ruby-on-rails - #<ActiveRecord::Relation []> 的未定义方法 `authenticate'

Question

我创建了一个方法“attempt_login”，如下所示:

def attempt_login
  if params[:username].present? && params[:password].present?
      found_user= AdminUser.where(:username=> params[:username].first)
  if found_user
    authorized_user= found_user.authenticate(params[:password])
  end
end
if authorized_user
  flash[:notice]="You are now logged in."
  redirect_to(:action=>'menu')
else
   flash[:notice]="Invalid username/password combination."
   redirect_to(:action=>'login')
  end
end

我收到这样的错误:

 ←[1m←[35mAdminUser Load (1.0ms)←[0m  SELECT `admin_users`.* FROM `admin_users`
  WHERE `admin_users`.`username` = 'u'
Completed 500 Internal Server Error in 18ms

NoMethodError (undefined method `authenticate' for #<ActiveRecord::Relation []>)
:
  app/controllers/access_controller.rb:13:in `attempt_login'

它可以从 Rails 控制台运行，但不能从 Rails 服务器运行。 请告诉我解决方案，我正在等待您的回复。

Answer 1

您的代码中有错误，如下:

found_user = AdminUser.where(:username => params[:username].first)

应该是:

found_user = AdminUser.where(:username => params[:username]).first

查看日志:

SELECT `admin_users`.* FROM `admin_users`
WHERE `admin_users`.`username` = 'u'

params[:username].first 从 params[:username] 返回第一个字符，但您需要第一个记录:

AdminUser.where(:username=> params[:username]).first