无法在Rails中通过Ajax请求传递参数

Question

I've been racking my brain trying to figure out what I'm doing wrong here - I'm trying to send an ajax request with some data and then open up a modal form:

var position = $(".exercise-list").sortable('toArray');
var positionData = "["+position+"]"

$.ajax({
  url: window.location.href + '/create_workout_routine',
  method: 'POST',
  data: {
    position: positionData
  },
  success: (function() {
    return false
  }),
  error: (function(XMLHttpRequest, textStatus, errorThrown) { 
    alert("Status: " + textStatus); alert("Error: " + errorThrown); 
    return false
  })
});
$('#createWorkoutModal').modal('show');

When I try console.log(positionData); I get

[4,2]

which is exactly what I need. Same with my logs:

Started POST "/workouts/new/create_workout_routine" for 127.0.0.1 at 2014-12-10 18:52:11 -0600
  Processing by WorkoutsController#new as */*
  Parameters: {"position"=>"[4,2]"}

Here's my controller:

def create
  exercise_order = params[:position]
  @workout = Workout.new(workout_params)

  WorkoutRoutine.create(
    exercise_order.each_with_index.map { |x,i| 
      {:exercise_id => x,
       ....
      }
    }
  )
  ...
end

When my createWorkoutModal pops up, I submit the form, and get this error:

NoMethodError (undefined method `each_with_index' for nil:NilClass):
  app/controllers/workouts_controller.rb:29:in `create'

I also tried including the modal popup to occur in the success functon of the ajax request as well with no luck, as well as getting rid of the "return false" part. I'm confused as to why it's giving me 'nil' when I can see the params being passed, any help is much appreciated!

Answer 1

replace the following line in your controller

exercise_order = params[:position]

with this

exercise_order = params["position"]