Learn-skills.dev rails-graphql-patterns

GraphQL patterns for Rails applications using graphql-ruby gem. Automatically invoked when working with GraphQL schemas, types, resolvers, mutations, subscriptions, or the app/graphql directory. Triggers on "GraphQL", "schema", "resolver", "mutation", "query type", "subscription", "graphql-ruby", "field", "argument", "N+1 graphql", "dataloader".

install

source · Clone the upstream repo

git clone https://github.com/NeverSight/learn-skills.dev

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/NeverSight/learn-skills.dev "$T" && mkdir -p ~/.claude/skills && cp -r "$T/data/skills-md/ag0os/rails-dev-plugin/rails-graphql-patterns" ~/.claude/skills/neversight-learn-skills-dev-rails-graphql-patterns && rm -rf "$T"

manifest: data/skills-md/ag0os/rails-dev-plugin/rails-graphql-patterns/SKILL.md

source content

Rails GraphQL Patterns

Patterns for building GraphQL APIs in Rails applications using graphql-ruby.

When This Skill Applies

Designing GraphQL schemas and types
Implementing resolvers and mutations
Optimizing queries and preventing N+1 problems
Handling authentication/authorization in GraphQL
Implementing subscriptions for real-time updates
Structuring the app/graphql directory

Quick Reference

Component	Purpose	Location
Types	Define object shapes	`app/graphql/types/`
Queries	Read operations	`app/graphql/types/query_type.rb`
Mutations	Write operations	`app/graphql/mutations/`
Resolvers	Query logic	`app/graphql/resolvers/`
Sources	DataLoader batching	`app/graphql/sources/`

Detailed Documentation

patterns.md - Complete GraphQL patterns with examples

Type Definition Basics

# app/graphql/types/user_type.rb
module Types
  class UserType < Types::BaseObject
    field :id, ID, null: false
    field :email, String, null: false
    field :name, String
    field :created_at, GraphQL::Types::ISO8601DateTime, null: false

    field :posts, [Types::PostType], null: true
    field :posts_count, Integer, null: false

    def posts_count
      object.posts.size  # Use size for counter cache
    end
  end
end

Mutation Basics

# app/graphql/mutations/create_post.rb
module Mutations
  class CreatePost < BaseMutation
    argument :title, String, required: true
    argument :content, String, required: true

    field :post, Types::PostType
    field :errors, [String], null: false

    def resolve(title:, content:)
      post = context[:current_user].posts.build(title: title, content: content)

      if post.save
        { post: post, errors: [] }
      else
        { post: nil, errors: post.errors.full_messages }
      end
    end
  end
end

N+1 Prevention with DataLoader

# app/graphql/sources/record_loader.rb
class Sources::RecordLoader < GraphQL::Dataloader::Source
  def initialize(model_class)
    @model_class = model_class
  end

  def fetch(ids)
    records = @model_class.where(id: ids).index_by(&:id)
    ids.map { |id| records[id] }
  end
end

# Usage in type
def author
  dataloader.with(Sources::RecordLoader, User).load(object.user_id)
end

Key Principles

Type Safety: Define explicit types for all fields
Null Handling: Be intentional about
```
null: true/false
```
Batch Loading: Use DataLoader to prevent N+1 queries
Authorization: Check permissions at field level
Error Handling: Return structured errors, not exceptions