mutation的部分，除了需要修改原先的CreatePost，還相新增一個RemovePost來刪除文章

修改完的程式碼如下:

app/graphql/type/mutation_type.rb

module Types
  class MutationType < BaseObject
    field :create_post, mutation: Mutations::CreatePost
    field :remove_post, mutation: Mutations::RemovePost
  end
end

app/graphql/mutations/create_post.rb

module Mutations
  class CreatePost < BaseMutation
    argument :title, String, required: true
    argument :content, String, required: true
    argument :type, Integer, required: true
    
    #回傳的type類型為PostType
    type Types::PostType
  
    def resolve(title: nil, content: nil, type: nil)
      new_post = Post.create!(
        title: title,
        content: content,
        type: Type.find(type),
      )
      return {
        id: new_post.id,
        title: title,
        content: content,
        type: Type.find(type).name,
      }      
    end
  end
end

app/graphql/mutations/remove_post.rb

module Mutations
  class RemovePost < BaseMutation
    argument :id, Integer, required: true  
    
    #回傳String
    type String
    
    def resolve(id: nil)
      if(Post.find(id).destroy)
        return "刪除成功"
      end   
    end
  end
end

使用結果如下:

rails的部分基本上就到此為止，我也不算是十分熟悉，但經過這次，的確更清楚GraphQL API的撰寫方法及原理了。
下個部分，我們回到Gatsby，試著從Gatsby上去抓取我們GraphQL server上的文章資料!

原始碼