Archive for June, 2008

28
Jun

Pleasing the JavaScript Download Time Whiners

By benhughes 2 Comments
Categories: Uncategorized

To me, the benefit of using JavaScript frameworks in an application cannot be overstated.  Though I’m also a fan of server-side frameworks, there is scarcely a reason not to use a client-side framework these days.  Of course the most common complaint against JavaScript frameworks is “bloat” and the long download time.  Funny that the most vocal of those complaining about the frameworks’ download time are those who haven’t even ever used a framework to experience it’s benefits.  The tradeoff of course is a noticeable load hit for some users on slower connections vs. architectural elegance, much higher productivity, more maintainability, and less code in general.  To me in most cases the trade-off is a no-brainer in any sufficiently modern web application, but not to all.

Released recently is the Google Ajax Libraries API which is basically a way of allowing browsers do download only one version of a given framework for all applications using that framework.  Currently most web applications host their own version of a given JavaScript library, which is inefficient across the spectrum of the internet since many sites are using the exact same library.  With Google Ajax Libraries you essentially reference Google’s hosted version of the library and the download hit is only incurred the first time a user visits any site using that framework.  So it’s quite likely that a user going to your site won’t have to download a thing – it’s as if the framework is at that point simply part of the user’s browser.

Of course this only works if it becomes widely used and I sure hope it will.  I’d encourange all developers to start using this in their production environments (development environments should still use local copies for local development:

Google AJAX Libraries API
Rails Plugin for Google AJAX Libraries API

25
Jun

named_scope with acts_as_tree

By benhughes 8 Comments
Categories: Rails General, Rails Techniques and Rails Tools

I fairly often use the acts_as_tree plugin in my applications.  While acts_as_nested_set (and superior variants..) is more powerful, often times a simple two-level deep hierarchy is all I need and acts_as_tree is simple.  I’ve found the new named_scope functionality in Rails 2.1 to be very helpful when dealing with tree data structures.

Firstly, it’s somewhat rare that I have one single root node in the tree structure (which is apparently how it’s meant to be used).  Instead I’ll have multiple “parent” nodes designated with a NULL parent_id and children beneath.  In the past I’ve always done something like: find(:all, :conditions => {:parent_id => nil}) to grab the top entries.  Instead with nested set you can do this:

named_scope :top, :conditions => {:parent_id => nil}

#Then:
Category.top

Another common task when dealing with hierarchical categories is to query on the base object (products for example) for members that are “part of” that category. Specifically, part of in a 2-level heirarchy simply means “where id = ? or parent_id = ?” on the joined categories table. Because this involves a join it was somewhat clunky to do before. Now with nested set, on the product model I can declare this:

named_scope :in_category, lambda {|c| {:include => [:category], :conditions => ["categories.id = ? OR categories.parent_id = ?", c, c]} }

# Then:
Product.in_category(3)

I would also highly encourage you all to check out RailsCasts Episode 112 “Anonymous Scopes” by Ryan Bates where he outlines a pattern for handling conditions elegantly with searches using named_scopes in Rails 2.1, something I’ve always found to be lacking from Rails core and always resorted to using plugins like criteria_query.

04
Jun

Mac OS 10.5.3 Fixes Spaces

By benhughes 2 Comments
Categories: Personal

Though I’ve been extremely happy with leopard (in fact, why I finally bought a Mac), little quirks with spaces were frustrating.  Specifically, spaces seems to have been designed for users who want to place a separate application in each space.  I use spaces in a task-oriented manner where each space typically has a Firefox window, tabbed terminal, and TextMate.  Command-Tabbing and others workflow situations were just quirky.  Also, a huge annoyance was going into the terminal, typing “mate .” and having it open up a new TextMate window in whatever space already had a TextMate window.

I’m very pleased to report that 10.5.3 solves all of these problems, with one new option in the spaces dialog called “When switching to an application, switch to a space with open windows for the application.”  In fact, you want to uncheck this option if you are working in a task-oriented manner like me.  There were also some bug fixes in 10.5.3 which transcend this new option.

With these frustrations gone I feel very solid working with 3-5 project workspaces at once and can move efficiently within and among them.

Upgrade to 10.5.3 now if you haven’t already done so!

  • Ben Hughes

    I'm a freelance developer working with Ruby and other modern tools to build web applications, based currently out of Rochester, NY. I love to learn about new technologies and am always trying to achieve elegance and beauty through code.

    When I'm not writing software, I like to play tennis, dabble in jazz piano, and ponder economics. I'm a big fan of: world travel and cultures, jazz music, Korean food, coffee, and having interesting conversations.

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