带json数组的强参数

Question

我已经阅读了这个答案how to permit an array with strong parameters，但我无法使用 params.permit 从使用 rails 4.2 的 byebug 会话中弄清楚这种情况：

如何提取 cmets 参数？

(byebug) params
{"comments"=>"[{\"comment\":\"ndjsnjakldnfljkasdbfhjae\",\"date\":\"2017-07-20 17:14:38\"}]", "format"=>:json, "controller"=>"airis/observations", "action"=>"create", "id"=>"13534543543"}
(byebug) params.permit(:id)
[2017-07-20 19:14:43 +0200] [f2b3d7c8-c84a-43a5-b48f-0f634be49dc7] Unpermitted parameters: comments, format
{"id"=>"13534543543"}
(byebug) params.permit(:comments)
[2017-07-20 19:14:43 +0200] [f2b3d7c8-c84a-43a5-b48f-0f634be49dc7] Unpermitted parameters: format, id
{"comments"=>"[{\"comment\":\"ndjsnjakldnfljkasdbfhjae\",\"date\":\"2017-07-20 17:14:38\"}]"}
(byebug) params.permit(comments: [:comment, :date])
[2017-07-20 19:14:43 +0200] [f2b3d7c8-c84a-43a5-b48f-0f634be49dc7] Unpermitted parameters: format, id
{"comments"=>nil}
(byebug) params.permit(:id, comments: [:comment, :date])
[2017-07-20 19:14:43 +0200] [f2b3d7c8-c84a-43a5-b48f-0f634be49dc7] Unpermitted parameter: format
{"id"=>"13534543543", "comments"=>nil}

甚至还有这个：

(byebug) params.permit( :comments => [:comment, :date])
[2017-07-20 19:14:43 +0200] [f2b3d7c8-c84a-43a5-b48f-0f634be49dc7] Unpermitted parameters: format, id
{"comments"=>nil}

Answer 1

试试这个：

2.3.1 :034 > JSON.parse(params.permit(:comments)[:comments])
Unpermitted parameters: format, id
 => [{"comment"=>"ndjsnjakldnfljkasdbfhjae", "date"=>"2017-07-20 17:14:38"}]  

params.permit(:comments) 返回仅包含“cmets”k,v 对的参数哈希（删除未经允许的参数，format 和 id）：

2.3.1 :035 > params.permit(:comments)
Unpermitted parameters: format, id
 => {"comments"=>"[{\"comment\":\"ndjsnjakldnfljkasdbfhjae\",\"date\":\"2017-07-20 17:14:38\"}]"} 

params.permit(:comments)[:comments] 从哈希中选择 :comments 键的值：

2.3.1 :036 > params.permit(:comments)[:comments]
Unpermitted parameters: format, id
 => "[{\"comment\":\"ndjsnjakldnfljkasdbfhjae\",\"date\":\"2017-07-20 17:14:38\"}]" 

JSON.parse(params.permit(:comments)[:comments]) 将字符串转换为正确的 ruby​​ 数组。

从那里，您可以随意使用 ruby​​ array 对象。

如果你想要:comments 和:id，那么只需：

params.permit(:comments, :id)
Unpermitted parameter: format
 => {"comments"=>"[{\"comment\":\"ndjsnjakldnfljkasdbfhjae\",\"date\":\"2017-07-20 17:14:38\"}]", "id"=>"13534543543"} 

获取各个部分：

2.3.1 :038 > params.permit(:comments, :id)[:comments]
Unpermitted parameter: format
 => "[{\"comment\":\"ndjsnjakldnfljkasdbfhjae\",\"date\":\"2017-07-20 17:14:38\"}]" 

和：

2.3.1 :039 > params.permit(:comments, :id)[:id]
Unpermitted parameter: format
 => "13534543543" 

你可能想把它包装成这样的东西：

def clean_params
  @clean_params ||= params.permit(:comments, :id)
end

所以你可以使用clean_params[:comments] 和clean_params[:id]。