导轨如何将对象传递给视图？

Question

如果操作是这样的：

def show 
    @post = Post.find(params[:id]) 
end 

那么我可以这样做：

<%= @post.title %> 

它是如何的对象传递给视图？

由于我的操作只有一行，所以使用什么编程技巧或模式将@post对象传递给视图（模板）页面？

我知道它假设视图与动作名称相同，但它是如何执行此操作的？

Answer 1

例如像这样： 我们将变量myController的转移到MyView的变量

class MyController 
    def my_action 
     @my_variable = 100 
    end 
end 

class MyView 
    def process_view_with_variables(variables) 
     puts variables.inspect # => [{"@my_variable"=>100}] 
     variables.each do |var| 
      var.each {|name,value| self.instance_variable_set(name,value)} 
     end 
     puts self.instance_variables # => @my_variable 
     # .. view_rendering here 
    end 
end 

# create new view and controller instances 
my_controller = MyController.new 
my_view = MyView.new 

# call my_action method in MyController instance (which will initialized some variables) 
my_controller.my_action 

# let know about instance variables in our controller 
puts my_controller.instance_variables.inspect # => ["@my_variable"] 

# simple array, for store variables (this is like a proxy) 
controller_variables = [] 

# transfer instance variables from controller to proxe 
my_controller.instance_variables.each do |variable| 
    controller_variables << {variable => my_controller.instance_variable_get(variable)} 
end 

# let know which instance variables bow in proxy array 
puts controller_variables.inspect # => [{"@my_variable"=>100}] 

# call method process_view_with_variables which will transfer variables from proxy to view 
my_view.process_view_with_variables(controller_variables) # => [{"@my_variable"=>100}]# 

Answer 2

首先您需要查看binding class。 “Metaprogramming Ruby”（高度推荐的BTW）一书很好地概括了它们：“绑定是一个整体，作为一个对象打包，想法是你可以创建一个绑定来捕获本地范围并将其运送。

然后看看ERB类应该回答你的问题。这个例子是直接从文档：

require 'erb' 

    x = 42 
    template = ERB.new <<-EOF 
    The value of x is: <%= x %> 
    EOF 
    puts template.result(binding) 

我希望有所帮助。