A Persistent Web IDentifier (PWID) URN Namespace
draft-pwid-urn-specification-04
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Expired".
|
|
|---|---|---|---|
| Author | Eld Maj-Britt Olmuetz Zierau | ||
| Last updated | 2018-11-04 | ||
| RFC stream | (None) | ||
| Formats | |||
| Additional resources | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | I-D Exists | |
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-pwid-urn-specification-04
Internet Engineering Task Force E. Zierau, Ed.
Internet-Draft Royal Danish Library
Intended status: Informational November 4, 2018
Expires: May 8, 2019
A Persistent Web IDentifier (PWID) URN Namespace
draft-pwid-urn-specification-04
Abstract
This document specifies a Uniform Resource Name (URN) for Persistent
Web IDentifiers to web material in web archives using the 'pwid'
namespace identifier.
The main purpose of the standard is to support specification of
references that are not covered by other reference techniques: to
support references to material in web archives with restricted
access. Furthermore, it supports persistent technology agnostic
references to web archives in general, in a form that can work as an
algorithmic basis for finding web archive resources in general. An
additional important benefit is that it can be used in specifying web
collections, which then can form a persistent computational basis for
the extract of the archived collection parts. Since the parts can be
specified generally, this further allow collections to be specified
with elements from one or more web archives.
The PWID is designed for researchers and therefore it is designed as
general, global, sustainable, humanly readable, technology agnostic,
persistent and precise web references for web materials in web
archives.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on May 8, 2019.
Zierau Expires May 8, 2019 [Page 1]
Internet-DraftA Persistent Web IDentifier (PWID) URN NamespNovember 2018
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 5
2. Namespace Registration Template . . . . . . . . . . . . . . . 5
3. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 20
4. References . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.1. Normative References . . . . . . . . . . . . . . . . . . 20
4.2. Informative References . . . . . . . . . . . . . . . . . 20
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 23
1. Introduction
The URN PWID is a supplement to existing reference standards, where
the PWID will support references to web archives, including areas
that are not supported today: support of references to material in
web archives with restricted access. Furthermore, it enables
technology agnostic references to web archives in general, which can
for instance can be needed for references to web material that is
dynamic (e.g. a news site) or a specific version of a web material
(e.g. specific version of the DOI handbook).
The URN PWID is a form that can work as an algorithmic basis for
finding the resource. This also enables basis for computation of
archived web parts to a collection from one or more web archives.
Furthermore, the PWID includes information about the resource which
makes it possible to find alternative resources, in cases where the
original precise resource have become unavailable.
The PWID URN is designed to be a persistent reference that is
general, global and technology agnostic in order to enhance its
chances for being sustainable. Furthermore, it is designed to be
Zierau Expires May 8, 2019 [Page 2]
Internet-DraftA Persistent Web IDentifier (PWID) URN NamespNovember 2018
humanly readable and with ability to make precision of the web
archive resource covers. This design enables a PWID URN to:
o be used for technical solutions e.g. to make them resolvable
o cover references to all sorts of materials in web archives
o cover references to materials from all sort of web archives
The motivation for defining a PWID namespace is the growing challenge
of references to archived web resources, which the PWID as a URN can
assist in overcoming. The standard is needed to address web
materials meeting precision and persistency issues on par precision
in with traditional references for analogue material. Furthermore,
it is needed in order to address web archive resources that are not
freely available online. The PWID URN covers both referencing of web
resources from research papers and definition of web collection/
corpus. In detail the challenges are:
o Citation guidelines generally do not cover general and persistent
referencing techniques for web resources that are not registered
by Persistent Identifier systems (like DOI [DOI]). However, an
increasing number of references point to resources that only exist
on the web, e.g. blogs that turned out to have a historical
impact. In order to obtain persistency for a reference, the
target need to be stable. As the live web is 'alive' and in
constant change, persistency can only be obtained by referring to
archived snapshots of the web. The PWID URN is therefore focused
on referencing archived web material in a technology agnostic way
(research documented in [IPRES2016] and [ResawRef]).
o There are many new initiatives for web archive referencing, - most
of them are centralised solutions which offers harvest and
referencing, but these cannot be used for existing materials in
web archives. Other initiatives only cover open web archives,
which does not cover material in archives with restricted access
and where there is a risk of imprecision if a resource in an
alternative archive is the result of resolving such a resource.
The PWID URN is needed in order to fill these gaps where other
techniques are not sufficient.
o There are many different requirements for construction of
collection definitions for web material besides precision and
persistency. Recent research have found that various legal and
sustainability issues leads to a need for a collection to be
defined by references to the web parts in the collection. The
PWID URN is needed in such definitions in order to fulfil these
Zierau Expires May 8, 2019 [Page 3]
Internet-DraftA Persistent Web IDentifier (PWID) URN NamespNovember 2018
requirements and to enable a collection to cover web materials
from more archives (research documented in [ResawColl]).
The PWID is especially useful for web material where precision is in
focus and/or there are references to materials from web archives
requiring special grants in order to gain access. The precision
regards both pointing to the archive where it was found and validated
against its purpose (other archived versions in other web archives
may differ both regarding completeness and contents even within short
time periods) as well as precision about what is actually referred by
the reference (e.g. is it the page or the whole website).
Furthermore the PWID is very useful in specification of contents of a
web collection (also known as web corpus). Definitions of web
collections are often needed for extraction of data used in
production of research results, e.g. for evaluations in the future.
Current practices today are not persistent as they often use some CDX
version, which vary for different implementations.
Strict syntax is needed for the PWID reference in order to ensure
that it can be used for computational purposes. This is especially
relevant for automatic extraction of parts from web collection
definitions. Furthermore, readers of research papers are today
expecting to be able to access a referenced resource by clicking an
actionable URI, therefore a similar facility will be expected for
references to available archived web material, which strict syntax
can make possible. Examples of technical solutions that is enabled
are:
o resolving of a references and automatic extraction of web
collection defined by PWID URNs [ResawRef] [ResawColl]
o Resolving of a PWID reference by resolving services. As a start,
there is work on a prototype that can work for the Danish web
archive data and open web archives with standard patterns for the
current technologies. There may come different implementations
for resolving which may rely on different protocols and
application
The purpose of the PWID is also to express a web archive reference as
simple as possible and at the same time meeting requirements for
sustainability, usability and scope. Therefore, the PWID URN is
focused on only having the minimum required information to make a
precise identification of a resource in an arbitrary web archive.
Resent research have found that this is obtain by the following
information [ResawRef]:
o Identification of web archive
Zierau Expires May 8, 2019 [Page 4]
Internet-DraftA Persistent Web IDentifier (PWID) URN NamespNovember 2018
o Identification of source:
* Archived URI or identifier
* Archival timestamp
o Intended precision (page, part, subsite etc.)
The PWID URN represents this information in a human readable way as
well as a well-defined way that enables technical solutions to
interpret the URN.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
2. Namespace Registration Template
Namespace Identifier:
PWID
Version:
4
Date:
2018-11-03
Registrant:
Eld Maj-Britt Olmuetz Zierau
Royal Danish Library
Soeren Kierkegaards Plads 1
1219 Copenhagen
Denmark
ph: +45 9132 4690
email: elzi@kb.dk
Purpose:
The URN PWID is a supplement to existing reference standards,
where the PWID will support references to web archives, including
areas that are not supported today: support of references to
Zierau Expires May 8, 2019 [Page 5]
Internet-DraftA Persistent Web IDentifier (PWID) URN NamespNovember 2018
material in web archives with restricted access. Furthermore it
enables technology agnostic references to web archives in general,
which can for instance can be needed for references to web
material that is dynamic (e.g. a news site) or a specific version
of a web material (e.g. specific version of the DOI handbook).
The URN PWID is a form that can work as an algorithmic basis for
finding the resource. This also enables basis for computation of
archived web parts to a collection from one or more web archives.
Furthermore, the PWID includes information about the resource
which makes it possible to find alternative resources, in cases
where the original precise resource have become unavailable.
The PWID URN is designed to be a persistent reference that is
general, global and technology agnostic in order to enhance its
chances for being sustainable. Furthermore, it is designed to be
humanly readable and with ability to make precision of the web
archive resource covers. This design enables a PWID URN to:
* be used for technical solutions e.g. to make them resolvable
* cover references to all sorts of materials in web archives
* cover references to materials from all sort of web archives
The motivation for defining a PWID namespace is the growing
challenge of references to archived web resources, which the PWID
as a URN can assist in overcoming. The standard is needed to
address web materials meeting precision and persistency issues on
par precision in with traditional references for analogue
material. Furthermore, it is needed in order to address web
archive resources that are not freely available online. The PWID
URN covers both referencing of web resources from research papers
and definition of web collection/corpus. In detail the challenges
are:
* Citation guidelines generally do not cover general and
persistent referencing techniques for web resources that are
not registered by Persistent Identifier systems (like DOI
[DOI]). However, an increasing number of references point to
resources that only exist on the web, e.g. blogs that turned
out to have a historical impact. In order to obtain
persistency for a reference, the target need to be stable. As
the live web is 'alive' and in constant change, persistency can
only be obtained by referring to archived snapshots of the web.
The PWID URN is therefore focused on referencing archived web
Zierau Expires May 8, 2019 [Page 6]
Internet-DraftA Persistent Web IDentifier (PWID) URN NamespNovember 2018
material in a technology agnostic way (research documented in
[IPRES2016] and [ResawRef]).
* There are many new initiatives for web archive referencing, -
most of them are centralised solutions which offers harvest and
referencing, but these cannot be used for existing materials in
web archives. Other initiatives only cover open web archives,
which does not cover material in archives with restricted
access and where there is a risk of imprecision if a resource
in an alternative archive is the result of resolving such a
resource. The PWID URN is needed in order to fill these gaps
where other techniques are not sufficient.
* There are many different requirements for construction of
collection definitions for web material besides precision and
persistency. Recent research have found that various legal and
sustainability issues leads to a need for a collection to be
defined by references to the web parts in the collection. The
PWID URN is needed in such definitions in order to fulfil these
requirements and to enable a collection to cover web materials
from more archives (research documented in [ResawColl]).
The PWID is especially useful for web material where precision is
in focus and/or there are references to materials from web
archives requiring special grants in order to gain access. The
precision regards both regards precise reference where there can
be no doubt about that you have the correct web material as well
as precision about what is actually referred by the reference
(e.g. is it the page or the whole website)
Furthermore, the PWID is very useful in specification of contents
of a web collection (also known as web corpus). Definitions of
web collections are often needed for extraction of data used in
production of research results, e.g. for evaluations in the
future. Current practices today are not persistent as they often
use some CDX version, which vary for different implementations.
Strict syntax is needed for the PWID reference in order to ensure
that it can be used for computational purposes. This is
especially relevant for automatic extraction of parts from web
collection definitions. Furthermore, readers of research papers
are today expecting to be able to access a referenced resource by
clicking an actionable URI, therefore a similar facility will be
expected for references to available archived web material, which
strict syntax can make possible. Examples of technical solutions
that is enabled are:
Zierau Expires May 8, 2019 [Page 7]
Internet-DraftA Persistent Web IDentifier (PWID) URN NamespNovember 2018
* resolving of a references and automatic extraction of web
collection defined by PWID URNs [ResawRef] [ResawColl]
* Resolving of a PWID reference by resolving services. As a
start, there is work on a prototype that can work for the
Danish web archive data and open web archives with standard
patterns for the current technologies. There may come
different implementations for resolving which may rely on
different protocols and application
The purpose of the PWID is also to express a web archive reference
as simple as possible and at the same time meeting requirements
for sustainability, usability and scope. Therefore, the PWID URN
is focused on only having the minimum required information to make
a precise identification of a resource in an arbitrary web
archive. Resent research have found that this is obtain by the
following information [ResawRef]:
* Identification of web archive
* Identification of source:
+ Archived URI or identifier
+ Archival timestamp
* Intended precision (page, part, subsite etc.)
The PWID URN represents this information in a human readable way
as well as a well-defined way that enables technical solutions to
interpret the URN.
Syntax:
The syntax of the PWID URN is specified below in Augmented Backus-
Naur Form (ABNF) [RFC5234] and it conforms to URN syntax defined
in [RFC8141]. The syntax definition of the PWID URN is:
pwid-urn = "urn" ":" pwid-NID ":" pwid-NSS
pwid-NID = "pwid"
pwid-NSS = archive-id ":" archival-time ":" precision-spec
":" archived-item
archive-id = +( unreserved )
Zierau Expires May 8, 2019 [Page 8]
Internet-DraftA Persistent Web IDentifier (PWID) URN NamespNovember 2018
precision-spec = "part" / "page" / "subsite" / "site"
/ "collection" / "recording" / "snapshot"
/ "other"
archived-item = URI / archived-item-id
archived-item-id = +( unreserved )
where
* 'archival-time' is a UTC timestamp as described in the W3C
profile of [ISO8601] [W3CDTF] (also defined in [RFC3339]), for
example YYYY-MM-DDThh:mm:ssZ. The 'archival-time' shall
represent the timestamp that the web archive have recorded for
the referenced archived URI. The archival-time may be
specified at any of the levels of granularity described in
[W3CDTF], as long as it reflects exactly the granularity of the
timestamp recorded in the web archive, which is in accordance
with the WARC standard [ISO28500].
* 'unreserved' is defined as in [RFC3986]
* 'precision-spec' values are not case sensitive (i.e. "PAGE" /
"PART" / "PaGe" / ... are valid values as well.)
* 'URI' is defined as in [RFC3986] but where occurrences of "[",
"]", "?" and "#" are %-encoded in order not to clash with URN
reserved characters [RFC8141]
The precision specification is expressing the intended precision
of the reference. For example, if the reference is to an html web
element, this element can be interpreted in several ways:
* As just one web part
Meaning the file containing the html, and precisely this file
* A web page
Meaning that an application like Wayback shows result in a
browser, and calculates referenced web parts (display
templates, images etc.) and use these found web parts in the
result.
If the full reference only contains the PWID URN for the page,
this may mean that the archived page can change look over time,
e.g. in case that parts referred by the page did not exist at
reference time, but are harvested at a later stage, - or in
case the web archive's algorithm for calculation of the
referred web parts are changed and given a different result.
In order to make a precise reference to a picture in context of
a web page, the most precise reference will be to provide the
Zierau Expires May 8, 2019 [Page 9]
Internet-DraftA Persistent Web IDentifier (PWID) URN NamespNovember 2018
PWID URN for the page (with page precision) and the PWID URN
for the image file part which contains the referred picture
(with part precision)
* As a site or subsite
Meaning that an application like Wayback shows result in a
browser showing the web page, - and if there are restricted
access according to the reference, the application also needs
to make sure that all parts/pages belonging to the site/subsite
is available.
If the full reference only contains the PWID URN for the site/
subsite, this may mean that the site/subsite can change its
appearance over time, in the same way as for the web page
described above.
The precision specification needs to be part of an URN PWID in
order to enable the person making the above described precision in
the reference. Furthermore this precesion specification will make
it possible for resolvers to display the referred source in a way
that corresponds to the precision specification.
Especially for web materials, there can be different ways to
represent e.g. a web page, which provides different precision of
the source as well. The above examples with part, page, subsite
and site are addressing the most common access via browser
functionality like in Wayback. However, there are also web
archives that archive snapshots of the web pages for the archived
URI. A third option can be to produce a collection of archived
URIs as basis for browser access instead of letting the web
archive calculate sub items (which may change over time). An
example of the production of such a collection is provided in the
section about assignment. Lastly, a web page may be archived via
a web recording.
As consequence of the above, there are following valid precision-
spec values:
* part
the single archived web part harvested as a file from the
specified URI, e.g. a pdf, an html text, an image
* page
the web page represented by the web page file (e.g. html)
harvested from the specified URI, where this contents is
interpreted as a web page with all referred parts relevant to
display the web page (but where referred parts must be
calculated as described above), e.g. an html page with referred
images
Zierau Expires May 8, 2019 [Page 10]
Internet-DraftA Persistent Web IDentifier (PWID) URN NamespNovember 2018
* subsite
The referred web page (as described under 'page') where it is
possible to browse to all references starting with the same
path as the archived URI
* site
The referred web page (as described under 'page') where it is
possible to browse to all references in the domain specified in
the archived URI
* collection
Representation of a collection specification, where it is up to
the web archive applications to find out how it is rendered
(e.g. collection specification in the XML format enabling
interpretation as in the example provided in [ResawColl])
* snapshot
a snapshot (image) representation of web material, e.g. a web
page
* recording
Representation of a web recording specification where it is up
to the web archive applications to find out how it is rendered
(where interpretation could depends on file-suffix for the web
recording), an example is web recording coded in a WARC file
* other
This is a placeholder to allow reference of a resource of any
kind with an assigned identifier (by the archive). In all
cases, it will be up to the application serving the web archive
to interpret how this item should be rendered
Assignment:
The PWID URNs does not have to be assigned by an authority, as
they are based on the information created at the time of
archiving. In other words: the PWID URNs are created
independently, but following an algorithm which ensures that the
referred item can be found if it is still available. It also has
the benefit that it includes information to look alternative
resources e.g. via Memento for some open web archives [MEMENTO] or
via possibly coming web archive infrastructures.
A PWID URN is created by finding the relevant information of the
syntax parts of the PWID on form:
"urn:pwid:" archive-id ":" archival-time ":" precision-spec
":" archived-item
Zierau Expires May 8, 2019 [Page 11]
Internet-DraftA Persistent Web IDentifier (PWID) URN NamespNovember 2018
The PWID URN for an archived item in hand can be constructed by
exchanging the unspecified PWID parts with relevant information,
as explained in the following:
* archive-id (identification of web archive):
In this version of the standard, it is recommended to use the
domain of the web archive as the identifier for the web archive
(e.g. archive.org for Internet Archives open web archive).
This is recommended, since browsing of this domain page
typically will lead to description of how to access the web
archive, e.g. online or by applying for access grants.
Furthermore, it is more precise than e.g. the name of the
archive, since there may be more than one installation of web
archives in the same organisation, e.g. archive.org and
archive-it.org are both covered by Internet Archive. When a
registry of web archives are established it will be more
precise and persistent to use the web archive identifier
specified in this registry (e.g. DKWA for the Danish web
archive with domain netarkivet.dk)
* archival-time (archival timestamp):
The archival time for the archived item in hand may be
displayed along with the archived item, but there are different
implementation where it is important to be aware of whether a
more precise timestamp can be found, and that it is the correct
timestamp that is used. For many Wayback implementation the
precise time can be found as part of the URI used for viewing
the archived item, e.g. in the example of
https://web.archive.org/web/20160122112029/http://www.dr.dk
viewable by the Internet Archives Wayback installation, the
number 20160122112029 represents the archival time
2016-01-22T11:20:29Z. In other installations. In other
installations, the most precise time may be found in the URI
from a search result leading to the resource (which usually
redirects on basis of a call to the underlying archive index).
Especially for web pages with frames, there may be cases where
the actual time is not displayed with the source, since only
the times for the contents of the frames are displayed.
* precision-spec (precision as represented page, part, site,
snapshot etc.):
The precision specification specifies how the user should view
the referred item - either as a specific representation (with
inherited precision) or by use of tools (e.g. browse web site
based on calculations or browse on basis of collection of
specific parts).
Zierau Expires May 8, 2019 [Page 12]
Internet-DraftA Persistent Web IDentifier (PWID) URN NamespNovember 2018
Since the archived URI can have different forms indicated by
the precision specification, this information may be used in
resolution and location.
For most imprecision types are the ones that involves
calculation, i.e. page, site or subsite. For items like an
image that have no references to calculate the precision is
best described by part, since it also tells that it is a
precise reference.
* archived-item (archived URI or identifier):
The archived item will be the URI (or identifier assigned for a
resource by the archive) of the displayed the archived item in
hand.
A much easier way to construct PWID URNs is to use tools that
construct them. Currently, there is also a prototype for a SOLR-
Wayback tool (Source at https://github.com/netarchivesuite/
solrwayback) [PWIDprovider], which can assist in finding the most
precise reference to an archived web page. This Wayback version
can provide all PWID URNs belonging a shown page (with the page
PWID URN at the top). For example, in netarkivet.dk, the archived
URI for the web page http://www.susanlegetoej.dk/shop/handskedyr-
siameser-killing-8681p.html archived 2008-11-29 01:19:16 UTC, has
the following parts calculated by the SOLR-Wayback tool:
urn:pwid:netarkivet.dk:2008-11-
29T00:41:42Z:part:http://www.susanlegetoej.dk/images/ddcss/
SK113_Master_NF.css
urn:pwid:netarkivet.dk:2008-11-
29T00:39:47Z:part:http://www.susanlegetoej.dk/shop/css/
print.css
urn:pwid:netarkivet.dk:2008-11-
29T00:40:06Z:part:http://www.susanlegetoej.dk/images/ddcss/
SK113_Basket_NF.css
urn:pwid:netarkivet.dk:2008-11-
29T00:40:00Z:part:http://www.susanlegetoej.dk/images/ddcss/
SK113_TopMenu_NF.css
urn:pwid:netarkivet.dk:2008-11-
29T00:40:00Z:part:http://www.susanlegetoej.dk/images/ddcss/
SK113_SearchPage_NF.css
urn:pwid:netarkivet.dk:2008-11-
29T00:40:35Z:part:http://www.susanlegetoej.dk/images/ddcss/
SK113_Productmenu_NF.css
Zierau Expires May 8, 2019 [Page 13]
Internet-DraftA Persistent Web IDentifier (PWID) URN NamespNovember 2018
urn:pwid:netarkivet.dk:2008-11-
29T00:40:22Z:part:http://www.susanlegetoej.dk/images/ddcss/
SK113_SpaceTop_NF.css
urn:pwid:netarkivet.dk:2008-11-
29T00:40:24Z:part:http://www.susanlegetoej.dk/images/ddcss/
SK113_SpaceLeft_NF.css
urn:pwid:netarkivet.dk:2008-11-
29T00:40:23Z:part:http://www.susanlegetoej.dk/images/ddcss/
SK113_SpaceBottom_NF.css
urn:pwid:netarkivet.dk:2008-11-
29T00:40:25Z:part:http://www.susanlegetoej.dk/images/ddcss/
SK113_SpaceRight_NF.css
urn:pwid:netarkivet.dk:2008-11-
29T00:37:23Z:part:http://www.susanlegetoej.dk/images/ddcss/
SK113_ProductInfo_NF.css
urn:pwid:netarkivet.dk:2008-11-
29T00:37:24Z:part:http://www.susanlegetoej.dk/Shop/js/
Variants.js
urn:pwid:netarkivet.dk:2009-03-
03T11:53:00Z:part:http://www.susanlegetoej.dk/Shop/js/Media.js
urn:pwid:netarkivet.dk:2009-03-
03T11:53:02Z:part:http://www.susanlegetoej.dk/images/design/
print.gif
urn:pwid:netarkivet.dk:2009-03-
03T11:54:19Z:part:http://www.susanlegetoej.dk/Shop/js/Scroll.js
urn:pwid:netarkivet.dk:2009-03-
03T11:54:09Z:part:http://www.susanlegetoej.dk/Shop/js/
Shop5Common.js
urn:pwid:netarkivet.dk:2006-11-
20T20:16:03Z:part:http://www.susanlegetoej.dk/images/602551.jpg
Security and Privacy:
Security and privacy considerations are restricted to accessible
web resources in web archives. Resolvers to PWID URNs will
usually only be possible using the web archives' access tools,
where security and privacy are covered by these tools. In such
cases security and privacy will covered by such tools, since the
Zierau Expires May 8, 2019 [Page 14]
Internet-DraftA Persistent Web IDentifier (PWID) URN NamespNovember 2018
information used for access has no security and privacy issues.
In the cases where resolution is made around the archives' access
tools, there should be made separate analysis.
Interoperability:
This is covered by comments in the Syntax description:
* the PWID URN conforms to the URI standard defined as in RFC
3986 [RFC3986] and the URN standard RFC 8141 [RFC8141]
* the 'archival-time' of the PWID URN conforms UTC timestamp as
described in the W3C profile of ISO 8601 [ISO8601] [W3CDTF] and
is in accordance with the WARC standard ISO 28500 [ISO28500].
* the 'archived-item' is either an assigned identifier (the URN
standard RFC 8141 [RFC8141]) or an URI which conforms to the
URI standard defined as in RFC 3986 [RFC3986], with %-encodings
of "[", "]", "#", and "?" in order to conform to the the URN
standard RFC 8141 [RFC8141]
Resolution:
The information in a PWID URN can be used for locating a web
archive resource, for any kind of web archive. It includes the
minimum information for web archive materials, which enables
resolvability, manually or by a resolver. Resolution of a PWID
URN is the primary motivation of making a formal URN definition,
instead of just textual representation of the for needed parts of
a PWID.
Resolution (manually or automatically) is done based on the PWID
parts:
* Web archive identification for web archive holding referred
resource
The identifier is either an identifier where location of the
web archive can be found by looking up the identifier in a
registry, - or it is the domain name for the web archive, where
browsing this domain page typically will lead to description of
how to access the web archive, e.g. online or by applying for
access grants
* Archived URI or identifier of archived item
If the resource is an archived URI, this URI must be used in
search for or construction of location of the resource. If the
resource is an identifier assigned to the resource (by the
Zierau Expires May 8, 2019 [Page 15]
Internet-DraftA Persistent Web IDentifier (PWID) URN NamespNovember 2018
archive), it is this identifier that must be used in search for
or construction of location of the resource
* Date and time associated with the archived item
The archival date and time must be used in search for or
construction of the location of the resource
* Precision of what is referred
The precision can either contribute to the guidance of
activating tools to view the referred item e.g. browse the
referred item as a page on basis of computed closest past,
browse the referred item on basis of parts specified in a
collection, or view the referred item as a snapshot. In the
example of the snapshot, it also contains a specification of
which resource to display
In the following the different resolution techniques are explained
(manual as well as via a service) .
An example of a PWID URN is:
urn:pwid:archive.org:2016-01-22T11:20:29Z:page:http://www.dr.dk
has the information:
* archive.org
Currently known identifier in form of the Internet Archive
domain name for their open access web archive. If Internet
Archive registered their open web archive in an IANA web
archive register, this identifier could currently be
"web.archive.org/web/" for Wayback resolution, or it could be
"archive.org/pwid/" if a PWID interface was created as
described below
* 2016-01-22T11:20:29Z
UTC date and time associated with the archived URI
* page
Clarification that the reference cover the full web page with
all its inherited parts selected by the web archive
* http://www.dr.dk
archived URI of item
Based on the current (2018) knowledge of Internet Archive's open
access web interface, which has the pattern:
https://web.archive.org/web/<time>/<uri>
Zierau Expires May 8, 2019 [Page 16]
Internet-DraftA Persistent Web IDentifier (PWID) URN NamespNovember 2018
If the web archive has registered an identifier for the web
archive along with the prefix before <time> and <uri>, then this
identifier can be used to manually (or automatically) deduce the
prefix via this register
we can manually (or automatically) deduce an actual (current 2018)
access https address for Internet Archives Wayback application
(where only digits from the date is included):
https://web.archive.org/web/20160122112029/http://www.dr.dk
The same recipe can be used for other Wayback platforms for open
web archives.
Another manual resolution would be to find the resource by use of
the specified web archive's search interface. This will work for
both open web archives and web archives with restricted access.
It is also noteworthy that the information in the PWID can help in
finding an alternative resource, in case the original referred
resource is not available anymore. The archived URI can be
searched in other web archives, where the date and time can help
to find the best match found, e.g. via Memento (for some open web
archives) or via possibly coming web archive infrastructures.
Regarding the precision specification, there are not yet any
implementations which support distinctive rendering depending on
such a parameter, e.g. only providing html for an html page
specified as part and the page with calculated elements if
specified as page etc. Therefore, the precision specification
will initially be ignored by a resolution to a Wayback interface.
A resolving service is currently available in form of code for a
prototype which run at the Royal Danish Library [PWIDresolver] and
is planned to be more broadly available. This service currently
covers both the Danish web archive (with the proper rights) and
open web archives with access services based on a patterns
including archive, archival time and archived URI. In other
words, for open web archives it covers conversion of PWID URNs
for: archive.org, archive-it.org, arquivo.pt, bibalex.org,
nationalarchives.gov.uk, stanford.edu and vefsafn.is. For the
Danish web archive with restricted access, the prototype works
locally accessing the CDX of the library, and providing access via
a local proxy to a restricted environment. The source code for
this prototype is available from
https://github.com/netarchivesuite/NAS-research/releases/
tag/0.0.6.
Zierau Expires May 8, 2019 [Page 17]
Internet-DraftA Persistent Web IDentifier (PWID) URN NamespNovember 2018
Automatic access of a referenced web resource may work on the open
web for open web archive or in restricted environments for the web
archives with restricted access. There may be a need for varied
operation depending on the available technology and applications,
e.g.:
* Via locally installed browser plug-ins or applications forming
http/https URIs as described above
* Via web research infrastructures
this is a future solution scenario as a web archive research
infrastructure do not yet exists. However, it is a likely
future scenario, as it is currently being proposed in the RESAW
community [RESAW]
Documentation:
None relevant
Additional Information:
The PWID was originally suggested as a URI, where the suggestion
was based on research between a computer science researcher with
knowledge of web archiving and researchers from humanity subject
(History and Literature). This resulted in the paper "Persistent
Web References - Best Practices and New Suggestions" [IPRES2016]
from the iPres 2016 conference. In this paper, the PWID is
referred to as WPID. However, one of the feedbacks has been a
concern that WPID was interpreted as a PID related to a PID-
system, e.g. as the DOI. All though PID does not have a precise
definition that makes it wrong to call it a "WPID. The danger is
that it is confused with PID systems, which is not the intension.
Consequently, this suggestion names the PWID instead.
The comments on the drafted PWID URI ([DraftPwidUri]) has been
that is seems to be a URN rather than a URI. Which is the reason
why it is now suggested as a URN.
At the RESAW 2017 conference there are two related papers: One on
referencing practices [ResawRef] and one on research data
management practices [ResawColl]. This practice is also planned
to be used for Danish web collections.
The interest for this new PWID has already been shown. There was
a lot of response at iPRES. Especially at the RESAW 2017
conference, web researchers from digital humanities have expressed
strong interest in the PWID, since it can fill a gap and make it
possible for them to make all the references they need to make.
Zierau Expires May 8, 2019 [Page 18]
Internet-DraftA Persistent Web IDentifier (PWID) URN NamespNovember 2018
Therefore, the ambition is to make the PWID URN namespace
definition a constituent part of a standard being developed in the
IETF or some other recognized standards body.
At iPRES 2018, the PWID URN was presented in a digital poster,
which had a lot of interest around it, and it won the "best
poster" award [IPRES2018]. A more researcher-oriented version of
this poster has been accepted to iDCC 2019.
Revision Information:
This is the fourth version of PWID as a URN, where remarks from
the URN PWID reviews have been incorporated. This large covers
the following:
* It has been more clear clear that the PWID URN is a needed
supplement to existing standards (especially in Abstract and
Introduction of RFC, as well as Purpose of URN template)
* It has been made more clear that the PWID URN also can be used
as basis for search of resources that has become unavailable
(especially in the Introduction of RFC, as well as Purpose and
Resolution sections of URN template)
* The Introduction section of the RFC and the Purpose section of
the URN template has been aligned.
* 'Coverage' has been renamed to 'precision' and it has been
explain in much more details (especially in the Syntax,
Assignment and Resolution sections)
* Use of the term "ambiguity" have been rephrased in order to be
more correct
* 'archival-time' and 'URI' have been decribed in more details
and more correctly (in the Syntax section)
* Description of Assignment has been expanded to provived more
thorough and precise description (in the Assignment section)
* Description of Resolution has been expanded to provived more
thorough and precise description (in the Resolution section)
* The Interoperability descriptions have been adjusted to reflect
the descrions in the Syntax section (in the Interoperability
section)
Zierau Expires May 8, 2019 [Page 19]
Internet-DraftA Persistent Web IDentifier (PWID) URN NamespNovember 2018
Furthermore the Security and Privacy section has been edited in
order to become more clear, and the Additional Information section
has been extended with mentioning of the price winning iPRES 2018
poster and coming iDCC 2019 poster.
3. Acknowledgements
A special thanks to Caroline Nyvang and Thomas Kromann who have
contributed to the research identifying the minimum information
required in a persistent web reference, and to Bolette Jurik
contributed with supplementary research concerning requirements for
web collection/corpora definitions. Also thanks to all that have
contributed to this work with the research and reviewing this RFC.
4. References
4.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet:
Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
<https://www.rfc-editor.org/info/rfc3339>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005,
<https://www.rfc-editor.org/info/rfc3986>.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008,
<https://www.rfc-editor.org/info/rfc5234>.
[RFC8141] Saint-Andre, P. and J. Klensin, "Uniform Resource Names
(URNs)", RFC 8141, DOI 10.17487/RFC8141, April 2017,
<https://www.rfc-editor.org/info/rfc8141>.
4.2. Informative References
[DOI] International DOI Foundation, "The DOI System", 2016,
<https://web.archive.org/web/20161020222635/
https:/www.doi.org/>.
Zierau Expires May 8, 2019 [Page 20]
Internet-DraftA Persistent Web IDentifier (PWID) URN NamespNovember 2018
urn:pwid:archive.org:2016-10-20T22:26:35:site:https://www.
doi.org/
[DraftPwidUri]
Zierau, E., "DRAFT: Scheme Specification for the pwid URI,
version 4", June 2018, <https://datatracker.ietf.org/doc/
draft-pwid-uri-specification/>.
[IPRES2016]
Zierau, E., Nyvang, C., and T. Kromann, "Persistent Web
References - Best Practices and New Suggestions", October
2016, <http://www.ipres2016.ch/frontend/organizers/media/
iPRES2016/_PDF/
IPR16.Proceedings_4_Web_Broschuere_Link.pdf>.
In: proceedings of the 13th International Conference on
Preservation of Digital Objects (iPres) 2016, pp. 237-246
[IPRES2018]
Zierau, E., "Precise and Persistent Web Archive References
- Status, context and expected progress of the PWID",
September 2018", September 2018.
In: proceedings of the 15th International Conference on
Preservation of Digital Objects (iPres) 2018
[ISO28500]
International Organization for Standardization,
"Information and documentation -- WARC file format", 2017,
<https://www.iso.org/standard/68004.html>.
[ISO8601] International Organization for Standardization, "Data
elements and interchange formats -- Information
interchange -- Representation of dates and times", 2004,
<https://www.iso.org/standard/40874.html>.
[MEMENTO] Memento Development Group, "About the Memento Project",
January 2015, <http://mementoweb.org/about/>.
urn:pwid:archive.org:2018-11-
01T15:26:28Z:page:http://mementoweb.org/about/
[PWIDprovider]
Royal Danish Library (Netarkivet), "SolrWayback 3.1",
2018, <https://github.com/netarchivesuite/solrwayback>.
Zierau Expires May 8, 2019 [Page 21]
Internet-DraftA Persistent Web IDentifier (PWID) URN NamespNovember 2018
urn:pwid:archive.org:2018-06-
11T02:00:05Z:page:https://github.com/netarchivesuite/
solrwayback
[PWIDresolver]
Royal Danish Library (Netarkivet), "Date and Time Formats:
note submitted to the W3C. 15 September 1997", 2018,
<https://github.com/netarchivesuite/NAS-research/releases/
tag/0.0.6>.
urn:pwid:archive.org:2018-07-
16T06:53:51Z:page:https://github.com/netarchivesuite/NAS-
research/releases/tag/0.0.6
[RESAW] The Resaw Community, "A Research infrastructure for the
Study of Archived Web materials", 2017,
<https://web.archive.org/web/20170529113150/
http://resaw.eu/>.
pwid:archive.org:2017-05-29T11:31:50Z:site:http://resaw.eu
/
[ResawColl]
Jurik, B. and E. Zierau, "Data Management of Web archive
Research Data", 2017,
<https://archivedweb.blogs.sas.ac.uk/files/2017/06/
RESAW2017-JurikZierau-
Data_management_of_web_archive_research_data.pdf>.
In: proceedings of the RESAW 2017 Conference, DOI:
10.14296/resaw.0002
[ResawRef]
Nyvang, C., Kromann, T., and E. Zierau, "Capturing the Web
at Large - a Critique of Current Web Referencing
Practices", 2017,
<https://archivedweb.blogs.sas.ac.uk/files/2017/06/
RESAW2017-NyvangKromannZierau-
Capturing_the_web_at_large.pdf>.
In: proceedings of the RESAW 2017 Conference, DOI:
10.14296/resaw.0004
[W3CDTF] W3C, "Date and Time Formats: note submitted to the W3C. 15
September 1997", 1997,
<http://www.w3.org/TR/NOTE-datetime>.
Zierau Expires May 8, 2019 [Page 22]
Internet-DraftA Persistent Web IDentifier (PWID) URN NamespNovember 2018
W3C profile of ISO 8601 urn:pwid:archive.org:2017-04-
03T03:37:42Z:page:http://www.w3.org/TR/NOTE-datetime
Author's Address
Eld Maj-Britt Olmuetz Zierau (editor)
Royal Danish Library
Soeren Kierkegaards Plads 1
Copenhagen 1219
Denmark
Phone: +45 9132 4690
Email: elzi@kb.dk
Zierau Expires May 8, 2019 [Page 23]