DZone Snippets: Ciconia's Code Snippets

Ruby password strength calculator

ciconia (Sharon Rosner) — Thu, 25 Oct 2007 14:35:45 GMT

This method returns the password lifetime in years. Based on this:
http://www.codeandcoffee.com/2007/06/27/how-to-make-a-password-strength-meter-like-google



class String

  PASSWORD_SETS = {

    /[a-z]/ => 26,

    /[A-Z]/ => 26,

    /[0-9]/ => 10,

    /[^\w]/ => 32

  }

  

  def password_strength

    set_size = 0

    PASSWORD_SETS.each_pair {|k,v| set_size += v if self =~ k}

    

    combinations = set_size ** length

    

    # assuming 1000 tries per second

    days = combinations.to_f / 1000 / 86400

    

    days / 365

  end

end

Better than methodphitamine?

ciconia (Sharon Rosner) — Tue, 14 Aug 2007 13:24:52 GMT

Original discussion here: http://jicksta.com/articles/2007/08/04/the-methodphitamine

I think this one is prettier (but maybe not as sophisticated):



module Enumerable

  def method_missing(sym, *args)

    if (sym.to_s =~ /^(.+)_with$/) && (msg = args.shift)

      send($1.to_sym) do |x|

        x.send(msg, *args)

      end

    end

  end

end



[1, 2, 3].map_with :to_s

Check for primality with a regexp

ciconia (Sharon Rosner) — Sun, 18 Mar 2007 14:48:42 GMT

Original perl code here:

http://montreal.pm.org/tech/neil_kandalgaonkar.shtml



class Fixnum

  def prime?

    ('1' * self) !~ /^1?$|^(11+?)\1+$/

  end

end

Ruby Thread Pool

ciconia (Sharon Rosner) — Fri, 12 Jan 2007 16:39:05 GMT

This is useful for a variety of scenarios. You create a thread pool, give it a maximum size, and pass a block to it everytime you need something processed. If all threads are busy, you block until a thread becomes free.

For example:



pool = ThreadPool.new(10) # up to 10 threads

email_addresses.each do |addr|

  pool.process {send_mail_to addr}

end



require 'thread'



class ThreadPool

  class Worker

    def initialize

      @mutex = Mutex.new

      @thread = Thread.new do

        while true

          sleep 0.001

          block = get_block

          if block

            block.call

            reset_block

          end

        end

      end

    end

    

    def get_block

      @mutex.synchronize {@block}

    end

    

    def set_block(block)

      @mutex.synchronize do

        raise RuntimeError, "Thread already busy." if @block

        @block = block

      end

    end

    

    def reset_block

      @mutex.synchronize {@block = nil}

    end

    

    def busy?

      @mutex.synchronize {!@block.nil?}

    end

  end

  

  attr_accessor :max_size

  attr_reader :workers



  def initialize(max_size = 10)

    @max_size = max_size

    @workers = []

    @mutex = Mutex.new

  end

  

  def size

    @mutex.synchronize {@workers.size}

  end

  

  def busy?

    @mutex.synchronize {@workers.any? {|w| w.busy?}}

  end

  

  def join

    sleep 0.01 while busy?

  end

  

  def process(&block)

    wait_for_worker.set_block(block)

  end

  

  def wait_for_worker

    while true

      worker = find_available_worker

      return worker if worker

      sleep 0.01

    end

  end

  

  def find_available_worker

    @mutex.synchronize {free_worker || create_worker}

  end

  

  def free_worker

    @workers.each {|w| return w unless w.busy?}; nil

  end

  

  def create_worker

    return nil if @workers.size >= @max_size

    worker = Worker.new

    @workers << worker

    worker

  end

end

foldr and foldl in Ruby

ciconia (Sharon Rosner) — Tue, 09 Jan 2007 11:52:51 GMT



module Enumerable

  def foldr(o, m = nil)

    reverse.inject(m) {|m, i| m ? i.send(o, m) : i}

  end



  def foldl(o, m = nil)

    inject(m) {|m, i| m ? m.send(o, i) : i}

  end

end



[1, 2, 3, 4, 5].foldl(:+) #=> 15

[1, 2, 3, 4, 5].foldl(:*) #=> 120



[1, 2, 3, 4, 5].foldr(:-, 0) #=> 3

[1, 2, 3, 4, 5].foldl(:-, 0) #=> -15

A Fast Ruby XML Builder

ciconia (Sharon Rosner) — Mon, 04 Sep 2006 22:30:54 GMT

Here's something I wrote this evening. It's a simple and fast XML builder. Some benchmark I ran show it to be about 4 times faster than Builder. Usage example:



items = ['abc', 'def', 'ghi']

xml = XML.new do

  instruct!

  reality(:time => Time.now) do

  event do

    type 1

    path "/sharon"

    value "abcdefg"

  end

  list.each {|i| item i}

end

puts xml.to_s

The XML class:



class XML

  # blank slate

  instance_methods.each { |m| undef_method m unless (m =~ /^__|instance_eval$/)}

  

  # Each item in @doc is an array containing three values: type, value, attributes

  

  def initialize(&block)

    @doc = []

    instance_eval(&block)

  end

  

  def method_missing(tag, *args, &block)

    value = block ? nil : args.pop

    attributes = args.pop

    @__to_s = nil # invalidate to_s cache

    if value

      @doc << [:open, tag, attributes] << [:value, value] << [:close, tag]

    else

      @doc << [:open, tag, attributes]

      instance_eval(&block)

      @doc << [:close, tag]

    end

  end

  

  def instruct!(atts = nil)

    @doc << [:instruct, atts || {:version => "1.0", :encoding => "UTF-8"}]

  end



  def to_s

    @__to_s ||= @doc.map{|i| _fmt_part i}.join

  end

  

  alias_method :inspect, :to_s

  

  def _fmt_part(part)

    case part[0]

    when :instruct

      ""

    when :open

      part[2] ? "<#{part[1]} #{_fmt_atts(part[2])}>" :

        "<#{part[1]}>"

    when :close

      ""

    when :value

      part[1].to_s

    end

  end



  def _fmt_atts(atts)

    atts.inject([]) {|m, i| m << "#{i[0]}=#{i[1].to_s.inspect}"}.join(' ')

  end

end

A replacement for Ruby's File.join

ciconia (Sharon Rosner) — Sun, 20 Aug 2006 12:27:36 GMT

File.join is ugly, there I've said it. So how about being able to replace this:



require File.join(LOAD_PATH, 'foobar')

With this:



require LOAD_PATH/:foobar

Trivial, really:



class String

  def /(o)

    File.join(self, o.to_s)

  end

end

Full information for Ruby errors

ciconia (Sharon Rosner) — Wed, 16 Aug 2006 10:51:14 GMT

Sometimes I want to be able to print out everything about an error: it's class, message and the stack trace. So how about this:

Update: followed suggestion by onarap and changed the line breaks to $/. No syntax highlighting because the code breaks the snippet parser.


class StandardError

  def info

    "#{self.class}: #{message}#$/#{backtrace.join($/)}"

  end

end

High-performance Ruby: faster Symbol.to_s

ciconia (Sharon Rosner) — Tue, 15 Aug 2006 11:22:50 GMT

Here's something that I found useful for shaving a few microseconds off. The performance gain ranges between 10% and 35%! YMMV.

Note: updated with suggestion by trans.



class Symbol

  def to_s

    @str_rep || (@str_rep = id2name.freeze)

  end

end

Easily get a single element with jQuery

ciconia (Sharon Rosner) — Tue, 18 Jul 2006 13:18:51 GMT

While jQuery is a great help, a lot of times I just need to grab a single element. It's a real PITA to have to write $('#mydiv').get(0) all the time, so here's a solution:



$.first = function(a, b) {return $(a, b).get(0)};