Tower Of Power

So, after reading Mark Shuttlework’s blog on ideas for notifications in Ubuntu (basically mimicking Growl notifications for the Mac), I decided I wanted that kind of functionality, but… you know, NOW!

There are a multitude of options available but currently I’m liking Mumbles. Unlike, say, Specto, which does the monitoring itself, Mumbles provides a DBus interface, a command-line app named mumbles-send, and (I’m not sure if it’s implemented in the current stable download) libnotify support. Woutc, from the Specto project, commented below explaining that Specto is not intended to be a Mumbles competitor, but a package to easily monitor system internals (I quote “…the purposes from mumbles and specto are different…specto is monitoring what happens outside your desktop, mumbles monitors what happens on your desktop (or in your network)…”) Apparently he has plans to build a Mumbles plugin so that one can optionally have Specto send its messages to Mumbles for display.

I decided the best easiest route is to access the internal DBus API, however the forums and other resources on the Mumbles site… well… just plain suck. And by suck I mean tell you that something exists and… thaaats about it.

D-Feet browsing Mumble's Growl interface

Well in my Google quest I discovered the existence of D-Feet, a DBus debugging tool (on Ars of all places). Thanks to a quick sudo apt-get install d-feet I found the existence of a public interface in info.growl.Growl that allows for a Notify(title, message) signal to be passed.

Well, with a place to access all I needed was DBus integration with PHP (because I want to start sending debug notification via Growl/Mumbles like this idea on the Zend Framework incubator).

Luckily, GREE Labs provides a DBus C extension for PHP that was easily downloaded and installed. Once installed I read the documentation to get an idea on how to use the API (which is a 1:1 mapping to the DBus API).

After a bit of hacking I finally came up with an alpha product:

<?php
function null_callback()
{
        var_dump(func_get_args());
}

$dbus = dbus_bus_get(DBUS_BUS_SESSION);

$m = new DBusMessage(DBUS_MESSAGE_TYPE_SIGNAL);

$m->setPath('/info/growl/Growl');
$m->setInterface('info.growl.Growl');
$m->setMember('Notify');
$m->appendArgs('Hello World!');
$m->appendArgs('Lorem Ipsum Dolor Sit Amet. (' . time() . ')');

$r= $dbus->send($m);

After running the script in the console, did I see success?

Mumbles and PHP Test: Success!

Damn right I did!

Though with a caveat:

Warning: dbusconnection::sendwithreplyandblock(): dbus_connection_send_with_reply_and_block() failed (Traceback (most recent call last):
File "/var/lib/python-support/python2.5/dbus/service.py", line 643, in _message_cb
(candidate_method, parent_method) = _method_lookup(self, method_name, interface_name)
File "/var/lib/python-support/python2.5/dbus/service.py", line 244, in _method_lookup
raise UnknownMethodException('%s is not a valid method of interface %s' % (method_name, dbus_interface))
UnknownMethodException: org.freedesktop.DBus.Error.UnknownMethod: Unknown method: Notify is not a valid method of interface info.growl.Growl
) in /home/daniel/test.php on line 21

Call Stack:
0.0002 64496 1. {main}() /home/daniel/test.php:0
0.0024 66372 2. dbusconnection->sendwithreplyandblock() /home/daniel/test.php:21


Apparently Mumbles seems to be throwing an Exception that it’s failing to to find the Notify signal (though everything works correctly). I guess I could ignore this, use the error suppressor (@), or even yell at GREE Labs to have the objects throw exceptions so I can catch them… I guess I’ll hack on it some more and report back. I should probably spend more time learning the DBus specs since this is my first project playing with DBus…

Update: Though it’s not listed on the API page for PHP DBus’s API, there is a method send() that takes only a single argument (the message object).

Edit:

I saw a question on Reddit asking what is the use of this technique if it’s limited to the desktop it was called on and PHP is primarily a server side language. Why not do this in Python or Perl?

Well, Mumbles was written in Python so there’s no point in me doing this in Python: it’s already been done.

However, the primary use case of a technique like this is having a web app post notifications and errors for the developer. When I work on a site I have a local copy running on my desktop and/or laptop, so when it posts Growl/Mumbles notifications, I get them on my desktop. It’s great for situations where, say, I have a page in my PHP app that never displays its contents because it processes data then redirects to another page. If a warning or other non-fatal error that I should really fix occurs, then I would normally have to dig through the system wide PHP error log (if you even have error logging enabled). However, if I wrote a custom error handler that posts errors to Growl/Mumbles as they happen, when I visit a transitory page like I described I get little Growl/Mumbles notifications showing that I screwed up!

Well, it’s been a while since I’ve done a PHP update hasn’t it? Well alls well here in CStat, I have a quickie for you folks.

Recently at work I had the need to run a script before every single controller (namely to add a plugin folder to Dwoo) for a specific module that I did not desire for any other modules.

I could have subclassed all my controllers to extend a custom action controller that handled this in the init() method, however I’m lazy so I wrote a quick Zend Controller Plugin to handle this for me.

What it does is grabs the module name from the request object on routeShutdown (the routeShutdown happens after the route has been parsed and the request object has been generated, but before the action controller is instantiated and executed). From there it uses Zend_Font_Controller::getInstance()->getModuleDirectory(...) to grab the literal path to the module directory, tacks on our init file name (in our case “init.php”), and if it exists execute it in its own clean environment.

The init.php file has access to $this, where $this is an instance of the controller plugin (in particular we can do $this->getRequest() inside the init script).

The code is as follows:

<?php
/**
 * This checks the current request module's directory for an initFile (defaults
 * to init.php) and runs it before the controller is loaded.
 *
 * @copyright 2009 Daniel Cousineau
 * @license http://opensource.org/licenses/mit-license.php MIT License
 * @version 0.1.0
 */
class My_Controller_Plugin_ModuleInit extends Zend_Controller_Plugin_Abstract
{
	public static $initFileName = "init.php";

	/**
	 * @param Zend_Controller_Request_Abstract $request
	 * @return null
	 */
	public function routeShutdown(Zend_Controller_Request_Abstract $request)
	{
		$moduleName = $request->getModuleName();

		$moduleDirectory = Zend_Controller_Front::getInstance()->getModuleDirectory($moduleName);

		//Trim the paths and filenames to prevent any problems
		$initFile = rtrim($moduleDirectory,'/\') . '/' . ltrim(self::$initFileName,'/\');

		$this->runInitFile($initFile);
	}

	/**
	 * Run the file in its own cleaned scope
	 *
	 * @param string $_initFile location of the input file
	 * @return null
	 */
	protected function runInitFile($_initFile)
	{
		if( file_exists($_initFile) )
			include_once $_initFile;
	}
}

As always all code I post on this blog is covered under the MIT license.