Abani

LDAP integration with AEM6 (OSGi Config way)

2014-07-16T09:35:00.000-07:00

In AEM 6, LDAP support comes with a new implementation that requires a different type of configuration than with previous versions.

All LDAP configurations are now available as OSGi configurations. They can be configured via the Web Management console at:

http://serveraddress:4502/system/console/configMgr

The required config classes are listed below.

org.apache.jackrabbit.oak.security.authentication.ldap.impl.LdapIdentityProvider
org.apache.jackrabbit.oak.spi.security.authentication.external.impl.DefaultSyncHandler
org.apache.jackrabbit.oak.spi.security.authentication.external.impl.ExternalLoginModuleFactory.

The configs can be updated manually via OSGi console or via deployment. We can use the follow steps & config files to add/update an LDAP provider.

Create OSGi config file of type "sling:OsgiConfig" & name it to
"org.apache.jackrabbit.oak.security.authentication.ldap.impl.LdapIdentityProvider.xml".

See here for reference.

Similarly create two more config files & name them as below.

org.apache.jackrabbit.oak.spi.security.authentication.external.impl.DefaultSyncHandler.xml

org.apache.jackrabbit.oak.spi.security.authentication.external.impl.ExternalLoginModuleFactory.xml

Now with this config files in place, do a config/content deployment & upon successful deployment your AEM instance is configured with the provided LDAP server.

Tested with OpenDS 2.2 & AEM 6

Please Note: You may need to restart your AEM instance once the configs are applied.

Inject OSGi services in Sling models (Pojos) - Sling model way

2014-07-08T02:27:00.001-07:00

Create the injection point in the sling model class with @Source annotation & assign "osgi-services" as a value to the source annotation.

By this we can inject the below OSGi service in the Sling Model class.

JCR content mapping with Sling Model

2014-07-08T02:17:00.001-07:00

follow the easy steps to use sling model for JCR content mapping.

Add sling model bundle dependency information in pom.xml
Add Sling-Model-Packages declaration in the instruction
Annotate pojo class with @Model annotation and use @Inject against the fields (with getters)
Now adapt this pojo with resource.adaptTo()
This Will map the below content structure easily without the bulgy or cluttered code.

Remote access of JCR repository in CQ5 | AEM

2013-10-22T00:43:00.002-07:00

Follow the below steps to access the CQ5 JCR repository (CRX) remotely.

Construct the remote URL of your CQ instance.

e.g. http://localhost:4502/crx/server

Where localhost is the host where CQ is running & 4502 is port where CQ is listening to the requests.
Get the repository by using the JCRUtils class which is available in the jackrabbit-jcr-commons.jar library.

repository = JcrUtils.getRepository("http://localhost:4502/crx/server");

Create a SimpleCredential object by passing username, password entries.

SimpleCredentials creds = new SimpleCredentials("admin", "admin".toCharArray());

Invoke the login method of repository object by passing the credential object & the workspace name.

Session session = repository.login(creds, "crx.default");

A code snippet for the above can be found below

Access different widgets inside the widget event listeners | CQ5 / AEM

2013-10-17T03:05:00.001-07:00

To access widgets inside the event listeners of any widget, follow the below step.

Get the "dialog" object first.

var dailogObject = this.findParentByType('dialog');

This will return the dialog object associated with your compoent dialog. Then look for the corresponding widget by invoking

var titleField = dailogObject .getField('./jcr:title');

The above function looks for a widget by name './jcr:title' and returns the widget object associated.

Use case scenario.

Let's create a component dialog with 2 widgets (Pathfield, TextField).

use case 1: if author selects any link URL then the corresponding title of the page should be set into the TextField widget.

Below steps can be followed to achieve this.

create a component dialog with two widgets.

One path field with name "./path" and xtype is "pathfield"
Text field with name "./title" and xtype is "textfield"

Attach a listener to the path field. And add "dialogclose" event to the listener.
The javascript function for the above event can be written as below.
Sample screen shot

Attach listeners to widgets in CQ5 / AEM

2013-10-17T02:06:00.000-07:00

Follow the below steps to create or attach listeners (javascript event listeners) to any widget in CQ5 / AEM.

Create a node by name "listeners" of type "nt:unstructured"
Find out the events which can be attached to a widget. You can find the list of events from the CQ Widget API documentation. Click here to visit.
e.g. The "pathfield" widget has got one event called "dialogclose". This event is fired when user selects any link from the browse field & clicks OK.
To attach this add one property by name "dialogclose" to the listeners node. The value should be any javascript function call.

e.g. function(){ console.log("You have selected a link in path field"); }

Please see below image for reference.

Edit the Bottom tool bar of SmartImage widget in CQ5 / AEM

2013-10-15T02:23:00.001-07:00

Modify the below properties to remove/edit the tool bar (appears on the bottom) of the HTML5 smart image widget. (xtype: html5smartimage)

disableZoom="{Boolean}true" This will disable the zoom functionality
mapParameter="0" This will disable the Map feature
rotateParameter="0" This will disable the image rotation capability
cropParameter="" This will disable the image crop capability

Ajax with JSF 2

2012-07-30T23:12:00.001-07:00

Clustering with Tomcat & Session replication

2012-07-16T11:00:00.001-07:00

Load Balancing, clustering with Apache & Tomcat

2012-07-15T11:27:00.001-07:00

InterceptorBinding in 4 Steps for CDI/JEE6 applications

2012-05-09T01:50:00.003-07:00

Interceptors with interceptor binding in CDI/JEE6 enabled applications can be written & used by following the below simple steps.

Create a custom annotation with @InterceptorBinding

@Inherited

@InterceptorBinding

@Retention (RetentionPolicy.RUNTIME)

@Target ({ElementType.METHOD, ElementType.TYPE})

public @interface Logged {

}
Create an interceptor class & annotate the class with the custom annotation.

@Logged

@Interceptor

public class LoggingInterceptor {
add a method to the interceptor. Annotate the method with @AroundInvoke annotation & pass InvocationContext object as a parameter.

@AroundInvoke

public Object logMethodEntry(InvocationContext invocationContext)
Specify the interceptor in beans.xml file.

Now, the interceptor is ready to be used via the custom annotation. Use the custom annotation created earlier in the methods of the service classes those are exposed via CDI. (see below). This will make the CDI container to invoke the interceptor's intercepting method ( this is the method which is present in the Interceptor class & annotated with @AroundInvoke ) .

@Logged

public String greet( final String greeter ){

    return "Hallo " + greeter + " from EJB";

}

The complete code can be found here. Please see the video below, where I have demonstrated uses of Interceptors.

Asynchronous Methods in EJB

2012-05-03T22:47:00.001-07:00

In this blog I will write about Asynchronous methods in EJBs. Will write an application where we will demonstrate how to access asynchronous methods in EJB.
Asynchronous methods are new in EJB 3.1. This can be achieved by an annotation named @Asynchronous. The annotation can be applied to class level & method level as well. See the code snippet below.

@Stateless

@LocalBean

@Asynchronous 

public class ServicesBean {

@Asynchronous

public void sendEmailAsync(final String recepient) {

When we annotate a method in EJB with @Asynchronous annotation, the EJB container executes the method in an asynchronous manner. The caller of the async method doesn't have to wait until the completion of the async method execution.

   @Asynchronous

   public void sendEmailAsync(final String recepient) {

        //perform all activities related to

        //the mailing actvity

        LOG.info("strat of sendEmailAsync");

/*

        below code snippet is to show case

        a long running process. Don't use

        it in real time 

*/

        try {

            Thread.sleep(4000l);

        } catch (InterruptedException ex) {

            LOG.log(Level.SEVERE, null, ex);

}

        LOG.info("end of sendEmailAsync");

} If we observe the above code block, the complete execution of the block will take minimum of 4 seconds
(For demonstration purpose I have used Thead.sleep(), please don't use such code blocks).
In normal scenarios if we invoke this method in synchronous way, then the caller has to wait for
minimum of 4 seconds.Which will impact heavily on the performance of whole application.

Through the asynchronous capability of EJBs, we can avoid this problems.
Handling Asynchronous method Responses:

If the async method returns some value or object, then the value/object needs to be sent

through java.util.concurrent.Future. Please see the code below.

public Future executeComputationAsync(final String employeeid){

return new AsyncResult(100);

}

In the above method the return type is an Future object of type Integer.

The AsyncResult class is part of javax.ejb package & implement the Future interface.

To get the resulting info from the Future object, we can invoke the get() method of Future
object. Please see the code below.

Future result = servicesBean.executeComputationAsync("213");

int res = result.get();

out.println("Async result is " + res);

In the below video, I have demonstrated developing & accessing asynchronous methods in EJB.

The complete working code can be found here.

Programmatic login with Servlet 3.0

2012-05-02T04:17:00.004-07:00

In this blog I will describe you how we can achieve programmatic login with Servlet 3.0 compliant JEE server or container.

The HttpServletRequest object in Servlet3 has got few new methods. Few of them are listed below.

login(username, password) - validate the user with specified username & password with the default realm & creates an authenticated subject in the current request.
logout() - logs out the current logged in user/subject
getParts() - returns array of Multi-part objects available in the request.
getPart(field) - return the multi-part object associated with the field name

In our case, I will use login & logout methods respectively.

The software used to illustrate the programmatic login are listed below.

NetBeans 7.1.1 ( IDE )
Tomcat 7.0.27 ( Server / Container )
Ubuntu LTS 12.04 ( OS )

I have created a dynamic web application named LoginDemo & my target runtime server is tomcat7. The project structure looks like below.

below. I have created two jsp pages index.jsp & myaccount.jsp. index.jsp has the login form where I will submit my action to a servlet, where I will perform my authentication.

To authenticate the user inputs I have created a servlet named AuthServlet in my application. The AuthServlet holds the business logic to perform login. Please see the code snippet below.

private void processLogin(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {

        String username = request.getParameter("uid");

        String password = request.getParameter("pwd");

        RequestDispatcher rd = null;

        try {

            request.login(username, password);

            rd = request.getRequestDispatcher("myaccount.jsp");

        } catch(Exception e){

            request.setAttribute("msg", "Unable to login with  " + username + "");

            rd = request.getRequestDispatcher("login.jsp");

}

        rd.forward(request, response);

}

The request object has login() method. which takes 2 parameters. The first one is the username & second parameter as password. Then the login method validates the username/password with the default realm. In case of tomcat the default realm is configured with file based tomcat-users.xml file. which can be found under $CATALINA_HOME/conf directory.

So we have to configure few users in the tomcat-users.xml file. See below for a sample config.

Tomcat creates an authenticated subjected by matching the username/password provided with the username password available in tomcat-users.xml file (The file based realm is the default realm in tomcat, we can change it to LDAPRealm/JNDIRealm, JDBCRealm, JAASRealm) .

Similar to login() method, the request object has another method named logout(), which just logs out the user from current authenticated subject. See the code below for logout functionality.

protected void processRequest(HttpServletRequest request, HttpServletResponse response)

            throws ServletException, IOException {

        if ( request.getServletPath().equalsIgnoreCase("/login") ) {

            processLogin(request, response);

}

        else {

            request.logout();

            request.setAttribute("msg", "You have successfully logged out of system");

            request.getRequestDispatcher("index.jsp").forward(request, response);

}

}

The complete code can be checked in at Google svn & can be found here. The screen shots of the above application in running mode are given below.

Let me know if you find any difficulty in accessing or executing the code.

Thanks,
Abani R. Behera

Accessing EJB methods from JSF pages via CDI

2012-05-01T21:26:00.001-07:00

Ajaxifying File Upload with HTML5/Servlet3.0

2012-02-20T23:57:00.000-08:00

This post will describe about uploading a file in ajax without any third party java script libraries or tools which are used to upload files in asynchronous way.

To show case the demo, I have used FormData javascript library as my client side API & Servlet3.0 as my server side component, Eclipse Indigo as IDE and Tomcat 7 as the web container. I have followed bellow steps to do the sample app.

I have created a Dynamic Web Application with version 3 supported. So that, servlet 3 support will be added.
Created a jsp file named index.jsp which is main UI page. the code snippet for index.jsp is given below .

Have used simple input type file & a button to upload the selected file. On click of the upload button, I am calling a javascript function startUploading(this). The former method will create a javascript FormData object & send the object in the XHR-Ajax post method. the code snippet for the same function is given below.

We can notice few javascript built in functions.
First we have created a FormData Object with passing the html form object.
var vFD = new FormData(document.getElementById('upload_form'));
vFD will hold all the information about the HTML file component.

Again, we have created XMLHttpRequest (V2) Object with method type:POST, the invoking URL as upload & async as true. The URL is nothing but the server side component, to which we will post our FormData Object through ajax. For our case I have used an servlet (v3) as my server side component which will save the received file in the disk or file system.

Servlet 3 has built in support for handling multipart/form-data. Which means we don't have to depend upon third party libraries like apache commons file upload. Servlet 3 has introduced new interface named as Part which can be retrieved from the HttpServletRequest object. The Part object will hold the file information available in the request. We can retrieve the file content, file length, file type from the Part object. The Part interface has a write method which write the file to a location being passed as a method parameter. Please see the code below.

Part p = request.getPart("image_file");
This will create a object of Part from the request object.
p.write(disk_path);
This will write the file to the disk path specified in the method.

The code snippet for the above servlet (UploadServlet) is given below

Working demo of this application can be found out here.

CDI (JSR 299) with JBoss WELD

2011-11-19T06:14:00.000-08:00

Here I will describe about the implementation of JSR 299, JBOSS WELD, by using this we can achieve context dependency injection (akka CDI). For JSR 299 till now there are two main implementations are available.

Apache WebBeans
JBoss WELD

I will show a demo of CDI with JBoss Weld in a simple web application. JBoss Weld has easier implementation when it compared with Apache WebBean. Tools used are JKD7, Tomcat7, Weld API, Netbeans IDE.

Below JBoss Weld jar files are required.

weld-api.jar
weld-build-config.jar
weld-core.jar
weld-servlet.jar
weld-sp.jar

These jar files can be downloaded at weld site.

Now create a simple Web Project in NetBeans IDE.

The project will look like this

Add the above jar files into WEB-INF/lib folder.For CDI we have to create an empty beans.xml file. We have place this is WEB-INF folder, parallel to web.xml file.

Now create a package like com.weld.beans in the source folder. Create a class named GreetService & add a method greet() into it. The class/method signature is given below.

public class GreetService {

public String greet (final String name){

return "Hallo "+ name + " from WELD";

}

This is simple java class with a simple method. we are going to inject the class in run-time & invoke the method. To do so we will create a servlet & inject GreetService class. Create servlet named CDIServlet in the package com.weld.servlets. The default created servlet will look like below.

@WebServlet(name = "CDIServlet", urlPatterns = {"/CDIServlet"})

public class CDIServlet extends HttpServlet {

/**

* Processes requests for both HTTP GET and POST methods.

* @param request servlet request

* @param response servlet response

* @throws ServletException if a servlet-specific error occurs

* @throws IOException if an I/O error occurs

protected void processRequest(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("text/html;charset=UTF-8");

PrintWriter out = response.getWriter();

try {

out.println("
Servlet CDIServlet
");

} finally {

out.close();

}

/**

* Handles the HTTP GET method.

* @param request servlet request

* @param response servlet response

* @throws ServletException if a servlet-specific error occurs

* @throws IOException if an I/O error occurs

@Override

protected void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

processRequest(request, response);

}

/**

* Handles the HTTP POST method.

* @param request servlet request

* @param response servlet response

* @throws ServletException if a servlet-specific error occurs

* @throws IOException if an I/O error occurs

@Override

protected void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

processRequest(request, response);

}

/**

* Returns a short description of the servlet.

* @return a String containing servlet description

@Override

public String getServletInfo() {

return "Short description";

}//

}

Now we will inject with an annotation @Inject (javax.inject.Inject part of CDI).

Add the below code at the top level of the servlet.

private @Inject GreetService greetService;

the @Inject will create a injection point for the class GreetService at this peace of the servlet code.

To test this let's print the GreetService object reference. to do so add the below code after processRequest method of CDI Servlet.

LOGGER.log(Level.INFO,"GreetService Object is {0}", greetService);

To invoke the greet method of the GreetService class update the processRequest method with beow code.

out.println("Servlet CDIServlet at " + greetService.greet("abani") );

Save the servlet. Now we have to test the CDI implementation. We can run the servlet & watch the servler log. To do so right click on the servlet & choose run file option in menu.

after successfully invoking the servlet we can see some logs as below.

Nov 19, 2011 8:28:37 PM com.weld.servlets.CDIServlet processRequest

INFO: GreetService Object is com.weld.beans.GreetService@68a427

The servlet output will look like below.