It has happened to me more than once that I make a commit without verifying the changes I am committing. Time after that I review the commit and I notice that there is something in the commit that doesn’t belong there.

In those times what I want to do is make a patch with the changes of the commit, delete the commit, apply the patch and then redo the commit only with the changes I intended. In this post I will only explain how to delete a commit in your local repository and in a remote repository in case you have already pushed the commit.

Once you have created an extension, you will probably want to make it easily available to the public.

For my tntfixer extension that I explained in some previous posts I had a folder structure similar to this one:

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/tntfixer
|----chrome.manifest
|----install.rdf
|----README
|----/chrome
|    |----/content
|    |    |----tntfixer.js
|    |    |----tntfixer.xul
|    |
|    |----/skin
|    |    |----overlay.css
|    |    |----/images
|    |    |    |----status-bar-icon-active.png
|    |    |    |----status-bar-icon-inactive.png

If you have sent e-mails in a different language than English or using characters outside the ASCII range you have probably already used utf8 to send them.

Specifying the use of UTF-8 in the body of an e-mail is very similar to doing it for a HTTP response. You can specify the content-type in an e-mail header like this:

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Content-Type: text/plain; charset=utf-8

But there is catch. The subject line of an e-mail is a header by itself, and headers must contain only ASCII characters. Happily, there is a work around. RFC 1342 is a recommendation that provides a way to represent non ASCII characters inside e-mail headers in a way that won’t confuse e-mail servers.

This is a common problem I find when I do a new Apache 2 install on Ubuntu. There is a simple solution to stop seeing this message. Edit httpd.conf, type this command in a terminal:

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sudo gedit /etc/apache2/httpd.conf

Add this line at the end of the file

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ServerName myserver

You can replace myserver with whatever name you want to use for your server.

If that doesn’t completely fix the problem try adding the same line:

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ServerName myserver

At the end of /etc/apache2/apache2.conf

That should do it.

If you are a web developer, virtual hosts is probably something you already use, if not, you should.

Virtual hosts allow you to have multiple domains configured in your computer so you can have different web sites in different locations on your hard drive and keep your environment better organized when developing. Virtual servers are also used by shared web hosting companies to host multiple web sites in the same machine, the difference is that they deal with a bunch more stuff that I am not going to deal with in here. This guide should only be used to create virtual servers for local development.

I am currently using Ubuntu 11.04 (Natty Narwhal) but I am pretty sure the instructions are the same for other versions of Ubuntu. Other Linux distributions not based on Debian have a slightly different folder structure, but you should be able to adapt this guide easily.

I am going to explain how to make a very simple hello world application using Zend Framework. While doing this I am going to try to explain how Zend Framework manages MVC.

Folder structure

Zend Framework uses the Front Controller pattern on its implementation of MVC. This means that all calls to your website are managed by one file and this files routes to a correct controller based on the URL of the call.

For this example we are going to create a folder for our application: /home/adrian/www/hello. Inside that folder we need to create three folders: application, library and public.

Changing the color of a tab on a Firefox extension is a very straight forward task. You can use this code to change the color of all the tabs on a window:

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var tabbrowser = window.getBrowser();
for (var i = 0; i < tabbrowser.browsers.length; i++)
{
    tabbrowser.tabContainer.childNodes[i].style.setProperty(
        "background-color",
        "#0f0",
        "important"
    );
}

If you don’t provide the third argument “important” you won’t be able to override the browser default and therefore you wont see your change.

This post is a continuation of Detecting when a tab or window is opened on Firefox post. We are going to be using what we did on that post as a base for this one.

Introduction

Continuing with the development of my Firefox extension, this time I am going to attach event listeners to the current tab so I can override its behavior.

I will first check if the tab matches the domain of the application, and if it does I will add an event listener to a button that I know exists on the page to do what I want it to do.

Approach

We are going to listen for location changes on our windows. For that we are going to use a progress listener that will notify us every time the location bar of our window changes. This happens every time a new tab is opened or every time you change the current tab.

This post is a continuation of using Firefox preferences to store data post. We are going to be using what we did on that post as a base for this one.

Introduction

For the ones who don’t know, these series of posts about Firefox extensions development is inspired by a need to fix some issues on a tool I use at my current job.

One of the problems with this tool is that it doesn’t allow to work on multiple tabs or windows in the same browser at the same time. Doing this could cause that when you save something on one tab the other tab is affected and your data could be corrupted. What I will do to avoid data corruption is check if there are two instances of the application open, and if so, I won’t allow to save until there is only one left.

This post is a continuation of  Adding an icon to our Firefox extension post. We are going to be using what we did on that post as a base for this one.

Introduction

The Firefox preferences system provides and easy way of storing small amounts of data for Firefox extensions. There are more advanced systems to store data for extensions but since what we are going to store is actually a user preference we are going to save it there. There are three data types that can be used for preferences: boolean, int and char.