Author: Ram

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Using JavaScript Promises with Cordova

JavaScript Promises

JavaScript Promises could make asynchronous programming a bit easier. Most of the APIs of Cordova are asynchronous. So when you want to call one asynchronous API after the other, you have to nest API in the callback functions of the previous API. Many APIs also take error handler as one of the parameter to API function. At some point the whole code could become very difficult to read and maintain.

JS Promises  could make this a bit simpler. Promise is an object, which takes a function callback with two arguments, resolve and reject. Promise represent a value that would be resolved sometime in future, it is is not already resolved or rejected. The promise can be rejected explicitly or when any JavaScript exception is thrown. See https://promisesaplus.com/ and Promises on MDN for details on JS Promises. Advantages of Promises is realized when you need to chain multiple asynchronous calls. Promises can also be useful if you want to guarantee then a piece of code is executed only once. Promises are executed only once. Continue reading “Using JavaScript Promises with Cordova”

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My Second Book Published

My second book “Java EE Development with Eclipse – Second Edition” has been published. One of the reasons I did not post much on the blog was this book. I had been working on the book for the past few months and I am very glad that it has been published now.

Java EE Development with Eclipse - Second Edition - Cover

JEE-Book-Cover-2

One of the challenges writing this book was the diverse topics that it covered – Servlets, JSP, JSF, JDO, EJB, JSM, SOAP, REST, Spring, Unit Testing, Debugging and trouble shooting performance and memory issues in Java applications. Separate books could be written, and books have been written, on some of these topics.

This book explains how to develop applications using these technology in Eclipse IDE. The focus is not just on how to use different technologies in JEE, but also on setting up development environment, testing, debugging and deploying applications developed using these technologies.

The book is available on the publisher’s site at bit.ly/1GryrTd.

-Ram Kulkarni

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My blog report for 2014

As at the end of past couple of years, WrodPress has created annual report of my blog activities. The report is available at http://jetpack.me/annual-report/33403624/2014/.

Some of the highlights are –

Unfortunately I did not get much time to blog in the last three months. I had many topics on which I wanted to write on, but the work schedule was quite hectic. I hope to write on those topics in the coming months.

-Ram Kulkarni

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Configuring Apache on Mac OS X (Mavericks) for Python scripting

I spent a couple of hours today trying to figure out how to configure Apache Web Server on Mac OS X to execute Python scripts, so I thought I would document the process for my own reference.

OS X is preinstalled with Apache and Python. Apache executable (apachectl) is at /usr/sbin/apachectl and Python is at /usr/bin/python. But the configurations for Apache are at /etc/apache2, specifically in the file httpd.conf. If you open the file and look for DocumentRoot, you will find that default document root is set to /Library/WebServer/Documents.

I did not want to change the default doc root but at the same time did not want to store my scripts in the default folder. I could have created a virtual host or an alias. I decided to do the later because it is simpler than creating virtual host; and I was configuring Python for development only. So just below the document root setting I added the alias – Continue reading “Configuring Apache on Mac OS X (Mavericks) for Python scripting”

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Encrypting data with Crypto-JS in JavaScript


I have been working intermittently on a HTML5 mobile application for some time now. This application stores some sensitive date locally (it is a standalone mobile application) and I did not want to store the data in clear text. I wanted to make retrieval of data difficult to some extent, if the device ends up in the wrong hands. So the data had to be encrypted. The application code is in JavaScript, so I started looking for a JS library that can encrypt data. I found that Crypto-JS met my requirements and it was easy to use too.

Before I proceed further, I must confess that my knowledge of encryption and digital security in general is very basic. So the solutions discussed in this post may not be the best in terms of protecting the data.

As I said, Crypto-JS is very simple to use. You can use different cipher algorithms like AES. DES etc. and APIs are simple. e.g. to encrypt using AES , you would call –

encryptedData = CryptoJS.AES.encrypt(textToEncrypt, secretPhrase); //include aes.js script

In the above API, the first argument to encrypt function is text data you want to encrypt, e.g. password. The second argument is a secret phrase (also called passPhrase). This could be any text. Secret phrase is the key that is used to encrypt the data. However you will have to use the same key (secret phrase) when decrypting the data. Continue reading “Encrypting data with Crypto-JS in JavaScript”

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My Last Day at Adobe

After working in Macromedia/Adobe for ten years I decided to quit Adobe. Today was my last day at Adobe.

The last ten years at Adobe have been professionally and personally very satisfying for me. I have worked on some of the most technically challenging assignments in my career so far. Learnt a lot and put my learnings back into the products I worked on.

On the last day when I was reflecting on my journey in Adobe, I recall my interview as a candidate. Macromedia did not have an office at that time in Bangalore and I was interviewed in Windsor Manor hotel. I was the first engineer recruited for ColdFusion in Bangalore. When I joined the ColdFusion team, ColdFusion 7 release was in the final stages. I started with fixing a few bugs towards the end of the release. After that I worked on many features of ColdFusion and ColdFusion Builder in the subsequent releases.

Till a couple of months back I was not thinking about quitting Adobe. But then an opportunity came along that was so different from the way I was working in Adobe that I decided to take it up. I might write more about it later.

My best wishes to the ColdFusion team and the ColdFusion community.

-Ram Kulkarni

P.S. I joined back Adobe in June 2015.

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AngularJS + JQueryMobile and Dynamic Loading of pages

I was experimenting with using AngularJS and JQueryMobile together and loading pages dynamically. The page loading and routing can either be handled by JQueryMobile ($.mobile.pageContainer.pagecontainer(“change”,“page_name”)) or AngularJS. With AngularJS you can use $route service along with ngView and/or use ngInclude .

ngInclude looked easy enough to start with, but did not turn out to be that easy. I will take as simple example of a login application. If user is not logged-in, the app will display the login page and after successfully logging in, the application will display the main page, with the option to logout. Continue reading “AngularJS + JQueryMobile and Dynamic Loading of pages”

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Creating CFMobile Application using AngularJS

In my previous blog articles I had explained how to create CFMobile applications using JQuery, Bootstrap/JQueryMobile. Here are links to sample (CFMobileExpenseTracker) applications using the two UI frameworks –

I wanted to create the same application using AngularJS. It had been on my ‘to learn’ list for sometime now. So I spent the last weekend learning it. If you already know concepts of MVC and Dependency Injection, then understanding AngularJS is not difficult. The well documented tutorials also helped.

I decided to re-write CFMobileExpenseTracker using AngularJS and JQueryMobile. Since AngularJS provides very easy way to manipulate DOM, you really don’t need JQuery. But I had to include it in the application anyway because JQueryMobile depends on it. I also used JQuery for basic event handling.

Earlier in my application I had used client side custom tag (expenseList.cfm) to display expense items by calling JQuery APIs to modify DOM and update UI. I could get rid of this custom tag entirely after using AngularJS, because of templating features  and automatic synchronisation between model and view provided by Angular JS.

Here are the screen shots of the application –
2014_04_24_image12014_04_24_image2

Though I said that I re-wrote the application, it was not a complete re-write. I could reuse CFCs and made small modifications to index_include.cfm. I added a new JS file (angular_app.js) to crate AngularJS application and controllers – Continue reading “Creating CFMobile Application using AngularJS”

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