将嵌套的关联呈现为json

如何解决将嵌套的关联呈现为json

下面是我的模型定义

# GoogleApp model
class GoogleApp < ApplicationRecord
  has_many :gmail_users,foreign_key: 'app_account',primary_key: 'google_account',dependent: :destroy
  has_many :gmail_threads,dependent: :destroy
end

# GmailUser model
class GmailUser < ApplicationRecord
  belongs_to :google_app,optional: true
  has_one :gmail_thread,foreign_key: 'user_id',primary_key: 'user_id',dependent: :destroy
end

# GmailThread model
class GmailThread < ApplicationRecord
  belongs_to :google_app,optional: true
  belongs_to :gmail_user,optional: true
  has_many :gmail_messages,-> { order "sent_at asc" },foreign_key: 'thread_id',primary_key: 'thread_id',dependent: :destroy
end

# GmailMessage model
class GmailMessage < ApplicationRecord
  belongs_to :gmail_thread,optional: true
  has_many :gmail_attachments,foreign_key: 'message_id',primary_key: 'message_id',dependent: :destroy
end

# GmailAttachment model
require "base64"
class GmailAttachment < ApplicationRecord
  belongs_to :gmail_message,optional: true

  def encode_as_base64_data
    Base64.encode64(self.base64_data)
  end
end

我正在尝试返回具有以下嵌套关联的GoogleApp实例

render status: 200,json: @google_app.to_json({include: [gmail_users: {include: [gmail_thread: {include: [gmail_messages: {include: {gmail_attachments: (except: :base64_data,methods: [:encode_as_base64_data])}}]}]}]})

但这会在except上给出语法错误，即

SyntaxError（/home/work/projects/backend/app/controllers/gmail_controller.rb:40：语法错误，意外的tLABEL ... e：{gmail_attachments：（除了：：base64_data，方法：[：enc ... ... ^ ~~~~~~ ）：

我无法解决此语法错误问题。当我这样做的时候

render status: 200,json: GmailAttachment.first.to_json(except: [:base64_data],methods: [:encode_as_base64_data])

然后按预期工作。

解决方法

exclude应该换成{}而不是()

render status: 200,json: @google_app.to_json({include: [gmail_users: {include: [gmail_thread: {include: [gmail_messages: {include: {gmail_attachments: {except: :base64_data,methods: [:encode_as_base64_data]}}]}]}]})

我建议使用jbuilder Gem以可维护的方式包括嵌套模型。