Rails - Feb 2007 - using a variable to invoke a custom method within autocomplete

I''m implementing a version of the autocompletion script found at
http://ricardo.pacheco.name/blog/articles/2006/07/26/using-
autocomplete-with-belongs_to-fields and have run into a stumbling
block.

The issue involves passing in a variable to indicate which custom
method should be invoked. I have an ugly workaround (a duplicate
function hardcoded to use the custom method), but would like to learn
a better way to handle this case. It feels like I''m missing something
simple, but I''ll be damned if I can see it.

# from: app/helpers/application_helper.rb

def indexed_auto_complete_result(entries, entityType, field, index)
  return unless entries
  items = entries.map { |entry| content_tag("li", entry[field],
"id"
=> entityType+''::''+entry[index].to_s) }
  content_tag("ul", items.uniq)
end

This works fine for referencing model attributes which exist in the
"Highlights" table (name, description, etc.) but fails if
''field'' is
passed in as "name_with_place". The unordered list is created, but
it''s full of empty <li> tags. If I change it to use entry.field I
get
NoMethodError (undefined method ''field'') errors in the log.

My eventual workaround was to add this function for those times I need
to access the name_with_place method. This works as desired, and
properly invokes the custom name_with_place method. It''s clearly not
DRY, though.

  def indexed_auto_complete_result_with_place(entries, entityType,
field, index)
    return unless entries
    items = entries.map { |entry| content_tag("li",
entry.name_with_place, "id" =>
entityType+''::''+entry[index].to_s)}
    content_tag("ul", items.uniq)
  end



# from: app/models/highlight.rb
belongs_to :place

def name_with_place
  if self.place.nil?
    self.name
  else
   "#{self.name} (#{self.place.name})"
 end
end

# from: app/controllers/highlights_controller.rb
def auto_complete_for_highlight_internal_name
  find_options = {
    :conditions => [ "LOWER(name) LIKE ?", ''%''
+params[:highlight]
[:internal_name].downcase + ''%'' ],
    :order  => "name ASC",
    :limit  => 10
  }
  @highlights = Highlight.find(:all,find_options)
  render :inline => "<%= indexed_auto_complete_result @highlights,
''highlight_id'', ''name_with_place'',
''id'' %>"
end

# from: public/javascripts/application.js

function auto_complete_on_select(element, selectedElement)
{
  var entityParts = selectedElement.id.split(''::'');
  var entityType = entityParts[0];
  var entityId   = entityParts[1];
  document.getElementById(entityType).value = entityId;
}

# from: app/views/highlights/index.rhtml

<% form_tag(''/highlights/edit'', :method => :post) do
%>
<%= text_field_with_auto_complete :highlight, :internal_name, { :size
=> 40 }, { :after_update_element =>
''auto_complete_and_redirect_on_select'' } %>
<%= hidden_field ''highlight'', ''id'' %>
<%= submit_tag("Edit") %>
<% end -%>


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Not sure if this is what you want, but object.send(function_name) will 
do the trick for cases like that.  Just be careful since I think .send 
will execute any function, public or private.

-- 
Posted via http://www.ruby-forum.com/.

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That works great for the dropdown. I''ll take a look at .send and the
potential for executing any object method, which might make this
approach a nonstarter.

Thanks, Jon

On Feb 15, 5:48 pm, Jon
<rails-mailing-l...-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org>
wrote:
> Not sure if this is what you want, but object.send(function_name) will
> do the trick for cases like that.  Just be careful since I think .send
> will execute any function, public or private.
>
> --
> Posted viahttp://www.ruby-forum.com/.

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