WRLC Library Resource LinkMaker

Description

LinkMaker is a Blackboard Building Blocks plugin that facilitates the inclusion of links to various electronic resources provided by a library in course content pages. These electronic resources include anything that the library provides access to through its own portal systems, such as electronic reserves documents, electronic journal articles, article database citations & full-text, and the online public access catalog.

Many of these resources are licensed from commercial vendors or have other intellectual property restrictions that require that students be authenticated as valid library patrons before they can access the resources. Library portal applications use various means to provide access to authorized users while enforcing the terms of licenses and intellectual property laws. The mechanisms include client IP recognition, proxying, and so forth. The LinkMaker Extension allows online course content to make use of the library portal to provide these access mechanisms for resources listed on the course pages.

The LinkMaker extension works by transforming the addresses (URLs) of online documents into a "durable" form that are not dependent on the current authentication or session of the person who is adding the links to the course pages. For some resources, this means redirecting the student through the library portal or proxy server, while other links may just need to have a session identifier stripped out of the address.

System Architecture

The LinkMaker Extension is designed to separate the generic interface for including library content on course pages from dependencies on specific portal applications and access mechanisms used by various libraries. Buttons on the course content management pages of Blackboard allow content creators to search for electronic resources through the library portal. (These buttons and resource locations are configurable from the Administration Panel --> System Extensions(Bridges) -->Manage System Extensions(Bridges) page for LinkMaker.) URLs for specified resources are transformed by a separate Link Server process that can be customized for each library. The extension adds the transformed link to the course where it can be accessed by students in a secure and convenient manner.

The Link Server does not need to run on the Blackboard server. It provides the transformation procedure as a Web Service, using the Simple Object Access Protocol (SOAP) for transmitting the transformation request and result over the Web. Figure 1 shows the SOAP deployment descriptor for the Link Server that has been written to transform resource URLs into proxied addresses.

Property	Details
ID	urn:EZLinkSvr
Scope	Application
Provider Type	java
Provider Class	ORG.wrlc.linksvr.EZLinkSvr
Methods	normalizeURL

Figure 1: LinkServer Deployment Descriptor

Institutions can use the extension if they provide their own Link Server with a normalizeURL() method that takes a character string containing a URL and returns a string with the transformed URL. The service must also return one of these SOAP fault codes if the URL is not transformable:

        FAULT_CODE_UNRECOGNIZED_URL= "LINKSVR:UnrecognizedURL"
        FAULT_CODE_MALFORMED_URL   = "LINKSVR:MalformedURL"

An unrecognized URL is not fatal; the resource can still be added to the course page even if the Link Server did not know how to transform it. A malformed URL is not a valid HTTP address and will be rejected.

System Requirement

Blackboard v.5.5 Level 2 or above. (Note: This extension has only been tested on our environment - Blackboard 5.5.1 (build 139) Level 2 Solaris/Oracle.)
In addition you will need a Web Service to transform resource URLs. The specifications are given above and a generic example, EZLinkSvr.java, is provided. This service is language independent and can be written in perl, C or some other language. A perl example is also provided, ezlinksvr.pl. This example uses urn:LinkServer and soaplite (see www.soaplite.com). Both examples can be tested with a third file soaptst.pl that is included.
Currently we are using.....
EZProxy (Rewriting Proxy Server configured to proxy by host name), http://www.usefulutilities.com/
Web Service using Soap, http://ws.apache.org/soap/
Tomcat Application Server, http://jakarta.apache.org/tomcat/index.html

We are in the process of working on a version for Blackboard 6. It will be released once it is complete.

Installation Instructions

LinkMaker consists of two parts - the application files (which run via the Blackboard Weblogic server) and the Link Server Soap Service examples and test script (which runs on a machine hosting the proxy server). The zip file includes both the Blackboard Extension and a generic example, EZLinkSrv.java. Unzip LinkMaker.zip. You should have four files, EZLinkSvr.java, ezlinksvr.pl, soaptst.pl and LinkMaker_v5.war. To install the application files into Blackboard:

Log in as a System Administrator
Go to "System Admin --> System Extensions(Bridges) --> Install System Extensions(Bridges)"
Browse for the LinkMaker_v5.war file and submit
Restart Weblogic
Go to "System Admin --> System Extensions(Bridges) --> Manage System Extensions(Bridges)" and use the "Properties" button beside the "LinkMaker" item to configure the plugin and the connection parameters.
- Section 1: Configure Link Anchor Text
  This section allows you to change the configured anchor text for links created in Link Maker. For example, the link anchor text may be "Click here to view". Once a change has been submitted and the Blackboard service restarted, all new links created with Link Maker will have this new text as the anchor text. Links that were previously created will not have their anchor text changed.
- Section 2: Configure Library Resource Information (Search Buttons and URLs)
  Space is provided to configure up to six Search Buttons. You may enter the label for a button. For display purposes it is suggested that you keep these labels short (under 16 characters). You must then enter an associated URL for the button. This is the URL that will be launched in a new window when a Content Creator clicks the button.
  Existing button labels and URLs that are displayed in this area may also be modified or removed. Additions and/or changes will not take effect until you have pressed "submit" and the Blackboard service has been restarted.
- Section 3: Configure Link Maker Help file location
  A default WRLC Library Resource Link Maker Help file has been provided but its URL is not visible in this area. If you wish to over ride the provided help, you may do so by adding the URL of your Help file. Once the changes has been submitted and the Blackboard service has been restarted, the Link Maker Help button will point to the location you have entered.
  Note, if you wish to revert to the default help, you must remove the location entered in the Help file location, submit and restart.
- Section 4: Configure Link Maker SOAP Information
  This section is for configuring the location of the SOAP service that you are using to create the LinkMaker links. Parameters for specifying how the LinkMaker Extension connects to the LinkServer can also be modified on the configuration form. This includes the URL for the SOAP request router and the identifier of the LinkServer SOAP service for that request router (see the CALL_URI in the deployment descriptor above).
- Section 5: Submit
  At this point you may either Cancel or Submit. If you choose to Cancel, all of your changes will be ignored. If you choose Submit, your changes will be submitted and the LinkMaker extension’s web.xml file will be updated. You may make changes as often as you like. The web.xml file will be updated, but the changes will not take effect until your Blackboard service is restarted.

LinkMaker should be set to available in the "Manage System Extensions(Bridges)" listing. This means LinkMaker will appear as a content type under the "Add Other" button of the Control Panel Content Areas. Instructors (and all course users with access to the course Control Panel) will be able to create, modify and remove LinkMaker content.

You will need to modify and compile the EZLinkSvr.java file or modify the ezlinksvr.pl file. Then you must install the executable file on your Link Server machine.

License and other information

This plugin is distributed as an open-source software program. For license information see Academic Free License Version 1.2. The source code is distributed along with the compiled plugin so that you can modify the code for your purposes as necessary. WRLC specific help files have been included in the package. They may be used as a guideline for help that you may wish to create.

This product includes the following software developed by the Apache Software Foundation (http://www.apache.org/), jakarta-oro-2.0.4.jar and a soap client, soap.jar.