Erreur d'utilisation de jquery-file-upload

application.js

// This is a manifest file that'll be compiled into application.js, which will include all the files
// listed below.
//
// Any JavaScript/Coffee file within this directory, lib/assets/javascripts, vendor/assets/javascripts,
// or vendor/assets/javascripts of plugins, if any, can be referenced here using a relative path.
//
// It's not advisable to add code directly here, but if you do, it'll appear at the bottom of the
// the compiled file.
//
// WARNING: THE FIRST BLANK LINE MARKS THE END OF WHAT'S TO BE PROCESSED, ANY BLANK LINE SHOULD
// GO AFTER THE REQUIRES BELOW.
//
//= require jquery
//= require jquery-ui
//= require jquery_ujs
//= require twitter/bootstrap
//= require gmaps4rails/bing.js
//= require gmaps4rails/googlemaps.js
//= require gmaps4rails/mapquest.js
//= require gmaps4rails/openlayers.js
//= require gmaps4rails/all_apis.js
//= require highcharts
//= require highcharts/modules/exporting
//= require shadowbox
//= require_tree .

metric.rb

class Metric < ActiveRecord::Base
  include Rails.application.routes.url_helpers
  mount_uploader :metering, MeteringUploader
  attr_accessible :metering
  
  def to_jq_upload
    {
      "name" => read_attribute(:metering),
      "size" => metering.size,
      "url" => metering.url,
      "thumbnail_url" => nil,
      "delete_url" => metrics_path(:id => id),
      "delete_type" => "DELETE" 
     }
  end
end

metrics_controller.rb

class MetricsController < ApplicationController

  def index
    @metrics = Metric.all
    respond_to do |format|
      format.html 
      format.json { render :json =>@metrics.collect { |p| p.to_jq_upload }.to_json}
    end
  end

  def create
    @metric = Metric.new(params[:metric])
    if @metric.save
      respond_to do |format|
        format.html { redirect_to metrics_url, notice: 'Metric was successfully created.' }
        format.json { render :json => [@metric.to_jq_upload].to_json           
        }
      end
    else 
      render :json => [{:error => "custom_failure"}], :status => 304
    end
  end
  
  def destroy
    @metric = Metric.find(params[:id])
    @metric.destroy
    render :json => true
  end
end

metricsindex.html.erb

<h2>Gestion des métriques</h2>
<%= form_for Metric.new, :html => { :multipart => true, :class => 'form-horizontal'  } do |f| %>
	<fieldset>
		<legend>Add a Metrics</legend>
		<div class="fileupload-buttonbar">
			<div class="progressbar fileupload-progressbar nofade"><div style="width:0%;"></div></div>
			<div class="form-actions">
				<span class="btn btn-success fileinput-button">
					<i class="icon-plus icon-white"></i>
					<span>Add files...</span>
					<input type="file" name="files[]">
				</span>
  	    <button type="submit" class="btn btn-primary"><i class="icon-upload icon-white"></i> Start Upload</button>
				<button type="reset" class="btn btn-warning"><i class="icon-ban-circle icon-white"></i> Cancel Upload</button>
				<button type="button" class="btn btn-danger"><i class="icon-trash icon-white"></i> Delete Selected</button>
				<input type="checkbox" class="toggle">
  	  </div>
		</div>
  </fieldset>
	<div class="fileupload-loading"></div>
	<br>
	<table class="table table-striped"><tbody class="files" data-toggle="modal-gallery" data-target="#modal-gallery"></tbody></table>
<% end %>

<script>
  var fileUploadErrors = {
    maxFileSize: 'File is too big',
    minFileSize: 'File is too small',
    acceptFileTypes: 'Filetype not allowed',
    maxNumberOfFiles: 'Max number of files exceeded',
    uploadedBytes: 'Uploaded bytes exceed file size',
    emptyResult: 'Empty file upload result'
  };
</script>

<!-- modal-gallery is the modal dialog used for the image gallery -->
<div id="modal-gallery" class="modal modal-gallery hide fade">
    <div class="modal-header">
        <a class="close" data-dismiss="modal">&times;</a>
        <h3 class="modal-title"></h3>
    </div>
    <div class="modal-body"><div class="modal-image"></div></div>
    <div class="modal-footer">
        <a class="btn modal-download" target="_blank">
            <i class="icon-download"></i>
            <span>Download</span>
        </a>
        <a class="btn btn-success modal-play modal-slideshow" data-slideshow="5000">
            <i class="icon-play icon-white"></i>
            <span>Slideshow</span>
        </a>
        <a class="btn btn-info modal-prev">
            <i class="icon-arrow-left icon-white"></i>
            <span>Previous</span>
        </a>
        <a class="btn btn-primary modal-next">
            <span>Next</span>
            <i class="icon-arrow-right icon-white"></i>
        </a>
    </div>
</div>
<!-- The template to display files available for upload -->
<script id="template-upload" type="text/x-tmpl">
{% for (var i=0, file; file=o.files[i]; i++) { %}
    <tr class="template-upload fade">
        <td class="preview"><span class="fade"></span></td>
        <td class="name"><span>{%=file.name%}</span></td>
        <td class="size"><span>{%=o.formatFileSize(file.size)%}</span></td>
        {% if (file.error) { %}
            <td class="error" colspan="2"><span class="label label-important">{%=locale.fileupload.error%}</span> {%=locale.fileupload.errors[file.error] || file.error%}</td>
        {% } else if (o.files.valid && !i) { %}
            <td>
                <div class="progress progress-success progress-striped active"><div class="bar" style="width:0%;"></div></div>
            </td>
            <td class="start">{% if (!o.options.autoUpload) { %}
                <button class="btn btn-primary">
                    <i class="icon-upload icon-white"></i>
                    <span>{%=locale.fileupload.start%}</span>
                </button>
            {% } %}</td>
        {% } else { %}
            <td colspan="2"></td>
        {% } %}
        <td class="cancel">{% if (!i) { %}
            <button class="btn btn-warning">
                <i class="icon-ban-circle icon-white"></i>
                <span>{%=locale.fileupload.cancel%}</span>
            </button>
        {% } %}</td>
    </tr>
{% } %}
</script>
<!-- The template to display files available for download -->
<script id="template-download" type="text/x-tmpl">
{% for (var i=0, file; file=o.files[i]; i++) { %}
    <tr class="template-download fade">
        {% if (file.error) { %}
            <td></td>
            <td class="name"><span>{%=file.name%}</span></td>
            <td class="size"><span>{%=o.formatFileSize(file.size)%}</span></td>
            <td class="error" colspan="2"><span class="label label-important">{%=locale.fileupload.error%}</span> {%=locale.fileupload.errors[file.error] || file.error%}</td>
        {% } else { %}
            <td class="preview">{% if (file.thumbnail_url) { %}
                <a href="{%=file.url%}" title="{%=file.name%}" rel="gallery" download="{%=file.name%}"><img src="{%=file.thumbnail_url%}"></a>
            {% } %}</td>
            <td class="name">
                <a href="{%=file.url%}" title="{%=file.name%}" rel="{%=file.thumbnail_url&&'gallery'%}" download="{%=file.name%}">{%=file.name%}</a>
            </td>
            <td class="size"><span>{%=o.formatFileSize(file.size)%}</span></td>
            <td colspan="2"></td>
        {% } %}
        <td class="delete">
            <button class="btn btn-danger" data-type="{%=file.delete_type%}" data-url="{%=file.delete_url%}">
                <i class="icon-trash icon-white"></i>
                <span>{%=locale.fileupload.destroy%}</span>
            </button>
            <input type="checkbox" name="delete" value="1">
        </td>
    </tr>
{% } %}
</script>


<%= javascript_include_tag 'jquery.iframe-transport.js' %>
<%= javascript_include_tag 'jquery.fileupload.js' %>
<%= javascript_include_tag 'jquery.fileupload-ui.js' %>

<script type="text/javascript" charset="utf-8">
    $(function () {
		    'use strict';

		    // Initialize the jQuery File Upload widget:
		    $('#fileupload').fileupload();

		    // Load existing files:
		    $('#fileupload').each(function () {
		    	var that = this;
		      $.getJSON(this.action, function (result) {
		      	if (result && result.length) {
		        	$(that).fileupload('option', 'done')
		          .call(that, null, {result: result});
		        }
		    	});
				});
		});
</script>