# Ransack [![Build Status](https://travis-ci.org/activerecord-hackery/ransack.svg)] (https://travis-ci.org/activerecord-hackery/ransack) [![Gem Version](https://badge.fury.io/rb/ransack.svg)] (http://badge.fury.io/rb/ransack) Ransack is a rewrite of [MetaSearch] (https://github.com/activerecord-hackery/meta_search) created by [Ernie Miller](http://twitter.com/erniemiller) and maintained by [Ryan Bigg](http://twitter.com/ryanbigg), [Jon Atack](http://twitter.com/jonatack) 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](http://ransack-demo.herokuapp.com/users/advanced_search) search forms against your application's models (demo source code [here](https://github.com/activerecord-hackery/ransack_demo)). 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](https://github.com/activerecord-hackery/squeel) instead. ## Getting started Because ActiveRecord has been evolving quite a bit, your friendly Ransack is available in several flavors! Take your pick: In your Gemfile, for the last officially released gem compatible with Rails 3.x, 4.0 and 4.1 (for Rails 4.2, use the dedicated `rails-4.2` branch described below for now): ```ruby gem 'ransack' ``` Or if you want to use the latest updates on the Ransack master branch: ```ruby gem 'ransack', github: 'activerecord-hackery/ransack' ``` If you are using Rails 4.1, you may prefer the dedicated [Rails 4.1 branch] (https://github.com/activerecord-hackery/ransack/tree/rails-4.1) which usually contains the latest updates on master (albeit sometimes with some delay), supports only 4.1, and is lighter and somewhat faster: ```ruby gem 'ransack', github: 'activerecord-hackery/ransack', branch: 'rails-4.1' ``` Similarly, if you are using Rails 4.0, you may prefer the dedicated [Rails 4 branch](https://github.com/activerecord-hackery/ransack/tree/rails-4) for the same reasons: ```ruby gem 'ransack', github: 'activerecord-hackery/ransack', branch: 'rails-4' ``` Last but definitely not least, an experimental [Rails 4.2 branch] (https://github.com/activerecord-hackery/ransack/tree/rails-4.2) is available: ```ruby gem 'ransack', github: 'activerecord-hackery/ransack', branch: 'rails-4.2' ``` ## 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 `Search#result`. 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. Please note that for many databases, a sort on an associated table's columns will result in invalid SQL with `distinct: true` -- in those cases, you're on your own, and will need to modify the result as needed to allow these queries to work. Thankfully, 9 times out of 10, sort against the search's base is sufficient, though, as that's generally what's being displayed on your results page. ####In your controller ```ruby def index @q = Person.search(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): ```ruby def index @q = Person.search(params[:q]) @people = @q.result.includes(:articles).page(params[:page]) end ``` The default `AND` grouping can be changed to `OR` by adding `m: 'or'` to the query hash. In Rails console: ```ruby artists = Artist.search(name_cont: 'foo', style_cont: 'bar', m: 'or') => Ransack::Search, Condition ], combinator: or>> artists.result.to_sql => "SELECT \"artists\".* FROM \"artists\" WHERE ((\"artists\".\"name\" ILIKE '%foo%' OR \"artists\".\"style\" ILIKE '%bar%'))" ``` This works with associations as well. Imagine an Artist model that has many Memberships, and many Musicians through Memberships: ```ruby artists = Artist.search(name_cont: 'foo', musicians_email_cont: 'bar', m: 'or') => Ransack::Search, Condition ], 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%'))" ``` ####In your view The two primary Ransack view helpers are `search_form_for` and `sort_link`, which are defined in [Ransack::Helpers::FormHelper](lib/ransack/helpers/form_helper.rb). #####1. Ransack's `search_form_for` helper replaces `form_for` for creating the view search form: ```erb <%= 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] (https://github.com/activerecord-hackery/ransack/blob/master/lib/ransack/constants.rb) for a full list and the [wiki] (https://github.com/activerecord-hackery/ransack/wiki/Basic-Searching) for more information. The `search_form_for` answer format can be set like this: ```erb <%= search_form_for(@q, format: :pdf) do |f| %> <%= search_form_for(@q, format: :json) do |f| %> ``` #####2. Ransack's `sort_link` helper creates table headers that are sortable links: ```erb <%= content_tag :th, sort_link(@q, :name) %> ``` Additional options can be passed after the column attribute, like a different column title or a default sort order: ```erb <%= content_tag :th, sort_link(@q, :name, 'Last Name', default_order: :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... ```ruby resources :people do collection do match 'search' => 'people#search', via: [:get, :post], as: :search end end ``` ... and add another controller action ... ```ruby def search index render :index end ``` ... and update your `search_form_for` line in the view ... ```erb <%= 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](lib/ransack/helpers/form_builder.rb) to construct much more complex search forms, such as the one on the [demo page](http://ransack-demo.heroku.com) (source code [here](https://github.com/activerecord-hackery/ransack_demo)). ### Ransack #search method Ransack will try to to make `#search` available in your models, but in the case that `#search` has already been defined, you can use `#ransack` instead. For example the following would be equivalent: ```ruby Article.search(params[:q]) Article.ransack(params[:q]) ``` ### Associations You can easily use Ransack to search for objects in `has_many` and `belongs_to` associations. Given you have these associations ... ```ruby class Employee < ActiveRecord::Base belongs_to :supervisor # has attribute 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 ... ```ruby class SupervisorsController < ApplicationController def index @q = Supervisor.search(params[:q]) @supervisors = @q.result.includes(:department, :employees) end end ``` ... you might set up your form like this ... ```erb <%= 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_last_name_cont %> <%= f.search_field :employees_last_name_cont %> <%= f.submit "search" %> <% end %> ... <%= content_tag :table %> <%= content_tag :th, sort_link(@q, :last_name) %> <%= content_tag :th, sort_link(@q, 'departments.title') %> <%= content_tag :th, sort_link(@q, 'employees.last_name') %> <% 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! ### Using SimpleForm If you want to combine form builders of ransack and SimpleForm, just set the RANSACK_FORM_BUILDER environment variable before Rails started, e.g. in ``config/application.rb`` before ``require 'rails/all'`` and of course use ``gem 'simple_form'`` in your ``Gemfile``: ```ruby require File.expand_path('../boot', __FILE__) ENV['RANSACK_FORM_BUILDER'] = '::SimpleForm::FormBuilder' require 'rails/all' ``` ### Authorization (whitelisting/blacklisting) By default, searching and sorting are authorized on any column of your model. 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: ```ruby def ransackable_attributes(auth_object = nil) # Returns the string names of all columns and any defined ransackers. column_names + _ransackers.keys end def ransackable_associations(auth_object = nil) # Returns the names of all associations. reflect_on_all_associations.map { |a| a.name.to_s } end def ransackable_scopes(auth_object = nil) # For overriding with a whitelist of symbols. [] end def ransortable_attributes(auth_object = nil) # Here so users can overwrite the attributes that show up in the sort_select. ransackable_attributes(auth_object) end ``` Any values not returned from these methods will be ignored by Ransack. 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): ```ruby # article.rb class Article < ActiveRecord::Base private 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 end ``` Here is example code for the `articles_controller`: ```ruby # articles_controller.rb class ArticlesController < ApplicationController def index @q = Article.search(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`: ```ruby > 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.search(id_eq: 1).result.to_sql => SELECT "articles".* FROM "articles" # Note that search param was ignored! > Article.search({ id_eq: 1 }, { auth_object: nil }).result.to_sql => SELECT "articles".* FROM "articles" # Search param still ignored! > Article.search({ 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. ### Scopes Continuing on from the preceding section, searching by scope requires defining a whitelist of `ransackable_scopes` on the model class. 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: ```ruby Employee.search({ active: true, hired_since: '2013-01-01' }) Employee.search({ salary_gt: 100_000 }, { auth_object: current_user }) ``` ### I18n Ransack translation files are available in [Ransack::Locale](lib/ransack/locale). You may also be interested in one of the many translations for Ransack available at http://www.localeapp.com/projects/2999. ## 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 is awesome. A pull request with tests that pass is even better! Before filing an issue or pull request, be sure to read the [Contributing Guide](CONTRIBUTING.md). * 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! ## Copyright Copyright © 2011-2014 [Ernie Miller](http://twitter.com/erniemiller)