Module: SortHelper

Overview

Helpers to sort tables using clickable column headers.

Author: Stuart Rackham <srackham@methods.co.nz>, March 2005.

Jean-Philippe Lang, 2009

License: This source code is released under the MIT license.

  • Consecutive clicks toggle the column's sort order.

  • Sort state is maintained by a session hash entry.

  • CSS classes identify sort column and state.

  • Typically used in conjunction with the Pagination module.

Example code snippets:

Controller:

helper :sort
include SortHelper

def list
  sort_init 'last_name'
  sort_update %w(first_name last_name)
  @items = Contact.find_all nil, sort_clause
end

Controller (using Pagination module):

helper :sort
include SortHelper

def list
  sort_init 'last_name'
  sort_update %w(first_name last_name)
  @contact_pages, @items = paginate :contacts,
    :order_by => sort_clause,
    :per_page => 10
end

View (table header in list.rhtml):

<thead>
  <tr>
    <%= sort_header_tag('id', :title => 'Sort by contact ID') %>
    <%= sort_header_tag('last_name', :caption => 'Name') %>
    <%= sort_header_tag('phone') %>
    <%= sort_header_tag('address', :width => 200) %>
  </tr>
</thead>
  • Introduces instance variables: @sort_default, @sort_criteria

  • Introduces param :sort

Defined Under Namespace

Classes: SortCriteria

Instance Method Summary collapse

Instance Method Details

#sort_clauseObject

Returns an SQL sort clause corresponding to the current sort state. Use this to sort the controller's table items collection.



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# File 'app/helpers/sort_helper.rb', line 192

def sort_clause()
  @sort_criteria.to_sql
end

#sort_clearObject

Clears the sort criteria session data



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# File 'app/helpers/sort_helper.rb', line 185

def sort_clear
  session[sort_name] = nil
end

#sort_header_tag(column, options = {}) ⇒ Object

Returns a table header <th> tag with a sort link for the named column attribute.

Options:

:caption     The displayed link name (defaults to titleized column name).
:title       The tag's 'title' attribute (defaults to 'Sort by :caption').

Other options hash entries generate additional table header tag attributes.

Example:

<%= sort_header_tag('id', :title => 'Sort by contact ID', :width => 40) %>


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# File 'app/helpers/sort_helper.rb', line 238

def sort_header_tag(column, options = {})
  caption = options.delete(:caption) || column.to_s.humanize
  default_order = options.delete(:default_order) || 'asc'
  options[:title] = l(:label_sort_by, "\"#{caption}\"") unless options[:title]
  ('th', sort_link(column, caption, default_order), options)
end

#sort_init(*args) ⇒ Object

Initializes the default sort. Examples:

sort_init 'name'
sort_init 'id', 'desc'
sort_init ['name', ['id', 'desc']]
sort_init [['name', 'desc'], ['id', 'desc']]


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# File 'app/helpers/sort_helper.rb', line 160

def sort_init(*args)
  case args.size
  when 1
    @sort_default = args.first.is_a?(Array) ? args.first : [[args.first]]
  when 2
    @sort_default = [[args.first, args.last]]
  else
    raise ArgumentError
  end
end

Returns a link which sorts by the named column.

  • column is the name of an attribute in the sorted record collection.

  • the optional caption explicitly specifies the displayed link text.

  • 2 CSS classes reflect the state of the link: sort and asc or desc



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# File 'app/helpers/sort_helper.rb', line 202

def sort_link(column, caption, default_order)
  css, order = nil, default_order

  if column.to_s == @sort_criteria.first_key
    if @sort_criteria.first_asc?
      css = 'sort asc'
      order = 'desc'
    else
      css = 'sort desc'
      order = 'asc'
    end
  end
  caption = column.to_s.humanize unless caption

  sort_options = { :sort => @sort_criteria.add(column.to_s, order).to_param }
  url_options = params.merge(sort_options)

   # Add project_id to url_options
  url_options = url_options.merge(:project_id => params[:project_id]) if params.has_key?(:project_id)

  link_to_content_update(h(caption), url_options, :class => css)
end

#sort_nameObject



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# File 'app/helpers/sort_helper.rb', line 148

def sort_name
  controller_name + '_' + action_name + '_sort'
end

#sort_update(criteria) ⇒ Object

Updates the sort state. Call this in the controller prior to calling sort_clause.

  • criteria can be either an array or a hash of allowed keys



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# File 'app/helpers/sort_helper.rb', line 175

def sort_update(criteria)
  @sort_criteria = SortCriteria.new
  @sort_criteria.available_criteria = criteria
  @sort_criteria.from_param(params[:sort] || session[sort_name])
  @sort_criteria.criteria = @sort_default if @sort_criteria.empty?
  session[sort_name] = @sort_criteria.to_param
end