I2Rs $code</title></head>\n";
 print "<BODY>\n";
 print "<h1>URN to URL resolution failed for the URN:</h1>\n";
 print "<hr><h3>$urn</h3>\n";
 print "</body>\n";
 print "</html>\n";
 exit;
}






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RFC 2648           A URN Namespace for IETF Documents        August 1999


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.



















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