Ransack

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Ransack is a rewrite of [MetaSearch] (https://github.com/activerecord-hackery/meta_search) created by Ernie Miller and maintained by Ryan Bigg, Jon Atack and a great group of [contributors] (https://github.com/activerecord-hackery/ransack/graphs/contributors). While it supports many of the same features as MetaSearch, its underlying implementation differs greatly from MetaSearch, and backwards compatibility is not a design goal.

Ransack enables the creation of both simple and advanced search forms for your Ruby on Rails application (demo source code here). If you're looking for something that simplifies query generation at the model or controller layer, you're probably not looking for Ransack (or MetaSearch, for that matter). Try Squeel instead.

If you're viewing this at github.com/activerecord-hackery/ransack, you're reading the documentation for the master branch with the latest features. View documentation for the last release (1.8.2).

Getting started

Ransack is compatible with Rails 3, 4 and 5 on Ruby 1.9 and later. JRuby 9 ought to work as well (see this). If you are using Ruby 1.8 or an earlier JRuby and run into compatibility issues, you can use an earlier version of Ransack, say, up to 1.3.0.

Ransack works out-of-the-box with Active Record and also features limited support for Mongoid 4 and 5 (without associations, further details below).

In your Gemfile, for the last officially released gem:

gem 'ransack'

If you would like to use the latest updates (recommended), use the master branch:

gem 'ransack', github: 'activerecord-hackery/ransack'

If you are using Rails 5 or master and need pagination compatible with it and Ransack, there is a Rails 5 version of the will_paginate gem here. It is also optimized for Ruby 2.2+. To use it, in your Gemfile: gem 'will_paginate', github: 'jonatack/will_paginate'.

Issues tracker

• Before filing an issue, please read the Contributing Guide.
• File an issue if a bug is caused by Ransack, is new (has not already been reported), and can be reproduced from the information you provide.
• Contributions are welcome, but please do not add "+1" comments to issues or pull requests 😃
• Please do not use the issue tracker for personal support requests. Stack Overflow is a better place for that where a wider community can help you!

Usage

Ransack can be used in one of two modes, simple or advanced.

Simple Mode

This mode works much like MetaSearch, for those of you who are familiar with it, and requires very little setup effort.

If you're coming from MetaSearch, things to note:

1. The default param key for search params is now :q, instead of :search. This is primarily to shorten query strings, though advanced queries (below) will still run afoul of URL length limits in most browsers and require a switch to HTTP POST requests. This key is [configurable] (https://github.com/activerecord-hackery/ransack/wiki/Configuration).

2. form_for is now search_form_for, and validates that a Ransack::Search object is passed to it.

3. Common ActiveRecord::Relation methods are no longer delegated by the search object. Instead, you will get your search results (an ActiveRecord::Relation in the case of the ActiveRecord adapter) via a call to Ransack#result.

####In your controller

def index
  @q = Person.ransack(params[:q])
  @people = @q.result(distinct: true)
end

or without distinct: true, for sorting on an associated table's columns (in this example, with preloading each Person's Articles and pagination):

def index
  @q = Person.ransack(params[:q])
  @people = @q.result.includes(:articles).page(params[:page])

  # or use `to_a.uniq` to remove duplicates (can also be done in the view):
  @people = @q.result.includes(:articles).page(params[:page]).to_a.uniq
end

####In your view

The two primary Ransack view helpers are search_form_for and sort_link, which are defined in Ransack::Helpers::FormHelper.

####Ransack's search_form_for helper replaces form_for for creating the view search form

<%= search_form_for @q do |f| %>

  # Search if the name field contains...
  <%= f.label :name_cont %>
  <%= f.search_field :name_cont %>

  # Search if an associated articles.title starts with...
  <%= f.label :articles_title_start %>
  <%= f.search_field :articles_title_start %>

  # Attributes may be chained. Search multiple attributes for one value...
  <%= f.label :name_or_description_or_email_or_articles_title_cont %>
  <%= f.search_field :name_or_description_or_email_or_articles_title_cont %>

  <%= f.submit %>
<% end %>

cont (contains) and start (starts with) are just two of the available search predicates. See Constants for a full list and the wiki for more information.

The search_form_for answer format can be set like this:

<%= search_form_for(@q, format: :pdf) do |f| %>

<%= search_form_for(@q, format: :json) do |f| %>

####Ransack's sort_link helper creates table headers that are sortable links

<%= sort_link(@q, :name) %>

Additional options can be passed after the column attribute, like a different column title or a default sort order:

<%= sort_link(@q, :name, 'Last Name', default_order: :desc) %>

You can use a block if the link markup is hard to fit into the label parameter:

<%= sort_link(@q, :name) do %>
  <strong>Player Name</strong>
<% end %>

With a polymorphic association, you may need to specify the name of the link explicitly to avoid an uninitialized constant Model::Xxxable error (see issue #421):

<%= sort_link(@q, :xxxable_of_Ymodel_type_some_attribute, 'Attribute Name') %>

You can also sort on multiple fields by specifying an ordered array:

<%= sort_link(@q, :last_name, [:last_name, 'first_name asc'], 'Last Name') %>

In the example above, clicking the link will sort by last_name and then first_name. Specifying the sort direction on a field in the array tells Ransack to always sort that particular field in the specified direction.

Multiple default_order fields may also be specified with a hash:

<%= sort_link(@q, :last_name, %i(last_name first_name),
  default_order: { last_name: 'asc', first_name: 'desc' }) %>

This example toggles the sort directions of both fields, by default initially sorting the last_name field by ascending order, and the first_name field by descending order.

The sort link may be displayed without the order indicator arrow by passing hide_indicator: true:

<%= sort_link(@q, :name, hide_indicator: true) %>

Alternatively, all sort links may be displayed without the order indicator arrow by adding this to an initializer file like config/initializers/ransack.rb:

Ransack.configure do |c|
  c.hide_sort_order_indicators = true
end

####Ransack's sort_url helper is like a sort_link but returns only the url

sort_url has the same API as sort_link:

<%= sort_url(@q, :name, default_order: :desc) %>

<%= sort_url(@q, :last_name, [:last_name, 'first_name asc']) %>

<%= sort_url(@q, :last_name, %i(last_name first_name),
  default_order: { last_name: 'asc', first_name: 'desc' }) %>

Advanced Mode

"Advanced" searches (ab)use Rails' nested attributes functionality in order to generate complex queries with nested AND/OR groupings, etc. This takes a bit more work but can generate some pretty cool search interfaces that put a lot of power in the hands of your users. A notable drawback with these searches is that the increased size of the parameter string will typically force you to use the HTTP POST method instead of GET. :(

This means you'll need to tweak your routes...

resources :people do
  collection do
    match 'search' => 'people#search', via: [:get, :post], as: :search
  end
end

... and add another controller action ...

def search
  index
  render :index
end

... and update your search_form_for line in the view ...

<%= search_form_for @q, url: search_people_path,
                        html: { method: :post } do |f| %>

Once you've done so, you can make use of the helpers in Ransack::Helpers::FormBuilder to construct much more complex search forms, such as the one on the demo app (source code here).

Ransack #search method

Ransack will try to to make the class method #search available in your models, but if #search has already been defined elsewhere, you can always use the default #ransack class method. So the following are equivalent:

Article.ransack(params[:q])
Article.search(params[:q])

Users have reported issues of #search name conflicts with other gems, so the #search method alias will be deprecated in the next major version of Ransack (2.0). It's advisable to use the default #ransack instead.

For now, if Ransack's #search method conflicts with the name of another method named search in your code or another gem, you may resolve it either by patching the extended class_method in Ransack::Adapters::ActiveRecord::Base to remove the line alias :search :ransack unless base.respond_to? :search, or by placing the following line in your Ransack initializer file at config/initializers/ransack.rb:

Ransack::Adapters::ActiveRecord::Base.class_eval('remove_method :search')

Associations

You can easily use Ransack to search for objects in has_many and belongs_to associations.

Given these associations...

class Employee < ActiveRecord::Base
  belongs_to :supervisor

  # has attributes first_name:string and last_name:string
end

class Department < ActiveRecord::Base
  has_many :supervisors

  # has attribute title:string
end

class Supervisor < ActiveRecord::Base
  belongs_to :department
  has_many :employees

  # has attribute last_name:string
end

... and a controller...

class SupervisorsController < ApplicationController
  def index
    @q = Supervisor.ransack(params[:q])
    @supervisors = @q.result.includes(:department, :employees)
  end
end

... you might set up your form like this...

<%= search_form_for @q do |f| %>
  <%= f.label :last_name_cont %>
  <%= f.search_field :last_name_cont %>

  <%= f.label :department_title_cont %>
  <%= f.search_field :department_title_cont %>

  <%= f.label :employees_first_name_or_employees_last_name_cont %>
  <%= f.search_field :employees_first_name_or_employees_last_name_cont %>

  <%= f.submit "search" %>
<% end %>
...
<%= content_tag :table do %>
  <%= content_tag :th, sort_link(@q, :last_name) %>
  <%= content_tag :th, sort_link(@q, :department_title) %>
  <%= content_tag :th, sort_link(@q, :employees_last_name) %>
<% end %>

If you have trouble sorting on associations, try using an SQL string with the pluralized table ('departments.title','employees.last_name') instead of the symbolized association (:department_title), :employees_last_name).

Ransack Aliases

You can customize the attribute names for your Ransack searches by using a ransack_alias. This is particularly useful for long attribute names that are necessary when querying associations or multiple columns.

class Post < ActiveRecord::Base
  belongs_to :author

  # Abbreviate :author_first_name_or_author_last_name to :author
  ransack_alias :author, :author_first_name_or_author_last_name
end

Now, rather than using :author_first_name_or_author_last_name_cont in your form, you can simply use :author_cont. This serves to produce more expressive query parameters in your URLs.

<%= search_form_for @q do |f| %>
  <%= f.label :author_cont %>
  <%= f.search_field :author_cont %>
<% end %>

Using Ransackers to add custom search functions via Arel

The main premise behind Ransack is to provide access to Arel predicate methods. Ransack provides special methods, called ransackers, for creating additional search functions via Arel. More information about ransacker methods can be found [here in the wiki] (https://github.com/activerecord-hackery/ransack/wiki/Using-Ransackers). Feel free to contribute working ransacker code examples to the wiki!

Problem with DISTINCT selects

If passed distinct: true, result will generate a SELECT DISTINCT to avoid returning duplicate rows, even if conditions on a join would otherwise result in some. It generates the same SQL as calling uniq on the relation.

Please note that for many databases, a sort on an associated table's columns may result in invalid SQL with distinct: true -- in those cases, you will will need to modify the result as needed to allow these queries to work.

For example, you could call joins and includes on the result which has the effect of adding those tables columns to the select statement, overcoming the issue, like so:

def index
  @q = Person.ransack(params[:q])
  @people = @q.result(distinct: true)
              .includes(:articles)
              .joins(:articles)
              .page(params[:page])
end

If the above doesn't help, you can also use ActiveRecord's select query to explicitly add the columns you need, which brute force's adding the columns you need that your SQL engine is complaining about, you need to make sure you give all of the columns you care about, for example:

def index
  @q = Person.ransack(params[:q])
  @people = @q.result(distinct: true)
              .select('people.*, articles.name, articles.description')
              .page(params[:page])
end

A final way of last resort is to call to_a.uniq on the collection at the end with the caveat that the de-duping is taking place in Ruby instead of in SQL, which is potentially slower and uses more memory, and that it may display awkwardly with pagination if the number of results is greater than the page size.

For example:

def index
  @q = Person.ransack(params[:q])
  @people = @q.result.includes(:articles).page(params[:page]).to_a.uniq
end

Authorization (whitelisting/blacklisting)

By default, searching and sorting are authorized on any column of your model and no class methods/scopes are whitelisted.

Ransack adds four methods to ActiveRecord::Base that you can redefine as class methods in your models to apply selective authorization: ransackable_attributes, ransackable_associations, ransackable_scopes and ransortable_attributes.

Here is how these four methods are implemented in Ransack:

  # `ransackable_attributes` by default returns all column names
  # and any defined ransackers as an array of strings.
  # For overriding with a whitelist array of strings.
  #
  def ransackable_attributes(auth_object = nil)
    column_names + _ransackers.keys
  end

  # `ransackable_associations` by default returns the names
  # of all associations as an array of strings.
  # For overriding with a whitelist array of strings.
  #
  def ransackable_associations(auth_object = nil)
    reflect_on_all_associations.map { |a| a.name.to_s }
  end

  # `ransortable_attributes` by default returns the names
  # of all attributes available for sorting as an array of strings.
  # For overriding with a whitelist array of strings.
  #
  def ransortable_attributes(auth_object = nil)
    ransackable_attributes(auth_object)
  end

  # `ransackable_scopes` by default returns an empty array
  # i.e. no class methods/scopes are authorized.
  # For overriding with a whitelist array of *symbols*.
  #
  def ransackable_scopes(auth_object = nil)
    []
  end

Any values not returned from these methods will be ignored by Ransack, i.e. they are not authorized.

All four methods can receive a single optional parameter, auth_object. When you call the search or ransack method on your model, you can provide a value for an auth_object key in the options hash which can be used by your own overridden methods.

Here is an example that puts all this together, adapted from [this blog post by Ernie Miller] (http://erniemiller.org/2012/05/11/why-your-ruby-class-macros-might-suck-mine-did/). In an Article model, add the following ransackable_attributes class method (preferably private):

class Article < ActiveRecord::Base
  def self.ransackable_attributes(auth_object = nil)
    if auth_object == :admin
      # whitelist all attributes for admin
      super
    else
      # whitelist only the title and body attributes for other users
      super & %w(title body)
    end
  end

  private_class_method :ransackable_attributes
end

Here is example code for the articles_controller:

class ArticlesController < ApplicationController
  def index
    @q = Article.ransack(params[:q], auth_object: set_ransack_auth_object)
    @articles = @q.result
  end

  private

  def set_ransack_auth_object
    current_user.admin? ? :admin : nil
  end
end

Trying it out in rails console:

> Article
=> Article(id: integer, person_id: integer, title: string, body: text)

> Article.ransackable_attributes
=> ["title", "body"]

> Article.ransackable_attributes(:admin)
=> ["id", "person_id", "title", "body"]

> Article.ransack(id_eq: 1).result.to_sql
=> SELECT "articles".* FROM "articles"  # Note that search param was ignored!

> Article.ransack({ id_eq: 1 }, { auth_object: nil }).result.to_sql
=> SELECT "articles".* FROM "articles"  # Search param still ignored!

> Article.ransack({ id_eq: 1 }, { auth_object: :admin }).result.to_sql
=> SELECT "articles".* FROM "articles"  WHERE "articles"."id" = 1

That's it! Now you know how to whitelist/blacklist various elements in Ransack.

Using Scopes/Class Methods

Continuing on from the preceding section, searching by scopes requires defining a whitelist of ransackable_scopes on the model class. The whitelist should be an array of symbols. By default, all class methods (e.g. scopes) are ignored. Scopes will be applied for matching true values, or for given values if the scope accepts a value:

class Employee < ActiveRecord::Base
  scope :activated, ->(boolean = true) { where(active: boolean) }
  scope :salary_gt, ->(amount) { where('salary > ?', amount) }

  # Scopes are just syntactical sugar for class methods, which may also be used:

  def self.hired_since(date)
    where('start_date >= ?', date)
  end

  def self.ransackable_scopes(auth_object = nil)
    if auth_object.try(:admin?)
      # allow admin users access to all three methods
      %i(activated hired_since salary_gt)
    else
      # allow other users to search on `activated` and `hired_since` only
      %i(activated hired_since)
    end
  end

  private_class_method :ransackable_scopes
end

Employee.ransack({ activated: true, hired_since: '2013-01-01' })

Employee.ransack({ salary_gt: 100_000 }, { auth_object: current_user })

In Rails 3 and 4, if the true value is being passed via url params or some other mechanism that will convert it to a string, the true value may not be passed to the ransackable scope unless you wrap it in an array (i.e. activated: ['true']). This is currently resolved in Rails 5 😃

Scopes are a recent addition to Ransack and currently have a few caveats: First, a scope involving child associations needs to be defined in the parent table model, not in the child model. Second, scopes with an array as an argument are not easily usable yet, because the array currently needs to be wrapped in an array to function (see this issue), which is not compatible with Ransack form helpers. For this use case, it may be better for now to use [ransackers] (https://github.com/activerecord-hackery/ransack/wiki/Using-Ransackers) instead, where feasible. Pull requests with solutions and tests are welcome!

Grouping queries by OR instead of AND

The default AND grouping can be changed to OR by adding m: 'or' to the query hash.

You can easily try it in your controller code by changing params[:q] in the index action to params[:q].try(:merge, m: 'or') as follows:

def index
  @q = Artist.ransack(params[:q].try(:merge, m: 'or'))
  @artists = @q.result
end

Normally, if you wanted users to be able to toggle between AND and OR query grouping, you would probably set up your search form so that m was in the URL params hash, but here we assigned m manually just to try it out quickly.

Alternatively, trying it in the Rails console:

artists = Artist.ransack(name_cont: 'foo', style_cont: 'bar', m: 'or')
=> Ransack::Search<class: Artist, base: Grouping <conditions: [
  Condition <attributes: ["name"], predicate: cont, values: ["foo"]>,
  Condition <attributes: ["style"], predicate: cont, values: ["bar"]>
  ], combinator: or>>

artists.result.to_sql
=> "SELECT \"artists\".* FROM \"artists\"
    WHERE ((\"artists\".\"name\" ILIKE '%foo%'
    OR \"artists\".\"style\" ILIKE '%bar%'))"

The combinator becomes or instead of the default and, and the SQL query becomes WHERE...OR instead of WHERE...AND.

This works with associations as well. Imagine an Artist model that has many Memberships, and many Musicians through Memberships:

artists = Artist.ransack(name_cont: 'foo', musicians_email_cont: 'bar', m: 'or')
=> Ransack::Search<class: Artist, base: Grouping <conditions: [
  Condition <attributes: ["name"], predicate: cont, values: ["foo"]>,
  Condition <attributes: ["musicians_email"], predicate: cont, values: ["bar"]>
  ], combinator: or>>

artists.result.to_sql
=> "SELECT \"artists\".* FROM \"artists\"
    LEFT OUTER JOIN \"memberships\"
      ON \"memberships\".\"artist_id\" = \"artists\".\"id\"
    LEFT OUTER JOIN \"musicians\"
      ON \"musicians\".\"id\" = \"memberships\".\"musician_id\"
    WHERE ((\"artists\".\"name\" ILIKE '%foo%'
    OR \"musicians\".\"email\" ILIKE '%bar%'))"

Using SimpleForm

If you would like to combine the Ransack and SimpleForm form builders, set the RANSACK_FORM_BUILDER environment variable before Rails boots up, e.g. in config/application.rb before require 'rails/all' as shown below (and add gem 'simple_form' in your Gemfile).

require File.expand_path('../boot', __FILE__)
ENV['RANSACK_FORM_BUILDER'] = '::SimpleForm::FormBuilder'
require 'rails/all'

I18n

Ransack translation files are available in Ransack::Locale. You may also be interested in one of the many translations for Ransack available at http://www.localeapp.com/projects/2999.

Predicate and attribute translations in forms may be specified as follows (see the translation files in Ransack::Locale for more examples):

locales/en.yml:

en:
  ransack:
    asc: ascending
    desc: descending
    predicates:
      cont: contains
      not_cont: not contains
      start: starts with
      end: ends with
      gt: greater than
      lt: less than
    models:
      person: Passanger
    attributes:
      person:
        name: Full Name
      article:
        title: Article Title
        body: Main Content

Attribute names may also be changed globally, or under activerecord:

en:
  attributes:
    model_name:
      model_field1: field name1
      model_field2: field name2
  activerecord:
    attributes:
      namespace/article:
        title: AR Namespaced Title
      namespace_article:
        title: Old Ransack Namespaced Title

Mongoid

Ransack works with Mongoid in the same way as Active Record, except that with Mongoid, associations are not currently supported. Demo source code may be found here. A result method called on a ransack search returns a Mongoid::Criteria object:

  @q = Person.ransack(params[:q])
  @people = @q.result # => Mongoid::Criteria

  # or you can add more Mongoid queries
  @people = @q.result.active.order_by(updated_at: -1).limit(10)

NOTE: Ransack currently works with either Active Record or Mongoid, but not both in the same application. If both are present, Ransack will default to Active Record only. The logic is contained in Ransack::Adapters#instantiate_object_mapper should you need to override it.

Semantic Versioning

Ransack attempts to follow semantic versioning in the format of x.y.z, where:

x stands for a major version (new features that are not backward-compatible).

y stands for a minor version (new features that are backward-compatible).

z stands for a patch (bug fixes).

In other words: Major.Minor.Patch.

Contributions

To support the project:

• Use Ransack in your apps, and let us know if you encounter anything that's broken or missing. A failing spec to demonstrate the issue is awesome. A pull request with passing tests is even better!
• Before filing an issue or pull request, be sure to read and follow the Contributing Guide.
• Please use Stack Overflow or other sites for questions or discussion not directly related to bug reports, pull requests, or documentation improvements.
• Spread the word on Twitter, Facebook, and elsewhere if Ransack's been useful to you. The more people who are using the project, the quicker we can find and fix bugs!