Rails 500 on OPTIONS request

Question

I'm making a cors ajax request to http://api.localhost.com:3000/v1/send.json and am getting a 500 error I can't explain (rails 4).

In /etc/hosts:

127.0.0.1 api.localhost.com

In routes/config.rb:

  # api
  namespace :api, :path => "", :constraints => {:subdomain => "api"}, :defaults => {:format => :json} do
    namespace :v1 do
      match "send" => "mvp#send", :as => "mvp_send", :via => [:post, :options]
    end
  end

In app/controllers/api/v1/mvp_controller.rb:

class API::V1::MvpController < ApplicationController
  skip_before_filter :verify_authenticity_token
  before_filter :cors_preflight_check
  after_filter :cors_set_access_control_headers

  layout false

  def send
    Rails.logger.debug "send in MVP Controller"
    render :json => { }, :status => 200
  end


  protected
  def cors_preflight_check
    Rails.logger.debug "cors_preflight_check in MVP controller"
    if request.options?
      access_control_headers
    else
      Rails.logger.debug "not an options method"
    end
    render :json => { }, :status => 200
  end

  def cors_set_access_control_headers
    access_control_headers
  end

  def access_control_headers
    headers['Access-Control-Allow-Origin'] = '*'
    headers['Access-Control-Allow-Methods'] = 'POST, OPTIONS'
    headers['Access-Control-Request-Method'] = '*'
    headers['Access-Control-Allow-Headers'] = 'Origin, X-API-Token, Content-Type'
    headers['Access-Control-Max-Age'] = '1728000'
  end
end

and the error in rails s console:

Started OPTIONS "/v1/send.json" for 127.0.0.1 at 2014-03-02 09:17:58 -0700
Processing by API::V1::MvpController#send as JSON
  Parameters: {"subdomain"=>"api"}
Completed 500 Internal Server Error in 0ms

ArgumentError - wrong number of arguments (1 for 0):
  activesupport (4.0.0) lib/active_support/callbacks.rb:369:in `__define_callbacks'
  activesupport (4.0.0) lib/active_support/callbacks.rb:79:in `run_callbacks'
  actionpack (4.0.0) lib/abstract_controller/callbacks.rb:17:in `process_action'
  actionpack (4.0.0) lib/action_controller/metal/rescue.rb:29:in `process_action'
  actionpack (4.0.0) lib/action_controller/metal/instrumentation.rb:31:in `block in process_action'
  activesupport (4.0.0) lib/active_support/notifications.rb:159:in `block in instrument'
  activesupport (4.0.0) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
  activesupport (4.0.0) lib/active_support/notifications.rb:159:in `instrument'
  actionpack (4.0.0) lib/action_controller/metal/instrumentation.rb:30:in `process_action'
  actionpack (4.0.0) lib/action_controller/metal/params_wrapper.rb:245:in `process_action'
  activerecord (4.0.0) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
  actionpack (4.0.0) lib/abstract_controller/base.rb:136:in `process'
  actionpack (4.0.0) lib/abstract_controller/rendering.rb:44:in `process'
  actionpack (4.0.0) lib/action_controller/metal.rb:195:in `dispatch'
  actionpack (4.0.0) lib/action_controller/metal/rack_delegation.rb:13:in `dispatch'
  actionpack (4.0.0) lib/action_controller/metal.rb:231:in `block in action'
  actionpack (4.0.0) lib/action_dispatch/routing/route_set.rb:80:in `dispatch'
  actionpack (4.0.0) lib/action_dispatch/routing/route_set.rb:48:in `call'
  actionpack (4.0.0) lib/action_dispatch/journey/router.rb:71:in `block in call'
  actionpack (4.0.0) lib/action_dispatch/journey/router.rb:59:in `call'
  actionpack (4.0.0) lib/action_dispatch/routing/route_set.rb:655:in `call'
  rack (1.5.2) lib/rack/etag.rb:23:in `call'
  rack (1.5.2) lib/rack/conditionalget.rb:35:in `call'
  rack (1.5.2) lib/rack/head.rb:11:in `call'
  actionpack (4.0.0) lib/action_dispatch/middleware/params_parser.rb:27:in `call'
  actionpack (4.0.0) lib/action_dispatch/middleware/flash.rb:241:in `call'
  rack (1.5.2) lib/rack/session/abstract/id.rb:225:in `context'
  rack (1.5.2) lib/rack/session/abstract/id.rb:220:in `call'
  actionpack (4.0.0) lib/action_dispatch/middleware/cookies.rb:486:in `call'
  activerecord (4.0.0) lib/active_record/query_cache.rb:36:in `call'
  activerecord (4.0.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:626:in `call'
  activerecord (4.0.0) lib/active_record/migration.rb:369:in `call'
  actionpack (4.0.0) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
  activesupport (4.0.0) lib/active_support/callbacks.rb:373:in `_run__4344846218965739481__call__callbacks'
  activesupport (4.0.0) lib/active_support/callbacks.rb:80:in `run_callbacks'
  actionpack (4.0.0) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
  actionpack (4.0.0) lib/action_dispatch/middleware/reloader.rb:64:in `call'
  actionpack (4.0.0) lib/action_dispatch/middleware/remote_ip.rb:76:in `call'
  better_errors (1.1.0) lib/better_errors/middleware.rb:84:in `protected_app_call'
  better_errors (1.1.0) lib/better_errors/middleware.rb:79:in `better_errors_call'
  better_errors (1.1.0) lib/better_errors/middleware.rb:56:in `call'
  actionpack (4.0.0) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
  actionpack (4.0.0) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
  railties (4.0.0) lib/rails/rack/logger.rb:38:in `call_app'
  railties (4.0.0) lib/rails/rack/logger.rb:21:in `block in call'
  activesupport (4.0.0) lib/active_support/tagged_logging.rb:67:in `block in tagged'
  activesupport (4.0.0) lib/active_support/tagged_logging.rb:25:in `tagged'
  activesupport (4.0.0) lib/active_support/tagged_logging.rb:67:in `tagged'
  railties (4.0.0) lib/rails/rack/logger.rb:21:in `call'
  actionpack (4.0.0) lib/action_dispatch/middleware/request_id.rb:21:in `call'
  rack (1.5.2) lib/rack/methodoverride.rb:21:in `call'
  rack (1.5.2) lib/rack/runtime.rb:17:in `call'
  activesupport (4.0.0) lib/active_support/cache/strategy/local_cache.rb:83:in `call'
  rack (1.5.2) lib/rack/lock.rb:17:in `call'
  actionpack (4.0.0) lib/action_dispatch/middleware/static.rb:64:in `call'
  railties (4.0.0) lib/rails/engine.rb:511:in `call'
  railties (4.0.0) lib/rails/application.rb:97:in `call'
  rack (1.5.2) lib/rack/lock.rb:17:in `call'
  rack (1.5.2) lib/rack/content_length.rb:14:in `call'
  rack (1.5.2) lib/rack/handler/webrick.rb:60:in `service'
  /Users/milesmatthias/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/webrick/httpserver.rb:138:in `service'
  /Users/milesmatthias/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/webrick/httpserver.rb:94:in `run'
  /Users/milesmatthias/.rbenv/versions/2.0.0-p353/lib/ruby/2.0.0/webrick/server.rb:295:in `block in start_thread'

Answer 1

may be this will work, it looks like you constraints are passing as parameters. try this

namespace :api, :path => "" do 
 constraints(lambda { |r| r.subdomain.present? && r.subdomain == "api"}) do
  namespace :v1 do
     match "send" => "mvp#send", :as => "mvp_send", :via => [:post, :options]
  end
 end
end

Answer 2

The answer came from one of my co-workers:

https://twitter.com/drawohara/statuses/440200619433795585

I changed the name from send to email and it worked.

Answer 3

Something else you may benefit from:

---

rack-CORS

You're currently handling your CORS headers in your controller

A better way will be to use the rack-CORS middleware to DRY it up:

#config/application.rb
config.middleware.use Rack::Cors do
  allow do
    origins '*'
    resource '/your_path*', :headers => :any, :methods => :post
  end
end