Troubleshooter

Troubleshooter is a restartless Firefox add-on that provides a simple Firefox troubleshooting API to Mozilla web sites. Here's the entire API:

window.mozTroubleshoot.snapshotJSON(function (json) {
  console.log(json);
});

json contains various data describing the user's Firefox including its version, modified preferences, installed add-ons, and more. It's the same data listed on Firefox's about:support page. Its schema is defined by the SNAPSHOT_SCHEMA object here.

Blessed Pages

By default, only pages on https://support.mozilla.org, https only, are blessed with mozTroubleshoot.

You can bless pages on other domains ad hoc with the environment variable TROUBLESHOOTER_ORIGIN. Set it to an origin, which is just a scheme + domain + optional port string, like "https://www.mozilla.org" and "http://www.mozilla.org:99". To bless pages on multiple domains, put their origins in a space-delimited string. Use "*" to bless all pages. This variable must be set before the add-on is loaded.

Detecting API Availability

The add-on is restartless and its API becomes available to all blessed pages immediately on installation. Pages that are open and loaded at the time of installation are notified of the API's availability by a mozTroubleshootDidBecomeAvailable event dispatched to their windows:

window.addEventListener("mozTroubleshootDidBecomeAvailable", function () {
  // Hot dang, do your stuff.
});

Of course, a conditional like the following can test if the API is available at any time, for example on load:

if ("mozTroubleshoot" in window)
  // Hot dang, do your stuff.

Supported Firefox Versions

Firefox 10 is the oldest supported Firefox. Some troubleshooting data is unavailable on versions older than 18. When particular data is unavailable, the value of the relevant property in the JSON-encoded object will likely be an error message.

The mozTroubleshoot API is backed by the Troubleshoot.jsm API introduced in Firefox 18. The add-on includes a copy of that module so that users running older versions can use it, too, although some data will be unavailable. The copy was pulled from mozilla-central revision f3f379beb585 and was modified to remove its preprocessing directives.

Logging

The add-on logs to the terminal (via dump) and Firefox's error console (via nsIConsoleService). By default only errors are logged, but you can make the log more verbose by setting the environment variable TROUBLESHOOTER_LOG_LEVEL to an integer indicating the desired log level. 0 is the debug log level and logs everything. See src/content/logger.jsm for details. This variable must be set before the add-on is loaded.