CODEWITHSUNDEEP
ruby-on-railsruby-on-rails-3web-servicesrestruby-on-rails-4
Katie
Katie

Reputation: 27

Validate paramaters in Restful endpoints

I am rookie in rails restful web service and i am trying build service that returns a json dump of deals.So far my app returns these deals in json format when you hit http://localhost:3000/api/deals. Now i want to add two mandatory parameters(deal_id and title) and two optional parameters in the uri http://localhost:3000/api/deals?deal_id=2&title=book. What is the best way to validate these two mandatory parameters?In other words I just want to do the query only if deal_id and title parameters are present. Assuming Deal model has fields deal_id, title, description and vendor.
Here is my code

Controller

  module Api
  class DealsController < ApplicationController
  respond_to :json

  def index
   @deals = Deal.all
   respond_with (@deals)
  end
 end
end

routes

 namespace :api,:defaults => {format:'json'} do
 resources :deals
end

Upvotes: 0

Views: 459

Answers (1)

steve klein
steve klein

Reputation: 2629

To validate presence of query parameters in a Rails route, you can use the :constraints option. So, in your case, if you want to require the presence of parameters deal_id and title, you can do so by changing:

resources :deals

To:

resources :deals, :constraints => lambda{ |req| !req.params[:deal_id].blank? && !req.params[:title].blank? }

Then, in your controller, you can access all four parameters in the params hash.

Alternatively, if you want to provide more user friendly error messages, you can do validation in the controller. There are a number of approaches. I would probably do something like this:

def action
  if params[:deal_id].blank? || params[:title].blank?
    flash[:warning] = 'Deal ID and title must be present'
    redirect_to root_path and return
  end

  #rest of your code goes here
end

Upvotes: 1

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