Rails配置使用jquery-fileupload-rails step by step

一步步安裝使用jquery-file-upload

1.安裝Gem

    在gemfile中添加jquery-fileupload-rails和paperclip的gem：

gem "jquery-fileupload-rails"
gem 'paperclip'

2.在app/assets/application.js添加

//= require jquery-fileupload

3.在app/assets/stylesheets/application.css添加

*= require jquery.fileupload-ui

4.創建Picture數據表

rails g model Picture avatar:attachment
rake db:migrate

     pictures表的avatar屬性代表上傳的文件對象。

     修改picture.rb的內容：

     在model中，使用類方法has_attached_file指明文件對象是avatar，並且定義了to_json_picture方法，該方法將picture對象轉換成一個hash，在jquery-fileupload和server的交互中被轉變爲json數據。

5.創建view

     只需要創建一個上傳界面index.html.erb，自定義你自己的view時，僅需要將form_for Picture.new和f.file_field :avatar修改爲自己model即可，其他內容都可以直接copy-paste。

<div class="container">
  <h2>Upload file</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 :avatar %>
        </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="width: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 %>

</div>
<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="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>

<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 = $('#fileupload').data('blueimpFileupload'), 
          template;
        fu._adjustMaxNumberOfFiles(-files.length);
        console.log(files);
        template = fu._renderDownload(files)
          .appendTo($('#fileupload .files'));
        // Force reflow:
        fu._reflow = fu._transition && template.length &&
          template[0].offsetWidth;
        template.addClass('in');
        $('#loading').remove();
      });

  });
</script>

6.創建controller

rails g controller pictures index create destroy

class PicturesController < ApplicationController
  def index
    @pictures = Picture.all

    respond_to do |format|
      format.html # index.html.erb
      format.json { render json: @pictures.map{|picuture| picuture.to_json_picture } }
    end
  end

  # POST /picture
  # POST /picture.json
  def create
    @picture = Picture.new(params[:picture])

    respond_to do |format|
      if @picture.save
        format.html {
          render :json => [@picture.to_json_picture].to_json,
          :content_type => 'text/html',
          :layout => false
        }
        format.json { render json: {files: [@picture.to_json_picture]}, status: :created, location: @picture }
      else
        format.html { render action: "new" }
        format.json { render json: @picture.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /picture/1
  # DELETE /picture/1.json
  def destroy
    @picture = Picture.find(params[:id])
    @picture.destroy

    respond_to do |format|
      format.html { redirect_to picture_url }
      format.json { head :no_content }
    end
  end
end

7.效果圖

    這就是最終結果了，如果想要達到jqeury-fileupload Demo中漂亮的結果，如下圖，就需要使用Twitter-bootstrap或者自己寫寫CSS了。