The OpenLink Data Explorer Extension
Table of Contents
What is the OpenLink Data Explorer Extension?
The OpenLink Data Explorer (ODE) is a browser extension (currently available for Firefox, Safari, Chrome, Opera, and Internet Explorer with additional browser support to follow) that adds a new option to the realm of Web User Agent functionality, in the form of new menu options for viewing Data Sources associated with Web Pages.
Why is the OpenLink Data Explorer Extension Important?
ODE allows Web users to explore the raw data and entity relationships that underly the Web resources it processes. The extension enables users to switch between Hypertext and Hyperdata link traversal of Web data.
Product Architecture
ODE uses a modular architecture to orchestrate component activities according to the M-V-C pattern. Orchestrated components, referred to as "Cartridges," deliver functionality comprising data extraction and modelling (Model), data display and presentation (View), and actions based upon and/or guided by that data (Controller). Each component is independent of the others, and all are coupled with ODE via HTTP messaging.
What is Linked Data?
The term "Linked Data," coined by Tim Berners-Lee, is the subject of a 2006 Design Issue note. There, he describes Linked Data as a principled approach to structured data representation, access, and integration for the World Wide Web, based on the use of HTTP URIs (Hyperlinks) to denote entities such that when these URIs are resolved (i.e., looked up, or "dereferenced"), they return RDF-model-based structured content (data) that describes the denoted entity.
Why is Linked Data Important?
Linked Data enables direct and easy integration of entity-relationship-model-based structured data into the Web, which enables users to construct powerful structured "data meshups" across the disparate data sources found on HTTP networks (e.g., the World Wide Web), without any programming. This forms a marked contrast to the unstructured "data mashups" commonly seen today, which typically require programming at several points in their production.
How Does Linked Data Work?
By incorporating HTTP into the resource naming schemes of Web accessible resources, so that the same linking mechanism used for retrieving a Web Page (and other information resources) also extends to the process of retrieving a structured description of a resource. This process is quite similar to accessing a SQL recordset via an ODBC or JDBC data source name (DSN). The fundamental differences between Linked Data and SQL CLI based data access are:
- Linked Data URIs name / identify individual records while SQL data access DSNs are scoped to record containers such as Database, Table, View, or Stored Procedure names
- Linked Data URIs facilitate untethered data access that transcends database vendor, database engine, operating system, programming language, application server, application development framework, and other infrastructural confines, unlike ODBC, JDBC, and other data access mechanisms.
The illustration below highlights Linked Data's parallels with ODBC in relation to DSN based data access.
What is the Linked Data Web?
An evolution of the Web that places you a click away from a structured description of any Web accessible resource. A more granular Web where interaction focus moves away from opaque compound documents to the entities they host.
What is the Linked Data Cloud?
As illustrated below, it's the moniker for the growing collection of Linked Data sources being injected into the Web by the Linking Open Data Community. As Kingsley Idehen stated in his blog post, "Semantic Web: Travails to Harmony Illustrated", harmonious intersections of instance data, data dictionaries (schemas, ontologies, rules etc.) provide a powerful substrate (smart data) for the development and deployment of "People" and/or "Machine" oriented solutions.
The clickable venn diagram below provides a simple exploration path that exposes the linkage that already exists, across the different Linked Data types, within the burgeoning Linked Data Web.
There are several paths to materialized Linked Data.
- "On the fly" generation via RDF middleware, from
- Annotated Web Documents (e.g., Semantic HTML)
- Web 2.0 Data Spaces
- Web Services
(click for full-size, clickable image) - Enterprise Data Sources, such as:
- SOA Web Services
- XML -based Data Warehouses and Views
- Enterprise Databases
- Community Driven Extraction Efforts, such as:
Why is the Linked Data Web Important?
By providing bridges between areas of interest and knowledge, the Linked Data Web can reveal relationships where information might otherwise be seen as unrelated. For instance, one might explore which industry and government leaders had previously been classmates or were somehow connected by family.
The OpenLink Data Explorer enables a user to browse from one "thing" to another just as easily as they would click from one page to another with standard hyperlinked document browsing, but with greater understanding and comprehension from the first click.
How can the OpenLink Data Explorer Extension help me exploit the Linked Data Web?
The best way to learn how this extension can help you is to install it, and follow along with the examples below. If you decide you can't benefit by exploiting the Linked Data Web in this way, you can un-install the extension without harm.
Download
The OpenLink Data Explorer can be downloaded from one of the following locations
ODE Extension for Firefox
ODE Extension for Safari
ODE Extension for Chrome
ODE Extension for Opera
ODE Extension for Internet Explorer
Installation
Firefox
The loading of the OpenLink Data Explorer tool differs slightly depending on which method was used to download it.
- From the Mozilla Add-ons site, click on "Add to Firefox", Firefox will then install the Extension as an "Add-on".
- From the OpenLink Web Site, download the "ode.xpi" file and load from the "Open File" menu item of the Firefox "File" menu.
- From the Amazon S3 Storage Site, you will immediately be presented with the option to install the ODE add-on.
- From the Softpedia Web Site, download the "ode.xpi" file and load from the "Open File" menu item of the Firefox "File" menu.
The OpenLink Data Explorer Firefox Add-ons installation dialog will then be presented.
You will need to restart Firefox after it has finished installing.
Once it has finished restarting, you should see the extension in your add-ons list.
Safari
From the Amazon S3 Storage Site, the ODE extension will be downloaded, double click on the "Safari_ODE.safariextz" file to start the installer.
Click the "install" button to commence the installation.
Once complete check the extension tab of the Safari preferences to see the installed extension.
Google Chrome
From the Amazon S3 Storage Site, the ODE extension will automatically be downloaded, click on the "continue" button to start the installer.
Click the "install" button to commence the installation.
Once complete check the "Extensions" menu item of the Windows menu to see the installed extension.
Opera
After downloading the ODE Extension from the Amazon S3 Storage Site, click on the "install" button to start the installer.
The ODE "installation complete" dialog bubble will be displayed when done.
You can check the "Manage Extensions" menu item of the "Extensions" menu to confirm the extension has been installed.
Internet Explorer
After downloading the Windows installer from the Amazon S3 Storage Site, double-click it to start the installation.
You can use the Internet Explorer "Tools" -> "Manage Add-ons" menu item to confirm the extension has been installed.
Configuration
To reach the preferences panel for the OpenLink Data Explorer Extension:
- In Firefox, select the Tools -> Add-ons menu item. Then select OpenLink Data Explorer and click on the Preferences button.
- In Safari, click on the new cubical-box icon in the toolbar to the left of the browser URL address window.
- In Google Chrome, select the Windows -> Extensions menu item, and select the options link of the OpenLink Data Explorer.
- In Opera, select the Tools -> Extensions -> Manage Extensions menu item, and select the Preferences link from the drop down list to the right of the OpenLink Data Explorer icon.
- In Internet Explorer, go to the Command toolbar, and click the ODE extension icon to load the preferences dialog.
There are two tabs for configuration:
- The "Viewers" tab
- The "RDF Data Access" tab
The Viewers Tab
The default "Viewer" option has the benefit of being built into the Browser Extension, and therefore provides the smoothest browsing experience. It is possible to modify the RDF Browser (Viewer) and SPARQL Endpoint to use any available server which has the right capabilities. The image below shows the default configuration which uses the OpenLink Data Explorer viewer hosted on the OpenLink linkeddata.uriburner.com server.
A list of supported viewers is displayed in the "Viewer" drop down list box as shown below:
- OpenLink Data Explorer
- Zitgist Data Viewer
- Marbles
- Disco
- Tabulator
- "Custom (URL)" allows the entry of the URL for a known third party viewer that can be used.
The RDF Data Access Tab
The RDF Data Access tab is used for specifying the location of the RDF sponger cartridges to used for sponging the RDF available data from the request URL, and by default uses the Virtuoso sponger cartridges hosted on the OpenLink linkeddata.uriburner.com server or this can be changed to use a Virtuoso instance of ones choice where the require sponger cartridges are loaded, as indicated in the diagram below:
The "RDFizer Service" drop down list box contains the entries below of supported RDF services that can be used for sponging data:
- OpenLink Virtuoso (Sponger) - default sponger method used by the OpenLink Data Explorer
- Triplr
-
"Custom URL" of the form "
http://server:port/proxy?url="
The Virtuoso default "SPARQL Endpoint" or a custom endpoint of the form "http://linkeddata.uriburner.com/sparql?query=" can be chosen from the drop down list box as indicated below:
Use
The steps to use the OpenLink Data Explorer are simple.
- Open any web document.
- Send it through to the OpenLink Data Explorer:
- Under the View Menu in Firefox only, click "Page Data Sources".
- Right-Click (or Ctrl-Click on Mac) the page or a link, then click "View Data Sources".
- View a description of the available Linked data:
- Under the View Menu in Firefox only, click "Page Description" link.
- Right-Click (or Ctrl-Click on Mac) the page or a link, then click "View Page Description".
- Describe Page (default: XHTML with embedded RDFa)
- Describe Page (RDF) (default format: RDF/XML)
The examples page walks through some of the options and functionalities of the OpenLink Data Explorer.
See Also
More information can be found at the following
Presentations
Documentation
- Virtuoso Sponger
- Virtuoso Universal Server
- OpenLink Data Spaces
- OpenLink Data Spaces and Virtuoso on Amazon EC2