Rails“参数数量错误(1代表0)"在to_json方法中 [英] Rails "wrong number of arguments (1 for 0)" in to_json method

问题描述

可能重复:
在Rails 2.3.5中覆盖to_json

Possible Duplicate:
Override to_json in Rails 2.3.5

lib/responses.rb

lib/responses.rb

module Responses
class Response
    def to_json
       JSON.pretty_generate(self)
    end
end

class ErrorResponse < Response
    def initialize(cause)
        self[:type]="Error"
        self[:casue]=cause

    end
end
class DataResponse < Response
    attr_accessor :data

end
end

这由控制器使用:

 response=Responses::DataResponse.new
 response.data=someData

 render :json => response

现在我在lib/responses.rb:3:in to_json中遇到错误wrong number of arguments (1 for 0). 为什么?没有传递给to_json的参数，该参数由render :json隐式调用.那我的错误在哪里?

Now I am getting an error wrong number of arguments (1 for 0) in lib/responses.rb:3:in to_json. Why? There is no argument passed to the to_json which is implicitly called by render :json. So where is my mistake?

推荐答案

这是因为在Rails中使用json渲染时，to_json方法将接收选项.

Its because in Rails when you render with json, the method to_json will receive options.

您可能想要执行以下操作:

You probably want to do something like this:

def to_json(options = {})
   JSON.pretty_generate(self, options)
end

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