Ruby-on-rails Rails Active Model Serializer - has_many 并访问父记录
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Rails Active Model Serializer - has_many and accessing the parent record
提问by Toms Mikoss
I'm trying to build a JSON representation of some Rails models using Active Model Serializer, where some models embed others. For example, I have Event and Attendees, Event has_and_belongs_to_many Attendees.
我正在尝试使用 Active Model Serializer 构建一些 Rails 模型的 JSON 表示，其中一些模型嵌入了其他模型。例如，我有 Event 和 Attendees，Event has_and_belongs_to_many Attendees。
class EventSerializer < ActiveModel::Serializer
attributes :name
has_many :attendees, serializer: AttendeeSerializer
end
class AttendeeSerializer < ActiveModel::Serializer
attributes :name
end
This would result in JSON like { name: 'Event One', attendees: [{ name: 'Alice' }, { name: 'Bob' }] }.
这将导致 JSON 之类的{ name: 'Event One', attendees: [{ name: 'Alice' }, { name: 'Bob' }] }.
Now, I'd like to add what the attendees have said about the event. Let's say, Comment belongs_to Event, belongs_to Attendee. I'd like to include said comments in the serialized output of event, so it would become { name: 'Event One', attendees: [{ name: 'Alice', comments: [{ text: 'Event One was great!'}] }, { name: 'Bob', comments: [] }] }.
现在，我想补充一下与会者对这次活动的看法。比方说，评论belongs_to 事件，belongs_to 参加者。我想在事件的序列化输出中包含上述评论，所以它会变成{ name: 'Event One', attendees: [{ name: 'Alice', comments: [{ text: 'Event One was great!'}] }, { name: 'Bob', comments: [] }] }.
I could have
我本可以有
class AttendeeSerializer < ActiveModel::Serializer
attributes :name
has_many :comments
end
but that would select all the comments by this attendee for all the events - not what I want. I'd like to write this, but how do I find the particular event for which I'm doing serialization? Can I somehow access the 'parent' object, or maybe pass options to a has_many serializer?
但这会选择该与会者对所有活动的所有评论 - 不是我想要的。我想写这个，但是如何找到我正在对其进行序列化的特定事件？我可以以某种方式访问“父”对象，还是将选项传递给 has_many 序列化程序？
class AttendeeSerializer < ActiveModel::Serializer
attributes :name
has_many :comments
def comments
object.comments.where(event_id: the_event_in_this_context.id)
end
end
Is this something that can be done, or should I just build the JSON in another way for this particular use case?
这是可以完成的事情，还是我应该为此特定用例以另一种方式构建 JSON？
回答by apneadiving
I'd do things manually to get control:
我会手动做一些事情来控制：
class EventSerializer < ActiveModel::Serializer
attributes :name, :attendees
def attendees
object.attendees.map do |attendee|
AttendeeSerializer.new(attendee, scope: scope, root: false, event: object)
end
end
end
class AttendeeSerializer < ActiveModel::Serializer
attributes :name, :comments
def comments
object.comments.where(event_id: @options[:event].id).map do |comment|
CommentSerializer.new(comment, scope: scope, root: false)
end
end
end
