How to query database and filter results (Ember.js + Rails)

Question

UPDATE: I've found a way that works, though it's not very flexible, by taking the params hash and comparing its keys to my model's column names. I then take that array of names and map it to a hash, that I then use in my ActiveRecord query. There must be a better way?

  def index
    if params
      hash = {}
      attributes = User.column_names & params.keys
      attributes.each do |attribute|
        hash.merge!(attribute.to_sym => params[attribute.to_sym])
      end
      @users = User.where(hash)
    else
      @users = User.all
    end
    respond_with @users
  end

---

BACKGROUND: I've hooked up an Ember app to a Rails JSON API and have figured out how to query the database using Ember-Data. Below is an example in Coffeescript:

App.UsersRoute = Ember.Route.extend
  model: ->
    # Step 1: Query database for all users
    @store.find('user')

    # Step 2: Filter results (keep male users named "Steve")
    @store.filter 'user', (user)->
      user.get('name') == "Steve" && user.get('gender') == "Male"

OBJECTIVE: I'm wondering if this is the best way to go about this? Wouldn't querying for all users get increasingly difficult as the number of users increases?

I'm thinking a good alternative would be to include the query as parameters on my initial query, like so:

@store.find 'user', {name: "Steve", gender: "Male"}
# Sends JSON request to /users.json?name=Steve&gender=Male

If this is a better approach, I am stumped as to how to make Rails take these two parameters and query the database for them. Below is my Rails controller that responds to the above request:

class Api::V1::UsersController < ApplicationController
  respond_to :json

  def index
    respond_with User.all
  end
end

In order to accommodate the above request, I'd have to do something like this:

  def index
    respond_with User.where(name: params[:name], gender: params[:gender])
  end

But this would not accommodate any additional queries, or queries that don't have both of these params set. Which of these two approaches is best?

Answer 1

You can try doing like this, it allows you to customize your where and other clauses depending upon input params:-

def index
    @user = User
if params[:name].present? && params[:gender].present?
    @user =  @user.where(name: params[:name], gender: params[:gender])
end

@user = @user.all
.....
  end