rails-graphql-patterns_skill

Overview

This skill provides proven GraphQL patterns for Rails apps using the graphql-ruby gem. It guides schema design, type definitions, resolvers, mutations, subscriptions, and directory structure. The goal is predictable, performant APIs with clear conventions for authorization, error handling, and N+1 prevention.

How this skill works

The skill inspects code in app/graphql and related GraphQL files to suggest patterns and fixes. It recommends type signatures, nullability choices, resolver placement, DataLoader batching, and mutation return shapes. It also flags common problems like N+1 queries, missing authorization checks, and unstructured errors.

When to use it

• When designing or reviewing GraphQL schemas and types in Rails
• Implementing or refactoring queries, resolvers, or mutations
• Adding subscriptions or real-time updates to a Rails app
• Optimizing database access and preventing N+1 queries
• Adding field-level authorization or structured error handling

Best practices

• Define explicit types for every field and be deliberate with null: true/false
• Place business logic in resolvers or service objects, keep types thin
• Use graphql-ruby’s DataLoader to batch DB access and avoid N+1 problems
• Return structured error arrays from mutations instead of raising exceptions
• Authorize at the field or resolver level, not only at controller entry points

Example use cases

• Create a Post mutation that returns the created object and an errors array
• Define a UserType with computed fields using object methods and cached counts
• Implement a RecordLoader DataLoader source to batch user or post lookups
• Add subscriptions to broadcast new comments to clients in real time
• Refactor query fields into resolver classes for easier testing and reuse