jQuery AJAX POST到Rails Controller。 执行each_with_index时出错（TypeError无法将Symbol转换为Integer）

Question

I'm trying to save the position of a jQuery-UI sortable connected list to a Rails backend. I'm having trouble with the Rails Controller action when trying to save the parameters to database. The error that I am getting is TypeError (can't convert Symbol into Integer):

The parameter from the Ajax POST request that I'm sending in looks like this which looks fine:

Activity:[{"id":"65","column":"48"},{"id":"65","column":"48"},{"id":"67","column":"48"}]

My Rails controller action is this (I'm trying to update an Activity with an id of 'id' and updating the attributes position with 'position' and day_id with 'column':

  def sort
    JSON.parse(params[:Activity]).each_with_index do |x, index|
      id = x["id"]
      position = index+1
      column = x["column"]
      Activity.update_all(position = position, day_id = column, id = id)
    end
    render nothing: true
  end

I'm getting this error in Terminal:

    Started POST "/trips/sort" for 10.0.2.2 at 2012-11-04 23:52:30 +0000
Processing by TripsController#sort as */*
  Parameters: {"Activity"=>"[{\"id\":\"66\",\"column\":\"49\"},{\"id\":\"66\",\"column\":\"49\"},{\"id\":\"67\",\"column\":\"49\"}]"}
Completed 500 Internal Server Error in 1ms

TypeError (can't convert Symbol into Integer):

This is my jQuery AJAX call if helpful:

    jQuery ->
  $('[id*="day"]').sortable(
    connectWith: ".day"
    placeholder: "ui-state-highlight"
    update: (event, ui) ->
      neworder = new Array()
      $(this).children().each ->
        column = $(this).parent().attr("id").match(/\d+/)[0]
        id = $(this).attr("id").match(/\d+/)[0]
        neworder.push(
          id: id
          column: column
        )
      alert neworder
      $.ajax
        url: "sort"
        type: "POST"
        data: { Activity: JSON.stringify(neworder) }
    ).disableSelection()

I've spent the past few hours on this and just can't figure it out. I really appreciate the time and help.

Answer 1

You want to update each activity individually, like so:

JSON.parse(params[:Activity]).each_with_index do |x, index|
  id = x["id"]
  position = index+1
  column = x["column"]
  activity = Activity.find(id)
  activity.update_attributes(:position=>position, :column=>column)
end

(assuming your JSON parsing works correctly, which I haven't checked)

Activity.update_all will update ALL of the activities with the same attributes (eg set all activities to column 5 and position 1), which is not what you want to accomplish here.