nil:NilClass 的未定义方法“original_filename”

Question

我正在尝试将文件上传到电子邮件 attachment.When 我尝试上传，但出现错误

"undefined method `original_filename' for nil:NilClass"我做错了什么？

我需要从控制器中捕获文件，并在 params[:file] 不存在时处理异常？

在我看来，有一个简单的上传文件标签

%strong Send Email with PDF attachment:
      = file_field_tag :file

我需要从控制器中获取文件，这是我的控制器..

 @name = params[:file].original_filename
        if params[:file].present?
          directory = "public/data"
          path = File.join(directory, @name)
          uniq_name = (0...10).map {(65 + rand(26)).chr}.join
          time_footprint = Time.now.to_formatted_s(:number)

          File.open(path, "wb") do |file|
            file.write(params[:file].read)
            @uniq_path = File.join(directory, uniq_name + time_footprint + File.extname(file))
            File.rename(file, @uniq_path)
          end
        else
          flash[:notice] = "You are going to send email without the invoice"
          redirect_to update_estimate_job_final_invoices_path(@ticket)

        end

Answer 1

第一行是@name = params[:file].original_filename。如果 params[:file] 不存在，那么对 original_filename 的调用将失败。将该行移动到 if 语句中：

if params[:file].present?
  @name = params[:file].original_filename
  directory = "public/data"
  path = File.join(directory, @name)
  ...
else
  ...
end

nil:NilClass 的未定义方法“original_filename”

undefined method `original_filename' for nil:NilClass

file-upload

ruby-on-rails

ruby-on-rails-4