Before we get to the code, validate you have the Ruby Subversion bindings installed correctly by running irb from a terminal:

irb(main):001:0> require 'svn/client'
=> true

Onto the source code. Start it off by including the required svn modules:

Then setup the context with your subversion credentials:

Now you can run any of the following commands on a remote subversion repository.

SVN Info

SVN Checkout

SVN Log

SVN List

That should get you started with the ruby bindings. If you want to know how to do anything else let me know in the comments.

The symfony debug toolbar will look like this when there is a validation error in one of the forms on the current page. This is one of the most incredibly useful features I've seen and greatly improves productivity while building forms in the symfony framework. Congratulations to the symfony developers who came up with this tool!

Have symfony 1.1 or 1.2? read catch symfony form errors.

I foresee a new framework will be created to make developing fully interactive AJAX applications as easy as it is to write current MVC applications. Current frameworks like Ruby on Rails and Symfony provide everything you need to develop a modern application without having to build plumbing infrastructure; however, they do not provide nice components for interactive applications. In addition to a robust server core, this new framework will have a client side JavaScript component that simplifies the process of building interactive web 2.0 applications. Some critical components would be:

• Form Validation. Libraries do exist to validate forms in JavaScript, but they don't integrate with the server side form validation. In this new framework you won't have to write form validation code twice.
• Paginated Lists. Almost all web applications have at least one page where data needs to be searched and listed with pagination. We need to have this same functionality in JavaScript to skip a full page reload and provide local caching of the results.
• Animation Library. While script.aculo.us and jQuery have made simple animations and visual effects much easier to do, I believe we can go even farther. Web applications also need to gain that fluidity and soft animations that desktop applications such as Exposé have had for a couple of years.

I also see huge resources being directed towards mobile development because ALL current generation smart phones are built for an incredible web browsing experience. As home users have switched from desktop computers to laptop computers in the last few years, people will slowly start switching to hand-held devices for their primary communication and Internet needs. Most likely this will have one primary effect: web frameworks will have a mobile optimized version of the site done automatically. Little to none developer intervention will be required as only resolution, text sizes, and layouts will be modified for the mobile version.

Lastly I see tools and libraries around 2D and 3D drawing elements. Most likely these libraries would be rendering to a Canvas or a WebGL element but something better could be created. Both of these are young standards right now that show a lot of promise on delivering the ability to draw pixels directly in a native HTML web page. While they will be used first in simple computer games, I am very interested to see what libraries are created to facilitate these elements being used appropriately inside next generation web applications.

What do you think the next 5 years will bring?

Start your script with She-Bang header:
#!/bin/bash

Variables are assigned by a key-value pairing:
FILENAME="~/docs/input"

You can print to the console by using echo:
echo $FILENAME

An IF statement:
if [ ! -s $FILENAME ] ; then
  touch $FILENAME
fi
The bang ! negates the result, and the -s parameter checks if a file exists.

Example of a function:
function getFile
{
  # function contents here
  # the hash symbol makes the rest of this line a comment
}

Call this function by using its name:
getFile

You can pass a variable to a function:
getFile "/home/user/docs/file.txt"

And use it within the function by reference to $1
function getFile
{
  echo $1
}

Content-Disposition: attachment; filename="filename.mp3"

Tested in: Firefox, Safari, IE, Opera, and Google Chrome

I wanted my users to remain logged in while navigating from www.example.com to site1.example.com. By default PHP will treat these domains as two separate sites and users would have to login to each subdomain.

All you have to do is to either set the following setting in your php.ini file:
session.cookie_domain = .example.com

Or, set it from within your code before you create your session:
ini_set("session.cookie_domain", ".example.com");
session_start();

When developing an application you must learn Rule #1 Facebook is the gatekeeper. Everything you do, be it HTML, CSS or JavaScript, is restricted by Facebook. Only the commands, functions, CSS properties, HTML tags etc. that Facebook allows are permissible. If you have an error in your HTML such as an unclosed tag or if you try to use a CSS property that does not exist, Facebook will render a very nice message saying you made an error.

Rule #2 The never ending cycle. The Facebook platform is constantly changing and APIs that you are using in your application could disappear one day without any notice. It's the life of a Facebook application, working one instant, inexplicably broken the next. Be prepared for irregular maintenance just to keep your application working.

A Facebook Application lives in the world of Facebook and while it might initially seem like you're developing a standard web application you are not. Rule #3 You're application is on the Facebook web. It's not a regular web application which is a very slight but critical distinction. Facebook has used their powers as the gatekeeper to make modifications to the web. Some HTML tags are allowed, some are not. JavaScript has been altered to remove a lot of its power and replace only some of them with Facebook specific functions and even CSS has restrictions. Don't expect existing code to function when placed in the Facebook web.

Additional Caveats

• You cannot include any external JavaScript or style sheet files, they must be included in-line. This is so Facebook can parse them and allow only approved commands. Yes it enhances the security of the social networking site as a whole, but it will slow down your development time.
• Facebook will filter, compile, and drastically alter your original code. Clicking view-source on a Facebook page with your application will show your JavaScript code mushed into awkward Facebook functions.

Do you see that it's a bit of a battle of you against the mighty Facebook? Don't sweat too much, other developers have persevered and with a few wounds and time you can build and maintain a successful Facebook application. Good luck!

The posts were originally posted on Senses and reproduced here for archival purposes. They touch on a lot of basic information for software developers including software design, upcoming technologies and useful tips to make your life easier.

Check the Quality Software page for links to each article.

Lets say you have a web application that needs to track how long an AJAX request took. If you were writing it in Ruby, PHP or Python you'd have a timer object that you can start() and stop() and a seconds() method to get the number of seconds that passed between calling the first two methods.

To build this in JavaScript we first create our constructor:

Here we are creating a Timer object with a private seconds_passed variable. To create this object we we simply create a new timer:

This timer object now needs some public methods. We can attach a public method by using this.method_name:

Our Timer class now has a start() function. Additional public methods can be added in the same way.

To add a private method, don't define it with the this keyword but instead create a regular function inside the class:

Now we have a Timer object with a public start method and a private increment method. The rest of the class is fairly simple, so lets jump to the finished solution.

Complete Example

There you have it. A simple JavaScript timer to keep track of time.

If it's a larger software project and nobody on the team knows what a change would do, then it would be fair to say the software is overly complex and making forward progress is like wading through a swamp. Software projects, especially larger software projects absolutely must have code that is understandable. When designing software applications, a key component to the architecture is managing complexity to a workable level.

Managing complexity is the most important technical topic in software development. In my view, it's so important that Software's Primary Technical Imperative has to be managing complexity.

- Steve McConnell in Code Complete

Unless its a small project, no software developer can contain the design, constraints, and all the technical details in their head at the same time. Software must be made modular so that a developer can work on one section of code without worrying about the rest of the project.

How do you deal with complexity?

1. Break up the problem into sub-problems and sub-tasks so you don't have to solve everything at the same time.
2. Contain the complexity to one part of the code.
3. Before you solve the complex issue take a step back and make sure you have to solve it that way. There might be a vastly simpler problem that you can solve that will still fulfill your requirements.

Tackle software complexity before it defeats your software project.