Introduction
On november 20th I joined the SAP Inside Track Netherlands 2010 to present my iGoogle Gadget at the Demo Jam.
I created a gadget that shows the Universal Worklist tasks of a user on my iGoogle start page.
This is how the end result looked at the Demo Jam:
To do this in a secure way i used the OAuth protocol for authentication and authorization, which is also commonly used by Twitter and Facebook.
In this weblog I want to show you how i have developed this OAuth Provider on SAP NetWeaver CE 7.2 and created an iGoogle Gadget for consuming data from that OAuth provider.
Used in this demo:
- iGoogle Account for the creating and testing the iGoogle Gadget
The weblog will consists of three parts:
1. Introduction + initial setup and retrieving the BPM Task from the UWL
2. Create an OAuth Provider on NetWeaver CE
3. Create the iGoogle Gadget for consuming the data
To create the applications we need we will use a new Software Component in the Development Infrastructure.
In NetWeaver Developer Studio go to the Development Infrastructure Perspective and right-click on “Local Development” and select “Create Software Component”. You can use the attributes below:
!https://weblogs.sdn.sap.com/weblogs/images/252125299/CreateSC.PNG|height=448|alt=image|width=396|src...!
Click Next and select the following dependencies:
h3. Create Development Components
In the newly created SC create the following Development Components:
- oauth/lib (External Library)
- oauth/provider/web (Java EE Web Module)
- oauth/provider/ear (Java EE Enterprise Application)
In the Component properties go to the Dependencies tab and add the dependencies for the two development components:
oauth/provider/web: tc/je/usermanagement/api, tc/kmc/bc.uwl/api, tc/bl/exception/lib and oauth/lib (all build time)oauth/provider/ear: tc/kmc/bc.uwl/api (build time and run time)
h3. OAuth Libraries
In part 2 of this weblog we will start using OAuth. The libraries are not available for download as binaries so we have to generate the binaries ourself with Maven.
Follow the instructions below to create the jar files:
Follow the instructions on the download page to configure Maven for your machine (you probably need to set JAVA_HOME).
- Check out the java code and maven repository to temporary directory with:
svn co https://oauth.googlecode.com/svn/code/maven maven
- Edit all of the pom.xml files in the java directory and replace the date in the version tags to the current date in YYYYMMDD format.
- Build the libraries with maven:
cd java
mvn - Copy the build jar files from the directory: javaexampleoauth-providerwebWEB-INFlib to your External library project.
!https://weblogs.sdn.sap.com/weblogs/images/252125299/CopyLibraries.PNG|height=326|alt=image|width=27...!
!https://weblogs.sdn.sap.com/weblogs/images/252125299/APIArchives.PNG|height=293|alt=image|width=377|...!
Now it’s time for the coding part:
h3. Retrieving the BPM tasksIn the DC oauth/provider/web start with creating a class which represents a Task object. ();
try {
// Look up UWL service
IUWLService uwlService = getUWLService();
// Session timeout period
final int sessionIdleTimeout = 200;
UWLContext uwlContext = new UWLContext();
// Find logged in user.
IUser user = UMFactory.getAuthenticator().getLoggedInUser();
uwlContext.setUser(user);
Locale locale = user.getLocale();
if (locale == null) {
locale = new Locale("en");
}
uwlContext.setLocale(locale);
// Begin session
IUWLSession uwlSession;
uwlSession = uwlService.beginSession(uwlContext, sessionIdleTimeout);
uwlContext.setSession(uwlSession);
IUWLItemManager itemManager = uwlService.getItemManager(uwlContext);
QueryResult result = itemManager.getItemsForItemType(uwlContext, ItemType.UWL_ITEM_TASK, null, null);
ItemCollection items = result.getItems();
Item item = null;
for (int i = 0; i < items.size(); i++) {
item = items.get(i);
UWLTask task = new UWLTask();
task.setId(i);
if (item.getDueDate() != null)
task.setDueDate(item.getDueDate().getTime());
task.setSubject(item.getSubject());
task.setPriority(textByKey(locale, "PRIORITY_" + item.getPriority().getText()));
task.setStatus(textByKey(locale, "STATUS_" + item.getStatus().getText()));
if (item.getCreatedDate() != null)
task.setSendDate(item.getCreatedDate().getTime());
String executionURL = host
+ "/webdynpro/dispatcher/sap.com/tcbpemwdui~taskinstance/ATaskExecution?taskId="
+ item.getExternalId().substring(0, item.getExternalId().lastIndexOf('@'));
task.setExecutionUrl(executionURL);
tasks.add(task);
}
} catch (Exception e) {
e.printStackTrace();
}
return tasks;
}
private IUWLService getUWLService() throws NamingException {
Properties env = new Properties();
env.put(InitialContext.INITIAL_CONTEXT_FACTORY, "com.sapportals.portal.prt.registry.PortalRegistryFactory");
// create initial context
InitialContext ctx = new InitialContext(env);
// retrieve UWL service
IUWLService uwlService = (IUWLService) ctx.lookup("/broker/services/" + IUWLService.ALIAS_KEY);
return uwlService;
}
private String textByKey(Locale locale, String key) {
String textMessage = null;
try {
UWLTaskResourceAccessor ra = new UWLTaskResourceAccessor(BUNDLE_NAME);
textMessage = ra.getMessageText(locale, key);
} catch (MissingResourceException e) {
e.printStackTrace();
}
return textMessage;
}
}
Some explanation about the UWLTaskService code above: The IUWLService is retrieved by looking it up via JNDI. This is why we need the reference to tc/kmc/bc.uwl/api for both the web and ear module.
Properties env = new Properties();
env.put(InitialContext.INITIAL_CONTEXT_FACTORY, "com.sapportals.portal.prt.registry.PortalRegistryFactory");
// create initial context
InitialContext ctx = new InitialContext(env);
// retrieve UWL service
IUWLService uwlService = (IUWLService) ctx.lookup("/broker/services/" + IUWLService.ALIAS_KEY);
With
IUser user = UMFactory.getAuthenticator().getLoggedInUser();we retrieve the current logged-in user and with the following code we can retrieve the UWL Tasks assigned to that user.
IUWLSession uwlSession;
uwlSession = uwlService.beginSession(uwlContext, sessionIdleTimeout);
uwlContext.setSession(uwlSession);
IUWLItemManager itemManager = uwlService.getItemManager(uwlContext);
QueryResult result = itemManager.getItemsForItemType(uwlContext, ItemType.UWL_ITEM_TASK, null, null);
Let's use this and extend the ResourceAccessor class. Create a new class UWLTaskResourceAccessor with the following implementation:
package nl.ciber.uwl.task;
import com.sap.localization.ResourceAccessor;
public class *UWLTaskResourceAccessor *extends ResourceAccessor {
public UWLTaskResourceAccessor(String bundleName) {
super(bundleName);
}
}
private static final String BUNDLE_NAME = "com.sap.netweaver.bc.uwl.ui.i18n.TextMessages";>
private String textByKey(Locale locale, String key) {
String textMessage = null;
try {
UWLTaskResourceAccessor ra = new UWLTaskResourceAccessor(BUNDLE_NAME);
textMessage = ra.getMessageText(locale, key);
} catch (MissingResourceException e) {
e.printStackTrace();
}
return textMessage;
}
+ item.getExternalId().substring(0,item.getExternalId().lastIndexOf('@'));
The basic part for retrieving tasks is now finished. For testing the service and not make this first blog to extensive, we will write a simple test servlet to see if we can retrieve tasks from the Universal Worklist. Create a new Servlet by right clicking on the “Java resource: source” folder and select New -> Servlet
Fill in the name of the servlet and the package and click Finish.
h3. JSON
For the communication between the iGoogle Gadget and the OAuth provider i use JSON. JSON is a lightweight data interchange format and is excellent for using with an iGoogle Gadget which we will see in part 3 of this blog.
To use JSON in our project we download the java classes from http://www.json.org/java/json.zip and unzip them in the “Java resource: source” folder of our Web Module.
!https://weblogs.sdn.sap.com/weblogs/images/252125299/JSON.png|height=212|alt=image|width=262|src=htt...!
Next the implementation of our test servlet to retrieve the tasks.
Create a new Servlet with NetWeaver Developer Studio. Right click on your Web project and select New -> Servlet.
package nl.ciber.task.uwl.task.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import nl.ciber.uwl.task.UWLTask;
import nl.ciber.uwl.task.UWLTaskService;
import org.json.JSONArray;
import com.sap.security.api.UMFactory;
import com.sap.security.api.logon.ILoginConstants;
/**
- Servlet implementation class RetrieveTasksServlet
public class RetrieveTasksServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
- @see HttpServlet#HttpServlet()
public RetrieveTasksServlet() {
super();
}
/**
- @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
UWLTaskService service = new UWLTaskService();
PrintWriter out = response.getWriter();
try {
UMFactory.getLogonAuthenticator().logon(request, response, null);
} catch (Exception e) {
e.printStackTrace();
out.println(e.toString());
}
String serverName = request.getServerName();
String host = "http://" + serverName + ":" + request.getServerPort();
// Retrieve Tasks
Listciber.nloauthprovider~web.wartask_retrieval
Now deploy the ear-file from NetWeaver Developer Studio and open the servlet in a browser.
Login with a user which has some tasks in his Universal Worklist and the JSON output should look like this:
!https://weblogs.sdn.sap.com/weblogs/images/252125299/JSONResult.png|height=205|alt=image|width=606|s...!
In part 2 we will create the OAuth Provider to add authentication and authorization to our application.
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