Webtracks Demontrators

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Project Document Cover Sheet

Project Information

Project Acronym

WebTracks

Project Title

Web
-
scale link tracking for research data and publications

Start Date

1
st

Aug 2010

End Date

30
th

Nov 2011

Lead Institution

University of Southampton

Project Director

Simon Coles

Project Manager &
contact details

Brian Matthews

01235 446648 brian.matthews@stfc.ac.uk

Partner Institutions

STFC

Project Web URL

http://webtracks.jiscinvolve.org/wp/

Programme Name
(and number)

Managing Research Data (Citing,

Linking and Integrating Research Data)

Programme Manager

Simon Hodson



Document Name

Document Title

Webtracks
2.2:

Implementation of the InteRCom

protocol
within demonstrator systems

Author(s)


Shirley Crompton, Brian Matthews

Date

8
/0
2
/201
2

Filename


URL

if document is posted on project web site

Access

X Project and JISC internal

X

General dissemination




Document History

Version

Date

Comments


0.1

08/02/2012

Initial version


Shirley Crompton

1.0

18/04/2012

Final version


Brian Matthews










Table of Contents


1

Introduction and General Overview

................................
................................
.......

5

2

STFC ePublications Archive

................................
................................
..................

5

2.1

Epubs Overview

................................
................................
..............................

5

2.2

Webtracks
-
Epubs Resources

................................
................................
...........

5

2.3

Webtracks
-
Epubs Resources URIs
................................
................................
..

6

2.4

HTTP Methods Applicable to Each Webtracks
-
ePubs Resource

...................

6

2.5

Webtracks
-
Epubs Implementation Details

................................
......................

7

2.6

Webtracks
-
Epubs Screenshots

................................
................................
........

9

3

STFC ISIS ICAT Data Catalogue

................................
................................
........

14

3.1

ICAT Overview

................................
................................
.............................

14

3.2

Webtracks
-
ICAT Resources

................................
................................
..........

14

3.3

Webtracks
-
ICAT Resources URIs

................................
................................

15

3.4

HTTP Methods Applicable to Each
Webtracks
-
ICAT Resource
..................

16

3.5

Webtracks
-
ICAT Implemenation Details

................................
......................

16

3.6

Webtracks
-
ICat Screenshots

................................
................................
.........

18

4

Logging

................................
................................
................................
.................

20

4.1

Receiving Ping

................................
................................
..............................

20

4.2

Sending Ping

................................
................................
................................
.

21

5

Terminolog
y Applicable to this Document

................................
..........................

21

Acknowledgements

................................
................................
................................
......

22

References

................................
................................
................................
....................

22





Webtracks
Demontrators



Editors:


Shirley Crompton
<shirley.crompton@stfc.ac.uk>

Brian Matthews
<brian.matthews@stfc.ac.uk>



© Copyright 201
2

Science and Technology Facilities Council



_____________________________________________________________________


Abstract


The Webtracks Restlet application
is

a Java
programme

built on the Restlet
Framework
vers.
2.0.8

(1)
.

It

provides a lightweight framework for
data repositories
and

management tools to
implement

the InteRCom
(2)

protocol,

another key
pr
oduct
of the Webtracks project

(3)
.


This document
describes the implementation of
Webtracks exemplars in two different research object repositories: ePublications
Archive (Section 2) and ISIS ICAT Data Catalogue (Sec
tion
3
). Both systems
manage a large collection of diverse information objects but each has its particular
niche. The following sub
-
sections provide an overview of each system, followed by
a discussion of the design and implementation, and conclude with

a walk
-
through of
their key features.



_____________________________________________________________________


1

Introduction

and General Overview

The Webtracks application is an open source product developed by the Webtracks
project

(3)

to facilitate the adoption of th
e Inter
-
Repository Communication protocol
(InteRCom)
.

This document
describes the implementation of Webtracks exemplars in
two different research object repositories: ePublications Archi
ve (Section

2
) and ISIS
ICAT Data Catalogue (Section
3
).

Both systems manage a large
collection of diverse
information objects but each has its particular niche. The following sub
-
sections
pro
vide an overview of each system
,
followed by

a discussion of
the design and
implementation
,
and conclude with a walk
-
through of the
ir

key features.


2

STFC ePublications Archive

2.1

Epubs
Overview

The STFC ePublication
s

archive

(informally known as ePubs)

(4)

records the
scientific output of the Chilbolton

Observatory
,

and the

Daresbury, and Rutherford
Appleton Laboratories

operated by STFC
. The output
s

are diverse in nature and
typically include

Journal Articles, Conference Papers,
Data, Patents,
Technical
R
eports, ePrints, Theses and Books.

S
cientific
publications are
based on the
generation and analysis of both primary and
derived data
, and t
hus, ePubs provides a
useful test case for
W
ebtracks
as

citations to and from diver
se digital research objects
are c
ommon and need to be recorded.

2.2

Webtracks
-
Ep
ubs Resources




Figure
1

CLADDIER

Data Model for ePubs Citation.


The ePubs system uses the FRBR data model for representing information about
publications
(
8
)
. FRBR uses the term
Expression
to describe a realisation of a
Work
,
the intellectual creation encapsulated by
an

entry in the repository.
CLADDIER

(
9
)

further extended the model for ePubs to
associate citations with an
Expression

(
Figure
1
)
. Webtracks
-
Epubs follows
CLADDIER
’s design and uses Expression
(ExprResource) as the
‘owner’

for citation

links (Links resource). The

Resources

exposed by Webtracks
-
Epubs

are described below:


Re
source Name

Description

ExprResource

Resource that identifies a single ePubs expression.

LnksResource

Resource that identifies the collection of all available citation links of an
expression.

SparqlResource

Resource that identifies a
n algorithm resource that answers sparql queries to
extract ePubs citation links.

UserAgentResource

Resource that identifies an algorithm resource that
exposes

Get and Post
requests

to trigger InteRCom operations.


2.3

Webtracks
-
Epubs

Resources URIs

The demo

application is hosted on a Tomcat 6 container running on “tiger.dl.ac.uk”
and is listening to port 8080
, and its resources are accessible via the following URIs
:


URI

Description

http://

tiger.dl.ac.uk:8080/
webtracks/

expression/{eid}
/v/{vid}

URI of the
Expression resource.

{ei d} denot es t he
Expr essi on i dent i fi er i n ePubs.

I t s houl d be not ed
t hat
t he
de mo app
l i cat i on

does not cur r e nt l y us e t he
t e mpl at e var i abl e vi d ( ver s i on i d).

ht t p://

t i ger.dl.a c.uk:8080/
web t r ac ks/

expr es s i on/{ei d}/v/{vi d}
/l i nks

URI of t he
Li nks ( Rec ei ver ) wher e {e i d}
i dent i f i e s
t he cur r ent

E
xpr es s i on

obj ec t
.

ht t p://

t i ger.dl.a c.uk:8080/
web t r ac ks/s
par ql

URI

of

the sparql resource.

This handles select, ask,
construct and describe query types and returns the
output as a Stream object in

either

XML, JSON,
RDF/XML, RDF/XML
-
ABBREV or N3 format.
Note that the output format is restricted for specific
query type.

http://

tiger.dl.ac.uk:8080/
webtracks/

u
ser
a
gent

URI

of the UserAgent (Sender) resource.


2.4

HTTP
Methods Applicable to Each
Webtracks
-
ePubs
Resource

Webtracks provides an implementation of the following HTTP Methods as part of its
RESTFUL web service interface





Resource

Method

Description

E
xpression

GET

Provides two representations of the current expression:



An HTML representation with embedded RDFa ,



An RDF representation using the Dublin Core
ontology.

L
inks

GET

Provides two representations of
the
collection of all
available citation links of the current expression:



An HTML representation displaying the RDF triples
in tabulated format
marked up

with html

links
,



An RDF XML representation.

L
inks

POST

Creates a new citation link according to the RDF d
ata
sent in the POST request (see Section
Error! Bookmark
not defined
.
).

L
inks

PUT

This uses
X
-
HTTP
-
Method
-
Override POST
. Updates
the link requested in the
post

RDF XML with a new link.
An example request RDF is given in

page
Error!
Bookmark not defined.
.

L
inks

DELETE

This uses
X
-
HTTP
-
Method
-
Override POST
.

Deletes
the citation link/s requested in the post RDF XML.

S
parql

GET

This handles a GET request. The method expects two
query parameters

appended to the request
:



query
: which contains the sparql query String.



format: the
o
utput format
.

S
parql

POST

This handles a POST request which sends an entity
containing the query parameters.

U
seragent

GET

Provides an RDF representation of the requested URI
resource according to data sent in the provided HTML
form. The form uses
J
avascript to GET HTML/RDFa
meta
data directly from the requested URI.

U
seragent

POST

This handles a Post request to perfo
r
m an InteRCom

operation to

optionally get metadata and post a citation
link request

according to data sent in the provided HTML
form
.




2.5

Webtracks
-
Epubs
Implementation

Details


The Webtracks
-
Epubs exemplar is developed in line with the implementation
procedure

outlined in
the Webtracks Deliverable 1.1,

and comprises the following
classes:


Package

Class

Superclass

Description

Webtracks
.epubs

App.java

webtracks.IntercomA
pp.java

The webtracks
-
epubs
application.

webtracks.

epubs.

resources


ExprResource.java

webtracks.resources.
UriResource.java

An

ePubs expression
resource
object.



LnksResource.java

webtracks.resources.L
A links collection of an ePubs
inksResource.java

expression resource object.


SparqlResource.java


org.restlet.resource.

S
erverResource.java

The sparql endpoint
for the
webtracks
-
epubs knowledge
store.


UserAgentResource.j
ava

webtracks.resources.B
aseResource.java

A HTML w
rapper to an
instance of the UserAgent.

webtracks.
epubs.

objects

MetadataBean
.java


POJO for
Expression
metadata
attributes.

webtracks.
epubs.

data

Facade.java

webtracks.objects.Dat
aFacade.java

Façade to provide access to
the SDB knowledge store and
ePubs

Oracle database.


webtracks.
epubs.

utils

CollectionUtils
.java


Conversion utilities for Java
Collection objects.


RdfHelper.java


Rdf utilities for compiling
RDF metadata on an ePubs
Expression object.


Html
Helper.java


Utilities to generate HTML
representation of a Resource
using the Freemarker template
engine.


Sd
b
Utils.java


Utilities to support interaction
with the Jena SDB knowledge
store.


SqlUtils.java


Utilities to support interaction
with the Oracle XE
database.



The
exemplar

is deployed on Tomcat
using the Restlet Servlet Adapter which adapts
Servlet calls to Restlet calls
as shown in
Figure
2
.


The existing ePubs application
does not
support RDF processing

and t
he GET metadata operation is
handled

direclty

by

the Expression Resource Restlet
. It supports the GET metadata method and
generates two different representations:
HTML with RDFa
,

or

RDF
using the Dublin
Core ontology
.

The HTML representation is generated

from template text

using the
Restlet Freemarker extension which is built on the

Java Freemarker template

engine
(7)
. The RDF representation is generated using the
Restlet RDF extension which
supports all major RDF serialization formats.
The Restlet content negotiation
algorithm uses the Client request
h
eader’
s Accept

content type

a
ttribute value

to
dete
rmine which method is called. The citation link and metadata triples are stored in
a Jena SDB and the Expression metadata is read from the existing ePubs Oracle XE
database.




Figure
2

Webtracks
-
epubs Archi
tecture Main Aspects


2.6

Webtracks
-
Epubs
Screenshots


This section presents a series of screenshots t
o illustrate using
the Webtracks
-
Epub
s

exempl
ar to perform InteRCom GET and POST operations.

The ePubs WorkInstance

or Expression 56580 is used in the example.




Figure
3
:

Expression 56580
HTML Representation,

with
HTML E
xce
r
pt Showing RDFa Markups


The UserAgent Restlet

provides an HTML form that permits user to get different
representations of an expression and to submit a Post only or GET and Post request
(
Figure
5
).


Performin
g a Get HTML request using the Expression URI of
http://tiger.dl.ac.uk:8080/webtracks/expression/56580/v/1

will return an HTML
representation as shown in
Figure
3
. Whereas a GET RDF request will return a RDF
representation as shown in
Figure
4
. (Please note that the result may be
unpredictable if using a browser to directly

access the URI as it is not possible to
explicitly control how the browser client set the request header Accept content type.)


Figure
6

shows the inputs required for

a GET and POST request. The Target Ping
Endpoint must be provided if performing a POST only request as the UserAgent will
not undertake the GET metadata stage to discover the POST Target’
s InteRCom ping
endpoint.
Figure
7

shows the results after the POST has been submitted correctly.




Figure
4
:


Expression 56580 RDF Representation






Figure
5
:

User
Agent

Resource with a HTML Form



Figure
6
:

Submitt
ing a Get and Post Link Request





Figure
7
:

Result Status Page with Excerpt Showing the Message



We can verify the outcome of the the request by retrieving the Links Resource
associated with the Expression.
Figure
8

shows the HTML represenation and
Figure
9

shows the RDF representation of the Links Resource object

respectively
.





Figure
8
:

Links Resource HTML Representation





Figure
9
:

RDF Representation of the Expression 56580 Links

3

STFC ISIS ICAT Data Catalogue

3.1

ICAT

Overview

ICAT
1

is an open source metadata management system designed for large
scientific
facilities
. It comprises a database with a well defi
ned API that provides an interface
to a large facility’s holding of experimental data. It also provides a mechanism to link
all aspects of the research chain from proposal through to publication.
ICAT

is in use
at ISIS
2
, the ILL
3
, SNS
4

and Diamond
5

and i
n development for use at
other

facilities
6
.

At ISIS, all experimental data file are produced, captured and catalogued into
ICAT

along with the metadata about sample conditions for that experimental run, and the
metadata from the proposal. ISIS also
register
s

citable DOIs for its experiments

which it encourages researchers to cite in publications relating to ISIS experiments.

Thus the
ISIS
ICAT

provides a complementary use case to that of ePubs. Similar to
ePubs, it also
catalogues and allows access

to

digital research objects of various
formats
, but in this case, the major assets are d
ata sets.
It is important for research
facilities such as ISIS to track the usage of the data collected within the facility in
order to be able to evaluate the impact

of the use of the facility. Traditionally, this is
particularly

the case for tracking journal publications, so the use of a DOI to refer to
data from within a publication is now encouraged; thus the link back from the
publication to the data, and thus t
he corresponding link forward from the data to the
publication needs to be recorded.

We would also anticipate that there may also be
scenarios in the future where the raw data is linked to secondary, or derived data, or
other research artefacts to for
m provenance traces. Again, a method to propagate and
record links is needed.

3.2

Webtracks
-
ICAT

Resources

ICAT is built on the
Core

Scientific Metadata Model

(CSMD)

(
5
)

developed within
STFC for scientific facilities to represent metadata associated with sci
entific studies.
A central concept of CSMD is to describe each Investigation associated with a
particular Experiment on a sample generating data, and the associated data holding
are then mapped to the Investigation with the appropriate parameters (see
Figure
10
).
ISIS currently registers DOI for each Investigation, thus all citations are made at the
Investigation level irrespective of the particular d
ata object/s used by the citing
publication. Webtracks
-
ICAT follows this design and adopts Investigation as the
‘owner’ of citation links.





1

http://code.g
oogle.com/p/icatproject/


2

http://www.isis.stfc.ac.uk/



3

http://www.ill.eu/


4

http://www.ornl.gov


5

http://www.diamond.ac.uk/


6

http://code.google.com/p/icatproject/wiki/UseOfICAT




Figure
10

CCLRC Scientific Metadata Model.


The Resources exposed by
Webtracks
-
I
CAT

are described below:



Resource Name

Description

InvResource

Resource that identifies a single
ICAT

Investigaton object.

LnksResource

Resource that identifies the collection of all
available citation links of an
I
nvestigation.

SparqlResource

Resource that identifies an algorithm resource that answers sparql queries to
extract ePubs citation links.

UserAgentResource

Resource that identifies an algorithm resource
exposing

Get and Post
requests to trigger InteRCom operations.


3.3

Webtracks
-
ICAT

Re
sources URIs


The demo application is
also
hosted on a Tomcat 6 container running on
“tiger.dl.ac.uk” and is listening to port 8080:


URI

Description

http://

tiger.dl.ac.uk:8080/
doi/

INVESTIGATION/{doiId}

URI of the
Investigation

resource.

{ d o i I d } i s t h e

DOI f o r t h e I n v e s t i g a t i o n.

h t t p://

t i g e r.d l.a c.u k:8 0 8 0/

d o i/

I NVES T I GAT I ON/{ d o i I d }
/l i n k s

URI o f t h e
Li n k s ( Re c e i v e r ) wh e r e {
d o i I d
}
identifies the current Investigation object
.

http://

tiger.dl.ac.uk:8080/
doi
/s
parql

URI

of

the sparql

resource. This handles select, ask,
construct and describe query types and returns the
output as a Stream object in XML, JSON,
RDF/XML, RDF/XML
-
ABBREV or N3 format.
Note that the output format is restricted for specific
query type.

http://

tiger.dl.ac
.uk:8080/
doi
/

u
ser
a
gent

URI

of the UserAgent (Sender) resource.


3.4

HTTP Methods Applicable to Each Webtracks
-
ICAT

Resource


Resource

Method

Description

INVESTIGATION

GET

Provides two representations of the current
investigation
:



An HTML representation with embedded RDFa ,



An RDF representation using the Dublin Core
ontology.

links

GET

Provides two representations of the collection of all
available citation links of the current
investigation
:



An HTML representation displaying the
RDF triples
in tabulated format marked up with html links,



An RDF XML representation.

links

POST

Creates a new citation link according to the RDF data
sent in the POST request

links

PUT

This uses
X
-
HTTP
-
Method
-
Override POST
. Updates
the link requested in the post RDF XML with a new link.
An example request RDF is given in page
Error!
Bookmark not defined.
.

links

DELETE

This uses
X
-
HTTP
-
Method
-
Override POST
.

Deletes
the citation link/s requested in the post RDF XML.

sparql

GET

This handles a GET request. The method expects two
query parameters appended to the request:



query : which contains the sparql query String.



format: the output format.

sparql

POST

This handles a POST request which sends an entity
containing the query parameters.

useragent

GET

Provides an RDF representation of the requested URI
resource according to data sent in the provided HTML
form. The form uses javascript to GET HTML/RDFa

metadata directly from the requested URI.

useragent

POST

This handles a Post request to perform an InteRCom
operation to optionally get metadata and post a citation
link request according to data sent in the provided HTML
form.


3.5

Webtracks
-
ICAT

Impleme
nation Details


The Webtracks
-
ICAT

exemplar development follows the same process used by
Webtracks
-
Epubs (see

Section

2.5
) and has a similar architecture.


Unlike

Webtracks
-
Epubs, this exemplar uses the ICAT
-
WS and ICAT
-
DOI web application as sources
on ISIS Investigation metadata. The use of different persistency technology is easily
accommodated by the façade design adopted by Webtracks.




Figure
11


Webtracks
-
ICAT

Architecture Main Aspects.



It should be noted that an ISIS Investigation is DOI
-
enabled. Therefore, it is
theoretically linked
-
data enabled via the DOI system
(6)
. However, the ISIS DOI
landing page currently d
oes not offer RDF. In the exemplar, the InvResource is
responsible for generating both HTML with RDFa and RDF Representations in
response to a GET metadata operation. In a production system, this functionality
could be shared or delegated completely to t
he ISIS DOI application.


The application comprises the following classes:


Package

Class

Superclass

Description

Webtracks
.icat

Icat
App.java

webtracks.IntercomA
pp.java

The webtracks
-
icat
application.

webtracks.

icat.

resources


Inv
Resource.java

webtracks.resources.
UriResource.java

An
ICAT

I
nvestigation
resource object.



LnksResource.java

webtracks.resources.L
inksResource.java

A links collection of an
ICAT

I
nvestigation resource object.


SparqlResource.java


org.restlet.resource.

ServerResource.java

The sparql endpoint for the
W
ebtracks
-
Icat

knowledge
store.


UserAgentResource.j
ava

webtracks.resources.B
aseResource.java

A HTML wrapper to an
instance of the UserAgent.

webtracks.

icat.

objects

DOIModel
.java


POJO for
Investigation
metadata attributes.

webtracks.

icat.

data

Icat
Facade.java

webtracks.objects.Dat
aFacade.java

Façade to provide access to
the SDB knowledge store.

webtracks.

icat.

utils

IcatHelper
.java


Utilities to facilitate
interactions with the
ICAT

Soap WS and the
ICAT

DOI
Web Application. Both are
used as
data
sources for the
Investigation metadata.

ICAT
-
WS has particular
access policies and if the
exemplar is unable to retrieve
metadata via ICAT
-
WS, it will
attempt to scrape the metadata
from the public DOI land
ing
page on the Investigation.


RdfHelper.java


Rdf utilities for compiling
RDF metadata on an
ICAT
Investigaton

object
,


Html
Helper.java


Utilities to generate HTML
representation of a Resource
using the Freemarker template
engine.


SdbUtils.java


Utilities to support interaction
with the Jena SDB knowledge
store.


3.6

Webtracks
-
IC
at Screenshots


This section presents a series of screenshots to illustrate the Webtracks
-
Icat
application

using Investigation 24080016
. As the exemplar uses the same framew
ork
as Webtracks
-
Epubs, to avoid repetition, only
screenshots

that are specific to this
exemplar

are presented
.


Figure
12

shows the HTML Repre
sentation for the Investigation with excerpts
showing the embedded RDFa within the source HTML. The RDF version is given
in
Figure
13
.

Creating a link using the UserAgentResource has

already

been
described in the Webtracks
-
Epubs walk through and
Figure
6

shows a link request
using Investigation
24080016 as the Source URI. The request return code and
verification of the result via the ePubs Links Representation are shown in
Figure
7
,
Figure
8

and
Figure
9

respectively.



Figure
12
:

Investigation 24080016 HTML Representation, with HTML Excerpt

Showing RDFa Markups




Figure
13
:

Investigation 24080016 RDF Representation


4

Logging

The InteRCom protocol

(2)

specifies that the protocol
it should either

work or
fail

silently. The protocol strongly recommends using logging to facilitate issue
resolution.

Both exemplars

use

the log4j framework for this purpose.
Examples of
the Sender and Receiver messages

are given below.


4.1

Receiving Ping



For Receiver events, apart logging failure messages, the appropriate HTTP response
codes are set as described in
Webtracks Deliverable 2.1
.


1.

Post Request (
Failure
)



the requested failed due to application exceptions:


(This particular
Webtracks
-
Ep
ubs example shows that the request failed because
the targeted resource does not exist on the server.)

INFO: 10
-
08
-
11 19:21
LnksResource.
class:90
-

@Webtracks
-
INCOMING

[L
nksResource:
targetURI(
http://localhost:8182/webtracks/expression/23
479/v/1/links)
createLink
-

FAILED :
NO SUCH RESOURCE
!


(This
Webtracks
-
Epubs
example shows that the request failed because the process
failed to extract any RDF from the post.)

INFO: 11
-
08
-
11 10:53 LnksResourc
e.class:100
-

@Webtracks
-
INCOMING

[L
nksResource:
targetURI(http://localhost:8182/webtracks/expression/56
583/v/1/links)
createLink
-

FAILED : no rdf


2.

Put Request (Failure)




(This
example shows that

the update request failed as the link to be replaced d
oes
not exist in the knowledge store.)

INFO: 1
3
-
10
-
11 10:53 LnksResource.class:
340
-

@Webtracks
-
INCOMING

[Lnks
Resource:
URI(
http://localhost:8182/webtracks/expression/56583/v/
1/links)
upateLink



Failed to update a
link
(
http://localhost:8182/webtracks/expression/56583/v
/1
,http://purl.org/spar/cito/citeAsRelated,
http://local
host:8182/webtracks/expression/24637/v/1
) :
LnksResource.updLink


the
link(
http://localhost:8182/webtracks/expression/56583/v
/1,http://purl.org/spar/c
ito/citeAsRelated,http://local
host:8182/webtracks/expression/24637/v/1)
does not exist


3.

Delete Request (Failure)




(This particular request
failed as the parent Expression does not exist.)

INFO: 13
-
10
-
11 12:01 LnksResource.class:253
-

@Webtracks
-
INCOMING

[L
nksResource:
URI(http://localhost:8182/webtracks/expression/56583/v/
1/links) deleteLink


FAILED : PARENT RESOURCE DOES NOT
EXIST!”



4.2

Sending Ping


The UserAgent (Sender) logs the outcomes of the send attempt:


1.

Success


the request was successfully
executed and the message was posted, as in
the following example:


INFO: 19
-
12
-
11 14:14 UserAgent.class:526
-

@Webtracks
-
OUTGOING

[userAgent:
sourceURI(http://localhost:8182/webtracks/expression/23
479/v/1),
targetURI(http://localhost:8182/webtracks/express
ion/56
583/v/1), link
property(http://purl.org/spar/cito/citesAsRelated)],
post
url[http://localhost:8182/webtracks/expression/56583/v/
1/links]

GET&
POST
-

ACCEPTED : 202


2.

Failure
-

the request failed due to application exceptions:


(T
his particular instance was caused by
the failure to obtain metadata on the
Source object)

ERROR: 11
-
08
-
11 10:33 UserAgent.class:448
-

@
Webtracks
-
OUTGOING

[userAgent:
sourceURI(http://localhost:8182/webtracks/expression/23
479/v/1),
targetURI(http://localho
st:8182/webtracks/expression/56
583/v/1)], post
url[http://localhost:8182/webtracks/expression/56583/v/
1/links]
GET&POST

-

FAILED. ObjectsException : retrieve
ResourceObj[http://localhost:8182/webt
racks/expression/
56583/v/1
]

ResourceException : Communicatio
n Error


5

Terminology

Applicable to this Document

Ping

An HTTP Post request send from an InteRCom agent to a server for the purpose of
establishing an explicit relationship between Web resources.


Restlet

In the Restlet architecture, a Restlet

is a dispatcher that provides a context and life
cycle
support. It extends the abstract
Uniform
class

which exposes a uniform
interface as defined by REST.

E v e r y c a l l h a n d l e r s t h a t i s e x p o s e d o v e r t h e
n e t wo r k i s a s u b c l a s s o f R e s t l e t ( e g
. C o n n e c t o r, C l i e n t, S e r v e r, R o u t e r, e t c ) a n d
r e s p e c t s t h i s u n i f o r m i n t e r f a c e. T h i s d e s i g n e n a b l e s R e s t l e t s t o b e c o mb i n e d i n
v e r y s o p h i s t i c a t e d wa y s.


R e s t l e t P r o j e c t

T h e R e s t l e t P r o j e c t

( 1 )

i s a n o p e n s o u r c e p r o j e c t. I t

p r o
v i d e s a l i g h t we i g h t b u t
c o mp r e h e n s i v e f r a me wo r k f o r ma p p i n g
n a t i v e
R E S T c o n c e p t s t o J a v a c l a s s e s.


U R I

A H T T P
-
b a s e d U n i f o r m R e s o u r c e I d e n t i f i e r t h a t c a n b e d e
-
r e f e r e n c e d t o a d i g i t a l
r e p r e s e n t a t i o n o f a R e s o u r c e.



U R I T e mp l a t e

A U R I T e mp l a t e i s a
c o mp a c t s e q u e n c e o f c h a r a c t e r s f o r d e s c r i b i n g a

r a n g e o f
U n i f o r m R e s o u r c e I d e n t i f i e r s t h r o u g h v a r i a b l e e x p a n s i o n.


Acknowl edgement s

Th e I n t e RCo m p r o t o c o l i s d e v e l o p e d a s p a r t o f t h e We b Tr a c k s P r o j e c t
[
h t t p://www.j i s c.a c.u k/wh a t we d o/p r o g r a mme s/mr d/c l i p/we b
t r a c k s.a s p x
] wh i c h i s
f u n d e d b y t h e J I S CMRD [
h t t p://www.j i s c.a c.u k/wh a t we d o/p r o g r a mme s/mr d.a s p x
]
Programme.


References

1.
The Restlet Project.

Restlet.
The Restlet Project.
[Online] 2.0.8, Noelios
Technologies, 2011.
http://www.restlet.org.

2.
STFC E
-
Science Centre.

The Inter
-
repository Communication Protocol.
InteRCom Specification.
Warrington

: Science and Technology Facilities Council,
2011.

3.
STFC.

Webtracks.
Webtracks.
[Online] JISC, 2011.
http://www.jisc.ac.uk/w
hatwedo/programmes/mrd/clip/webtracks.aspx.

4.
STFC E
-
Science Centre
.

ePublication Archive.
ePublication Archive.
[Online]
http://
epubs.stf
c.ac.uk/.

5.
B. Matthews, S. Sufi, D. Flannery, L. Lerusse, T. Griffin, M. Gleaves, K.
Kleese.
:
Using a Core Scientifi
c Metadata Model in Large
-
Scale Facilities.
IDCC,
2009. 5th International Digital Curation Conference.

6
.
The International DOI Foundation.

DOI System and Linked Data.
DOI System.
[Online] 20 April 2011. http://www.doi.org/news/DOINewsApr11.html#2.

7
.
Freemarker Project.

FreeMarker.
http://freemarker.sourceforge.net/.
[Online]
http://freemarker.sourceforge.net/.

8
.
IFLA Study Group.

Functional Requirements for Bibliographic Records.
International Federation of Library Associations .
[Online] 1998.
http:
//www.ifla.org/en/publications/functional
-
requirements
-
for
-
bibliographic
-
records.

9
.
Brian Matthews, Katherine Portwin, Catherine Jones, Bryan Lawrence.

Recommendations for Data/Publication Linkage, CLADDIER Project Report III.
BADC.
[Online] Nov 2007.
htt
p://claddier.badc.ac.uk/trac/attachment/wiki/WikiStart/Report_III_Recommend
ationsForDataLinking
-
final.doc.