Dan Kubb

[Ruby] On Very Simple Rack framework

2008-09-14T18:48:06-07:00

What about being able to nest blocks according to their path?

Also, why the explicit render() call? Just make it so the return value from the block is the text that is rendered in the response body.

Here's an example:

app = App.new do
  get do
    "hi"
  end

  get "echo/(.*)" do |text| # Regexp matches are passed as block args
    text
  end

  # nested
  path "session" do
    get "set" do
      session[params.first.key] = params.first.value
    end

    get do
      session.inspect
    end
  end

  path "form" do
    get do
      erb(:form) # Can have helper methods to render erb and the like
    end

    post do
      params.inspect
    end
  end
end

run app

[Ruby] On Better Nest Ifs

2008-04-13T04:26:40-07:00

This refactoring uses a guard clause to short-circuit the method at the beginning. Guard clauses are a clean way to exit out of a method if some condition isn't immediately met. Also since the comparison statement returns true/false, there's no need to use a ternary operator to explicitly return true or false.

def self.valid?(key)
  return false unless h = find_by_key(key)
  h.invitation_details_count < h.total
end

[Ruby] On Importing large collection of emails separated by comma.

2008-03-22T21:31:55-07:00

Here is how I would write this. I wouldn't bother with the counters, just accumulate all the results into an array and loop over them to find out how many are valid or not, as needed. The only optimization I would make over what I have below, is if @list has a subscribers association, I'd use @list.subscribers.create instead of Subscribers.create :list_id => @list.id. Since I don't know what your data model is I chose the safest route below.

def create
  subscribers = []
  params[:recipients].to_s.each_line do |line|
    email, full_name = line.split(',').map(&:strip)
    subscribers << Subscriber.create :list_id => @list.id, :email => email, :full_name => full_name
  end
  flash[:notice] = "Added #{subscribers.select(&:valid?).size} new subscribers, and a #{subscribers.size - subscribers.select(&:valid?).size} records has been skipped or invalid."
  redirect_to list_path(@list)
end

[Ruby] On Adding default html option to 'link_to'

2008-02-29T17:17:03-08:00

This will add the "squarebutton" class to any existing html :class you pass in, as well as work in cases when you don't pass in any :class. content_tag automatically stringifies the name variable, so there's no need to do name.to_s any longer (actually there was never the need, since #{} does the same thing). Also the parameters_for_method_reference arguments passed in other examples have been deprecated in recent versions of Rails, so I chose to leave them out.

def squarebutton(name, options = {}, html_options = {})
  html_options[:class] = [ html_options[:class], 'squarebutton' ].compact * ' '
  link_to content_tag(:span, name), options, html_options
end

[Ruby] On ActiveRecord Attributes rejig before save

2008-02-28T18:22:52-08:00

This iterates over just the attributes, and titleizes each attribute that is present (non-blank).

before_save :titlecase_fields

def titlecase_fields
  %w[ name f_name m_name f_desg m_desg house_name ].each do |attribute|
    self[attribute] = self[attribute].titleize if attribute_present?(attribute)
  end
end

[Ruby] On Same methods, different ActiveRecord attributes

2008-01-08T20:06:39-08:00

Here's an alternate approach that dynamically defines the methods.

[ :planned, :actual ].each do |type|
  define_method("#{type}_percent_complete") do
    return 0 if send("#{type}_complete_in_dollars").nil?
    ((send("#{type}_complete_in_dollars").to_f / task.budget.to_f) * 100).round(2)
  end

  define_method("#{type}_percent_complete=") do |ppc|
    send "#{type}_complete_in_dollars=", (ppc.to_i / 100.0) * task.budget
  end
end

[Ruby] On Is This String Postal?

2007-12-02T16:29:54-08:00

According to http://en.wikipedia.org/wiki/Canadian_postal_code the letters D, F, I, O, Q, or U are excluded because OCR equipment used for automatic mail sorting confuses them with other letters and digits. The letters W and Z are also used, just not in the first character.

If you're storing this in a DB or anything, I would suggest normalizing it so that all the characters are uppercase, leading/trailing spaces are stripped, and a space (not a hyphen) is used between the first 3 characters and the last 3 characters.

class String
  def postal?
    self.strip.upcase =~ /\A[A-CEGHJ-NPR-TVXY]\d[A-CEGHJ-NPR-TV-Z][ -]?\d[A-CEGHJ-NPR-TV-Z]\d\z/
  end
end