1
2
3
4
5
6
7
8
9

$ irb
>> 5 * "a"
TypeError: String can't be coerced into Fixnum
  from (irb):1:in `*'
  from (irb):1
>> "a" * 5
=> "aaaaa"
>> 

The reason is quite simple — everything in Ruby is an object. The '*' behaves differently when applied to different objects (and, in fact, can be overridden). So, because the '*' method as implemented for Fixnum expects a number as its argument, and a String isn't a number, it complains. By the same token, the behaviour of '*' for String is for the string to repeat itself as many times as the argument specifies, it works.

I've had a jruby rails app deployed to jboss for quite some time now. For grins and giggles I decided to try it under Glassfish today. After I deleted the old WEB-INF and .war file which were created by goldspike, it worked very easily. I'm surprised and tempted to replace the existing jboss install with glassfish, provided it has similar throughput. The footprint is definitely smaller and it is much easier.

You can find more about using glassfish with jruby at the jruby wiki.

• What ruby gems are installed?
• Documentation for each gem?

rubygems has a built-in server which you can use to peruse the rdocs for a gem. To use it, type gem server at a prompt and then point your browser to href://localhost:8808.

ruport comes with an extension, ruport-util which adds, among other things, the ability to create graphs from reports. However, it's hardcoded to do line graphs. This is a code snippet which will (for png and jpg graphs, the others should follow) allow you to create other types -- it's just bar graphs, but the others would follow....

You only see what your eyes want to see
How can life be what you want it to be
You're frozen... -- Madonna

The way to ensure that your production rails apps don't get messed up should the provider update gems is to freeze them. Moreover, it's a good idea to embed the gems/plugins needed for a particular application; it makes distribution of different versions easier, not to mention that you know exactly with which resources your code is working.

To freeze rails, you can either do a rake rails:freeze:gems, which uses the installed gems to freeze, or rake rails:freeze:edge which freezes off of the rails subversion repository. The last one allows you to specify a version to which to freeze. When it's time to thaw, rake rails:unfreeze will remove the frozen rails installation.

To embed gems in your application, use Gems On Rails, which will place gems into vendor/gems.

This isn't much of a tip, per se, but it's something I ran into today.

The way to having multiple rubygem repositories is to set the GEM_PATH environmental variable. This will allow you to use gems from more than one location -- something useful on shared servers.

Next, to figure out how to specify the version of rubygems you're using -- I've tried GEM_HOME and RUBY_LIB and my PATH, but it's not working properly on the shared host. More once I figure that one out.

This is a quick note on two ways of placing boxes around elements in the form.

The first is to use blueprintcss-rails(http://code.google.com/p/blueprintcss-rails/), a plugin which uses the Blueprint CSS framework, and add a box class to the elements.

The second is a little more involved (although more flexible). It requires installing Shaded Border, and adding the following methods to applicationhelper.js:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29

  def add_to_options(options,option,value)
    if options.nil?
      options={ }
    end
    if options[option].nil?
      options[option] = value
    else
      options[option] = "#{options[option]} #{value}"
    end
    options
  end


  def boxed_layout(boxid = 'boxy_box_box', content_or_options_with_block = nil, options = nil, &block)
    e=""
    if block_given?
       options = content_or_options_with_block if content_or_options_with_block.is_a?(Hash)
      options=add_to_options(options, :id, boxid)
       content = capture(&block)
       e = concat(content_tag(:div,content,add_to_options(options,:class,"sb")),block.binding)
    else
      content = content_or_options_with_block
      options=add_to_options(options, :id, boxid)
      e = content_tag(:div, content, add_to_options(options,:class,"sb"))
    end
    e << javascript_tag("border.render('#{boxid}')")
    e
  end

• Seth Godin
• Presentation Zen
• Eirikso.com

• How I made my presentations a little better | 43 Folders
• Ask E.T.: PowerPoint Does Rocket Science--and Better...
• Everything I Know About Presentations, I Learned in Theatre...

• A List Apart
• Ajaxian
• Particle Tree
• Smashing Magazine
• Humanized

  
1
2

  

foo = Bar.find(:first, :conditions => {:name => "Fred"}) || Bar.new(:name => "Fred")

In Rails 2.0.x, application.rb has a:

1
2

helper :all

1. ApplicationHelper
2. BarHelper
3. FooHelper

So, if you expect to have different behaviours in Foo and Bar, you'll be disappointed. The behaviours override each other, leaving a single behaviour across the application. In order to fix this, remove or comment out the declaration in application.rb.