导轨；验证服务对象中的参数

Question

我在 Rails 中创建了一个服务对象来封装为 Stripe（https://stripe.com/）创建计划的业务逻辑。 有没有什么好的模式来处理Service对象的参数验证？

对于验证：

• 我必须检查所有输入是否为 nil 或类型错误。有什么方法可以轻松验证吗？也许是 Rails 扩展？

这是一个例子；

# app/services/service.rb
module Service
  extend ActiveSupport::Concern

  included do
    def self.call(*args)
      new(*args).call
    end
  end
end

# app/services/plan/create.rb
class Plan::Create
  include Service

  attr_reader :params

  def initialize(params = {})
    @params = params.dup
  end

  def call
    plan = Plan.new(attrs)
    return plan unless plan.valid?

    begin
      external_card_plan_service.create(api_attrs)
    rescue Stripe::StripeError => e
      plan.errors[:base] << e.message
      return plan
    end

    plan.save
    plan.update(is_active: true, activated_at: Time.now.utc)
    plan
  end

  private

  def external_card_plan_service
    Stripe::Plan
  end

  def build_data_hash
    {
      id: params.fetch(:stripe_plan_id)
      stripe_plan_id: params.fetch(:stripe_plan_id)
      amount: params.fetch(:amount)
      currency: params.fetch(:currency)
      interval: params.fetch(:interval)
      name: params.fetch(:name)
      description: params.fetch(:description)
    }
  end

  def attrs
    build_data_hash.slice(:stripe_plan_id, :amount, :currency, :interval, :name, :description)
  end

  def api_attrs
    build_data_hash.slice(:id, :amount, :currency, :interval, :name)
  end
end

参考：http://brewhouse.io/blog/2014/04/30/gourmet-service-objects.

更新

上面的例子并不复杂。 但是，如果在服务对象中调用服务对象，最好验证参数。 CreateUser.call(email_address)

class CreateSubscription
  def self.call(plan, email_address, token)
    user, raw_token = CreateUser.call(email_address)

    subscription = Subscription.new(
      plan: plan,
      user: user
    )

    begin
      stripe_sub = nil
      if user.stripe_customer_id.blank?
        customer = Stripe::Customer.create(
          source: token,
          email: user.email,
          plan: plan.stripe_id,
        )
        user.stripe_customer_id = customer.id
        user.save!
        stripe_sub = customer.subscriptions.first
      else
        customer = Stripe::Customer.retrieve(user.stripe_customer_id)
        stripe_sub = customer.subscriptions.create(
          plan: plan.stripe_id
        )
      end

      subscription.stripe_id = stripe_sub.id

      subscription.save!
    rescue Stripe::StripeError => e
      subscription.errors[:base] << e.message
    end

    subscription
  end 
end

我尝试使用 Virtus(https://github.com/solnic/virtus)。 但是我不知道如何在这种类型的服务对象中使用它。

更新

# api/v1/controller/plans_controller.rb
    module Api
      module V1
        class PlansController < Api::V1::ApiController
          before_action :check_type, only: [:create]

          def create
            @result = Plan::Create.call(plan_info_params)

            if @result.errors.blank?
              resource = Api::V1::PlanResource.new(@result, nil)

              # NOTE: Include all domains created within this routine.
              serializer = JSONAPI::ResourceSerializer.new(Api::V1::PlanResource)
              json_body = serializer.serialize_to_hash(resource)
              render json: json_body, status: 201 # :ok
            else
              errors = jsonapi_errors(@result)
              response = { errors: errors }
              render json: response, status: 422 # :unprocessable_entity
            end
          end

          private

          def check_type
            data_type = 'plans'
            unless params.fetch('data', {}).fetch('type', {}) == data_type
              render json: { errors: [{ title: 'Unprocessable Entity', detail: "Type must be #{data_type}" }] }, status: 422
            end
          end

          def plan_info_params
            params.require(:data).require(:attributes).permit(:stripe_plan_id, :amount, :currency, :interval, :name, :description)
          end
        end
      end
    end

Answer 1

dry-validation 是一个不错的解决方案。

class PlanForm
    include DryValidationForm

    Schema = Dry::Validation.Form do
      required(:stripe_plan_id).filled(:int?)
      required(:stripe_plan_id).filled(:int?)
      required(:amount).filled(:int?, gt?: 0)
      required(:currency).filled(:str?)
      required(:name).filled(:str?)
      optional(:description).maybe(:str?)
    end
  end
end

调用表单的最佳位置可能是您获取参数的控制器。然后将有效参数传递给服务对象