Ajax Autocompletion With Rails

First, I’d like to apologize for the long delay in posting to my blog. My wife and I had our second child at the end of September and things have been hectic since then. I was playing around with the ajax autocompletion code from script.aculo.us but couldn’t get it working in my own code. It turns out that in addition to prototype.js in your layout RHTML, you also need to include effects.js and controls.js, so the code looks as follows:

  <%= javascript_include_tag :defaults %>

In the controller, I wrote my own autocomplete_for_XXX method since I wanted to search several different fields in my database. Note that there is probably a much better way to achieve the following without making three different calls to find and without making calls using LIKE %foo% …

  def auto_complete_for_resource_name
@search_term = params[:resource][:name].strip.downcase
@resources = Resource.find(:all,
:conditions => [ 'LOWER(name) LIKE ?',
'%' + @search_term + '%' ],
:order => 'name ASC',
:limit => 10)
:conditions => [ 'LOWER(name) LIKE ?',
'%' + @search_term + '%' ],
:order => 'name ASC',
:limit => 10))
:conditions => [ 'LOWER(name) LIKE ?',
'%' + @search_term + '%' ],
:order => 'name ASC',
:limit => 10))
render :partial => 'resources'

You’ll need a partial _resources.html such as this:

<ul class="resources">
<% for resource in @resources do -%>
<li class="resource">
<div class="name"><%=h resource.name %></div>
<% end -%>

Finally, in the RHTML where you want the autocompletion to appear you need to add a text_field_with_autocomplete, but since I’m using this in a search field (similar to Google’s usage), I needed to place it within a form:

<%= start_form_tag :action => 'search' %>
<label for="reservation_resource">Search</label>
<%= text_field_with_auto_complete :resource, :name %>
<%= submit_tag 'Search' %>
<%= end_form_tag %>

That’s all there is to it. Hope that helps — all of the other documentation I’ve seen only has you include prototype.js and that’s where I ran into difficulty.