Unicorn Power

John Adams — Wed, 31 Mar 2010 01:25:51 +0000

Ben Sandofsky and I just put a new post on the Twitter Engineering blog about our transition to Unicorn.

http://engineering.twitter.com/2010/03/unicorn-power.html

Autocomplete in rails 2.0

John Adams — Thu, 20 Mar 2008 09:08:23 +0000

There’s been some changes in the way that Rails 2.0 processes forms and form interaction with Ajax. Here’s a quick write-up on how to use auto completion in Rails 2.0 without a database connection.

In my case, I was parsing an Apache configuration file and displaying VirtualHost entries, but you can use this for just about anything (of course, models work too if you’d like to go against the DB)

First, install the auto complete plugin. Rails 2.0 doesn’t have autocomplete in the core anymore, so you’ll have to create your project with the usual rails myproject syntax, and then enter that directory with cd myproject.

Type “script/plugin install auto_complete” to install the auto complete plugin.

Next, we create a simple class to hold our data. You could parse a file here (say, with File.open()), or pull data from other sources in the initialize function of this class. If you’ve got a model in the database, you can use that.

class Apacheconf

@names = []

def names
@names
end

def initialize
# replace this code later with parsing code

@names = Array.new
@names << “alpha”
@names << “beta”
@names << “gamma”
@names << “delta”
end

end

… then we add some code and CSS to our view for the affiliate/index method in app/views/affiliate/index.rhtml

<%= javascript_include_tag :defaults %>

<% form_tag :action => “edit” do %>

<%= text_field ‘affiliate’, ‘name’, :autocomplete => ‘off’ %>

<%= auto_complete_field :affiliate_name,
   :url => { :action=>’autocomplete_affiliate_name’ },
   :tokens => ‘,’ %>
   <%= submit_tag %>
   <% end %>

… and then we insert a very small amount of code into the controler (in app/controllers/affiliate_controler.rb) to handle the Ajax callback:

class AffiliateController < ApplicationController
skip_before_filter :verify_authenticity_token, nly => [:autocomplete_affiliate_name]

def autocomplete_affiliate_name
   # this code is called over and over again by Ajax
#
   # the next line does a search through the array for terms starting with the
   # specified parameters.

@x = Apacheconf.new.names
@affiliates = @x.select { |v| v =~ /^#{params[:affiliate][:name]}/ }

# don’t render the layout – we only want the partial to be rendered
render :layout=>false
end

end

The beauty of this that with the plugin installed, it takes very little work to get autocomplete working.

Retina Technology Blog » ruby on rails

Unicorn Power

Autocomplete in rails 2.0