Ruby on Rails Get Query Filter

Given a GET request is made to “/users?<some-query-here>”, then all users that meet the query criteria are returned in a JSON array, and the status code is 200.

first we will create our index action that renders users and set a before_action that calls filter_users before the index action is called.

class UsersController < ApplicationController
  before_action :filter_users, only: %i[ index ]
  # GET /users
  def index
    render json: @users, status: :ok
  end
end

The next step is to write filter_users action. In our filter_users action we will check first if there is a query string using request.query_string.present?. If query string is present in the url parse it using CGI.parse(request.query_string) then return query from database using where, else return all users.

private
# filters users based on query params
def filter_users
  if request.query_string.present?
     filter_params = CGI.parse(request.query_string)
     @users = User.where(filter_params)
  else
    @users = User.all
  end
end

Full Code

class UsersController < ApplicationController
  before_action :filter_users, only: %i[ index ]
  # GET /users
  def index
    render json: @users, status: :ok
  end
  private
  # filters users based on query params
  def filter_users
    if request.query_string.present?
      filter_params = CGI.parse(request.query_string)
      @users = User.where(filter_params)
    else
      @users = User.all
    end
  end
end

Happy Coding