integer range collection_select form helper

July 9th, 2008 •
tags: rails, rails views

<%= f.collection_select :priority, (1..5), :to_i, :to_i %>

checking for local variables in rails partials

February 15th, 2008 •
tags: rails, rails views

# You cannot test whether a certain key
# (:somevar) was present in the locals
# hash passed to render using

defined?(:somevar),

# due to the way template compilation works in Rails.
# But you can use the following pattern instead:

local_assigns.include?(:somevar)

layout possibilities in rails

October 17th, 2007 •
tags: rails, rails views

Layouts in rails can be accomplished in quite a few ways. Here are the most common:

• layouts/application.html.erb #default for all controllers
• layouts/my_controller.html.erb #layout for a controller with the same name
• layout "my_layout" in controller # explicitly set layout in controller
• layout :decide_on_layout # with ‘decide_on_layout being a method returning a layout name as string
• render :layout => false # no layout at all
• render :partial => ‘my_partial’, :layout => ‘my_other_partial’ # partials as layouts

clean page titles (from Ryan Bates’ screencasts)

October 16th, 2007 •
tags: rails, rails views

# application_helper.rb

def title(page_title)
content_for :title { page_title }
end

# e.g. show.html.erb

<% title "overidden title" %>
...

# layouts/some_layout.html.erb
<%= yield(:title) %>

<%= yield %>

blog archive helper

October 15th, 2007 •
tags: playground, rails, rails routing, rails views

# ------------------------------------------
#                 routes.rb
# ------------------------------------------

# show posts by date
map.connect ':year/:month/:day',
  :controller => 'posts',
  :action => 'index',
  :year => /\d{4}/,
  :month => /\d{1,2}/,
  :day => /\d{1,2}/

# show posts by month
map.connect ':year/:month',
  :controller => 'posts',
  :action => 'index',
  :year => /\d{4}/,
  :month => /\d{1,2}/

# ------------------------------------------
#            post_controller.rb
# ------------------------------------------

def index
  if params[:year] && params[:month]
    datestring = "#{params[:year]}-#{params[:month]}"
    datestring << "-#{params[:day]}" if params[:day]
      @posts = Post.find_all_by_date_like(datestring)
    else
      @posts = Post.find(:all)
    end

    respond_to do |format|
      format.html # index.html.erb
      format.xml  { render :xml => @posts }
      format.atom
    end
  end
end

# ------------------------------------------
#          post.rb
# ------------------------------------------

class Post < ActiveRecord::Base
  class << self
    def find_all_by_date_like(datestring)
      self.find(:all, :conditions => ['created_at LIKE ?', datestring + '%'])
    end
  end
  #...
end

# ------------------------------------------
#          application_helper.rb
# ------------------------------------------

MONTHS =
  [
    'January', 'February', 'March', 'April', 'May', 'June',
    'July', 'August', 'September', 'October', 'Novemeber', 'December'
  ]

def archive_content(posts)
  raise ArgumentError unless block_given?
  with_unique_dates_from_resource posts do |year, month|
    link_name = "#{MONTHS[month.to_i - 1]} #{year}"
    yield(link_to(link_name, "/#{year}/#{month}"))
  end
end

def with_unique_dates_from_resource(resource, timestamp = :created_at, find_options = {})
  if resource.is_a?(Array)
    collection = resource
  else
    proxy = resource.to_s.singularize.camelcase.constantize
    collection = proxy.find(:all, find_options)
  end
  collection.map do |model|
    model.send(timestamp).strftime("%Y/%m")
  end.uniq.each do |date|
    dates = date.split('/')
    yield(*dates)
  end
end

# ------------------------------------------
#               in some view
# ------------------------------------------

<% archive_content :posts do |archive_link| %>
<%= archive_link %>

<% end %>

# or

<% archive_content Post.find(:all) do |archive_link| %>
<%= archive_link %>

<% end %>

one line client block helpers for rails views

October 10th, 2007 •
tags: rails, rails helper, rails views

# somewhere in a view
<%= one_line_block_helper books, binding %>

# somewhere in a helper
def one_line_client_block_helper(some_collection, erb_binding)
  concat("
“, erb_binding)
  show_some_collection(some_collection) do |item|
    concat(”
#{item.name}

“, erb_binding)
  end
  concat(”

“, erb_binding)
end

# of course this can be used separately like every block helper
def show_some_collection(some_collection)
  # this can get arbitrarily complex
  some_collection.each do |item|
    yield item
  end
end

recursive rails view helper that prints a tree

November 15th, 2006 •
tags: rails, rails helper, rails views

def display_tree_recursive(tree, parent_id)
  ret = "\n
”
  tree.each do |node|
    if node.parent_id == parent_id
      ret += “\n\t
”
      ret += yield node
      ret += display_tree_recursive(node.children, node.id) { |n| yield n } unless node.children.empty?
      ret += “\t

\n”
    end
  end
  ret += “

\n”
end

def print_path_to_node(node, separator)
  path = “”
  path += print_path_to_node(node.parent, separator) { |n| yield n } unless node.parent.nil?
  path += yield node
  path += separator unless node.children.empty?
  return path
end