Doing search by count in json with params results

Question

I'm trying to implement a counter filter in my json. When I access the url api/v1/contacts?Results=2 [sic], I would like to get only two results from my json.

For this, I created two methods in my controller: an index that takes the information from the database and turns render into json, and a method that returns the number of times the json is returned.

class Api::V1::ContactsController < ApplicationController

  before_action :results, only: [:index]

  def index
    @contacts = Contact.all
    render json: {results: @contacts[0..@number_results]}
  end


  def results
    if params[:results]
      results = params[:results]["results"]
      @number_results = results.to_i
    else
      @number_results = 3
    end
  end
end

Regardless of the value entered for results =, the value of @number_results is set to 0, so whenever I type results = I, get only the first result of json. If I do not type results = in the url, it sets @number_results to 3, and shows four results on the screen.

Can anyone help?

Answer 1

First, in the url you propose, "Results" is capitalized. If that is how you intend to submit it, then you'll need to search for it that way on the back end. But since all your code uses lowercase "results", we'll go with that. You should modify your url in the same way: api/v1/contacts?results=2.

If that's what your url looks like then the number you pass in is accessible in params[:results]. If you pass no parameter, then params[:results] will return nil. Don't call #to_i on the param before you check for its existence, because nil.to_i is 0.

All that said, here's what you probably want:

class Api::V1::ContactsController < ApplicationController
  def index
    number_results = params[:results] || 3
    @contacts = Contact.all.limit(number_results.to_i)
    render json: {results: @contacts}
  end
end

If the result of params[:results] is nil, then number_results is assigned 3.

Now we use #limit to return only the number of contacts that was requested. This allows us to do away with the #results method entirely. You can also get rid of the before_action callback.