在Rails中上传文件 [英] Uploading a file in Rails

问题描述

我是rails新手，正在使用CRUD技术编写一个RESTful网站。到目前为止，我已经创建了三个页面，所有这些页面都允许用户创建，编辑和删除数据库中的一行。不过，我的第四页需要包含一个上传文件的形式，但是a）我不知道文件系统如何与Rails协同工作，因此我不知道应该在哪里存储文件。该文件将是100kb左右，不能存储在临时存储，因为它会不断下载。和b）我不知道如何写入一个文件。

I'm new to rails, and I'm writing a RESTful website using the CRUD technique. So far I have created three pages, all of which allow the user to create, edit, and delete a row from the database. However, my fourth page will need to include an upload file form, but a) I don't know how the filesystem works with Rails thus I don't know where files should be stored. The file would be around 100kb and couldn't be stored in temporary storage because it will be constantly downloaded. And b) I don't know how to write to a file.

如果你能告诉我如何去做我上面提到的 - 创建一个上传输入一个输入表单，然后将文件写入一个文件路径到一个单独的目录中。

It would be great if you could tell me how to do what I mentioned above - create an upload input on an input form, and to then write the file to a filepath in a separate directory.

推荐答案

虽然有很多解决文件上传非常好的宝石（请参阅 https://www.ruby-toolbox.com/categories/rails_file_uploads 对于列表），rails有内置的帮助器，可以很容易地推出自己的解决方案。

While there are plenty of gems that solve file uploading pretty nicely (see https://www.ruby-toolbox.com/categories/rails_file_uploads for a list), rails has built-in helpers which make it easy to roll your own solution.

使用 file_field -form助手在你的表单中，而rails则为你处理上传：

Use the file_field-form helper in your form, and rails handles the uploading for you:

<%= form_for @person do |f| %>
  <%= f.file_field :picture %>
<% end %>

您可以在控制器中访问上传的文件，如下所示：

You will have access in the controller to the uploaded file as follows:

uploaded_io = params[:person][:picture]
File.open(Rails.root.join('public', 'uploads', uploaded_io.original_filename), 'wb') do |file|
  file.write(uploaded_io.read)
end

这取决于你想要达到的复杂性，但是这对于简单的文件上传/下载任务是完全足够的。这个例子是从导轨指南，你可以去那里获得更多的信息： http://guides.rubyonrails.org /form_helpers.html#uploading-files

It depends on the complexity of what you want to achieve, but this is totally sufficient for easy file uploading/downloading tasks. This example is taken from the rails guides, you can go there for further information: http://guides.rubyonrails.org/form_helpers.html#uploading-files

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