验证失败时如何保留文件字段值 [英] How to keep file field value when validation failed

问题描述

我有一个带有文件字段的经典Rails 3表单，一切正常，上传作品并将数据保存到数据库.

I have a classic rails 3 form with a file field, everything works fine, upload works and data is saved to database.

当验证失败(例如，标题丢失)时，用户将被带回render :action => new的表单.普通的.但是这里的问题是，用户不得不再次选择文件.

When a validation failed, for example, title is missing, then the user is sent back to the form with a render :action => new. Normal. But the problem here, is that the user have to select another time its file.

有什么方法可以避免这种情况?

Any way to avoid that?

推荐答案

通常，您不希望在运行验证后才处理文件，或者要重复存储可能没有相关记录的文件.像回形针和attachment_fu这样的宝石就可以做到这一点.

Typically you don't want to process files until after validations have run or you're going to repeatedly store files that possibly don't have the associated records. Gems like Paperclip and attachment_fu do this.

如果您宁愿在首次提交文件时将其存储为有效文件，则可以存储该文件，然后在视图中进行快速检查以查看是否已经为您要为其构建表单的对象设置了文件:

If you would rather store the file the first time it's submitted and is valid you can store the file and then do a quick check in your view to see if it's already set for the object you're building a form for, e.g:

<% unless foo.attachment? %>
  # file field
<% end %>

有道理吗?

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