Canadaduane's Code Snippets

Getting the _session_id from SWFUpload (Flash 8 multiple file uploader)

It appears that Ruby's CGI::Session class will not use the _session_id in the query string when the Request is a POST.

Normally, a POST-type request occurs when a form is submitted to the server (e.g. a Rails application). In this scenario, there is an easy workaround since we can send the _session_id as a hidden field.

With Flash 8, however, there is no way to add a 'hidden field' to the multi-part form data, thus Rails will fail to recognize the _session_id in the query string portion of our request.

Here is a hackish work-around:

# The following code is a work-around for the
# Flash 8 bug that prevents our multiple file uploader
# from sending the _session_id.  Here, we hack the
# Session#initialize method and force the session_id
# to load from the query string via the request uri. 
# (Tested on Lighttpd)

class CGI::Session
  alias original_initialize initialize
  def initialize(request, option = {})
    session_key = option['session_key'] || '_session_id'
    option['session_id'] =
      request.env_table["REQUEST_URI"][0..-1].
      scan(/#{session_key}=(.*?)(&.*?)*$/).
      flatten.first
    original_initialize(request, option)
  end
end

to ruby rubyonrails upload file session session_id flash8 by canadaduane on Dec 09, 2006 1 Comments

ActiveRecord::Errors#to_xml

Here’s a method that will allow you to call to_xml on an ActiveRecord::Errors object. We’re using this to pass errors between web apps via a web service api.

class ActiveRecord::Errors
  def to_xml(options = {})
    options[:indent] ||= 2
    options.reverse_merge!({ :builder =>
      Builder::XmlMarkup.new(:indent =>
        options[:indent]), :root => "errors" })
    options[:builder].instruct! unless options.delete(:skip_instruct)

    options[:builder].__send__(options[:root].to_s.dasherize) do |xml|
      @errors.each do |key, value|
        xml.__send__(key.to_s.dasherize) do |xm|
          for message in value
            xm.message(message)
          end
        end
      end
    end

  end
end

to ruby rails activerecord Errors web-service by canadaduane on Apr 25, 2006 1 Comments

Validate URIs by Pinging the Server

require 'open-uri'

class ActiveRecord::Base
  def self.validates_uri_existence_of(*attr_names)
    configuration = { :message => "is not a valid web address" }
    configuration.update(attr_names.pop) if attr_names.last.is_a?(Hash)
    validates_each attr_names do |m, a, v|
      begin
        # Try to open the URI
        open v
      rescue
        # Report the error if it throws an exception
        m.errors.add(a, configuration[:message])
      end
    end
  end
end

Details on my blog.

to ruby rails url uri validation by canadaduane on Apr 13, 2006

Use background color to show error fields instead of wrapping them in a div

Using the default rails field_error_proc may lead to some layout headaches--your form looks perfect until, uh-oh, someone entered an invalid email address and Rails adds a fieldWithError-styled div that wraps around the problem field.

While this works in many cases, some pixel-perfect layouts may not be able to tolerate the 2-pixel padding around the text_field caused by the red border. An alternative is to change the background color of the offending field.

Include the following code in environment.rb (or use a "require" like I do):

ActionView::Base.field_error_proc = Proc.new do |html_tag, instance|
  error_style = "background-color: #ffff80"
  if html_tag =~ /<(input|textarea|select)[^>]+style=/
    style_attribute = html_tag =~ /style=['"]/
    html_tag.insert(style_attribute + 7, "#{error_style}; ")
  elsif html_tag =~ /<(input|textarea|select)/
    first_whitespace = html_tag =~ /\s/
    html_tag[first_whitespace] = " style='#{error_style}' "
  end
  html_tag
end

See my blog.inquirylabs.com for more Rails stuff.

to ruby rails stylesheets Errors field field_error_proc by canadaduane on Apr 13, 2006 2 Comments

content_tag that accepts a block = block_tag

Sometimes I want to do something like this:

<% content_tag("div", :class => "section_with_error" do %>
  HTML GOES HERE
<% end %>

instead of this:

<%= content_tag("div", "HTML GOES HERE", :class => "section_with_error") %>

Put the following code in ApplicationHelper, and you can do just that (replacing "content_tag" in the example above with "block_tag", of course):

  def block_tag(tag, options = {}, &block)
    concat(content_tag(tag, capture(&block), options), block.binding)
  end

to ruby rails block tag by canadaduane on Apr 12, 2006

String#to_id

Convert any (English) text to a programming-language friendly identifier.

class String
  def to_id
    downcase.gsub(/\W+/, ' ').strip.gsub(' ', '_')
  end
 
  def to_id!
    replace to_id
  end
end

to ruby string identifier by canadaduane on Apr 04, 2006 1 Comments

Parse Technorati-style Tags from HTML

An enhancement to the String class that parses out Technorati-style tags. Uses Typo's strip_html method to remove img tags and other markup.

class String
  # Strips any html markup from a string
  TYPO_TAG_KEY = TYPO_ATTRIBUTE_KEY = /[\w:_-]+/
  TYPO_ATTRIBUTE_VALUE = /(?:[A-Za-z0-9]+|(?:'[^']*?'|"[^"]*?"))/
  TYPO_ATTRIBUTE = /(?:#{TYPO_ATTRIBUTE_KEY}(?:\s*=\s*#{TYPO_ATTRIBUTE_VALUE})?)/
  TYPO_ATTRIBUTES = /(?:#{TYPO_ATTRIBUTE}(?:\s+#{TYPO_ATTRIBUTE})*)/
  TAG = %r{<[!/?\[]?(?:#{TYPO_TAG_KEY}|--)(?:\s+#{TYPO_ATTRIBUTES})?\s*(?:[!/?\]]+|--)?>}
  def strip_html
    self.gsub(TAG, '').gsub(/\s+/, ' ').strip
  end

  def tags
    scan(/<a\s+[^>]*\s*rel=\s*(.?)tag\1[^>]*>(.+?)<\/a>/i).
    map { |match| match.last.strip_html rescue nil }.
    compact.select { |s| !s.strip.empty? }
  end
end

# Example usage

s = %{<a href="http://www.docstrangelove.com/tag/civil-war" rel="tag">civil war</a> <a href="http://www.technorati.com/tag/civil+war" rel="tag"><img src="http://www.docstrangelove.com/wp-content/plugins/UltimateTagWarrior/technoratiicon.jpg" alt="Technorati tag page for civil war"/></a> <a href="http://www.docstrangelovecom/tag/iraq" rel="tag">iraq</a> <a href="http://www.technorati.com/tag/iraq" rel="tag"><img src="http://www.docstrangelove.com/wp-content/plugins/UltimateTagWarrior/technoratiicon.jpg" alt="Technorati tag page for iraq"/></a>}

s.tags
# => ["civil war", "iraq"]

to ruby rails tags string by canadaduane on Mar 24, 2006

Array#randomly_pick( n )

Adds a handy function that lets you randomly pick n elements from an array.

class Array
  # If +number+ is greater than the size of the array, the method
  # will simply return the array itself sorted randomly
  def randomly_pick(number)
    sort_by{ rand }.slice(0...number)
  end
end

to ruby random array pick by canadaduane on Jan 17, 2006 3 Comments

Firing a controller's action from the console

It seems like a simple task, but here's how you can simulate the calling of a controller's action:

ruby script/console

irb> require 'action_controller/test_process'
irb> require 'application'
irb> require 'site_controller'
irb> request = ActionController::TestRequest.new
irb> response = ActionController::TestResponse.new
irb> request.env['REQUEST_METHOD'] = 'GET'
irb> request.action = "late_employee"
irb> InfoController.process(request,response)

Basically, it's like getting inside of a TestUnit method, but you have to do the dirty work yourself.

to ruby rails controller action by canadaduane on Aug 25, 2005 4 Comments

Make an html link update several dom elements at the same time.

    <a href="#" onClick="<%= remote_function(:update => 'fashion1', :url => { :action => :get_fashion_for_color, :color_name => color_name, :number => 1 })%>;
                         <%= remote_function(:update => 'fashion2', :url => { :action => :get_fashion_for_color, :color_name => color_name, :number => 2 })%>;
                         <%= remote_function(:update => 'fashion3', :url => { :action => :get_fashion_for_color, :color_name => color_name, :number => 3 })%>;
                         return false;">

to ruby rails ajax link remote_function by canadaduane on Jul 29, 2005 1 Comments

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