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Acts_as_modified Plugin

Sun, 23 Nov 2008 14:33:16 GMT

Sometimes when you are dealing with some of your models, you ask yourself has this model changed? if so then, which attributes? and what were their values before that change?

When should you care about these questions?

Suppose you have a model doing an expensive operation before saving. This operation is useful only if one specific attribute changed, so doing it on every save, neglecting which attributes have changed, will degrade performance significantly.

So what can you do?

Easy Application Development for the iPhone

Thu, 20 Nov 2008 10:15:39 GMT

Most Developers who are new to the stormy currents of iPhone development in Objective-C would stay at the shores for quite some time before they get their boats wet and start sailing.

But with Jiggy at hand, development for the iPhone can be like a walk in the park for most developers who are familiar with Javascript. It's really nice to use such a flexible and powerful language to script your applications.

Since Jiggy runtime wraps native Objective-C API for you, you won't even need a compiler or the tool chain to start developing. All you'll need is a browser on your machine and a iPhone with jiggy runtime and jiggy (ide) installed and you can start writing your native applications in javascript. (You can get Jiggy from here)

Javascript Multiple Inheritance

Wed, 19 Nov 2008 14:06:19 GMT

Since "this" in the body of a function is the reference to the object used to call the function, e.g.

obj.setProp = function(p) { this.prop = p }
obj.setProp(5)
obj.prop
=> 5

and since JavaScript constructor function is the same as any other JavaScript function -and the only difference that happens is through the use of the new operator-, we can use "this" to inject functionality provided by multiple constructor functions (sort of multiple inheritance) into our own objects. This can happen as long as these constructor functions are not only natively implemented (e.g. Array, String, Function, .... etc), and as long as the injected functionalites are not dependent on their prototypes.

Rails Plugins: Metaprogramming vs Generators

Wed, 19 Nov 2008 08:43:13 GMT

One of the most powerful features of Rails is plugins; plugins enable developers to make generic extensions to Rails applications that others can benifit from. One can use two different approaches to add new logic/aspects to a Rails application through a plugin: metaprogramming and generators. This entry is not a tutorial about writing Rails plugins; assuming that you know the basics of metaprogramming in Ruby, and using a very basic example, we'll try to conduct a simple comparison between the two approaches that can be generalized.

FCKEditor and Radiant: Adjusting the Link Target According to Link Type

Tue, 18 Nov 2008 12:49:08 GMT

In one of my projects at eSpace, I was building a site using Radiant CMS. I decided toput FCKEditor as the rich text editor to be used by the site administrator. FCKEditor is one of the great text editors available; using it you can add links to the page content and decide whether those links open in the same window or in new window. The default for the link is to open in the same window, but we decided that any external links must open by default in a new window and any internal links (links to site pages) must open by default in the same window.

FitNesse in Ruby- Installation

Tue, 18 Nov 2008 09:57:42 GMT

FitNesse is a framework for acceptance testing that is needed to test the business logic of an application; it's for documenting the customer requirements of a system and testing them against the implemented code. FitNesse is a wiki-based web server with which you can easily create and edit pages. It's based on fit, and it's motto is: Download-and-go.

FitNesse is a lightweight, open-source framework that makes it easy for software teams to:

Collaboratively define acceptance tests
Run those tests and see the results (see TwoMinuteExample).

IE6 Background Image Problem

Mon, 17 Nov 2008 09:28:55 GMT

Imagine that you have a blog and you are designing a new rating system where you will use the golden stars to rate your entries, so you make an HTML prototype to create the layout of your new rating system. Here is the code you have written:

1 <html>
  2     <body>
  3         <h1>
  4             <div id="stars">
  5             </div>
  6             How is the BG IMG fixed in IE
  7         </h1>
  8     </body>
  9     <style>
10         #stars{
11             height: 20px;
12             width: 100px;
13             float: right;
14             background: url("star_on.png") repeat;
15         }
16     </style>
17 </html>

The "star_on" image you are using is 20 x 20 px, the height of the stars' DIV is 20px to fit with the image, image is set to repeat, and the width is set to 100px so that you will see 5 stars.

Installing Mephisto 0.8 on Rails 2

Sun, 16 Nov 2008 08:46:16 GMT

Finally I'm done with installing and running mephisto for my personal website. However, it was not that easy, so I thought documenting it may help me in the future and may save someone else's time. Actually, a lot of time.

Well, if you don't know, mephisto is a simple, elegant and free Ruby on Rails blogging system that can run fantastic websites. Unfortunately, due to the lack of documentation, especially after mephisto releasing mephisto 0.8, which supports Rails 2, it took me a long time to get it installed and running. The good news is that I will show you how I did it. So, to the tutorial...

Different Encoding Error

Thu, 13 Nov 2008 14:46:13 GMT

If you found yourself encountering this error, don't worry or double-check your code to make sure that that data you saved doesn't have left any bad characters around causing you this misery. All you need to do is to check the used database connection encoding against your db tables' encoding; most probably you will find them different.

Reading Arabic in a PuTTY Connection

Thu, 13 Nov 2008 09:00:14 GMT

When using PuTTY to connect to your production or deployment servers, either to inspect a log file or to run a MySQL command, have you ever wished that you can read those characters instead of using two or three other tools just to inspect a server log? Frankly, I did!

In the PuTTY Configuration window, by selecting Translation from under the Window section on the left, you can change the character-set that the received data will be assumed to be in. Selecting UTF-8 changed the world for me. By doing this you can see all Arabic text in the server log crystal clear.