Monday, 6 May 2013

[How To] - Fix GlassFish not listening to port 80 after updating security group's rule on Amazon EC2 instance

In one of my projects, after I've correctly updated the security groups's rules on my Amazone Linux EC2 instance to allow incoming connections to port 80 (HTTP) and 443  (HTTPS), my requests to these 2 ports are still ignored. If you do a sudo netstat -lntp, you will see that there is a process listening on port 4848 which is your GlassFish app server but it is NOT listening to port 80 and 443! Why!!?

If you take a look at the app server's log file right after starting it, you will see the Connection refuse exception. Assuming that you've already correctly set up GlassFish's http-listeners to listen to port 80 and 443, the solution is actually pretty simple: you have to start the server using the root privilege (i.e. sudo ./<GLASSFISH-FOLDER>/bin/asadmin start-domain). These 2 special ports seem to be protected by Linux OS. You cannot listen to these 2 ports without having access to root privilege.

I hope this helps! :).. 

Thursday, 4 April 2013

[Fact] - The order of calling for Action and Listener in JSF

During the coding process, sometimes, I still mix up the order that Action and ActionListener components would be triggered in JSF. In this small post, I will make a small experiment as a reminder to both you and me :).

Our test page will contain the following button:

And this is our test bean:

The following outcome was observed from the console:

At times, I tried in vain to set a property of the backing bean using <f:setPropertyActionListener> and get it out in the method inside actionListener. Don't make the same mistake :P!

From the above outcome, the actionListener attribute of the button is always called first while the action attribute is always called last. For the others, they will be called based on the order in which you declare them inside the button.

Hope this helps! :)

Tuesday, 2 April 2013

[How To] - Redirect to original page after login in JSF

Nowadays, redirecting users to where they were before logging is a common & desired feature for any web applications. For instance, if a user was surfing a page at, the application should be able to redirect the user to the same page and, at the same time, retain the complete query string at the end of the requestURL.

In this tutorial, I will assume that your application has a login bar on top of all pages. Based on this assumption, your application needs to handle the following 3 scenarios:
  1. The user logs in directly from the top login bar and succeed.
  2. The user entered wrong password, etc.
  3. The user was forwarded or redirected to the login.xhtml page when they tried to access a restricted resource.
For the first scenario, one very important thing to note is that when a user clicks the Login button, the requestURL for that click will not carry the original query string anymore. As a consequence, if you capture the requestURL at this point, it's too late and you will only have In other words, to get the full requestURL, you need to capture the requestURL even before the user clicks the Login button. To achieve this goal, in your templates, you need to define the following <f:event>:

This is our  @SessionScoped managed bean:

And this is the Login managed bean:

For the second scenario, users will usually arrive at the login.xhtml page where you display a big & fat error message. At this point, you might have jumped into your own trap if you have also included the above <f:event> inside your login.xhtml page. The event would be triggered and your originalURL property would be wrongly updated to the login page's URL. So, in brief, you must NOT include the above <f:event> inside your login.xhtml page.

Done? No, this is a double-trap :O!  We still need to take care of the situation in which the user didn't surf any pages before logging in.

For the third scenario, you need to understand the difference between a forward and a redirect. When a user is forwarded to the login.xhtml page, the requestURL will still be even though the content of the view is from the login.xhtml page. On the other hand, if the user is redirected, the requestURL will become

In case the user was redirected, I will assume that you're using a homegrown Filter to perform the login check and redirect users afterward. In this situation, you need to include the original requestURL as a parameter in the redirecting URL:

After that, you need to update your LoginBean#init() function to retrieve the parameter in both cases as following:

Finally, after spilling much sweat, you can enjoy your work now! :)

Sunday, 31 March 2013

[How To] - Implement Facebook login in JSF using SocialAuth

As a matter of fact, Facebook does not provide an official library for Java developer. To make the matter worse, the provided official Javascript SDK is not very easy to use (at least for me) or to integrate with a JSF application. Luckily, there are several unofficial projects going on at the moment and in my opinon, the best of all should be either RestFB or SocialAuth. Between these two alternatives, I prefer SocialAuth because of 2 reasons. First of all, RestFB doesn't support authentication. In other words, using RestFB, we have to dive into the JavaScript SDK mess to fetch the accessToken from Facebook on our own. Another thing is that SocialAuth supports not only Facebook but also a wide range of other providers such as Google, LinkedIn, etc. So, today, I will use SocialAuth to show you how to implement Facebook login in JSF.

One thing to note is that on SocialAuth's wiki page, there is actually a step-by-step tutorial on connecting to Facebook in a JSF CDI application. I've tried the provided solution but it didn't work out for me. Somehow, I ran into the Unsatisfied dependencies for type [SocialAuth] with qualifiers [@Named] at injection point [[field] error and no one has yet to provide an answer for my question on StackOverflow. So in this post, I will show you another way that I have figured out to connect to Facebook.

In brief, there are 4 steps that you need to follow:
  1. Create an application on Facebook.
  2. Download the latest SocialAuth SDK. In this tutorial, I am using v4.0.
  3. Copy, paste and edit!
  4. Enjoy your achievement :).
Firstly, you need to create an application on Facebook.

From the above page, you need to write down your App ID and App Secret, which would be used to connect to Facebook later. Another thing to note is that the Site URL property needs to be the same as the domain where you deploy your application. So, if you want to test your application locally, simply enter http://localhost:8080/.

After downloading the latest SDK from SocialAuth, which is v4.0 at the moment of this writing, you can proceed to the most interesting part which is coding!

In order to redirect users back to where they have been before logging in, copy and paste this code inside your <f:view>:

After that, copy and paste the following snippet where you want to put your Social login buttons:

One important thing to note is that you should put the login buttons on the top most of your page where no other components can be loaded before these buttons. Otherwise, you may run into java.lang.IllegalStateException when our socialConnect() function attempts to redirect the user if part of the response has been committed. You can also edit the above snippet to add in more buttons for other providers if needed. This is the list of IDs of all providers:

The following is the socialLoginSuccess.xhtml page where users would be redirected to on successful login:

One very important thing to note is that in the above success page, I didn't have the <f:event> component. If your success page uses the same template, which contains the <f:event>, as other pages, you will run into the following exception:

The above exception occurs because the originalURL was wrongly updated to be the authenticationURL. In other words, you will be authenticated one more time.

Finally, this is our @SessionScoped managed bean:

Based on this sample for the file, you should be able to figure out the properties to put in the props easily. In fact, instead of using Java's Properties, there are also several other ways to load the configuration. The complete list includes:

Enjoy your work! :)

Friday, 29 March 2013

[How To] - Set up SSL certificate on GlassFish app server

Under your development environment, it may not be very important to have a signed Digital certificate. However, eventually, your application will be accessed by the world. Nowadays, all browsers have a mechanism for alerting users when they enter untrusted environment (i.e. websites with unsigned certificates). Most people will either be scared away or think that your site is not working when they see the following warning page:

So, before serving pages securely, you should configure your app server to use a signed certificate. In case you don't have one yet, entering the following lines into a Terminal should do the job:

One very important thing to note is the -alias s1as portion. You cannot randomly assign a string for this parameter. Normally, GlassFish app server uses s1as as the default Certificate Nickname. To check what your app server is actually using, open the Admin console, under Configurations section, choose server-config, then HTTP Service, then Http Listeners. You will see the Certificate Nickname under the SSL tab on the right.

Next, after creating a digital certificate, you should have it cryptographically signed, which would make it became very difficult for anyone else to forge. For sites involved in e-commerce or any other business transaction in which authentication of identity is important, a certificate can be purchased from a well-known certificate authority such as VeriSign or Thawte.

After that, open your Admin console, under Configurations section, choose server-config, then JVM Settings. Under the JVM Options tab on the right, add the following options:

The next task is to copy the keystore.jks and the cacerts.jks files that you have created earlier into the <GLASSFISH_FOLDER>/glassfish/domains/domain1/config folder.

Lastly, restart your GlassFish app server and you're done! :)

Thursday, 28 March 2013

[How To] - Fix javax.mail.NoSuchProviderException: No provider for smtp

At times, you may run into the above Exception even though you're absolutely sure that your sendEmail function is working normally on another project. This Exception happened to me after I updated my project to Use dedicated folder for storing libraries.

The solution in my case was pretty simple.
  1. First, you need to go to Oracle's site to download JavaMail API
  2. After that, add the mail.jar file to your Project's libraries. 
  3. Lastly, right click on your Project, choose Properties, under the Packaging section, you need to check the Package required JARs in EJB jar option.

Hope this helps! :)

[How To] - Change the context root of your EAR project

In your EAR project, normally, you will have a WAR project named yourproject-war, which would also be the context-root of your application if you don't make necessary changes. I have seen many tutorials on the Internet instructing people to update their WAR project's glassfish-web.xml or sun-web.xml file and add the following line:

The above solution will NOT work without deploying the WAR project directly!

What you should do, instead, is to update your EAR project's application.xml file which should be found inside your EAR project's Configuration Files folder in NetBeans.

If the file is not there, simply right-click on your EAR project, choose New and create a Standard Deployment Descriptor.

After opening the application.xml file, the next task is straight-forward.

Good luck! :)