Forum: Ruby on Rails using a variable to invoke a custom method within autocomple

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777892eb38d2e6a4eb915d558068c971?d=identicon&s=25 Dimmerswitch (Guest)
on 2007-02-16 02:22
(Received via mailing list)
I'm implementing a version of the autocompletion script found at
autocomplete-with-belongs_to-fields and have run into a stumbling

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 = { |entry| content_tag("li", entry[field], "id"
=> entityType+'::'+entry[index].to_s) }
  content_tag("ul", items.uniq)

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 = { |entry| content_tag("li",
entry.name_with_place, "id" => entityType+'::'+entry[index].to_s)}
    content_tag("ul", items.uniq)

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

def name_with_place
   "#{} (#{})"

# 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' %>"

# from: public/javascripts/application.js

function auto_complete_on_select(element, selectedElement)
  var entityParts ='::');
  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 -%>
71c90d30f8c437a593aeb5588408ec1a?d=identicon&s=25 Jon (Guest)
on 2007-02-16 02:48
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.
777892eb38d2e6a4eb915d558068c971?d=identicon&s=25 Dimmerswitch (Guest)
on 2007-02-16 14:57
(Received via mailing list)
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
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