Archive for the ‘Software and Technology’ Category

Installing SASS 3.0 on Ubuntu 10.4

Posted on the July 9th, 2010 under HTML, CSS,Linux,Software and Technology by Tohir

Currently, the HAML/Sass version on Ubuntu is 2.2.17. Version 3, also known as Classy Cassidy, includes new features. So how can you install it on Ubuntu.

Firstly, you need Ruby:

sudo apt-get install ruby

Thereafter (without sudo):

gem install haml-edge

This will install Haml and Sass into your directory, but at least you will have access to the latest version. Message that appears:

WARNING:  Installing to ~/.gem since /var/lib/gems/1.8 and
 /var/lib/gems/1.8/bin aren't both writable.
WARNING:  You don't have /home/tohir/.gem/ruby/1.8/bin in your PATH,
 gem executables will not run.
Successfully installed haml-edge-3.1.49
1 gem installed

You can test that it is the latest version by:

~/.gem/ruby/1.8/bin/sass -version

Which should return:

Haml/Sass 3.1.49 (Bleeding Edge)

Lastly, there is a nice command to watch files and auto generate an updated version:

~/.gem/ruby/1.8/bin/sass -t compact --watch [inputfile]:[outputfile]

like:

~/.gem/ruby/1.8/bin/sass -t compact --watch browseView.scss:browseView.css

How to Loop through the Properties of an Object in JavaScript

Posted on the May 10th, 2010 under Internet,JavaScript by Tohir

for (var key in object) {
    alert('value of '+key+is+object[key]);
}

Wireshark and [truncated]

Posted on the May 10th, 2010 under Internet,Linux by Tohir

I’ve posted a tutorial on how to get wireshark up and running on Ubuntu. The one problem , though, is that sometimes (actually often) you get [truncated]. How can you untruncate or turn it off or increase its size.

This isn’t the answer, but a way of how to get access to the full response:

Right Click on the Packet in Line-based text data, then choose Copy > Bytes (Printable Text Only).

This will place the full response, and you can paste it in a text editor.

MySQL – getting two items per source in a single query

Posted on the February 4th, 2010 under Software and Technology by Tohir

Assume you have the following table called stories with the following data. And you have run the following query:

SELECT * FROM stories ORDER BY storydate DESC
id source title storydate
10 cnn Story 10 2010-01-21
9 bbcnews Story 9 2010-01-20
8 bbcnews Story 8 2010-01-19
7 skynews Story 7 2010-01-18
6 cnn Story 6 2010-01-17
5 bbcnews Story 5 2010-01-16
4 cnn Story 4 2010-01-15
3 skynews Story 3 2010-01-14
2 skynews Story 2 2010-01-13
1 cnn Story 1 2010-01-12

Now for the challenge. What happens if you are required to get the top two stories from each source? One option is to first get the order of the sources, and then loop through each one of them:

SELECT DISTINCT source FROM stories ORDER BY storydate DESC

<loop “source” as “sourceid”>

      SELECT * FROM stories WHERE source = "{sourceid}" ORDER BY storydate DESC LIMIT 2

</loop>

Another option is to do the in MySQL itself! Unsure if there is a better way of doing this, but here’s mine using UNION and Sub Selects:

(SELECT * FROM stories WHERE source =
(SELECT DISTINCT source FROM stories ORDER BY storydate DESC LIMIT 0,1) ORDER BY storydate DESC LIMIT 2)
UNION
(SELECT * FROM stories WHERE source =
(SELECT DISTINCT source FROM stories ORDER BY storydate DESC LIMIT 1,1) ORDER BY storydate DESC LIMIT 2)
UNION
(SELECT * FROM stories WHERE source =
(SELECT DISTINCT source FROM stories ORDER BY storydate DESC LIMIT 2,1) ORDER BY storydate DESC LIMIT 2)

Explanation:

The bold section are subselects and form the WHERE clause of the query. Here  we want the first, second and third as per source, but only one at a time. Once we have two results per item, we use UNION to join them together.

One thing to note though. Even though it returns the latest two stories per source, the final table is not sorted by storydate! This can be done using PHP sorting techniques. Is there a way of doing this one time in MySQL?

Getting started with Wireshark, the Fiddler for Ubuntu

Posted on the February 1st, 2010 under Internet,Linux,Software and Technology by Tohir

Fiddler is a useful tool for tracking http requests and responses. It’s similar to the Net tag in Firebug, except that it can be used to track all requests, not only browser-based ones.

For Ubuntu users, the recommended alternative is Wireshark. Wireshark is noted as being more powerful than Fiddler, but the focus will be on the features most commonly used by web developers for tracking.

Installation

Wireshark is found in the Ubuntu repositories, so simply search for wireshark in Synaptic, or enter sudo apt-get install wireshark

Usage

Under Applications > Internet, you will notice there are two options. Wireshark and Wireshark (as root). Run the second one (as root) as this gives you more data to track.

wireshark-1

After wireshark has started, the process is straightforward:

  1. Choose which network interfaces to capture traffic from
  2. Start capturing
  3. Filter captured requests

1. Choosing which network interfaces to capture traffic from. From the menu, choose: Capture > Interfaces

wireshark-2

This will bring up a list of network devices.

2. Since my work involves debugging work off my laptop (http://localhost etc), I only start device lo (127.0.0.1). This is useful as it immediately ignores all other traffic.

3. The one thing you will notice is that fiddler will log both the TCP and HTTP requests. For the purpose of debugging AJAX, etc., we are only interested in HTTP requests, TCP requests are not required. These can be hidden by adding a filter.

wireshark-3

In the field next to Filter:, enter http and click on Apply.

wireshark-4

The steps will now show all traffic coming on 127.0.0.1 via HTTP. The last step is picking up the AJAX parts for debugging. Notice that for each request, there is a response. Unlike Fiddler, Wireshark does not combine the request and the response. So click on the response line, and then expand the Line-based text data row. This will show the text of the AJAX response.

wireshark-5

Conclusion

Wireshark takes more steps than Fiddler, and Fiddler is a more focussed program than Wireshark. Wireshark also captures traffic without having to install a plugin into firefox, etc., so it’s useful for debugging applications as well. The biggest improvement to make Wireshark truly replace Fiddler is to turn off truncation of the response text. Wish I knew how!

How to use ExtJS Abstract functions

Posted on the September 22nd, 2009 under ExtJS by Tohir

For some methods in ExtJS, you will see:

Class Ext.grid.GridDragZone

onDrag( Event e ) : void

Abstract method called during the onMouseMove event while dragging an object.

Parameters:

e : Event

the mousemove event

Returns:Class Ext.grid.GridDragZone

void

In this case, GridDragZone is part of GridView which is part of GridPanel. Accessing it will be, GridPanel->GridView->GridDragZone.

The GridDragZone gets implemented for a GridPanel when you set enableDragDrop to true, but it only becomes available when the grid renders, so:

var grid = new Ext.grid.GridPanel({
    // etc
});
grid.on('render', function(obj) {
    obj.getView().dragZone.onDrag=function(evt){
        alert('being dragged');
    }
});

Simple Drag and Drop from Adobe AIR

Posted on the August 21st, 2009 under Adobe AIR by Tohir

Quite a few articles and tutorials show you how to drag and drop a file onto an Adobe AIR application. This one will show you how to drag one FROM an Adobe AIR application TO YOUR DESKTOP (or any other location you provide. The code is really simple:





Drag Me to the Desktop

Download: Source Code

To run, extract files from archive, and then run: adl application.xml

Dynamically generating a Sandbox in Adobe AIR

Posted on the August 19th, 2009 under Adobe AIR by Tohir

Something that seems to have worked


Thoughts?

Focus Booster App

Posted on the August 4th, 2009 under Adobe AIR,Reflections/Thoughts,Software and Technology by Tohir

For the past couple of days, I’ve been experimenting with a tool called Focus Booster. It’s a simple app with an easy method to help you measure and increase your focus and concentration:

 

  1. Firstly, choose the amount of time you would like to complete a particular task. By default it is set to 25 minutes.
  2. Prepare to do the task, clear your PC desktop of any distractions, and start the timer.
  3. Continue working until you’ve completed the task or the timer runs out.
  4. Take a break
  5. Restart the process with your next task

Tiny app, simple process, but it works for me, and these are the benefits I believe are derived:

  • Forces you to plan and think about a single task you would like to perform
  • A quick glance at the timer helps you focus, there is something watching you!
  • Helps you to persevere, (just another 8 more minutes to go, etc.)
  • Provides some type of measurement of how long you can focus, and challenges you to better it. The next version will allow you to record your focus sessions.

Focus Booster is a free application and requires Adobe AIR to run. Download it at: http://www.focusboosterapp.com/ . Follow updates on twitter @focusboosterapp
 

How to: Uninstall Adobe AIR Apps on Ubuntu (via Synaptic)

Posted on the August 3rd, 2009 under Adobe AIR,Linux by Tohir

There are two ways to uninstall Adobe AIR apps on Ubuntu.

1) Access to original .air file

If you have access to the original .air file, run it and it will give you a screen with options to either Uninstall, Run Now or Cancel. Simply click on Uninstall.

Screenshot-Application Install

 

2) Use Synaptic Package Manager

A second more easier approach (particularly if you lost the .air package) is to use Synaptic. From the sidebar, simply choose: Status > Installed (local or obsolete)

Adobe AIR apps list in Synaptic

 

Discovering this makes me less hesitant to try our different AIR apps, trying to find out which one works best.