Ferret

Chapter 1. Getting Started

Installing Ferret

First things first: let’s get Ferret installed. Thanks to RubyGems, this is pretty easy. If you haven’t used RubyGems before, there is a great introduction at the RubyGems web site (http://docs.rubygems.org/). If you are on Windows and you used the Ruby One-Click Installer to install Ruby, you’ll have everything you need. Other systems, such as Linux or Mac, need to have make and a C compiler such as gcc to build the extension. Other than that, Ferret comes dependency-free. You simply need to run the gem install script:

dave$ sudo gem install ferret

Once this process successfully completes, you will have Ferret installed on your system. The easiest way to check that everything is working correctly is to open an irb session, as shown in Example 1-1.

Example 1-1. irb session

dave$ irb -rubygems
>> require 'ferret'                           #=> true
>> index = Ferret::I.new                      #=> #<Ferret::Index:...>
>> index << "Time heals all wounds"           #=> #<Ferret::Index:...>
>> index << "A rolling stone gathers no moss" #=> #<Ferret::Index:...>
>> index << "A stitch in time saves nine"     #=> #<Ferret::Index:...>
>> index << "Look before you leap"            #=> #<Ferret::Index:...>
>> index << "Time and tide wait for no man"   #=> #<Ferret::Index:...>
>> index << "Time wounds all heels"           #=> #<Ferret::Index:...>
>> puts index.search("time")

All we’ve done here is load RubyGems and Ferret, create a new in-memory index, add a few strings to it, and run a search, printing out the results. If everything is working correctly, you will see the results of your search printed out in order of relevance. It doesn’t get much simpler than that. irb is a great way to play around with Ferret and try out new things. Next, we’ll show you how to index all the text files under a particular directory.