ruby 42 lines · 2 tabs

GraphQL API with graphql-ruby gem

Alex Kumar Jan 2026

2 tabs

module Types
  class PostType < Types::BaseObject
    field :id, ID, null: false
    field :title, String, null: false
    field :body, String, null: false
    field :excerpt, String, null: true
    field :published_at, GraphQL::Types::ISO8601DateTime, null: true
    field :author, Types::UserType, null: false
    field :comments, [Types::CommentType], null: false
    field :views, Integer, null: false
    field :likes_count, Integer, null: false

    def excerpt
      object.body&.truncate(200)
    end

    def comments
      # Use dataloader to batch load comments
      dataloader.with(Sources::AssociationSource, Comment, :post_id).load(object.id)
    end
  end
end

module Types
  class QueryType < Types::BaseObject
    field :posts, [Types::PostType], null: false do
      argument :first, Integer, required: false, default_value: 20
      argument :offset, Integer, required: false, default_value: 0
    end

    field :post, Types::PostType, null: true do
      argument :id, ID, required: true
    end

    def posts(first:, offset:)
      Post.published.includes(:author).limit(first).offset(offset)
    end

    def post(id:)
      Post.find(id)
    end
  end
end

2 files · ruby Explain with highlit

GraphQL provides clients flexibility to request exactly the data they need, reducing over-fetching and under-fetching compared to REST. The graphql-ruby gem integrates GraphQL into Rails with a schema-first approach. I define types for each model, fields for attributes, and resolvers for custom logic. The N+1 query problem is more pronounced in GraphQL, so I use graphql-batch for automatic batching and caching of database queries. Authorization happens at the field level using policies or pundit integration. GraphQL's introspection enables powerful tooling like GraphiQL for exploration. The trade-off is increased complexity—REST is simpler for straightforward CRUD, but GraphQL shines for complex frontend requirements with varied data needs.

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class Post < ApplicationRecord
  belongs_to :author, class_name: 'User'
  has_many :comments, dependent: :destroy

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  exp: 15.minutes.from_now.to_i,
  iat: Time.now.to_i,

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module Api
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class PostsController < ApplicationController
  def index
    @posts = Post.includes(:author)
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                 .page(params[:page])
                 .per(10)

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