Module: ActionView::Helpers::ActiveRecordHelper
- Defined in:
- lib/action_view/helpers/active_record_helper.rb
Overview
The Active Record Helper makes it easier to create forms for records kept in instance variables. The most far-reaching is the form
method that creates a complete form for all the basic content types of the record (not associations or aggregations, though). This is a great way of making the record quickly available for editing, but likely to prove lackluster for a complicated real-world form. In that case, it’s better to use the input
method and the specialized form
methods in classes/ActionView/Helpers/FormHelper.html
Instance Method Summary collapse
-
#error_message_on(object, method, prepend_text = "", append_text = "", css_class = "formError") ⇒ Object
Returns a string containing the error message attached to the
method
on theobject
if one exists. -
#error_messages_for(*params) ⇒ Object
Returns a string with a
DIV
containing all of the error messages for the objects located as instance variables by the names given. -
#form(record_name, options = {}) {|contents| ... } ⇒ Object
Returns an entire form with all needed input tags for a specified Active Record object.
-
#input(record_name, method, options = {}) ⇒ Object
Returns a default input tag for the type of object returned by the method.
Instance Method Details
#error_message_on(object, method, prepend_text = "", append_text = "", css_class = "formError") ⇒ Object
Returns a string containing the error message attached to the method
on the object
if one exists. This error message is wrapped in a DIV
tag, which can be extended to include a prepend_text
and/or append_text
(to properly explain the error), and a css_class
to style it accordingly. object
should either be the name of an instance variable or the actual object. As an example, let’s say you have a model @post
that has an error message on the title
attribute:
<%= error_message_on "post", "title" %>
# => <div class="formError">can't be empty</div>
<%= error_message_on @post, "title" %>
# => <div class="formError">can't be empty</div>
<%= error_message_on "post", "title", "Title simply ", " (or it won't work).", "inputError" %>
# => <div class="inputError">Title simply can't be empty (or it won't work).</div>
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# File 'lib/action_view/helpers/active_record_helper.rb', line 105 def (object, method, prepend_text = "", append_text = "", css_class = "formError") if (obj = (object.respond_to?(:errors) ? object : instance_variable_get("@#{object}"))) && (errors = obj.errors.on(method)) content_tag("div", "#{prepend_text}#{errors.is_a?(Array) ? errors.first : errors}#{append_text}", :class => css_class) else '' end end |
#error_messages_for(*params) ⇒ Object
Returns a string with a DIV
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 DIV
can be tailored by the following options:
-
:header_tag
- Used for the header of the error div (default: “h2”). -
:id
- The id of the error div (default: “errorExplanation”). -
:class
- The class of the error div (default: “errorExplanation”). -
:object
- The object (or array of objects) for which to display errors, if you need to escape the instance variable convention. -
:object_name
- The object name to use in the header, or any text that you prefer. If:object_name
is not set, the name of the first object will be used. -
:header_message
- The message in the header of the error div. Passnil
or an empty string to avoid the header message altogether. (Default: “X errors prohibited this object from being saved”). -
:message
- The explanation message after the header message and before the error list. Passnil
or an empty string to avoid the explanation message altogether. (Default: “There were problems with the following fields:”).
To specify the display for one object, you simply provide its name as a parameter. For example, for the @user
model:
'user'
To specify more than one object, you simply list them; optionally, you can add an extra :object_name
parameter, which will be the name used in the header message:
'user_common', 'user', :object_name => 'user'
If the objects cannot be located as instance variables, you can add an extra :object
paremeter which gives the actual object (or array of objects to use):
'user', :object => @question.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.
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# File 'lib/action_view/helpers/active_record_helper.rb', line 152 def (*params) = params..symbolize_keys if object = .delete(:object) objects = [object].flatten else objects = params.collect {|object_name| instance_variable_get("@#{object_name}") }.compact end count = objects.inject(0) {|sum, object| sum + object.errors.count } unless count.zero? html = {} [:id, :class].each do |key| if .include?(key) value = [key] html[key] = value unless value.blank? else html[key] = 'errorExplanation' end end [:object_name] ||= params.first [:header_message] = "#{pluralize(count, 'error')} prohibited this #{[:object_name].to_s.gsub('_', ' ')} from being saved" unless .include?(:header_message) [:message] ||= 'There were problems with the following fields:' unless .include?(:message) = objects.sum {|object| object.errors..map {|msg| content_tag(:li, msg) } }.join contents = '' contents << content_tag([:header_tag] || :h2, [:header_message]) unless [:header_message].blank? contents << content_tag(:p, [:message]) unless [:message].blank? contents << content_tag(:ul, ) content_tag(:div, contents, html) else '' end end |
#form(record_name, options = {}) {|contents| ... } ⇒ Object
Returns an entire form with all needed input tags for a specified Active Record object. For example, if @post
has attributes named title
of type VARCHAR
and body
of type TEXT
then
form("post")
would yield a form like the following (modulus formatting):
<form action='/posts/create' method='post'>
<p>
<label for="post_title">Title</label><br />
<input id="post_title" name="post[title]" size="30" type="text" value="Hello World" />
</p>
<p>
<label for="post_body">Body</label><br />
<textarea cols="40" id="post_body" name="post[body]" rows="20"></textarea>
</p>
<input name="commit" type="submit" value="Create" />
</form>
It’s possible to specialize the form builder by using a different action name and by supplying another block renderer. For example, if @entry
has an attribute message
of type VARCHAR
then
form("entry",
:action => "sign",
:input_block => Proc.new { |record, column|
"#{column.human_name}: #{input(record, column.name)}<br />"
})
would yield a form like the following (modulus formatting):
<form action="/entries/sign" method="post">
Message:
<input id="entry_message" name="entry[message]" size="30" type="text" /><br />
<input name="commit" type="submit" value="Sign" />
</form>
It’s also possible to add additional content to the form by giving it a block, such as:
form("entry", :action => "sign") do |form|
form << content_tag("b", "Department")
form << collection_select("department", "id", @departments, "id", "name")
end
The following options are available:
-
:action
- The action used when submitting the form (default:create
if a new record, otherwiseupdate
). -
:input_block
- Specialize the output using a different block, see above. -
:method
- The method used when submitting the form (default:post
). -
:multipart
- Whether to change the enctype of the form to “multipart/form-data”, used when uploading a file (default:false
). -
:submit_value
- The text of the submit button (default: “Create” if a new record, otherwise “Update”).
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# File 'lib/action_view/helpers/active_record_helper.rb', line 75 def form(record_name, = {}) record = instance_variable_get("@#{record_name}") = .symbolize_keys [:action] ||= record.new_record? ? "create" : "update" action = url_for(:action => [:action], :id => record) submit_value = [:submit_value] || [:action].gsub(/[^\w]/, '').capitalize contents = form_tag({:action => action}, :method =>([:method] || 'post'), :enctype => [:multipart] ? 'multipart/form-data': nil) contents << hidden_field(record_name, :id) unless record.new_record? contents << (record, record_name, ) yield contents if block_given? contents << submit_tag(submit_value) contents << '</form>' end |
#input(record_name, method, options = {}) ⇒ Object
Returns a default input tag for the type of object returned by the method. For example, if @post
has an attribute title
mapped to a VARCHAR
column that holds “Hello World”:
input("post", "title")
# => <input id="post_title" name="post[title]" size="30" type="text" value="Hello World" />
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# File 'lib/action_view/helpers/active_record_helper.rb', line 21 def input(record_name, method, = {}) InstanceTag.new(record_name, method, self).to_tag() end |