Asari

Description

Asari is a Ruby wrapper for AWS CloudSearch, with optional ActiveRecord support for easy integration with your Rails apps.

Why Asari?

"Asari" is Japanese for "rummaging search." Seemed appropriate.

Usage

Your Search Domain

Amazon Cloud Search will give you a Search Endpoint and Document Endpoint. When specifying your search domain in Asari omit the search- for your search domain. For example if your search endpoint is "search-beavis-er432w3er.us-east-1.cloudsearch.amazonaws.com" the search domain you use in Asari would be "beavis-er432w3er". Your region is the second item. In this example it would be "us-east-1".

Basic Usage

asari = Asari.new("my-search-domain-asdfkljwe4") # CloudSearch search domain
asari.add_item("1", { :name => "Tommy Morgan", :email => "tommy@wellbredgrapefruit.com"})
asari.search("tommy") #=> ["1"] - a list of document IDs
asari.search("tommy", :rank => "name") # Sort the search
asari.search("tommy", :rank => ["name", :desc]) # Sort the search descending
asari.search("tommy", :rank => "-name") # Another way to sort the search descending

Boolean Query Usage

asari.search(filter: { and: { title: "donut", type: "cruller" }})
asari.search("boston creme", filter: { and: { title: "donut", or: { type: "cruller", type: "twist" }}}) # Full text search and nested boolean logic

For more information on how to use Cloudsearch boolean queries, see the documentation.

Geospatial Query Usage

While Cloudsearch does not natively support location search, you can implement rudimentary location search by representing latitude and longitude as integers in your search domain. Asari has a Geography module you can use to simplify the conversion of latitude and longitude to cartesian coordinates as well as the generation of a coordinate box to search within. Asari's Boolean Query syntax can then be used to search within the area. Note that because Cloudsearch only supports 32-bit unsigned integers, it is only possible to store latitude and longitude to two place values. This means very precise search isn't possible using Asari and Cloudsearch.

coordinates = Asari::Geography.degrees_to_int(lat: 45.52, lng: 122.68)
  #=> { lat: 2506271416, lng: 111298648 }
asari.add_item("1", { name: "Tommy Morgan", lat: coordinates[:lat], lng: coordinates[:lng] })
  #=> nil
coordinate_box = Asari::Geography.coordinate_box(lat: 45.2, lng: 122.85, meters: 7500)
  #=> { lat: 2505521415..2507021417, lng: 111263231..111334065 } 
asari.search("tommy", filter: { and: coordinate_box }
  #=> ["1"] = a list of document IDs

For more information on how to use Cloudsearch for location search, see the documentation.

Sandbox Mode

Because there is no "local" version of CloudSearch, and search instances can be kind of expensive, you shouldn't have to have a development version of your index set up in order to use Asari. Because of that, Asari has a "sandbox" mode where it does nothing with add/update/delete requests and just returns an empty collection for any searches. This sandbox mode is enabled by default - any time you want to actually connect to the search index, just do the following:

Asari.mode = :production

You can turn the sandbox back on, if you like, by setting the mode to :sandbox again.

Pagination

Asari defaults to a page size of 10 (because that's CloudSearch's default), but it allows you to specify pagination parameters with any search:

asari.search("tommy", :page_size => 30, :page => 10)

The results you get back from Asari#search aren't actually Array objects, either: they're Asari::Collection objects, which are (currently) API-compatible with will_paginate:

results = asari.search("tommy", :page_size => 30, :page => 10)
results.total_entries #=> 5000
results.total_pages   #=> 167
results.current_page  #=> 10
results.offset        #=> 300
results.page_size     #=> 30

Retrieving Data From Index Fields

By default Asari only returns the document id's for any hits returned from a search. If you have result_enabled a index field you can have asari resturn that field in the result set without having to hit a database to get the results. Simply pass the :return_fields option with an array of fields

results = asari.search "Beavis", :return_fields => ["name", "address"]

The result will look like this

{"23" => {"name" => "Beavis", "address" => "One CNN Center,  Atlanta"},
"54" => {"name" => "Beavis C", "address" => "Cornholio Way, USA"}}

ActiveRecord

By default the ActiveRecord module for Asari is not included in your project. To use it you will need to require it via

require 'asari/active_record'

You can take advantage of that module like so:

class User < ActiveRecord::Base
  include Asari::ActiveRecord

  #... other stuff...

  asari_index("search-domain-for-users", [:name, :email, :twitter_handle, :favorite_sweater])
end

This will automatically set up before_destroy, after_create, and after_update hooks for your AR model to keep the data in sync with your CloudSearch index - the second argument to asari_index is the list of fields to maintain in the index, and can represent any function on your AR object. You can then interact with your AR objects as follows:

# Klass.asari_find returns a list of model objects in an
# Asari::Collection... 
User.asari_find("tommy") #=> [<User:...>, <User:...>, <User:...>]
User.asari_find("tommy", :rank => "name")

# or with a specific instance, if you need to manually do some index
# management...
@user.asari_add_to_index
@user.asari_update_in_index
@user.asari_remove_from_index

You can also specify a :when option, like so:

asari_index("search-domain-for-users", [:name, :email, :twitter_handle,
:favorite_sweater], :when => :indexable)

or

asari_index("search-domain-for-users", [:name, :email, :twitter_handle,
:favorite_sweater], :when => Proc.new { |user| !user.admin && user.indexable })

This provides a way to mark records that shouldn't be in the index. The :when option can be either a symbol - indicating a method on the object - or a Proc that accepts the object as its first parameter. If the method/Proc returns true when the object is created, the object is indexed - otherwise it is left out of the index. If the method/Proc returns true when the object is updated, the object is indexed - otherwise it is deleted from the index (if it has already been added). This lets you be sure that you never have inappropriate data in your search index.

Because index updates are done as part of the AR lifecycle by default, you also might want to have control over how Asari handles index update errors - it's kind of problematic, if, say, users can't sign up on your site because CloudSearch isn't available at the moment. By default Asari just raises these exceptions when they occur, but you can define a special handler if you want using the asari_on_error method:

class User < ActiveRecord::Base
  include Asari::ActiveRecord

  asari_index(... )

  def self.asari_on_error(exception)
    Airbrake.notify(...)
    true
  end
end

In the above example we decide that, instead of raising exceptions every time, we're going to log exception data to Airbrake so that we can review it later and then return true so that the AR lifecycle continues normally.

AWS Region

By default, Asari assumes that you're operating in us-east-1, which is probably not a helpful assumption for some of you. To fix this, either set the aws_region property on your raw Asari object:

a = Asari.new("my-search-domain")
a.aws_region = "us-west-1"

...Or provide the :aws_region option when you call asari_index on an ActiveRecord model:

class User < ActiveRecord::Base
  include Asari::ActiveRecord

  asari_index("my-search-domain",[field1,field2], :aws_region => "us-west-1")

  ...
end

Get it

It's a gem named asari. Install it and make it available however you prefer.

Asari is developed on ruby 1.9.3, and the ActiveRecord portion has been tested with Rails 3.2. I don't know off-hand of any reasons that it shouldn't work in other environments, but be aware that it hasn't (yet) been tested.

Contributions

If Asari interests you and you think you might want to contribute, hit me up on Github. You can also just fork it and make some changes, but there's a better chance that your work won't be duplicated or rendered obsolete if you check in on the current development status first.

Gem requirements/etc. should be handled by Bundler.

Contributors

• Lance Gleason
• Emil Soman
• Chris Vincent
• Kyle Meyer
• Brentan Alexander

License

Copyright (C) 2012 by Tommy Morgan

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.