Originally I tried setting the media ID and the media path properties, but that didn’t quite work.  Eventually I found that you have to set the media ID, media path, source, and a custom attribute (“showineditor“).  I was surprised that it wasn’t easier to assign a media file to an ImageField object, but that’s easily resolved using extension methods introduced in .Net 3.5.  For the lazier among us, I’ve included a small snippet of code that does the important stuff.  This code is written for Sitecore 5.3, but should work on Sitecore 6.x with minor tweaking if some nicer methods haven’t already been put in place.  Obviously, production code should be made a bit robust than what’s below, which has no exception handling and assumes the item is already in editing mode.

public void AssignMediaItem(ImageField field, Item mediaItem)
{
    field.MediaID = mediaItem.ID;
    MediaUrlOptions options = new MediaUrlOptions();
    field.Src = MediaManager.GetMediaUrl(mediaItem, options);
    field.MediaPath = mediaItem.Paths.MediaPath;
    field.SetAttribute("showineditor", "1");
}

First of all, for anyone who isn’t familiar with MVC (or Model View Controller), it’s a design pattern that emphasises the separation of concerns within the application, essentially: presentation data is kept separate from the application data, which – in turn – is separated from the logic relating to data storage, manipulation and retrieval.  The result is – for the most part – an application that is surprisingly easy to maintain and adapt.

The idea is to have a controller class, which exposes several public methods – or, actions – which can be called by a web request.  These actions execute a task, often involving communication with data storage through the model layer, and then finally pass data to a view, which renders the data and returns that to the user.  Some actions may have filters that run at various stages in the request, and can alter the end result of the request (a common example is to ensure a user is authenticated before processing an action).

For the most part, I have been pleased with the ASP.Net MVC Framework.  It bears striking resemblances in many places to Ruby on Rails, however it is often apparent that the framework is in its early stages as it is not as polished as Ruby on Rails.

Filters were one thing that irritated me somewhat, however they also had some features that I thought were original.  First, I thought that the usage of filters was cumbersome and quite inelegant: filters can be placed either on an action or an all actions in a controller class by decorating the method or class with the appropriate filter attribute.  The result of this method is that your controllers can become a hodgepodge of filter attributes.  I wish I had the syntactic sugar of Ruby on Rails’ before_filter function, where it’s possible to write:

before_filter :require_admin, :only => [:delete, :create, :edit]
before_filter :require_logged_in, :except => [:login, :register]

I think that something based on the above would be a much neater way of specifying filters.

I liked having access to the “request context” from all the main parts of the application.  It serves as a rather straight-forward method of passing data between the layers and of accessing the original request information.  Something that can be difficult to do when you get deep into Rails applications: you lose the context of the request; you can’t get the original controller action or other request data.

I thought that the approach of using the ActionResult type to offload the work of processing each type of result was an excellent idea.  It actually neatly avoids a common source of errors encountered during the development or Rails applications: the “double render” error.  This error happens when, for example, a redirect is issued but then the controller continues to issue a view result also (caused because Ruby on Rails controller functions responsible for issuing results do not cause the controller action to return). Returning the ActionResult neatly avoids that issue.

Initially I took great issue with the typical method of passing data into views via the ViewData dictionary.  I didn’t like the lack of strong-typing, the messiness this introduced into the view code, nor the ease with which certain things could be omitted from the dictionary.  I’m aware that the first and last really also apply to Ruby on Rails: the first I can ignore because Ruby, unlike C#, is dynamically typed; the second however, remains equally valid.  I would like to have some sort of contract between the View and the Controller that specified what data will be supplied, although I’m aware this is heading more toward the MCP design pattern.

Shortly after my disappointment over the ViewData dictionary, I discovered the existence of page models.  The ASP.Net MVC framework allows you to create strongly typed views by use of a page model (in most cases, a class that exposes a number of properties containing information that would normally be passed via the ViewData.  It doesn’t allow you to require values to be passed into the view, but it’s much better than the alternative.

Then finally we have the Model Binding of the ASP.Net Framework.  This is still a bit of a black art to me; I’ve not yet had time to sufficiently examine its workings, but it is rather nifty.  It enables the binding of values to objects in the controller and views; this allows controller actions to use model objects (e.g. a user object) as a parameter rather than having a parameter for each field of the user.  It also allows “sticky fields” to be implemented very easily in the View.

That’s all that’s come to mind right now – although I’m certainly sure there are other things that I’ve overlooked.  You may notice that I’ve omitted practically any reference to the Model part of MVC; this isn’t a co-incidence, it’s an avenue that I’m leaving open to the possibility of future posts given the fact that the ASP.Net MVC framework does not tie you to one particular ORM like Ruby on Rails does (generally speaking).  It would make the scope of the post far too large, and I feel that this post is pushing the bounds of length regardless.

Anyway, these are my thoughts; if anyone has some other views, contributions or corrections, I look forward to reading them in the comments.

Fortunately, after my own trip to the TinyMCE API, I spotted the init_instance_callback option, which allowed a function to be called upon the creation of a new editor.  Perfect.  The initial version of the code is below, hopefully if anyone else finds themselves in a tight spot, it might help them out.

tinyMCE.init({
    mode : 'textareas',
    theme : 'advanced',
    theme_advanced_buttons1 : 'bold,italic,underline',
    theme_advanced_buttons2 : '',
    theme_advanced_buttons3 : '',
    theme_advanced_toolbar_location : 'top',
    theme_advanced_toolbar_align : 'left',
    theme_advanced_statusbar_location : 'bottom',
    init_instance_callback : "initialiseInstance"
});

function initialiseInstance(editor)
{
    //Get the textarea
    var container = $('#' + editor.editorId);

    //Get the form submit buttons for the textarea
    $(editor.formElement).find("input[type=submit]").click(
        function(event)
        {
            container.val(editor.getContent());
        }
    );
}

I think I might start looking at some proper accreditations in the near future, as they can only help my career prospects, and I think they’d really be quite interesting.  The question is whether I’ll have to cough up the money myself or if it will be covered under CPD…

Aside from that, it was all fairly easy thankfully.  Now I just need to see about getting some extra hard disks for storage and possibly a new screen… my dual 15″ screens are getting a bit old, I just need to decide whether I want to stay with a dual screen system or get a big widescreen.  I don’t think my finances will quite stretch to two widescreens; or my desk space for that matter.

Add in a nice OEM version of Vista and I’ve got a new favourite toy.

The proposed design contains an accelerometer, so that when you flick/prod/sledgehammer it, the alarm snoozes for 9 or so minutes. Sadly, someone else got to the comment board before me, pointing out that the duration of the snooze should be directly proportional to the amount of force applied to the offending clock. Must be quicker.

Who wouldn’t want this nifty little e-trash receptacle sat on their desk? I really like the way that it shows capacity too. One thing that did strike me, though, was the issue of power: where does it get it’s juice? I think that having to run a power cable to the unit would really ruin the aesthetics – after all, who wants another cable on their desktop? The file transfer can be accomplished easily enough through WiFi, Bluetooth, or maybe even this wireless USB thing that I’ve seen bandied about.

Clearly, a prime case for wireless power. Less of a pipe dream now than previously, but still not quite available to us the unwashed masses yet, unfortunately.

Another interesting little thing that I found, published this month, the paper outlines several conditions that are often perceived to be the cause of hard disk failure and, using the data that they have gathered from the hard disk in their server farms, have compiled some interesting statistics. It is, though, a technical paper – so not suited to everyone’s tastes, but it is quite a quick read.

Unfortunately, they don’t release the data about which manufacturers and models have the highest rates of failure, although it does refer in several instances to one hard disk manufacturer – for example: “When examining our population, we find that seek errors are widespread within drives of one manufacturer only…”[p. 9] It would be nice to know which this is, so they can be avoided; still, perhaps that is the very reason for why they did not publish the name.

While I was aware of this issue before now, the video in the article prompted me to write something. As I’m also procrastinating, it seems like a good idea to me.

RFID tags are the bits inside those cool little cards or dongles that you can wave at a reader to let you into a building. They’re widely used on campus, and I’ve also seen them used in the more modern apartment buildings for the main door. Unfortunately, these aren’t quite as secure as everyone would like to think. The video shows a compact sniffer device that can be used to record the signal that an RFID tag sends out, then replicate it at a later point, alowing them to impersonate you.

Obviously, this situation could easily be resolved by having a challenge-response system: both the system and the card know the card’s “password” – the number that’s is hard-coded into it, the reader sends out a challenge string, the card encrypts the challenge with the password and transmits the result, the reader checks the result against the expected answer, and access is either granted or denied. Simple… unfortunately, not so.

In the majority of cases, the RFID tag is passive, meaning that it does not have its own power source, it gets its power from the signal it receives from the reader. Thus, it is difficult to integrate the encryption hardware without increasing power requirements. Other methods include a rolling response – the response changes with each access – and many others. Hopefully, though, we see one coming into mainstream usage soon, as I don’t think it will be long until these devices become readily available.