Makes sense, but it took me a while to figure this one out since it does not seem to be documented anywhere. For a while there, I was a very frustrated developer!

The alteration will ensure that “$” is referencing jQuery, at least within the scope of the library. This symbol is used by a variety of JavaScript libraries, most notably Prototype.

Obviously, the ready() method used to initialize IMapper will be slightly different depending upon your setup.  I would highly recommend reading up using jQuery with other libraries before you actually attempt too.

I haven’t extensively tested the update.  If you are using IMapper (with jQuery) and another JavaScript library that uses the “$” symbol please let me know if there are any name conflicts or bugs.

Please note that due to how the Facebook UI works, FB_PIC has trouble keeping up with page changes.  I am still working on an efficient work around to coupe with Facebook’s very unique UI.  In the mean time if you notice that FB_PIC isn’t working as exepected just refresh the page.  This will re-bind all of the nessecary events to the apporiate elements.

For more details exactly what FB_PIC is and how to get it, head on over the FB_PIC page and check it out.

This plugin functioned as expected and something can certainly be said for sheer simplicity that this particular tree structure employs.  The complication arose when my application called for a full select of all the descendants from a given node.  This particular tree structure doesn’t support an efficient way to grab all of the corresponding descendant records.

So I decided to implement a Materialized Path on top of my simple tree structure by adding a path column to the table. Here is a sample of what my tree table would look like.  For the sake of the example, we’ll call this table Nodes:

You can see here how each path is being constructed by concatenating a given node’s parent path with a it’s ID number.  I like to prefix each ID number with the first letter of the models name, hence the “N” from “Nodes”.  Keep in mind that any piece of unique data can be used, it doesn’t need to be the ID number. My analytics system uses an alternative string of unique data for the materialized path.

Now grabbing all of the descendants for node 2 is quite simple really; here’s a sample SQL query:

SELECT * FROM nodes WHERE path LIKE "N2%";

This will grab N2 as well as all of it’s descendants.  If you just want to exclusively grab the descendants of N2 simply added a “.” to end of our LIKE clause; such a query would look like:

SELECT * FROM nodes WHERE path LIKE "N2.%";

The Rails code for adding this functionality is equally simple.  A before_create callback in the given for the model will do the trick.  Here is a quick sample:

before_create do |n|
  self.path = "#{n.parent.path}.N#{id}"
end

Also note, that depending on the data type used for the path column, you maybe limited on how deep the descendants can go.  For instances, a varchar(255) column only allows 255 characters, so if each node takes up an average 5 characters we’re limited to 51 nodes.  While this may seem like a lot, it’s something to just keep in mind when implementing this solution.

will prevent anyone from logging in through GDM after a reboot. I might use this little trick in my upcoming Case Studies live fire exercise this Wednesday, but I will explain more about that in later posts.

The solution is quite simple really; first reboot your box into recovery mode and then drop into a root shell.  Now run the following commands and all will be well:

By the way, I am going to make an effort to post here more often.  Between my security classes this semester and my internship I should have a lot of advice, code and tidbits of information to post about.  So in the coming weeks my blog should have a lot more content to it!

As expected, the features and functionality provided to individual developers by the API is impressive.  One can achieve virtually all of the functions that Google’s own mapping service provides and then some.  Since the project I was working on called for a fairly simple mapping system (the basic markers and info window we’re all accustomed too), I didn’t really get a chance to learn all of the nifty features provided by the API.  Once I get some much needed free time over winter break, I am sure I will learn more about the API and possibly throw together a simple web application showcasing what I have learned.

In developing the mapping feature for this project, it became clear that I needed some sort of library to help manage the various pieces of data and events.  I decided to create a Singleton Class that uses jQuery to help manage the map overall.  My code uses the Module Pattern as described by Douglas Crockford.  While the name, Module Pattern, may seem misleading (I think ‘Singleton Pattern’ does it better justice), the Module Pattern is a rather useful JavaScript design pattern that eliminates the need for global variables and enables some key Object Oriented Design concepts (private variables and methods anyone?).  I decided to dub this simple class IMapper.

Via IMapper, one is able to add markers by supplying an address string or an array containing latitude and longitude coordinates.  One can also specify various options like a title or a body message for the info window.  My favorite option is the external option; mainly an HTML element can be passed when adding markers.  When a user clicks on that element, the map centers to the respected marker and the info window is shown.

My goal was to create a simple, lightweight, re-usable JavaScript library to help manage some common tasks associated with using Google Map’s API within a web application.  I believe I accomplished just that!  If you are interested in using my code you can find it here along with a simple demo and tutorial.

I promise within the next few days I will start to post more on my blog. I have just been so busy with term projects and my internship, it’s difficult to find a free moment.  So stay tuned everyone…

All in all, I am extremely happy with how everything came out.  I hope my readers (do I have any yet?) enjoy my blog and all my rants.  Check back frequently because I do have a lot to say!