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Model 分为学生，老师，课程三种，所有的模型都只有 id 和 name两个属性（关联字段除外）；
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学生与老师，学生与课程均为多对多关系（N to N）；
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一名老师能带多门课程，但同一门选修课只会由一名老师带（1 to N）。
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GET /students/:id, 以 Json 返回该名学生的所有课程与对应课老师的信息； -
GET /teachers, 以 Json 返回所有的老师及其所带课程的信息； -
DELETE /teachers/:id, 删除该老师与所带课程的全部信息。
# students_controller.rb
def show
@student = Student.find(params[:id])
render :json @student.to_json(include: { courses: { include: :teacher } } )
end
# teachers_controller.rb
def index
@teachers = Teacher.all
render :json @teachers.to_json(include: :courses)
endhttps://stackoverflow.com/questions/9983436/nesting-json-include-in-rails
ActiveModel::Serializer::JSON#as_json
as_json(options = nil) Link
Returns a hash representing the model. Some configuration can be passed through options.
The option include_root_in_json controls the top-level behavior of as_json. If true, as_json will emit a single root node named after the object's type. The default value for include_root_in_json option is false.
user = User.find(1)
user.as_json
# => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
# "created_at" => "2006/08/01", "awesome" => true}
ActiveRecord::Base.include_root_in_json = true
user.as_json
# => { "user" => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
# "created_at" => "2006/08/01", "awesome" => true } }
This behavior can also be achieved by setting the :root option to true as in:
user = User.find(1)
user.as_json(root: true)
# => { "user" => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
# "created_at" => "2006/08/01", "awesome" => true } }
Without any options, the returned Hash will include all the model's attributes.
user = User.find(1)
user.as_json
# => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
# "created_at" => "2006/08/01", "awesome" => true}
The :only and :except options can be used to limit the attributes included, and work similar to the attributes method.
user.as_json(only: [:id, :name])
# => { "id" => 1, "name" => "Konata Izumi" }
user.as_json(except: [:id, :created_at, :age])
# => { "name" => "Konata Izumi", "awesome" => true }
To include the result of some method calls on the model use :methods:
user.as_json(methods: :permalink)
# => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
# "created_at" => "2006/08/01", "awesome" => true,
# "permalink" => "1-konata-izumi" }
To include associations use :include:
user.as_json(include: :posts)
# => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
# "created_at" => "2006/08/01", "awesome" => true,
# "posts" => [ { "id" => 1, "author_id" => 1, "title" => "Welcome to the weblog" },
# { "id" => 2, "author_id" => 1, "title" => "So I was thinking" } ] }
Second level and higher order associations work as well:
user.as_json(include: { posts: {
include: { comments: {
only: :body } },
only: :title } })
# => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
# "created_at" => "2006/08/01", "awesome" => true,
# "posts" => [ { "comments" => [ { "body" => "1st post!" }, { "body" => "Second!" } ],
# "title" => "Welcome to the weblog" },
# { "comments" => [ { "body" => "Don't think too hard" } ],
# "title" => "So I was thinking" } ] }
Source: show | on GitHub
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