ruby-on-rails-3 - 向自定义验证器添加错误消息

Question

我有一个自定义验证器，并且尝试输出错误消息但无法执行时，我尝试这样做。有人可以告诉我我是否在正确的地方进行此操作。

class User < ActiveRecord::Base
  self.table_name = "user"

  attr_accessible :name, :ip, :printer_port, :scanner_port

  validates :name,        :presence => true,
                          :length => { :maximum => 75 },
                          :uniqueness => true                          

  validates :ip,          :length => { :maximum => 75 },
                          :allow_nil => true     

  validates :printer_port, :presence => true, :if => :has_association? 

  validates :scanner_port, :presence => true, :if => :has_association?          

  def has_association?
    ip != nil
  end
end

我有如下内容:

validates :printer_port, :presence => true, :message => "can't be blank", :if => :has_wfm_association?

但是收到一个错误

Unknown validator: 'MessageValidator'

当我尝试将消息放在验证器的末尾时，用逗号分隔has_association吗？将问号和逗号变成橙色

Answer 1

message和if参数应该在presence的散列中:

validates :printer_port, :presence => {:message => "can't be blank", :if => :has_wfm_association?}

这是因为您可以在一行中加载多个验证:

validates :foo, :presence => true, :uniqueness => true

如果您尝试以这种方式或if条件向其中添加消息，Rails将不知道将消息/条件应用于哪个验证。因此，您需要设置每个验证的消息:

validates :foo, :presence => {:message => "must be present"},
                :uniqueness => {:message => "must be unique"}