Rails 3的Api错误定制，如Github Api v3

Question

我在一个rails应用程序上添加了一个API，并且进展得很顺利。但我看到以下Github api v3在http://developer.github.com/v3/

HTTP/1.1 422 Unprocessable Entity
 Content-Length: 149
 {
   "message": "Validation Failed",
   "errors": [
     {
       "resource": "Issue",
       "field": "title",
       "code": "missing_field"
     }
   ]
 }

我喜欢错误消息结构。但不能让它繁殖。我怎样才能使我的api做出这样的响应呢?

Answer 1

你可以很容易地通过为JSON格式添加ActionController::Responder来实现这个错误格式。请参阅http://api.rubyonrails.org/classes/ActionController/Responder.html获取该类的(非常模糊的)文档，但简而言之，您需要重写to_json方法。

在下面的例子中，我在ActionController:Responder中调用一个私有方法，它将构造json响应，包括您选择的自定义错误响应;你所要做的就是填补空白，真的:

def to_json
  json, status = response_data
  render :json => json, :status => status
end
def response_data
  status = options[:status] || 200
  message = options[:notice] || ''
  data = options[:data] || []
  if data.blank? && !resource.blank?
    if has_errors?
      # Do whatever you need to your response to make this happen.
      # You'll generally just want to munge resource.errors here into the format you want.
    else
      # Do something here for other types of responses.
    end
  end
  hash_for_json = { :data => data, :message => message }
  [hash_for_json, status]
end