Ruby on Rails в России

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Maxim Kulkin, Tue Feb 02 11:18:00 +0300 2010

Building tree out of nested set

Maxim Kulkin, Mon Sep 14 11:10:00 +0400 2009

# Class that allows performance wise traversing a list of items
# that form a part of nested set structure.
class NestedSetTreePresenter
  include Enumerable

  # Constructs presenter with a items that form part of nested set,
  # offset of first item on desired level and count - number of items
  # on current level.
  # Items should be ordered by their left bound values.
  def initialize(items, offset = 0, count = nil)
    @items = items
    @offset = offset
    @count = count || @items.size
  end

  # For each item of the same level in nested set as the first item
  # calls block passing corresponding item.
  def each
    i = @offset
    bound = @offset   @count
    bound = @items.size if bound > @items.size

    while i<bound
      item = @items[i]
      descendants_count = (item.rgt-item.lft)/2
      yield item
      i  = 1   descendants_count
    end
  end

  # For each item of the same level in nested set as the first item
  # calls block passing corresponding item and collection, that
  # represent all immediate children of that item. Collection is also
  # an instance of this class.
  def each_with_children
    i = @offset
    bound = @offset   @count
    bound = @items.size if bound > @items.size

    while i<bound
      item = @items[i]
      descendants_count = (item.rgt-item.lft)/2
      yield item, NestedSetTreePresenter.new(@items, i 1, descendants_count)
      i  = 1   descendants_count
    end
  end
end

def print_tree(items, level = 0)
  items.each_with_children do |item, children|
    puts "  "*level   item.name
    print_tree(children, level 1)
  end
end

print_tree(NestedSetTreePresenter.new(items))

RSpec's matchers without all bullshit

Maxim Kulkin, Tue Aug 25 10:11:00 +0400 2009

Allowing ssh access to Darcs repositories

Maxim Kulkin, Wed Jul 22 01:09:00 +0400 2009

#!/bin/sh

first_word() { echo $1; }

line="$SSH_ORIGINAL_COMMAND"

command=$(first_word $line)
if [ "$command" = "darcs" ]; then
  sh -c "$line"
else
  echo "$command is not allowed"
fi

#!/bin/sh

first_word() { echo $1; }
unquoted_words() {
  for word in $@; do
    echo $(echo $word | sed -E "s/^'(.*)'$/\1/; s/^\"(.*)\"$/\1/")
  done
}

line="$SSH_ORIGINAL_COMMAND"

command=$(first_word $line)
if [ "$command" = "darcs" ]; then
  exec $(unquoted_words $line)
else
  echo "$command is not allowed"
fi

Specific or default templates in Rails

Maxim Kulkin, Sat Jan 10 22:02:00 +0300 2009

map.resources :users, :controller => 'items',
    :requirements => { :item_type => 'User' }
map.resources :regions, :controller => 'items',
    :requirements => { :item_type => 'Region' }

app/views/items
    index.html.erb
    new.html.erb
    edit.html.erb
    _item.html.erb
    _form.html.erb
app/views/items/users
    _item.html.erb
    _form.html.erb
app/views/items/regions
    _form.html.erb

app/views/items
app/views/items/users/items
    _item.html.erb

class ItemsController < ApplicationController
  def self.controller_path
    nil
  end
  self.view_paths = [ RAILS_ROOT   '/app/views/items' ]

  before_filter :setup_model

  # ... action code

  private

  def setup_model
    @model  = params[:item_type].constantize
    prepend_view_path(RAILS_ROOT   '/app/views/items/'   params[:item_type].underscore)
  end
end

Back to Rails

Maxim Kulkin, Fri Jan 09 17:37:00 +0300 2009

Sphinx FAIL

Maxim Kulkin, Wed May 21 15:34:00 +0400 2008

Installing Sphinx on Mac OS Leopard

Maxim Kulkin, Thu May 15 00:57:00 +0400 2008

On Prototype vs jQuery

Maxim Kulkin, Wed Apr 30 16:47:00 +0400 2008

  $('element').addClassName('className')
  $('element').removeClassName('classsName')

  new Ajax.Updater('element', url   '&'   parameters)

  Element.addMethods({
    load: function(element, url) {
      new Ajax.Updater(element, url)
    }
  })

  $('element').load(url   params)

  $$('.element').invoke('addClassName', 'className')

ActiveRecord's database shortcut methods

Maxim Kulkin, Tue Dec 11 11:36:00 +0300 2007

Giles Bowkett: IRB: What Was That Method Again?

Maxim Kulkin, Tue Nov 06 09:36:00 +0300 2007

On Auto Migrations

Maxim Kulkin, Tue Nov 06 09:04:00 +0300 2007

Завершение саги о датах

Maxim Kulkin, Thu Jul 05 00:52:00 +0400 2007

ParseDate.class_eval do
 class << self
   def parsedate_with_ru_format(str, comp=false)
     str = str.to_s
     str = "#{$3}-#{$2}-#{$1}" if /(\d{2})\.(\d{2})\.(\d{4})/ =~ str
     parsedate_without_ru_format(str, comp)
   end

   alias_method_chain :parsedate, :ru_format
 end
end

ActiveRecord::Base.class_eval do
 class << self
   def date_columns
     columns.select { |column| column.type == :date }
   end
 end

 def validate_dates_format(record)
   record.class.date_columns.each do |column|
     if record.send(column.name).nil? &&
        record.send("#{column.name}_before_type_cast").empty?
       record.errors.add(column.name, "has invalid date format")
     end
   end
 end

 validate :validate_dates_format
end

Maxim Kulkin, Wed Jun 27 23:05:00 +0400 2007

Валидация многопараметровых значений

Maxim Kulkin, Tue Jun 26 09:51:00 +0400 2007

  if values.empty?
    send(name   "=", nil)

class String
  def to_n
    Integer(self) rescue nil
  end
end

  def extract_callstack_for_multiparameter_attributes(pairs)
    attributes = { }

    for pair in pairs
      multiparameter_name, value = pair
      attribute_name = multiparameter_name.split("(").first
      attributes[attribute_name] = [] unless attributes.include?(attribute_name)

      # запил N1: не пропускать пустые значения
      #unless value.empty?
        attributes[attribute_name] <<
          [ find_parameter_position(multiparameter_name), type_cast_attribute_value(multiparameter_name, value) ]
      #end
    end

    # запил N2: заменять массив из только nil'ов на пустой
    attributes.each do |name, values|
      attributes[name] = values.sort_by{ |v| v.first }.collect { |v| v.last }
      attributes[name] = [] unless attributes[name].detect { |x| !x.nil? }
    end
  end

Что если нет никаких богов ?

Maxim Kulkin, Fri Dec 22 08:55:00 +0300 2006

Работа с данными в ActiveRecord

Maxim Kulkin, Wed Nov 08 17:59:00 +0300 2006

class Event < ActiveRecord::Base
  def time_text
    "%d:d" % [self.time/60, self.time`]
  end

  def time_text=(value)
    self.time = begin
      parts = value.split ':'
      parts[0].to_i*60 parts.to_i
    rescue
      nil
    end
  end
end

class Event < ActiveRecord::Base
  def time_text
    self[:time_text] || ("%d:d" % [self.time/60, self.time`])
  end

  def time_text=(value)
    self[:time_text] = value
    self.time = begin
      parts = value.split ':'
      parts[0].to_i*60 parts[1].to_i
    rescue
      nil
    end
  end
end

class Event < ActiveRecord::Base
  validates_format_of :time_text, :with => /\d?\d\:\d\d/
end

Сборка / разборка данных

Maxim Kulkin, Thu Nov 02 19:00:00 +0300 2006

class CalendarTime
  attr_reader :minutes_since_midnight

  def initialize(minutes)
    @minutes_since_midnight = minutes
  end

  def hour
    @minutes_since_midnight / 60 rescue nil
  end

  def min
    @minutes_since_midnight % 60 rescue nil
  end

  def to_s
    "%d:d" % [ hour, min ]
  end
end

class CalendarEvent < ActiveRecord::Base
  composed_of :time,
    :class_name => 'CalendarTime',
    # отображаем AR атрибут time на поле
    # minutes_since_midnight нашего класса
    :mapping => [:time, :minutes_since_midnight ],
    # разрешить nil в качестве значения агрегата
    :allow_nil => true 
end

module ApplicationHelper
  def time_select(object_name, method, options = {})
    # Получим сам объект
    object = options[:object] ||
      instance_variable_get('@' object_name)
    # и значение
    value = object.send(method)

    # Подготовим опции
    options.delete :object
    object[:discard_type] = true

    # Подготовим шаблон для имени элементов
    name = "#{object_name}[#{attr}(%di)]"

    # Наш объект CalendarTime поддерживает свойства hour и minute
    # поэтому можно будет воспользоваться стандартными хэлперами
    select_hour(value, options.merge :prefix => name%1)   ' : '  
      select_minute(value, options.merge :prefix => name%2)
  end
end

<p>
  <label for="event_time">Time</label><br/>
  <%= time_select 'event', 'time', :include_blank => true %>
</p>

class CalendarTime
  def initialize(*args)
    if args.size == 1 && args[0].is_a?(Numeric)
      @minutes_since_midnight = args[0]
    elsif (args.size == 2 &&
           args[0].is_a?(Numeric) &&
           args[1].is_a?(Numeric))
      @minutes_since_midnight = args[0]*60   args[1]
    end
  end
end

Inline layouts

Maxim Kulkin, Tue Oct 03 18:16:00 +0400 2006

<% inside_inline_layout @layout_template do %>
  content
<% end %>

IF/UNLESS блоки в RJS шаблонах

Maxim Kulkin, Mon Oct 02 15:52:00 +0400 2006

page.if page['element_id'].visible do
  page['element_id'].hide
end

page.unless "$('element_id').visible()" do
  page['element_id'].show
end

  ./script/plugin install svn://rubyforge.org/var/svn/js-if-blocks/trunk/js-if-blocks

element = page['element_id]
page.if element.visible do
  element.hide
end