
It's been few months since I started the [twikural][1] service. For the people who didn't know about Twikural;

[1]: http://twikural.veerasundar.com/ "Twikural - Daily thirukural"

[Twikural][2] is a web service that sends two couplets from the well known *[Thirukkural book][3] *everyday to its subscribers. People can subscribe to the service via either [Twitter][4] or [Facebook][5].

I have already open sourced the [code behind twikural][6]. If you like to browse the source code, you are welcomed to do so in [Github][7].

[2]: http://twikural.veerasundar.com/ "Twikural - Daily Thirukural"
[3]: http://en.wikipedia.org/wiki/TirukkuÃ¡¹€ºaÃ¡¸· "Thirukkural"
[4]: https://twitter.com/twikural "twikural"
[5]: https://www.facebook.com/twikural
[6]: https://veerasundar.com/blog/open-sourcing-twikural-an-app-engine-project "Open sourcing Twikural"
[7]: https://github.com/vraa/twikural "Twikural source code in Github"

In this post, I'm going to explain the details behind the project and how the entire thing works. Lets begin.

## The Big Picture

[![][9]][9]

[]: http://twikural.veerasundar.com

The site runs on **Google App Engine **and built using **Java 7**. The Java code does not use any fancy frameworks - it's all plain old Servlets and JSPs. But in the front end, I am using **Twitter Bootstrap** to ease the designing task and supporting different screen sizes. To interact with Twitter, I'm using **Twitter4j**.

There are two *cron jobs *that scheduled to run at 9 AM and 6PM respectively and sends out the tweets and Direct messages to the subscribed users. Then twitter takes care of updating the Facebook status of Twikural page.

As you can see in the above picture, the site talks only to Twitter, even though it supports Facebook as a subscription channel. This made possible by using the Facebook integration feature that Twitter provides. Using this, whenever there's a tweet is published, Twitter will automatically update the connected Facebook page status.

Users can subscribe via either [Twitter][9] or [Facebook][5]. The advantage of subscribing via Twitter is that the user will get an direct message (and possibly an SMS if he'd enabled it).

[9]: https://twitter.com/twikural

So that's pretty much about what's happening behind Twikural at a higher level. If you'd like to read Thirukkural everyday, you should [subscribe to Twikural][10]. And feel free to share your feedback. The comments are always welcomed.

[10]: http://twikural.veerasundar.com/subscribe.jsp "Subscribe to Twitter"


Twikural - How it works?


![Google App Engine on Netbeans][1]If you just started with App engine development, you might be having a feeling that Eclipse is the preferred IDE. And, Google also has offered its [official plug-in][2] to Eclipse IDE alone.

[1]: https://veerasundar.com/img/2011/04/nb.png "Google App Engine on Netbeans"
[2]: http://code.google.com/appengine/docs/java/tools/eclipse.html "It's easy to use the Eclipse development environment to develop your Java App Engine application, just as you can to develop any other servlet-based web application. With the Google Plugin for Eclipse, it's even easier. The plugin lets you create, test and upload App Engine applications from within Eclipse."

But what about the people who are not using Eclipse? Of course, you can always do a command line development but who does that these days!?

For **[Netbeans][3]** users, the plug-in **[nbappengine][4] **brings the Java app engine development to the Netbeans platform. Here's how you can start developing your app engine apps on Netbeans.

[3]: http://netbeans.org/
[4]: http://kenai.com/projects/nbappengine/pages/Home "Plugin enables J2EE development web modules on Google App Engine."

## Installing nbappengine plugin on Netbeans

1.  First thing first: Install the latest Netbeans (6.9 at the time of typing these characters) and open the IDE.
2.  Go to **Tools -> Plugins -> Settings **and click 'Add' button to add the nbappengine update center URL.
3.  Now give a name and the URL of the update center according to your version of Netbeans.
    - **Netbeans 6.9**: http://kenai.com/downloads/nbappengine/NetBeans69/updates.xml
    - **Netbeans 6.8**: http://kenai.com/projects/nbappengine/downloads/download/Latest_NetBeans68/updates.xml
    - **Netbeans 6.7**: http://kenai.com/projects/nbappengine/downloads/download/1.0_NetBeans671/updates.xml
4.  After adding it, now come back to the **'Available Plugins' **tab and do a search for 'Google'. Select all the plug-ins that are related to the App Engine and click install button.

## Configuring App Engine SDK with Netbeans

Now you've installed the nbappengine plugin on your Netbeans IDE.  The coming steps will tell you how you can configure the plugin with the App Engine SDK.

1.  Download the [App Engine SDK][5] for Java and extract the zip contents to your favorite location.
2.  In the Netbeans IDE, go to **Services window **(Ctrl 5 is the shortcut key) and right click on the **Servers **menu and select '**Add Server**'.
3.  Now select the '**Google App Engine' **from the list of servers and in the next screen choose the folder where you extracted your SDK files.
4.  Configure the server properties if you wish to change it and then click '**Finish'**

[5]: http://code.google.com/appengine/downloads.html#Google_App_Engine_SDK_for_Java

## Creating and deploying your first App Engine app on Netbeans

Now its the time to create a brand-new app engine application.

1.  In Netbeans, select '**File -> New Project -> Java Web -> Web application' **and follow the wizard to create the project.
2.  In the '**Server and Settings' **page choose '**Google App Engine' **as your server so that you'll get the app-engine related files (such as appengine-web.xml) pre-created for you.
3.  When you run/debug this application, Netbeans will start the app engine server (Jetty) and will deploy your application there.
4.  To deploy the application to the App Engine server, just right click on the project and choose '**Deploy to Google App Engine'. **it'll prompt you for the Google account credentials. After you provided that info, your app will be uploaded to the cloud.


App Engine Java development on Netbeans


Note: This post is written by/for the Java web developer who is using Google App Engine. Even if you are not an Java developer, but interested, you are welcome to read further.

![google-app-engine-logo][1]

[1]: https://veerasundar.com/img/2011/04/google-app-engine.png "google-app-engine"

When you create a new application in Google App Engine, you'll get a domain name 'yourapp.appspot.com'. But, who'll want to host their app with such a suffix (unless you like it!)?

To improve your app branding, the best thing to do is to host your app in '**www.yourapp.com**'. So, how to do this in App Engine?

There are two ways.

1.  You can buy a new domain name with Google partnered sites (such as GoDaddy).
2.  If you have already bought a domain, you can map that domain to 'yourapp.appspot.com'.

I'm going to explain the second method in this post.

## Steps to host GAE app in your own domain

### 1. Buy Hosting Space and Signup for Google Apps

1.  The first step, obviously, is you should buy a **domain hosting**. You will be adding CNAME entry in the DNS mapping to make things work and some hosting providers wont let you to add CNAME if you just bought only the domain name from them. So, it is good to buy the domain name as well as the hosting space so that you have full control over it.
2.  Then you need to signup for **Google apps** with your domain name. You can get a [free Google Apps version][2] which is pretty much sufficient for a small company/individual. You'll be asked to verify the ownership of your domain. Just follow the steps given there. You'll be also creating a admin account to manage Google Apps.

[2]: https://www.google.com/a/cpanel/domain/new "Free version of Google Apps - Signup page"

### 2. Add your application to Google Apps account

1.  Next, login to and go to the Dashboard of your app and choose '**Application Settings -> Domain Setup -> Add Domain**'.
2.  In the '**Add Domain**' screen, enter your domain name. You'll be asked to login to Google Apps with the admin account which you would have created during the second step. Once you login, your application will be added to your Google Apps account.

### 3. Add 'Ëœwww.yourapp.com' sub-domain mapping to yourapp.appspot.com

1.  Now login to **www.google.com/a/yourapp.com **with your admin account (if you are not logged in already). There you can see you app engine application listed in the Google Apps dashboard. Click on your appspot application.
2.  In the next screen, enter **www** in the text box to add a URL in the form of **www.yourapp.com**. As Google app engine does not support naked domains, you have to map the sub-domain, in our case **www**, to the appspot application. Once you add the URL you'll be given steps to add the CNAME record in your domain. After adding the CNAME record (explained in next steps), you should come back to this page and click complete.

### 4. Using CPanel, add a CNAME entry to ghs.google.com

1.  Now login to your domain admin panel. Since most of the hosting providers support CPanel, i'm giving the steps for CPanel.
2.  Login to **yourapp.com/cpanel **and go to '**Advanced DNS Zone editor' **where you can see the DNS mappings.
3.  Click the 'Edit' link against the **www.yourapp.com **and type '**ghs.google.com**' against the CNAME field. Leave other fields as it is. Save the changes.
4.  Thats it. It will take some time for the DNS propagation to happen. After that you can start accessing your appspot application with the URL **www.yourapp.com**!


Hosting Google App Engine application in your own domain


Initially there were no problems with Google Chrome browser. It just worked out of the box. But suddenly one fine day, it stopped loading web pages, showing 'Error 104 (net::ERR_CONNECTION_FAILED)' message. At first I thought it's a fresh bug coming out of chrome, Since Firefox and IE were just fine, I had to put the blame on Chrome.

But later, I found that **Zone Alarm firewall is blocking Chrome**. Somehow, the application settings for Chrome in Zone alarm are all set to 'Deny' and Chrome was failing to make a connection to internet. At first, I didn't have a clue why chrome was failing but when I googled for the error message '[`Error 104 (net::ERR_CONNECTION_FAILED)`][1]', it came to my mind that firewall might be the problem.

[1]: http://www.google.com/search?rlz=1C1GGLS_enIN291&sourceid=chrome&ie=UTF-8&q=Error 104 (net::ERR_CONNECTION_FAILED)

Now changed the setting and Chrome is back in action.


#google (4)