James Crisp – Page 14 – Software dev, tech, mind hacks and the occasional personal bit

ScreenCasting

On September 16, 2007

In Personal, Technical, YourWeddingPresents.com

Update: I closed down yourweddingpresents.com in 2013, and let the domain lapse. In 2023, a zombie version was set up by parties unknown at the same domain, using my pages scraped from the wayback machine. This site does not work, and is not run by me despite having my name on it. I am attempting to have it closed down.

After being inspired by the Rails screencast long ago, I thought it would be fun to make a screencast for my free wedding registry site. It takes a bit of work.

I checked out a few different screencast recording packages and ended up going with CamStudio. It is a fairly basic product but free and good enough for my needs. It lets you choose a window to record and also lets you include an audio track. I think the easiest way to use it is by recording to AVI (very quick) and then converting to Flash SWF (slow), when you are happy with the movie. In terms of SWF settings, I found the best combination was 16 bit colour, Playback rate and Keyframe rate at 20 frames / second. It is also a good idea to set the ‘Percent of movie to preload’ to something like 15%, to get things rolling quickly for your viewers.

I’m reasonably happy with the resulting wedding registry screencast, although there is certainly room for improvement. CamStudio unfortunately doesn’t let you set the look and feel of the playback controls, so they feel a bit out of place. When I get time, I might also split the screencast into two – one from the bridal couple’s perspective, and one from a guest’s perspective.

YourWeddingPresents.com (wedding registry site) now live!

By James

On September 13, 2007

In Personal, Ruby / Rails, Technical, YourWeddingPresents.com

Update: I closed down this site in 2013, and let the domain lapse. In 2023, a zombie version was set up by parties unknown at the same domain, using my pages scraped from the wayback machine. This site does not work, and is not run by me despite having my name on it. I am attempting to have it closed down.

I’m really pleased to announce that YourWeddingPresents.com (a free, independent, wedding registry site) is now live!

When my sister was getting married, she had a lot of trouble finding a good free wedding registry that was not tied to any particular shop. I developed the wedding registry site to fill this gap, and also to improve my web programming skills. I’ve tried to design Your Wedding Presents to be really quick to sign up and easy to use. Please tell me if there are any problems with the site, or ways the site could be made better.

On the technical side, I developed Your Wedding Presents using Ruby on Rails. It is running on an Apache load-balanced Mongrel cluster and data is stored in MySQL. It is hosted on Rails Playground.

JRuby, Rails and Statics

By James

On September 9, 2007

In Java, JRuby, Ruby / Rails, Technical

Say you wanted to store some information across different calls to your JRuby/Rails application on the server side. You could use a database, or memcached. However, what if you just want to do something very simple like a basic cache, and you don’t have a database for your application? Memcached seems like overkill, and would complicate your deployment considerably. So, what about just using statics?

Well, you can’t do it in Ruby, as the Rails integration servlet spawns multiple instances of the JRuby interpreter.

Ruby code in a page view:

<h1>Ruby global number</h1>
<% $i ||= 0 %>
<% $i += 1 %>
<%= $i %>

<h1>Ruby obj id</h1>
<% $o ||= Object.new %>
<%= $o.object_id %>

Results between multiple refreshes of the page:

Ruby global number
1 
Ruby obj id
244 

Ruby global number
1 
Ruby obj id
256 

Ruby global number
2 
Ruby obj id
244 

Ruby global number
2 
Ruby obj id
256

Our requests seem to be switching between two instances of the Ruby interpreter.

However, we *can* do it in Java. My clever, Java-literate colleagues explained that Java application servers and servlet containers use a single instance of the JVM, but have a class loader for each application. The class loader stores class information and static values. This means that within one application, the static values will be maintained between requests, but a different application on the same server will have its own set of unrelated static values (similar to AppDomains in .NET).

If we add a call to a static method in Java that increments an integer and returns it, our view looks like this:

<h1>Ruby global number</h1>
<% $i ||= 0 %>
<% $i += 1 %>
<%= $i %>

<h1>Ruby obj id</h1>
<% $o ||= Object.new %>
<%= $o.object_id %>

<h1>Java incrementing static integer</h1>
<%= TestClass.incrementAndReturnNumber() %>

Our results now look a lot more useful. The Java static integer is getting incremented each call to the view:

Ruby global number
1 
Ruby obj id
244 
Java number
1 

Ruby global number
1 
Ruby obj id
256 
Java number
2 

Ruby global number
2 
Ruby obj id
244 
Java number
3 

Ruby global number
2 
Ruby obj id
256 
Java number
4

From this little experiment, Java statics seem like a possible way to go for storing temporary data on the server side (eg, a cache implemented as a singleton) for JRuby / Rails. Another option may be to use the ServletContext from the JRuby Rails integration servlet – probably an area worth investigating.

Web Design and CSS, how hard can it be?

By James

On September 2, 2007

In Book Reviews, Technical

So, audaciously, I decided to do the theme for my pet Rails project. How hard can CSS and Photoshop really be? Having made basic layouts and modified various themes, I thought my CSS skills were adequate, and Photoshop is, after all, just another Windows application.

With the help of my talented fiancee and flatmate, the Photoshop side of things went fairly well for a banner image. Not too hard, find a good image and apply some layers, effects and text.

When time came to hit the CSS, I felt confident. Based on my vague trial and error understanding of floats etc, I managed to spend a fair bit of time messing around, painfully, slowly getting a good layout in Firefox, only to be frustrated by an awful rendition in Internet Explorer. Then trying to make a compromise layout between the two that looked reasonable in both, only to have a slight change throw everything into disarray. Repeat ad nauseum.

Clearly, I my confidence was misplaced, and my CSS skills sucked. Time to actually learn something. I turned to my yet un-opened copy of “Beginning CSS Web Development – From Novice to Professional” by Simon Collison, recommended by a ThoughtWorks buddy, Warren. I read it pretty much cover to cover on Saturday. It was quite a good read, practical with useful examples and a light tone. Lots of good stuff within:

Clear explanation of the basics
Coverage of different browsers
Some insight into a web designer’s mind
A number of useful page layouts
Different options for form layouts
Some advanced CSS tricks
A nice worked example of cutting up a Photoshop mock-up and turning it into image slices, CSS and HTML.

Overall, the book was pretty much exactly what I needed to get back on track and bring my misbehaving CSS under control.

Here’s a few things I learnt that solved some of the most pressing woes I was having with CSS:

Margins collapse into each other. Ie, if you have two elements next to each other and each has a 10px margin, the total distance between the two will only be 10px. Adding 1px of padding will mean the borders of the two elements don’t touch and hence won’t collapse
Generally avoid padding on fixed width elements. Instead, wrap them in another element such as a div, and put the padding on it. That way, you avoid needing to do any hacks for the broken box model in older versions of IE.
You can put an ID on each pages’ BODY, and that way, you can easily target elements on individual pages using their body’s ID.
Often a good way of doing layout with floats is to keep the document as much using the normal flow layout, and then put in appropriate margins or padding to make space for floats, rather than floating the whole document.
The order of values in short declarations like ‘margin: 1px 2px 3px 4px;’ is top, right, bottom, left.
It is a good idea to stick to the limited set of web-safe fonts, and also use a number of fallbacks for font family to cover all viewers.

My app’s theme is not finished yet, but CSS has now become more a pleasure than a frustration.

BarCamp Sydney this Saturday

By James

On August 22, 2007

In C#, JRuby, Personal, Ruby / Rails, Talks, Technical

It is BarCamp in Sydney this Saturday. I haven’t been to one of these unconference style events before, but I’ve heard good things about it from my colleagues. I’m quite excited to go along and see what it is like.

If you’re in Sydney and interested in stopping by, details are as follows:

When: Sat 25th August 2007 from about 9am
Where: University of Technology, Sydney (Jones St entrance)
More details…

One of the novel aspects of BarCamp is that all participants are encouraged to present or start a discussion around something that interests them. For my part, depending on what people are interested in, I was thinking of one of the following:

new stuff in the .net space (C# 3.0, .NET 3.5, LINQ, WPF, WCF, etc) and showing some demos
giving a bit of a Ruby/JRuby introduction with help from Ola’s JavaBin slides
or, if people are keen, a discussion around JRuby vs C# 3 vs Java vs ?? and their stacks for different situations and problems

By the way, the conference is free, and it is not too late to sign up 🙂
Hope to see you there!

Slides from ‘Learning to live with the static-typing fascist and the dynamic-typing fan-boy in your enterprise…’

By James

On August 15, 2007

In C#, Ruby / Rails, Talks, Technical

Here’s the slides from Jim‘s and my recent presentation at Tech Ed 07 on the Gold Coast and in Auckland:

LearningToLiveWithTheStaticTypingFascistAndTheDynamicTypingFanboy-TechEd07.pptx (Powerpoint 2007)

LearningToLiveWithTheStaticTypingFascistAndTheDynamicTypingFanboy-TechEd07.ppt (Powerpoint 2003)

You may also be interested in having a read of the abstract.

TechEd 07 – Some interesting snippets

By James

On August 14, 2007

In C#, Ruby / Rails, Technical

Silverlight

Silverlight runs on MAC and PC.
There is now a CLR for the Mac.
Microsoft is not currently planning to provide Silverlight for any unix platform (although there is MoonLight).
Silverlight 1.0 is basically a media player. It has hooks for javascript etc and some might say it has similar functionality to the Flash movie player.
Silverlight 1.1 has the real programming API. All further Silverlight references are to 1.1.
Silverlight will do a (currently undefined) simplified subset of WPF.
Silverlight gives acess to DOM in the browser.
Currently, the alpha allows 1mb local storage per page. In future, the storage is probably going to be shared across a domain rather than on a page by page basis.
Silverlight provides the capability to open a file on disk for read to allow for file uploads etc.
Interop between JavaScript and hosted Silverlight app is quite easy.
Silverlight looks a bit fiddly to set up, requiring javascript and sometimes xaml bootstrap – but being improved.

Software Factories

Allow solution and project structures to be auto-generated based on wizards.
Can provide code snippets and some (often template-based) code auto-generation.
Comes with documentation in help files and some context specific stuff.
Can include GUI designers that generate code.
People can develop their own domain specific factories.

DSLs
Currently, Microsoft’s take on DSLs is GUI editors, not written language or code. At the Software Factories talk, a GUI tool in Visual Studio for drawing your business entities and relationships was billed as a DSL.

Windows Workflow Foundation (WF)

Activity based with GUI designer for connecting and composing activities.
Custom activities and compositions can be developed and inherit from base classes.
Single threaded and mainly queue based, with some events sprinkled through.
Activities can reference data from other activities using a mechanism vaguely like data binding.
Hosted in the CLR, so can be part of a console app, ASP.NET, WinForms etc.
Handles pickling and reconstitution of long running activities.
Base Activity classes provide virtual hooks. Eg, ‘Execute’ for doing the work, ‘Cancel’, and ‘Compensate’ for handling rollback scenarios.

New in the Enterprise Library 3.1

Validation Application Block: provides simple, attribute based property validation. Easy integration with standard ErrorProvider on WinForms and WebForms and WPF is possible. Looks ok but somewhat basic – don’t think it supports warnings for example. It has GUI tool support and also capability to specify related objects which need to be validated.
Policy Injection Application Block: provides aspect oriented programming (AOP) style coding using attributes. All new AOP objects need to be created using the block’s object factory. Looks useful – there is out of the box support for validation, caching and logging in AOP fashion.

Tech Ed Talks

By James

On August 2, 2007

In C#, Personal, Ruby / Rails, Talks, Technical

Jim Webber and I will be co-presenting at Tech Ed Australia and Tech Ed New Zealand this year. Here’s the low down:

Learning to live with the static-typing fascist and the dynamic-typing fan-boy in your enterprise…

Gold Coast
Thursday 9 Aug
5pm – 6:15pm

Auckland
Tuesday 14 Aug
2:20pm – 3:35pm

“What’s best for your enterprise? Is it the ‘glue that never sets’ and flexibility of dynamic languages like Ruby, or the tried and true, hard and fast rules and tool support of static languages like C# 3.0? Are there different trade-offs for green field development and integration?

And more importantly, which is best, the Mac or PC?

In a dynamic, and combative presentation, Jim and James will let their alter-egos run amok and answer these questions from the perspective of a seasoned enterprise architect and a l33t hax0r. By the end of this session you will understand the interplays between the two personality types, have had a few laughs, and picked up a few tips on how to use both technology
sets in harmony in your enterprise. “

Hope to see you there!