8 Jun 2009 clarkbw   » (Master)

The pattern is not full

This past Friday I made my first Jetpack and on Sunday while lazily waiting for chores to finish themselves I posted my Jetpack on userscripts.org.

Bugzilla - Air Traffic Control

For Jetpackers a mid-air collision is an especially scary thing.

Mid-air collision!

So this Jetpack does a pretty simple thing to help you avoid the mid-air collision by notifying you before it’s about to happen.

Mid-air collision warning

For every tab you have with a bug open this Jetpack does a simple check in the background to see if someone else has modified the bug while you were looking at it.


The code for this is pretty simple and in total it probably took me only an hour to get up and running and then a bunch more time polishing things off.  Here’s the break down.

I have a simple regex to find urls that are showing a bug:

var show_bug_regex = /^https:\/\/bugzilla\.mozilla\.org\/show_bug\.cgi\?id=(\d+)/;

Then I check if the url matches whenever a new page is loaded in a tab:

jetpack.tabs.onReady(function(doc) {
  // here we setup our persistent check
  var match = this.url.match(show_bug_regex);
  if (match) {
    this.bug_id = match[1];

Also for good measure I do a similar check when a tab is focused, in case the Jetpack wasn’t installed or running during the original load.

jetpack.tabs.onFocus(function() {
  // here we just double check out status
  var match = this.url.match(show_bug_regex);
  if (match) {

    /* if we've already notified then we aren't checking anymore */
    if ( alreadyNotifiedTab(this) )

    if ( ! areCheckingTab(this) ) {
      // they focused a url match that we haven't been checking!
      this.bug_id = match[1];
    } else {

The start checking function simply runs an ajax request against the bug on an interval.  All that was needed for this was to know if the bug had changed from the last time we looked so we build a url that only retrieves the delta_ts field to create a Date object.

"https://bugzilla.mozilla.org/show_bug.cgi?id=" + bug_id +  "&ctype=xml&field=delta_ts";

That’s about it.  If you want to check out the source or install it yourself you can go to the Bugzilla - Air Traffic Control page at userscripts.

Syndicated 2009-06-08 15:47:50 from Bryan Clark

Latest blog entries     Older blog entries

New Advogato Features

New HTML Parser: The long-awaited libxml2 based HTML parser code is live. It needs further work but already handles most markup better than the original parser.

Keep up with the latest Advogato features by reading the Advogato status blog.

If you're a C programmer with some spare time, take a look at the mod_virgule project page and help us with one of the tasks on the ToDo list!