Ruby-on-rails ActiveRecord：如何获取可以批量分配的模型的所有属性？
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ActiveRecord: How to get all attributes of a model that can be mass-assigned?
提问by Vincent
I would like to have a list of all attribute names that can be mass assigned. I need this for a custom form builder that will not add input fields by default that cannot be mass assigned.
我想要一个可以批量分配的所有属性名称的列表。我需要这个自定义表单构建器，默认情况下不会添加无法批量分配的输入字段。
For example if I have the following model:
例如，如果我有以下模型：
class Post < ActiveRecord::Base
attr_protected :account
belongs_to :author
validates_presence_of :title, :author
end
I would like to have as a result [:author, :title].
我想有这样的结果[:author, :title]。
回答by semanticart
Post.accessible_attributes would cover it if you explicitly defined attr_accessible
如果您明确定义了 attr_accessible，则 Post.accessible_attributes 将覆盖它
Barring, that, doing something like this is clunky but works:
除非，做这样的事情很笨拙但有效：
Post.new.attributes.keys - Post.protected_attributes.to_a
回答by Victor S
Some of the previously mentioned answers may not apply for Rails 4.
前面提到的一些答案可能不适用于 Rails 4。
You can use MyModel.attribute_namesto get the array of table attributes, although, that might not give you mass assignable attributes, as this aspect of Rails changes with version 4 http://weblog.rubyonrails.org/2012/3/21/strong-parameters/
您可以使用MyModel.attribute_names来获取表属性数组，尽管这可能不会为您提供大量可分配的属性，因为 Rails 的这一方面随着版本 4 http://weblog.rubyonrails.org/2012/3/21/strong-parameters发生变化/
回答by Antoine
Just use
只需使用
Post.accessible_attributes
That will return all the attributes accessibleof the class
这将返回该类的所有可访问属性
回答by Scudelletti
For Models you can use MyModel.attribute_namesor MyModel.column_names.
对于模型，您可以使用MyModel.attribute_names或MyModel.column_names。
For instances you can use MyModel.new.attribute_names.
例如，您可以使用MyModel.new.attribute_names.
回答by Rajesh Paul
Post.accessible_attributes.to_a.map(&:to_sym)
Post.accessible_attributes.to_a.map(&:to_sym)
