Question

我正在尝试关注this tutorial。它已在Rails的早期版本中编写，我正在使用Rails 4.我正在尝试上传文件，但我收到以下错误：

NoMethodError in UploadController#uploadfile
undefined method `[]' for nil:NilClass

Extracted source (around line #3):

class DataFile < ActiveRecord::Base
  def self.save(upload)
    name =  upload['datafile'].original_filename
    directory = "public/data"
    # create the file path
    path = File.join(directory, name)

Rails.root: C:/Ruby193/mylibrary

Application Trace | Framework Trace | Full Trace
app/models/data_file.rb:3:in `save'
app/controllers/upload_controller.rb:6:in `uploadfile'

这是data_file.rb

class DataFile < ActiveRecord::Base
  def self.save(upload)
    name =  upload['datafile'].original_filename
    directory = "public/data"
    # create the file path
    path = File.join(directory, name)
    # write the file
    File.open(path, "wb") { |f| f.write(upload['datafile'].read) }
  end
end

这是控制器upload_controller.rb

class UploadController < ApplicationController
  def index
    render :file => 'app\views\upload\uploadfile.html'
  end
  def uploadfile
    post = DataFile.save(params[:upload])
    render :text => "File has been uploaded successfully"
  end
end

这是uploadfile.html

<h1>File Upload</h1>
<%= form_tag({:action => 'uploadfile'}, :multipart => true) do %>
<p><label for="upload_file">Select File</label>
    <%= file_field 'upload', 'datafile' %></p>
<%= submit_tag "Upload" %>
<% end %>

我该怎么办？提前致谢

Answer 1

看起来params [：upload]并不是你想象的那样。您忘记将表单设置为多部分。如果修复不能使其起作用，请开始检查参数以查看您实际获得的内容。

def uploadfile
  puts params.inspect # Add this line to see what's going on
  post = DataFile.save(params[:upload])
  render :text => "File has been uploaded successfully"
end

此外，它不是一个很好的回答，＆＃34;但是我使用paperclip来处理文件上传取得了很大的成功。如果你只想要一些有效的东西（而不是自己学习如何去做），请检查一下。

Ruby Rails：上传文件

1 个答案: