Some time ago I promised to create a small tutorial about live fulltext search. A fulltext search, that gives you results as you type.

Ingredients:

Ruby on rails

ferret gem (gem install ferret)

acts_as_ferret gem (gem install acts_as_ferret)

auto_complete plugin (from the application root: ruby script/plugin install auto_complete)

What we will do

Create an empty application – simple book database Add fulltext search capabilities Create the live search Create search pane partial – the one that will display the search box Create the search results partial – that will render the hints (search results) Modify controller to respond to the search pane

Create a book database application

We will create a small application for book management. It will store, list, update books and it will also provide the live search.

So, lets create the skeleton of the aplication:

# Create the rails application rails books # create database books echo "create database books" | mysql -u root -p cd books

Configure database login and password in app/config/database.yml.

development: adapter: mysql database: books username: root password: password host: localhost port: 3306

Create skeleton of the application. From root of the application run:

ruby script/generate scaffold Book title:string abstract:text

Create the books table

rake db:migrate

Start up the development server

ruby script/server

Now, browse to http://127.0.0.1:3000/books and type in some data.

Add fulltext search capabilities

Change the app/models/book.rb to support fulltext search

require "acts_as_ferret" class Book < ActiveRecord::Base acts_as_ferret end

You can check in the console, that the fulltext is enabled. Just start the console via

ruby script/console and put there

Book. find_by_contents ( "book" ) .

It should return a result set, similar to this:

=> #<ActsAsFerret::SearchResults:0x2540f54 @results=[#<Book id: 2, title: "Book secondo", abstract: "Book about book", created_at: "2008-07-07 23:16:38", updated_at: "2008-07-07 23:16:38">, #<Book id: 1, title: "First book", abstract: "This is a first book", created_at: "2008-07-07 23:16:23", updated_at: "2008-07-07 23:16:23">], @total_hits=2>

Create the live search

Finally, create the live search.

Create search pane partial

The search_pane will be used to display search box.

Create a partial _search_pane.html.erb in app/views/books and put there simple tag. The tag create Ajax Autocompleter that calls auto_complete_for_search_query method of the default controller (in our case it will be books)

<%= text_field_with_auto_complete :search , :query %>

Add javascript include and partial rendering to the books template app/views/layouts/books.html.erb.

Do not forget! The javascript include must be in the head of the template.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <meta http-equiv="content-type" content="text/html;charset=UTF-8" /> <title>Books: <%= controller.action_name %></title> <!-- HERE --> <%= stylesheet_link_tag 'scaffold' %> <%= javascript_include_tag :defaults %> </head> <body> <!-- AND HERE --> <%= render :partial=>"books/search_pane" %> <p style="color: green"><%= flash[:notice] %></p> <%= yield %> </body> </html>

Create the search results partial

The search_results will format the results of the full text search and will “offer” the resulting records. Create a partial app/views/books/_search_results.html.erb and add there the formatting code:

<ul> <% for book in @books %> <li><%= link_to h(book.title), :controller=>"books", :action=>"show", :id=>book %></li> <% end %> </ul>

Modify controller

Add the following line at the beginning of the books_controller.

protect_from_forgery :only => [ :create , :update , :destroy ]

Create a method in books_controller that will search for the books

def auto_complete_for_search_query @books = Book. find_by_contents ( params [ "search" ] [ "query" ] + "*" , { :limit => 5 } ) render :partial => "search_results" end

We do not want to generate the whole page layout, so it is necessary to specify it in the books controller:

layout 'books' , :except => [ :auto_complete_for_search_query ]

And now, navigate to http://127.0.0.1:3000/books and start searching. As soon as you start typing into the search box, it shows results. Click on one of the proposed links to see what happens. Source code is here.