DZone Snippets: ruby code

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

canadaduane (Duane Johnson) — Sun, 10 Dec 2006 03:14:32 GMT

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

ActiveRecord::Errors#to_xml

canadaduane (Duane Johnson) — Wed, 26 Apr 2006 00:09:45 GMT

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

Validate URIs by Pinging the Server

canadaduane (Duane Johnson) — Fri, 14 Apr 2006 02:12:38 GMT



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.

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

canadaduane (Duane Johnson) — Thu, 13 Apr 2006 22:21:47 GMT

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.

content_tag that accepts a block = block_tag

canadaduane (Duane Johnson) — Thu, 13 Apr 2006 02:08:07 GMT

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

String#to_id

canadaduane (Duane Johnson) — Wed, 05 Apr 2006 03:04:13 GMT

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

Parse Technorati-style Tags from HTML

canadaduane (Duane Johnson) — Sat, 25 Mar 2006 02:02:46 GMT

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(/]*\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 = %{civil war  iraq }



s.tags

# => ["civil war", "iraq"]

Array#randomly_pick( n )

canadaduane (Duane Johnson) — Tue, 17 Jan 2006 05:17:11 GMT

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

Firing a controller's action from the console

canadaduane (Duane Johnson) — Fri, 26 Aug 2005 02:44:03 GMT

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.

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

canadaduane (Duane Johnson) — Sat, 30 Jul 2005 02:46:30 GMT