jquery_file_upload in Rails(ajax实现多张图片上传)

在此，我们要实现的是http://blueimp.github.com/jQuery-File-Upload/上传功能和效果。

1.准备工作

关键gem：carrierwave 和rmagick

在安装rmagick这个gem之前需要安装ImageMagick和相关库ImageMagick和ImageMagick-devel，直接yum install


下载关键js库函数和css

　　http://blueimp.github.com/jQuery-File-Upload/在这里有完全的下载，

jquery.iframe-transport.js

jquery.ui.widget.js

jquery.fileupload.js
jquery.fileupload-ip.js
jquery.fileupload-ui.js
locale.js

2.创建uploader

在Gemfile中添加

gem 'rmagick'

gem 'carrierwave'

bundle install

rails g uploader image

修改生成的image_uploader.rb

  include CarrierWave::RMagick

  # Create different versions of your uploaded files:
  version :thumb do
    process :resize_to_limit => [100, 100]
  end

修改这里是为了生成thumb图片。

3.生成picture的scaffold

rails g scaffold picture image:string

修改model

class Picture < ActiveRecord::Base
  attr_accessible :image
  include Rails.application.routes.url_helpers
  mount_uploader :image, AvatarUploader  #关联uploader

  #one convenient method to pass jq_upload the necessary information
  def to_jq_upload
    {
      "name" => read_attribute(:image),
      "size" =>image.size,
      "url" =>image.url,
      "thumbnail_url" =>image.thumb.url,
      "delete_url" => picture_path(:id => id),
      "delete_type" => "DELETE" 
    }
  end
end

修改controller

class PicturesController < ApplicationController

  def index
    @pictures = Picture.all
    render :json => @pictures.collect { |p| p.to_jq_upload }.to_json
  end
  def new
    
  end

  def create
    @picture = Picture.new(params[:picture])
    if @picture.save
      respond_to do |format|
        format.html {  
          render :json => [@picture.to_jq_upload].to_json, 
          :content_type => 'text/html',
          :layout => false
        }
        format.json {  
          render :json => [@picture.to_jq_upload].to_json           
        }
      end
    else 
      render :json => [{:error => "custom_failure"}], :status => 304
    end
  end

  def destroy
    @picture = Picture.find(params[:id])
    @picture.destroy
    render :json => true
  end
end

修改new.html.reb

<!-- Bootstrap CSS Toolkit styles -->
<link rel="stylesheet" href="http://blueimp.github.com/cdn/css/bootstrap.min.css">
<!-- Bootstrap styles for responsive website layout, supporting different screen sizes -->
<link rel="stylesheet" href="http://blueimp.github.com/cdn/css/bootstrap-responsive.min.css">
<!-- Bootstrap CSS fixes for IE6 -->
<!--[if lt IE 7]><link rel="stylesheet" href="http://blueimp.github.com/cdn/css/bootstrap-ie6.min.css"><![endif]-->

<!-- Bootstrap Image Gallery styles -->
<link rel="stylesheet" href="http://blueimp.github.com/Bootstrap-Image-Gallery/css/bootstrap-image-gallery.min.css">
<!-- Shim to make HTML5 elements usable in older Internet Explorer versions -->
<!--[if lt IE 9]><script src="http://html5shim.googlecode.com/svn/trunk/html5.js"></script><![endif]-->

<h2><%= t('photos.title') %></h2>
<%= form_for Picture.new, :html => { :multipart => true, :id => "fileupload"  } do |f| %>
        <!-- The fileupload-buttonbar contains buttons to add/delete files and start/cancel the upload -->
        <div class="row fileupload-buttonbar">
            <div class="span7">
                <!-- The fileinput-button span is used to style the file input field as button -->
                <span class="btn btn-success fileinput-button">
                    <i class="icon-plus icon-white"></i>
                    <span>Add files...</span>
                    <%= f.file_field :image %>
                </span>
                <button type="submit" class="btn btn-primary start">
                    <i class="icon-upload icon-white"></i>
                    <span>Start upload</span>
                </button>
                <button type="reset" class="btn btn-warning cancel">
                    <i class="icon-ban-circle icon-white"></i>
                    <span>Cancel upload</span>
                </button>
                <button type="button" class="btn btn-danger delete">
                    <i class="icon-trash icon-white"></i>
                    <span>Delete</span>
                </button>
                <input type="checkbox" class="toggle">
            </div>
            <div class="span5">
                <!-- The global progress bar -->
                <div class="progress progress-success progress-striped active fade">
                    <div class="bar" style="0%;"></div>
                </div>
            </div>
        </div>
        <!-- The loading indicator is shown during image processing -->
        <div class="fileupload-loading"></div>
        <br>
        <!-- The table listing the files available for upload/download -->
        <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>

<!-- 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="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>



<!-- The jQuery UI widget factory, can be omited if jQuery UI is already included -->
<%= javascript_include_tag "jquery.ui.widget.js" %>
<!-- The Templates plugin is included to render the upload/download listings -->
<script src="http://blueimp.github.com/JavaScript-Templates/tmpl.min.js"></script>
<!-- The Load Image plugin is included for the preview images and image resizing functionality -->
<script src="http://blueimp.github.com/JavaScript-Load-Image/load-image.min.js"></script>
<!-- The Canvas to Blob plugin is included for image resizing functionality -->
<script src="http://blueimp.github.com/JavaScript-Canvas-to-Blob/canvas-to-blob.min.js"></script>
<!-- Bootstrap JS and Bootstrap Image Gallery are not required, but included for the demo -->
<script src="http://blueimp.github.com/cdn/js/bootstrap.min.js"></script>
<script src="http://blueimp.github.com/Bootstrap-Image-Gallery/js/bootstrap-image-gallery.min.js"></script>
<!-- The Iframe Transport is required for browsers without support for XHR file uploads -->
<%= javascript_include_tag "jquery.iframe-transport.js" %>
<!-- The basic File Upload plugin -->
<%= javascript_include_tag "jquery.fileupload.js" %>
<!-- The File Upload image processing plugin -->
<%= javascript_include_tag "jquery.fileupload-ip.js" %>
<!-- The File Upload user interface plugin -->
<%= javascript_include_tag "jquery.fileupload-ui.js" %>
<!-- The localization script -->
<%= javascript_include_tag "locale.js" %>


<!-- The XDomainRequest Transport is included for cross-domain file deletion for IE8+ -->
<!--[if gte IE 8]><%= javascript_include_tag "jquery.xdr-transport.js" %><![endif]-->


<script type="text/javascript" charset="utf-8">
    $(function () {
        // Initialize the jQuery File Upload widget:
        $('#fileupload').fileupload();
        // 
        // Load existing files:
        $.getJSON($('#fileupload').prop('action'), function (files) {
          var fu = $('#fileupload').data('fileupload'), 
            template;
          fu._adjustMaxNumberOfFiles(-files.length);
          template = fu._renderDownload(files)
            .appendTo($('#fileupload .files'));
          // Force reflow:
          fu._reflow = fu._transition && template.length &&
            template[0].offsetWidth;
          template.addClass('in');
          $('#loading').remove();
        });

    });
</script>