葡萄：葡萄实体的必需参数

Question

我正在用grape 编写一个API 服务器，我选择使用grape-entity，因为它能够自动生成swagger 的文档。 但是现在当我根据需要设置参数时我遇到了问题。因为葡萄不验证参数是否存在。看起来葡萄忽略了实体参数的required: true。

app.rb

module Smart
  module Version1
    class App < BaseApi

      resource :app do

        # POST /app
        desc 'Creates a new app' do
          detail 'It is used to re gister a new app on the server and get the app_id'
          params  Entities::OSEntity.documentation
          success Entities::AppEntity
          failure [[401, 'Unauthorized', Entities::ErrorEntity]]
          named 'My named route'
        end
        post do
          app = ::App.create params
          present app, with: Entities::AppEntity
        end
      end
    end
  end
end

os_entity.rb

module Smart
  module Entities
    class OSEntity < Grape::Entity

      expose :os, documentation: { type: String, desc: 'Operative system name', values: App::OS_LIST, required: true }

    end
  end
end

app_entity.rb

module Smart
  module Entities
    class AppEntity < OSEntity

      expose :id, documentation: { type: 'integer', desc: 'Id of the created app', required: true }
      expose :customer_id, documentation: { type: 'integer', desc: 'Id of the customer', required: true }

    end
  end
end

现在其他一切都很好，但我不知道如何以 DRY 方式使用实体，并使葡萄验证参数的要求。

Answer 1

经过一些工作，我能够按照我认为应该工作的方式制作葡萄。因为我不想重复验证和文档的代码。您只需将其添加到初始化程序中（当然，如果您在 rails 中）。我还能够支持嵌套关联。如您所见，API 代码看起来很简单，招摇看起来很完美。 以下是 API 和所有需要的实体：

app/api/smart/entities/characteristics_params_entity.rb

module Smart
  module Entities
    class CharacteristicsParamsEntity < Grape::Entity

      root :characteristics, :characteristic
      expose :id, documentation: { type: Integer, desc: 'Id of the characteristic' }

    end
  end
end

app/api/smart/entities/characterisitcs_entity.rb

module Smart
  module Entities
    class CharacteristicsEntity < CharacteristicsParamsEntity

      expose :id, documentation: { type: Integer, desc: 'Id of the characteristic' }
      expose :name, documentation: { type: String, desc: 'Name of the characteristic' }
      expose :description, documentation: { type: String, desc: 'Description of the characteristic' }
      expose :characteristic_type, documentation: { type: String, desc: 'Type of the characteristic' }
      expose :updated_at, documentation: { type: Date, desc: 'Last updated time of the characteristic' }

    end
  end
end

app/api/smart/entities/apps_params_entity.rb

module Smart
  module Entities
    class AppsParamsEntity < Grape::Entity

      expose :os, documentation: { type: String, desc: 'Operative system name', values: App::OS_LIST, required: true }
      expose :characteristic_ids, using: CharacteristicsParamsEntity, documentation: { type: CharacteristicsParamsEntity, desc: 'List of characteristic_id that the customer has', is_array: true }


    end
  end
end

app/api/smart/entities/apps_entity.rb

module Smart
  module Entities
    class AppsEntity < AppsParamsEntity

      unexpose :characteristic_ids
      expose :id, documentation: { type: 'integer', desc: 'Id of the created app', required: true }
      expose :customer_id, documentation: { type: 'integer', desc: 'Id of the customer', required: true }
      expose :characteristics, using: CharacteristicsEntity, documentation: { is_array: true, desc: 'List of characteristics that the customer has' }

    end
  end
end

app/api/smart/version1/apps.rb

module Smart
  module Version1
    class Apps < Version1::BaseAPI

    resource :apps do

        # POST /apps
        desc 'Creates a new app' do
          detail 'It is used to register a new app on the server and get the app_id'
          params Entities::AppsParamsEntity.documentation
          success Entities::AppsEntity
          failure [[400, 'Bad Request', Entities::ErrorEntity]]
          named 'create app'
        end
        post do
          app = ::App.create! params
          present app, with: Entities::AppsEntity
        end

      end

    end
  end
end

这就是让它发挥作用的代码：

config/initializers/grape_extensions.rb

class Evaluator
  def initialize(instance)
    @instance = instance
  end

  def params parameters
    evaluator = self
    @instance.normal_params do
      evaluator.list_parameters(parameters, self)
    end
  end

  def method_missing(name, *args, &block)
  end

  def list_parameters(parameters, grape)
    evaluator = self
    parameters.each do |name, description|
      description_filtered = description.reject { |k| [:required, :is_array].include?(k) }
      if description.present? && description[:required]
        if description[:type] < Grape::Entity
          grape.requires name, description_filtered.merge(type: Array) do
            evaluator.list_parameters description[:type].documentation, self
          end
        else
          grape.requires name, description_filtered
        end
      else
        if description[:type] < Grape::Entity
          grape.optional name, description_filtered.merge(type: Array) do
            evaluator.list_parameters description[:type].documentation, self
          end
        else
          grape.optional name, description_filtered
        end
      end
    end
  end
end

module GrapeExtension
  def desc name, options = {}, &block
    Evaluator.new(self).instance_eval &block if block
    super name, options do
      def params *args
      end

      instance_eval &block if block
    end
  end
end

class Grape::API
  class << self
    prepend GrapeExtension
  end
end

这是示例的结果：

Answer 2

我喜欢用于构建 API 的 grape/grape-swagger/grape-entity 组合。我通常使用葡萄实体来构建结果，而不是用于记录/验证 API。根据文档（对于葡萄实体）它应该可以工作，但我猜只是为了构建文档。

根据葡萄documentation on parameter validation and coercion，它需要block 来强制执行任何验证/强制。

[编辑：混合参数]

您可以使用实体在desc 中定义参数，但要进行验证，您必须提供与desc 块相同级别的params 块，例如：

    # POST /app
    desc 'Creates a new app' do
      detail 'It is used to re gister a new app on the server and get the app_id'
      params  Entities::OSEntity.documentation
      success Entities::AppEntity
      failure [[401, 'Unauthorized', Entities::ErrorEntity]]
      named 'My named route'
    end
    params do
      requires :name, String
      optional :description, String
    end 
    post do
      app = ::App.create params
      present app, with: Entities::AppEntity
    end

它们都称为params，但位置完全不同，功能也不同。
我不确定desc 块是否除了文档还有其他用途（以及如何提取此文档对我来说有点神秘）。

grape-swagger gem 不用，我典型的desc 长这样：

  desc "list of batches", {
    :notes => <<-NOTE
      Show a list of all available batches.

      ## Request properties

      * _Safe:_ Yes
      * _Idempotent:_ Yes
      * _Can be retried:_ Yes
    NOTE
  }
  params do
    optional :page, desc: 'paginated per 25'
  end
  get do
    present Batch.page(params[:page]), with: API::Entities::Batch
  end

:notes 使用 markdown 呈现。这在 swagger-ui 中看起来如何