= Sunspot::Rails

Sunspot::Rails is a Rails plugin that provides drop-in integration of the
Sunspot[http://outoftime.github.com/sunspot] Solr search library with Rails. It
provides the following features:

* Configure Sunspot using config/sunspot.yml
* Extend ActiveRecord for easy index configuration, search, and indexing
* Automatically index ActiveRecord objects when they are saved, and remove them
  from the index when they are destroyed (can be disabled)
* Automatically commit Solr changes at the end of each request
* Provide utility methods to find and fix orphaned documents and rebuild the
  Solr index for a given class
* Provide rake tasks for starting and stopping the development Solr instance,
  using the configuration in sunspot.yml

Sunspot::Rails has been tested with Rails versions 2.1, 2.2, and 2.3

== Installation

For recent versions of Rails, In your project's <code>config/environment.rb</code>, add the following gem dependencies:

  config.gem 'outoftime-sunspot', :lib => 'sunspot',
    :source => 'http://gems.github.com'
  config.gem 'outoftime-sunspot_rails', :lib => 'sunspot/rails',
    :source => 'http://gems.github.com'
    
Install the gems with:

  rake gems:install

If you are using an older version of Rails that doesn't support plugins-as-gems, install the gems manually and install the plugin:

  sudo gem install outoftime-sunspot outoftime-sunspot_rails --source=http://gems.github.com
  
  script/plugin install git://github.com/outoftime/sunspot_rails.git
  
Generate the file <code>config/sunspot.yml</code>:

  script/generate sunspot

Rails doesn't automatically load rake tasks from plugins installed as gems
(https://rails.lighthouseapp.com/projects/8994/tickets/59). If you installed
Sunspot::Rails as a gem, add the following line to your project's Rakefile:

  require 'sunspot/rails/tasks'

If you wish to make modifications to the Solr schema, you can create a custom
Solr home in your project directory. In order to do so, create the directory
<code>RAILS_ROOT/solr/conf</code>, and copy in the contents of the Solr gem's
<code>solr/solr/conf</code> directory. If the files are in the right place,
Sunspot::Rails will detect them and tell Solr to use your local configurations.
Use caution when modifying <code>schema.xml</code> - Sunspot relies on the
field naming scheme in the packaged schema file.

To start up a Solr instance, issue the following:

  rake sunspot:solr:start

Note that using the built-in Solr instance packaged with Sunspot is great for
development, but is not recommended for production. See the Sunspot
documentation for more information.

== Usage

=== Setup

In order for an ActiveRecord model to be indexable and searchable, it must be
configured for search. For example:

  class Post < ActiveRecord::Base
    searchable do
      text :title, :body
      integer :blog_id
      time :updated_at
      string :sort_title do
        title.downcase.sub(/^(an?|the) /, '')
      end
    end
  end

See the documentation for Sunspot.setup for full details on what can go in the
configuration block.

=== Indexing

By default, models are indexed whenever they are saved, and removed from the
index whenever they are destroyed. This behavior can be disabled:

  class Post < ActiveRecord::Base
    searchable :auto_index => false, :auto_remove => false do
      # setup...
    end
  end

Note that <b>using the <code>:auto_remove</code> option is not recommended
</b>, as destroying an object without removing it from the index will
create an orphaned document in the index, which is a Bad Thing. Turning off
<code>:auto_index</code> is perfectly safe if you prefer to manage indexing manually
(perhaps using a background job).

If you have disabled lifecycle indexing hooks, you can invoke indexing
operations directly on your model:

  post = Post.create
  post.index
  post.remove_from_index

=== Committing

When data is changed in Solr, it is initially stored in memory and not made
available to the currently running searcher instance. Issuing a +commit+ to Solr
will cause it to write the changes to disk, and instantiate a new searcher
instance. This operation is fairly expensive, so rather than issuing a commit
every time a document is added or removed, Sunspot::Rails issues a commit at
the end of any request where data has been added to or removed from Solr. If
you need to immediately issue a commit, bang!-versions of the methods are
available:

  post = Post.create
  post.index!
  # this is the same as...
  post.index
  Sunspot.commit

When writing tests outside of the context of a controller request, you will want
to use one of these two approaches.

=== Searching

Do it like this:

  Post.search do
    with :blog_id, 1
    with(:updated_at).greater_than(Time.now - 2.weeks)
    order :sort_title, :asc
    paginate :page => 1, :per_page => 15
  end

See the documentation for <code>Sunspot.search</code> for all the options
available in the search block, and the information available in the result
block.

=== Searching for IDs

In some situations, you may want to get the IDs for models returned by a search
without actually loading the models out of the database. For that, you can
call +search_ids+, using the same block format as #search. This will return an
array of IDs.


=== Searching for multiple types

Sunspot is entirely agnostic about whether searches are for one or more types;
the only restriction is that columns used for restriction, ordering, etc. are
defined in the same way for all types being searched. Sunspot::Rails does not
provide any additional support for this, since there is not anything useful to
be added, so just use the interface provided by Sunspot:

  Sunspot.search(Post, Comment) do
    with :blog_id, 1
    order :created_at, :asc
  end

Be sure to check out the Sunspot documentation for all the details.

=== Adding search functionality in mixins

Sunspot does not require that search setup for a given class happen all in one
place; it is perfectly acceptable to call the <code>Sunspot.setup</code> method
more than once. This capability is particularly useful for adding search
functionality in mixins. For instance, if you have a +Ratable+ module, you may
wish to add additional search fields for searchable classes that mix in that
module. For example:

  module Ratable
    def self.included(base)
      if base.searchable?
        base.searchable do
          float :average_rating do
            ratings.average(:value)
          end
        end
      end
    end
  end

Note the use of <code>base.searchable?</code> - this ensures that only classes
that already have search enabled will have the additional configuration added.
The above pattern requires that the class be declared searchable before the
module is mixed in; other patterns (such as passing a :searchable option to an
acts_as_-style declaration) may be more flexible.

=== Utility methods

If you need to completely reindex all of the instances of a given model class,
you can issue:

  Post.reindex

If for some reason models get deleted from the database, but not from the index,
they will become index orphans - not a good situation. To get IDs that exist in
the index but not the database, you can use the +index_orphans+ method; to
remove those documents from the index, use +clean_index_orphans+. Note that
neither of these operations should be needed if Sunspot and Sunspot::Rails are
used as intended.

== Further Reading

Reading the {Sunspot documentation}[http://outoftime.github.com/sunspot/docs] is
highly recommended. Sunspot::Rails exists to wrap Sunspot with a Rails-friendly
API, but almost all of the functionality you use in Sunspot::Rails is
implemented in Sunspot.

Posts about Sunspot on my blog are available at http://outofti.me/tagged/sunspot

== Bugs

Please submit bug reports to
http://outoftime.lighthouseapp.com/projects/20339-sunspot

== Contributors

- Mat Brown (mat@patch.com)
- Peer Allan (peer.allan@gmail.com)
- Michael Moen (michael@underpantsgnome.com)
- Benjamin Krause (bk@benjaminkrause.com)
- Adam Salter (adam@codebright.net)
- Brandon Keepers (brandon@opensoul.org)

== License

Sunspot::Rails is distributed under the MIT License, copyright (c) 2009 Mat Brown