Rails 5 ActiveRecord::SerializationTypeMismatch，同时通过 API 创建资源答案

【问题标题】：Rails 5 ActiveRecord::SerializationTypeMismatch while creating a resource via APIRails 5 ActiveRecord::SerializationTypeMismatch，同时通过 API 创建资源
【发布时间】：2016-06-21 23:46:04
【问题描述】：

我正在为 API 使用 Rails 5 (beta3) 应用程序。我的模型有一个序列化的属性，序列化为一个数组。当我从 Postman 发送测试请求时，我收到以下错误：

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)

我了解错误的含义，但我无法序列化从发布请求中获得的数据。在尝试创建请求之前，我不知道如何或在哪里序列化它。

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

我将请求作为原始 JSON 发送：

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

【问题讨论】：

你的测试请求是什么样的？您在请求中发送数组还是字符串？
添加到问题中。

标签： ruby-on-rails ruby activerecord serialization ruby-on-rails-5

【解决方案1】：

我想通了，我需要明确告诉 rails 在 params 中期待一个数组：

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

【讨论】：