Infomaniac is a Firefox extension for Fluidinfo.
Infomaniac is a Firefox extension that makes it easy to follow web
pages, see the info other people have stored and to add one's own info
about them. The extension adds a sidebar to the browser and, as such,
must be XUL-based. The sidebar contains a
browser XUL element which
displays a mini-object browser served from
fluidinfo.com. As the
user changes tabs and pages the sidebar is updated to show the
Development and testing
Follow the instructions here to prepare a development profile and tweak some settings to get information about errors when the extension runs:
When that's done put a file in
firstname.lastname@example.org with a single line containing the
path to this repository. Start Firefox and hit
Ctrl-Shift-f to see
the extension in action:
/usr/bin/firefox -no-remote -P dev
You need to restart the browser whenever you make a change to the
extension logic before it will be visible. When the browser is
running install the Firebug extension. You'll need to use the
infomaniac.log function to write messages to the log; calls to
console.log succeed but the messages disappear into a blackhole.
When you use Firebug for the first time click on the little box next to "Console" to enable it. Then click on the little menu arrow beside "Console" and turn on the following options:
- Show Chrome Errors
- Show Chrome Messages
They'll persist between browser restarts so you should only need to do this once.
Handling page and tab changes
The extension needs to detect a few several kinds of state changes and update itself to ensure that the content it displays always matches the current page:
- A new tab is opened showing the empty
- A new tab is opened showing a page that can be followed.
- The active tab is switched from one to another.
- The page in the active tab isn't loaded yet.
- The page in the active tab finishes loading.
- The page in the active tab is changed.
- The page in an inactive tab has changed since the last time the extension updated itself (say because of an automatic refresh or because a page was loading slowly and the user switched away while it finished).
As you can see many things can happen that must result in the extension updating its state. The way it does this is by listening for and responding to a combination of events, which are described on these pages:
Setting the root URL
The root URL, used to fetch the extension content, is stored in the
extensions.infomaniac.rootURL preference. Preferences are described
in some detail here:
The default can be overridden by opening
about:config and setting a
new endpoint. It's quite useful to use a browser profile just for
development, as described above, with the root URL set to a local
Making a new release
This will create an
infomaniac.xpi file that's ready to deploy.
There are a number of resources you'll need to have on hand to understand and modify the extension:
- https://developer.mozilla.org/en/XUL_tutorial provides a nice introduction to XUL.
- https://developer.mozilla.org/en/XUL_reference provides a list of XUL elements with links to detailed API documentation for each one.
- https://developer.mozilla.org/en/Code_snippets provides a list of examples, nicely organized by topic, which are indispensable when learning how to perform basic (and not-so-basic) tasks.
- https://developer.mozilla.org/en/Extension_packaging provides instructions for making an XPI. It also has some information about how to install the extension directly and serve the file correctly from a web server.