varidates_presence_ofの仕組みを追いかける

railsでvalidをかけると、以下のようなメッセージが出力される。

以下の内容をご確認の上、再度お試し下さい。

* Nameを入力して下さい

これって、どんな仕組みになってるんだろう?ということで追いかけてみた。

<div class="errorExplanation" id="errorExplanation"><h2>以下の内容をご確認の上、再度お試し下さい。</h2><ul><li>Nameを入力して下さい</li></ul></div>

errorExplanationでmdfind。

% mdfind -onlyin "/opt/local/" "errorExplanation"

/opt/local/lib/ruby/gems/1.8/doc/actionpack-2.0.2/rdoc/classes/ActionView/Helpers/ActiveRecordHelper.html

/opt/local/lib/ruby/gems/1.8/doc/actionpack-2.0.2/rdoc/classes/ActionView/Helpers/ActiveRecordHelper.src/M000414.html

/opt/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/test/template/form_helper_test.rb

/opt/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/test/template/active_record_helper_test.rb

/opt/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_view/helpers/active_record_helper.rb

/opt/local/lib/ruby/gems/1.8/doc/actionpack-1.13.3/rdoc/classes/ActionView/Helpers/ActiveRecordHelper.html

/opt/local/lib/ruby/gems/1.8/doc/actionpack-1.13.3/rdoc/classes/ActionView/Helpers/ActiveRecordHelper.src/M001129.html

/opt/local/lib/ruby/gems/1.8/gems/actionpack-1.13.3/test/template/active_record_helper_test.rb

/opt/local/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_view/helpers/active_record_helper.rb

/opt/local/lib/ruby/gems/1.8/gems/gettext-1.90.0/lib/gettext/rails.rb

/opt/local/lib/ruby/gems/1.8/doc/actionpack-1.13.6/rdoc/classes/ActionView/Helpers/ActiveRecordHelper.html

/opt/local/lib/ruby/gems/1.8/doc/actionpack-1.13.6/rdoc/classes/ActionView/Helpers/ActiveRecordHelper.src/M001136.html

/opt/local/lib/ruby/gems/1.8/gems/actionpack-1.13.6/test/template/active_record_helper_test.rb

/opt/local/lib/ruby/gems/1.8/gems/actionpack-1.13.6/lib/action_view/helpers/active_record_helper.rb

/opt/local/lib/ruby/gems/1.8/doc/actionpack-2.0.2/rdoc/classes/ActionView/Helpers/ActiveRecordHelper.src/M001525.html

% vim /opt/local/lib/ruby/gems/1.8/gems/actionpack-1.13.6/lib/action_view/helpers/active_record_helper.rb

errorExplanation で検索。

# Returns a string with a <tt>DIV</tt> containing all of the error messages for the objects located as instance variables by the names

# given.  If more than one object is specified, the errors for the objects are displayed in the order that the object names are

# provided.

#

# This <tt>DIV</tt> can be tailored by the following options:

#

# * <tt>header_tag</tt> - Used for the header of the error div (default: h2)

# * <tt>id</tt> - The id of the error div (default: errorExplanation)

# * <tt>class</tt> - The class of the error div (default: errorExplanation)

# * <tt>object_name</tt> - The object name to use in the header, or

# any text that you prefer. If <tt>object_name</tt> is not set, the name of

# the first object will be used.

#

# To specify the display for one object, you simply provide its name as a parameter.  For example, for the +User+ model:

# 

#   error_messages_for 'user'

#

# To specify more than one object, you simply list them; optionally, you can add an extra +object_name+ parameter, which

# be the name in the header.

#

#   error_messages_for 'user_common', 'user', :object_name => 'user'

#

# NOTE: This is a pre-packaged presentation of the errors with embedded strings and a certain HTML structure. If what

# you need is significantly different from the default presentation, it makes plenty of sense to access the object.errors

# instance yourself and set it up. View the source of this method to see how easy it is.

def error_messages_for(*params)

options = params.last.is_a?(Hash) ? params.pop.symbolize_keys : {}

objects = params.collect {|object_name| instance_variable_get("@#{object_name}") }.compact

count   = objects.inject(0) {|sum, object| sum + object.errors.count }

unless count.zero?

html = {}

[:id, :class].each do |key|

if options.include?(key)

value = options[key]

html[key] = value unless value.blank?

else

html[key] = 'errorExplanation'

end

end

header_message = "#{pluralize(count, 'error')} prohibited this #{(options[:object_name] || params.first).to_s.gsub('_', ' ')} from being saved"

error_messages = objects.map {|object| object.errors.full_messages.map {|msg| content_tag(:li, msg) } }

content_tag(:div,

content_tag(options[:header_tag] || :h2, header_message) <<

content_tag(:p, 'There were problems with the following fields:') <<

content_tag(:ul, error_messages),

html

)

else

''

end

end

このerror_messages_forで色々とやっているようだ。深追いはまた今度。