Rails 5 ActiveRecord::SerializationTypeMismatch通过API创建资源

Question

我正在为API使用Rails 5 (beta3)应用程序。我的模型有一个序列化属性，序列化为一个数组。当我从邮递员发送测试请求时，我得到以下错误：

ActiveRecord::SerializationTypeMismatch (Attribute was supposed to be a Array, but was a String. -- "[\"amat\",\"bmat\",\"cmat\"]"):

app/controllers/api/v1/services_controller.rb:23:in `create'
  Rendered vendor/cache/gems/actionpack-5.0.0.beta3/lib/action_dispatch/middleware/templates/rescues/_source.html.erb (3.1ms)
  Rendered vendor/cache/gems/actionpack-5.0.0.beta3/lib/action_dispatch/middleware/templates/rescues/_trace.html.erb (1.3ms)
  Rendered vendor/cache/gems/actionpack-5.0.0.beta3/lib/action_dispatch/middleware/templates/rescues/_request_and_response.html.erb (0.8ms)
  Rendered vendor/cache/gems/actionpack-5.0.0.beta3/lib/action_dispatch/middleware/templates/rescues/diagnostics.html.erb within rescues/layout (15.3ms)

我理解错误的含义，但无法序列化从post请求中获得的数据。在尝试创建请求之前，我不知道如何或在何处序列化。

我的控制器的相关部分：

before_action :set_service, only: [:show, :edit, :update, :destroy]

def create
  @service = Service.new(service_params)
  if @service.save
    render json: {message: 'Service created.'}, status: 200
  else
    render json: {message: 'Error creating Service.'}, status: 500
  end
end

private
  def set_service
    @service = Service.find(params[:id])
  end

  def service_params
    params.require(:service).permit(:name, :sub_service, :material, :parts)
  end

服务模式：

class Service < ApplicationRecord
  serialize :parts,Array
end

我以原始JSON的形式发送请求：

{
  "service" : {
    "name": "Foiling",
    "sub_service":"Full",
    "material":"plastic",
    "parts":["parta","partb","partc"]
  }
}

Answer 1

我明白了，我需要显式地告诉rails对params中的数组进行预期：

def service_params
  params.require(:service).permit(:name, :sub_service, :material, :parts => [])
end