ruby-on-rails - Rails 3 获取原始发布数据并将其写入 tmp 文件

Question

我正在实现 Ajax-Upload用于在我的 Rails 3 应用程序中上传照片。文档说:

1. For IE6-8, Opera, older versions of other browsers you get the file as you normally do with regular form-base uploads.

2. For browsers which upload file with progress bar, you will need to get the raw post data and write it to the file.

那么，如何在我的 Controller 中接收原始发布数据并将其写入 tmp 文件，以便我的 Controller 可以处理它？ (在我的例子中， Controller 正在做一些图像处理并保存到 S3。)

一些额外的信息:

正如我现在配置的那样，帖子正在传递这些参数:

Parameters:
{"authenticity_token"=>"...", "qqfile"=>"IMG_0064.jpg"}

... CREATE 操作如下所示:

def create
    @attachment = Attachment.new
    @attachment.user = current_user
    @attachment.file = params[:qqfile]
    if @attachment.save!
        respond_to do |format|
            format.js { render :text => '{"success":true}' }
        end
    end
end

...但我收到此错误:

ActiveRecord::RecordInvalid (Validation failed: File file name must be set.):
  app/controllers/attachments_controller.rb:7:in `create'

Answer 1

那是因为 params[:qqfile] 不是 UploadedFile 对象，而是一个包含文件名的字符串。文件的内容存储在请求的正文中(可使用 request.body.read 访问)。当然，你不能忘记向后兼容，所以你仍然必须支持UploadedFile。

因此，在以统一方式处理文件之前，您必须捕获两种情况:

def create
  ajax_upload = params[:qqfile].is_a?(String)
  filename = ajax_upload  ? params[:qqfile] : params[:qqfile].original_filename
  extension = filename.split('.').last
  # Creating a temp file
  tmp_file = "#{Rails.root}/tmp/uploaded.#{extension}"
  id = 0
  while File.exists?(tmp_file) do
    tmp_file = "#{Rails.root}/tmp/uploaded-#{id}.#{extension}"        
    id += 1
  end
  # Save to temp file
  File.open(tmp_file, 'wb') do |f|
    if ajax_upload
      f.write  request.body.read
    else
      f.write params[:qqfile].read
    end
  end
  # Now you can do your own stuff
end