Ruby-on-rails 如何向 Rails 模型添加错误？
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How to add errors to Rails model?
提问by SonIcco
I tried to add an exception in the before_savemethod in a rails model, but in the view, no error message exists.
我试图before_save在rails模型中的方法中添加异常，但在视图中，不存在错误消息。
Model:
模型：
before_save do
doing_some_stuff
begin
File.open('some_file', 'w+') do |file|
if file.write(file_content)
return true
else
return false
end
end
rescue => e
self.errors.add(:base, e.message)
return false
end
View:
看法：
<%= @model.errors.any? %>
This is always false.
这总是错误的。
How do I add error messages to the model?
如何向模型添加错误消息？
EDIT:
编辑：
The problem was, I had a redirect after the update_attribute function instead of rendering the action again. Thx for help.
问题是，我在 update_attribute 函数之后进行了重定向，而不是再次呈现该动作。谢谢你的帮助。
回答by Chris Heald
You should be performing this on validation, not on before_save. By the time you get to the before_savecallback, the record is assumed to be valid.
您应该在验证上执行此操作，而不是在before_save. 当你到达before_save回调时，记录被认为是有效的。
validate do
doing_some_stuff
begin
File.open(some_file, 'w+') do |file|
if !file.write(file_content)
self.errors.add(:base, "Unable to write #{some_file}")
end
end
rescue => e
self.errors.add(:base, e.message)
end
end
