I have been waiting for a long time to write about this great news. Since bug #488270 has been fixed in Firefox 3.6 (beta), Firebug 1.5 (beta) uses a new API to measure timing of underlying network activity more precisely.
Firebug now uses a component called http-activity-distributor that allows to register a listener and get notifications about various phases of each network request (DNS Lookup, connecting, sending, etc.). The most important thing is that one of the parameters passed to the listener is a time-stamp. This is something what was missing till now.
Having the time-stamp is critical since Javascript code (and Firebug is entirely implemented in Javascript) is executed on Firefox UI thread. In case when the UI is blocked by time expensive operation (e.g. DOM rendering, script execution, etc.) any event sent to a Javascript handler (and so, handled on the UI thread) can be delayed. So, getting the time-stamp withing JS handler can produce impaired time results.
Firebug Net panel now fixes this problem and the timing info is correct. See couple of examples I have analyzed when testing with a nice online tool called Cuzillion developed by Steve Souders.
Read more...
We have been working with Simon Perkins and Steve Souders on an open format for exporting HTTP tracing information. It's called HTTP Archive (HAR) and we have just finished spec v1.1.
The format is already supported by Firebug (with NetExport extension installed), HTTPWatch 6.2 and also DebugBar 5.3. Further tools like Show Slow and Cesium could be the next.
The key idea is to have a common format for archiving HTTP information that are captured by HTTP sniffers. These logs contain valuable info about page load performance and can be further used to analyze and optimize weaknesses of the monitored page.
There is already a few blog posts about this, explaining all details and so, let me just summarize the most important links here.
Links
HAR Specification
HAR Discussion Group (first post moderated)
HAR Viewer Online preview of *.har files.
NetExport Firebug Extension for exporting HTTP logs.
Recommended Firebug Configuration: Firebug 1.5a26+, NetExport 0.7b5
One of the new features introduced in Firebug 1.5 (you need a24) is a possibility to specify what info should be displayed within the Net panel.
This is achieved by introducing a new header with customizable columns. Just right click on the header and pick any column you want to show or hide. Of course, the current state of the header is stored in preferences and so persistent across Firefox sessions.
(click to enlarge)
Notice that the Reset Header item can be used to get back the default header state.
I am personally often interested in the HTTP timeline and so, it's nice to get more horizontal space by hiding the other columns that I don't need at the moment.
(click to enlarge)
Having the header is also useful for couple of other features:
- Sorting according to a specific column
- Customizable size of a column
In order to create additional source of information for Firebug contributors and extension developers, there is new API Reference documentation generated from Firebug source code.
The source code processing is made by js-doc-toolkit, which is an extensible doc generator for JavaScript, supporting its very specifics.
Comments are based on JavaDoc like syntax and using tags like e.g. @param (check out complete list of default tags). Firebug also defines its own specific tags like: @module, @panel, @domplate that help to match its specific architecture features.
Read more...
Since JSON explorer for HTTP network responses was quite successful feature (at least according to all the feedback I have got), I have implemented a XML Explorer that can be used to inspect XML based responses received from the server.
This feature allows to see XML data in pretty-printed and colorized fashion. Similarly to the JSON Explorer, the view is available within the Net panel (as soon as the response is XML).
See the following screenshot (click to enlarge).
The user can also right click on specific element and pick one of the Copy... actions to copy portions of the XML into the clipboard.
See an online example here.
Notice that you need Firebug 1.5a23 and higher.
Since we have released a new Firebug 1.4 (read my post), I have also updated Firecookie, which is a Firebug extension for cookie management within the browser.
I have fixed bunch of reported bugs (thanks to all who took the time to do these reports!) and solved some compatibility issues with Firebug 1.4. See release notes for more details.
There is also a couple of new enhancements. In case when the cookie value is JSON or XML, there are additional tabs in the UI that present the value in more readable format.
JSON Inspector
If the value is formatted as JSON, there is a new JSON tab (selected by default) displaying the value using expandable tree. Similarly as for network responses in Firebug's Net panel.
XML Inspector
If the value is valid XML document, there is a XML tab (also selected by default) displaying pretty printed & colorized XML (I think there could be something similar in the Net panel for network responses).
Try online example here (sure, you need Firecookie 0.9)
There is already several posts available about fresh new release of Firebug 1.4.
And not to forget, the latest version available just today is Firebug 1.4.2 fixing some last issues.
John J. Barton writes: Firebug 1.4 is a true community achievement. We have had contributions from many developers and a few designers, with additions both large and small.
Yes, it's true, and BIG thanks also to all translators who spent time on translating Firebug to many various locales. Specifically, Firebug 1.4 has been fully translated to:
- Polish (pl-PL) Leszek Życzkowski
- Dutch (nl-NL) markh
- Swedish (sv-SE) peter3
- Danish (da-DK) AlleyKat
- Chinese (Simplified) (zh-CN) Hector Zhao, lovelywcm
- Czech (cs-CZ) Lukáš Kucharczyk, Michal Kec
- German (de-DE) Team erweiterungen.de, ReinekeFux, Benedikt Langens
- Italian (it-IT) l0stintranslation, gonzalopirobutirro
- Romanian (ro-RO) alexxed
- French (fr-FR) Nicolas Martin, Franck Marcia
- Hungarian (hu-HU) gLes
- Catalan (ca) Xavi Ivars - Softcatalà
- Turkish (tr-TR) gezmen
- Spanish (Argentina) (es-AR) eternoendless
- Russian (ru-RU) Dark Preacher
- Portuguese (Brazilian) (pt-BR) Tiago Oliveira, Diego de Carvalho Zimmermann, Alexandre Rapaki
- Spanish (Spain) (es-ES) Juan Botías
- Ukrainian (uk-UA) Andriy Zhouck
- Japanese (ja-JP) Hisateru Tanaka
I couldn't miss the chance to mention that we are yet looking for help to translate following locales:
Bulgarian, Greek, Spanish (Chille), Basque, Persian, Finnish, Korean, Mongolian, Indonesian (Indonesia), Kazakh (Kazakhstan), Chinese (Traditional), Dutch and Telugu.
If you are interested to help or know somebody please let us know. Thanks!
About a month ago, I wrote a post introducing a HTTP Archive format that is used to export data from Firebug's Net panel.
Since that time we have made further progress and following info could be useful for all who are dealing with HTTP tracing logs and page load performance.
- NetExport - (requires Firebug 1.4a26 and higher) an extension that allows exporting HTTP tracing data from Firebug. This extension appends a new Export button into Firebug's Net panel toolbar (see the screenshot bellow).
- HTTP Archive Viewer - online tool that allows previewing of existing logs. The viewer uses the same visual style for visualizing HTTP tracing data as the Net panel. Note that it's possible to compare tracing info generated by multiple pages (which is also something what is planned for Firebug 1.5)
- HTTP Archive Format - description of the format for exported data (doc updated according to feedback we've got).
NetExport
HTTP Archive Viewer
See also post related to Firebug 1.5 activation.
A while ago, I have written a post about Firebug 1.2 activation that is used to enable and disable certain Firebug features and avoid performance penalties the user could pay when not using Firebug and just browsing with Firefox.
Since that time we have gathered a lot of feedback related to the activation model saying in short: it's too complicated, I don't understand how to use it. Even if it's not exciting to receive negative responses, thanks to all who took the time to explain what could be done better!
We worked hard to improve the activation. Kudos to John J. Barton who put a good deal of work into this and also thanks to Steve Souders for all his input.
So, read the rest of the post if you interested in how the activation model has been designed for Firebug 1.4.
Read more...
Since there is not much user documentation related to Firebug features (and there is a lot what to know about) I have decided to put together several posts about existing features.
This post is intended as a detailed explanation of the Net panel from the user perspective. This post is not about developing an extension for this panel or Firebug itself. Also notice that all features described below are available (some of them introduced) in Firebug 1.4.
You'll be surprised how many features is there! 
Read more...
