Building Firefox Extensions
Like many Linux Journal readers, Firefox is my browser of choice. One of its core strengths is the number of available extensions. Early extensions were focused around merely changing the look of the browser; however, in the past few years, extensions have been used to provide a very rich user experience while straddling the line between desktop and Web applications.
In this article, I explain how easy it is to extend Firefox by building an extension that integrates with a photo editing API provided by Picnik.
The first thing a new extension developer should do is set up a development profile. Although you can do extension development using your normal Firefox profile, it often is easier to create a new profile dedicated to development. First, start Firefox's profile manager:
$ firefox -ProfileManager
Next, click the Create Profile button. Once the wizard is loaded, click Next to get started. At this point, you should see a window similar to the one shown in Figure 1. Enter a name for your new profile (I used dev). Make sure you write down the path to the folder where your profile will be stored before clicking Finish. You'll be using that path later.
Now that you have a dedicated profile, you should install some extensions that make development easier. The first one you should install is the Extension Developer. This is a compilation of several handy extensions—all designed to make developers' lives easier. See Resources for several other handy extensions. I highly recommend that you install all of them.
At this point, you're ready to start your first extension. Nearly all extensions start with the same basic boilerplate code, so the same person who made the Extension Developer put together the Firefox Extension Wizard to automate this part of the process. You can find its URL in the Resources for this article.
Most of the required fields should make sense. The main one of note is the Extension ID. This is used to identify the extension uniquely for updates and other purposes. In the past, standard practice was to use a GUID (Globally Unique Identifier). Most developers recently have switched to a format that bears resemblance to an e-mail address. For this example, I used firstname.lastname@example.org. I also selected the option to create a context (right-click) menu. Figure 2 shows how I filled in the rest of the fields.
Once you are satisfied with your choices, click the Create Extension button. After a few seconds, your browser should prompt you to download a zip file. Go ahead and extract it:
$ unzip linuxjournal.zip Archive: linuxjournal.zip inflating: linuxjournal/install.rdf inflating: linuxjournal/chrome.manifest inflating: linuxjournal/readme.txt inflating: linuxjournal/content/firefoxOverlay.xul inflating: linuxjournal/content/overlay.js inflating: linuxjournal/skin/overlay.css inflating: linuxjournal/locale/en-US/linuxjournal.dtd inflating: linuxjournal/locale/en-US/linuxjournal.properties inflating: linuxjournal/config_build.sh inflating: linuxjournal/build.sh
Before going into the purpose of all those files, you should install it to see what the auto-generated extension actually looks like. Firefox can use extensions installed in two ways. The normal installation method involves opening the extension's .xpi file in Firefox. This is the way most extensions are distributed and installed. The other method is to create a pointer file that tells Firefox where to find your extension's files. With this method, you don't have to re-install the extension every time you want to test a change; all you have to do is create the pointer file:
$ cd linuxjournal $ pwd > ~jjhuff/.mozilla/firefox/lhn85ppm.dev/extensions/ ↪extension\@linuxjournal.com
Of course, you'll want to replace ~jjhuff/.mozilla/firefox/lhn85ppm.dev with your Firefox development profile directory.
Now, go ahead and start up Firefox using your development profile:
$ firefox -P dev
First, check to see that the extension is installed. Select Tools→Add-ons, and verify that LinuxJournal 1.0 is listed. You should see a window like the one shown in Figure 3. While you have the Tools menu open, you probably noticed the new (and red) menu item (Figure 4). Go ahead and right-click in the browser window. You should see a menu similar to the one shown in Figure 5. If everything looks right, your extension is installed properly.
Practical Task Scheduling Deployment
July 20, 2016 12:00 pm CDT
One of the best things about the UNIX environment (aside from being stable and efficient) is the vast array of software tools available to help you do your job. Traditionally, a UNIX tool does only one thing, but does that one thing very well. For example, grep is very easy to use and can search vast amounts of data quickly. The find tool can find a particular file or files based on all kinds of criteria. It's pretty easy to string these tools together to build even more powerful tools, such as a tool that finds all of the .log files in the /home directory and searches each one for a particular entry. This erector-set mentality allows UNIX system administrators to seem to always have the right tool for the job.
Cron traditionally has been considered another such a tool for job scheduling, but is it enough? This webinar considers that very question. The first part builds on a previous Geek Guide, Beyond Cron, and briefly describes how to know when it might be time to consider upgrading your job scheduling infrastructure. The second part presents an actual planning and implementation framework.
Join Linux Journal's Mike Diehl and Pat Cameron of Help Systems.
Free to Linux Journal readers.Register Now!
- Paranoid Penguin - Building a Secure Squid Web Proxy, Part IV
- SUSE LLC's SUSE Manager
- Google's SwiftShader Released
- Murat Yener and Onur Dundar's Expert Android Studio (Wrox)
- My +1 Sword of Productivity
- Managing Linux Using Puppet
- Non-Linux FOSS: Caffeine!
- SuperTuxKart 0.9.2 Released
- Parsing an RSS News Feed with a Bash Script
- Rogue Wave Software's Zend Server
With all the industry talk about the benefits of Linux on Power and all the performance advantages offered by its open architecture, you may be considering a move in that direction. If you are thinking about analytics, big data and cloud computing, you would be right to evaluate Power. The idea of using commodity x86 hardware and replacing it every three years is an outdated cost model. It doesn’t consider the total cost of ownership, and it doesn’t consider the advantage of real processing power, high-availability and multithreading like a demon.
This ebook takes a look at some of the practical applications of the Linux on Power platform and ways you might bring all the performance power of this open architecture to bear for your organization. There are no smoke and mirrors here—just hard, cold, empirical evidence provided by independent sources. I also consider some innovative ways Linux on Power will be used in the future.Get the Guide