IndexQueryBuilder

This gem provides a DSL on top of ActiveRecord to get collection of models for index pages with filters.

Add this line to your application's Gemfile:

gem 'index_query_builder'

And then execute:

$ bundle

Or install it yourself as:

$ gem install index_query_builder

Let's say you have the following schema:

create_table :posts, force: true do |t|
  t.text :title
  t.integer :view_count
end

create_table :comments, force: true do |t|
  t.integer :post_id
  t.text :text
end

And the following models

class Post < ActiveRecord::Base
  has_many :comments
end

class Comment < ActiveRecord::Base
  belongs_to :post
end

And you are building an index page for posts with the following requirements:

• Posts should be ordered by view_count.
• The user should be able to filter posts by texts in post's comments. For example, if filters is { comment_text: 'This post is amazing' }, then we should return all the posts with a comment containing 'This post is amazing'.
• More filters will be added soon.

Without Index Query Builder, you will probably have to do something like this.

conditions_strings = []
conditions_params = {}

unless filters[:comment_text].blank?
  conditions_strings << "comments.text ILIKE :comment_text"
  conditions_params[:comment_text] = "%#{filters[:comment_text]}%"
end

conditions = (conditions_params.empty? ? "" : [conditions_strings.join(" AND "), conditions_params])

joins_list = []
joins_list << {:posts => :comment} if filters[:comment_text].present?

posts = Post.where(conditions).joins(joins_list).order("expected_ship_at desc, id desc")

Or, with Index Query Builder, you can just write this.

posts = IndexQueryBuilder.query Post, with: filters do |query|
  query.filter_field [:comments, :text], contains: :comment_text
  query.order_by "view_count DESC"
end

Operators will apply where clauses to query only if the filter_name is present in filters hash.

• :equal_to applies field_name = filter_value
• :contains applies substring (ILIKE '%filter_value%')
• :greater_than_or_equal_to applies field_name >= filter_value
• :less_than applies field_name < filter_value
• :present_if applies:
  • field_name IS NOT NULL if filter_value
  • field_name IS NULL if !filter_value

Find more in the docs

It requires PostgreSQL.

$ cp config/database.yml.sample config/database.yml

Update config/database.yml with your connection information.

$ rake db:test:setup
$ rspec

1. Fork it ( https://github.com/arturopie/index_query_builder/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request