将参数从视图传递到模型中定义的范围 [英] Pass a parameter from view to a scope defined in the model

问题描述

我正在重构我的代码并尝试遵循约定瘦控制器，胖模型"现在我尝试将查询移动到模型:

Im refactoring my code and try to follow the convention "Skinny controllers, fat models" Now i tried to move a Query to the model:

scope :scope1_department, where(sender_username: params[:username], recipient_username: params[:username])
scope :scope2_department, where(recipient_username:  params[:username])
scope_department  = scope1_department.merge(scope2_department).sort_by(&:created_at)

在我的控制器中，我有:

And in my controller i have:

 @messages = Message.scope_department(params[:username])

现在我的模型代码出现此错误:

Now i get this error for my model code:

 undefined local variable or method `params' for #<Class:0x85d0b80>

我也尝试在我的模型中用简单的用户名替换 params[:username] 但是我得到了错误:

I also tried in my model to replace the params[:username] with simply username but then i get the error:

 undefined local variable or method `username' for #<Class:0x459fa50>

有一个类似的问题，但你怎么能看到我做错了什么:Rails3 如何在命名范围内使用 :params?

There is a similar question, but how you can se i made something wrong: Rails3 How can I use :params in named scope?

谢谢！

推荐答案

您不能在模型中使用 params 变量.您可以做的是使用 lambda 将变量传递给作用域:

You can not use params variable in your model. What you can do is to pass a variable to the scope using a lambda:

scope :scope1_department, ->(username){ where(sender_username: username, recipient_username: username)}

在您的控制器中:

@messages = Message.scope1_department(params[:username])

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