How to create a custom loader in GraphQL::Batch?

Define a class inheriting from GraphQL::Batch::Loader with an initialize method for grouping and a perform method to batch load data, as shown in the RecordLoader example in the README. This allows you to handle specific data models and edge cases like caching.

GraphQL::Batch vs DataLoader in JavaScript?

GraphQL::Batch is Ruby's implementation of the DataLoader pattern, tailored for graphql-ruby and promise.rb, whereas DataLoader in JavaScript is more generic and works with various GraphQL servers. GraphQL::Batch integrates directly into Ruby's ecosystem, offering similar batching but with Ruby-specific APIs and ActiveRecord examples.

How to handle errors in GraphQL::Batch promises?

Use the .then method with two lambda arguments: the first for success and the second for handling exceptions, as demonstrated in the README's CacheLoader example. This allows fallback logic, such as retrying with a different loader if an error occurs.

Can GraphQL::Batch work with non-ActiveRecord databases?

Yes, it doesn't depend on ActiveRecord, but you'll need to write custom loaders for your data source, as the README states it handles edge cases for ActiveRecord but provides a framework for other setups. This requires more manual implementation compared to using the provided examples.

How to test GraphQL::Batch loaders outside of GraphQL?

Use the GraphQL::Batch.batch helper to run batch loads in a block, as described in the unit testing section. This sets up thread-local state to simulate batching and clears it after, allowing isolated testing of loader logic without executing full GraphQL queries.

What are common performance issues with GraphQL::Batch?

If loaders are not implemented correctly, it can still lead to N+1 problems or memory leaks due to caching. The README emphasizes proper grouping in perform methods and cache priming, but misuse, such as inefficient queries or missing fulfill calls, can negate benefits.

graphql-batch — Ruby GraphQL Query Batching

What is graphql-batch?

GraphQL::Batch is a Ruby gem that provides a batch loading executor for the graphql-ruby library. It solves the N+1 query problem in GraphQL APIs by grouping similar database requests into single queries, dramatically reducing database roundtrips and improving performance.

Target Audience

Ruby developers building GraphQL APIs with the graphql-ruby gem who need to optimize database queries and eliminate N+1 problems in their resolvers.

Value Proposition

Developers choose GraphQL::Batch because it implements the DataLoader pattern specifically for graphql-ruby with minimal configuration, provides a clean promise-based API, and includes ActiveRecord integration examples for real-world use cases.

A query batching executor for the graphql gem

Use Cases

Best For

Eliminating N+1 queries in graphql-ruby APIs
Batch loading ActiveRecord associations in GraphQL resolvers
Reducing database roundtrips in complex GraphQL queries
Implementing the DataLoader pattern in Ruby GraphQL servers
Optimizing GraphQL API performance with minimal code changes
Testing batch loading logic outside of GraphQL execution context

Not Ideal For

Projects not using the graphql-ruby gem for their GraphQL server
Simple GraphQL APIs with minimal nested queries where N+1 issues are negligible
Teams seeking a drop-in batching solution that automatically handles all queries without custom loader classes
Applications using ORMs other than ActiveRecord without existing adapter support

Pros & Cons

Pros

Efficient Batch Loading

Groups multiple data requests into single database queries, eliminating the N+1 problem as described in the README's basic usage with RecordLoader examples.

Flexible Custom Loaders

Allows creation of reusable loader classes with custom grouping logic, evidenced by the need to define a perform method for different data models.

Promise-based API

Uses promise.rb for chaining and transforming results with methods like .then and Promise.all, shown in the promises section for dependent queries.

ActiveRecord Integration

Includes examples for ActiveRecord with edge case handling, such as type casting IDs, as mentioned in the README for real-world use.

Cons

Manual Loader Implementation

Requires writing custom loader classes for each data model, which can be boilerplate-heavy and time-consuming, as seen in the need to define initialize and perform methods.

Limited to graphql-ruby

Only works with the graphql-ruby gem, making it incompatible with other GraphQL frameworks in Ruby or other languages, as it's a plugin for that specific library.

ActiveRecord-Centric Examples

While not dependent on ActiveRecord, the provided examples focus on it, potentially requiring additional effort for other database layers or ORMs, as acknowledged in the README.

Frequently Asked Questions

What is graphql-batch?

Target Audience

Ruby developers building GraphQL APIs with the graphql-ruby gem who need to optimize database queries and eliminate N+1 problems in their resolvers.

Value Proposition

Use Cases

Best For

Eliminating N+1 queries in graphql-ruby APIs
Batch loading ActiveRecord associations in GraphQL resolvers
Reducing database roundtrips in complex GraphQL queries
Implementing the DataLoader pattern in Ruby GraphQL servers
Optimizing GraphQL API performance with minimal code changes
Testing batch loading logic outside of GraphQL execution context

Not Ideal For

Projects not using the graphql-ruby gem for their GraphQL server
Simple GraphQL APIs with minimal nested queries where N+1 issues are negligible
Teams seeking a drop-in batching solution that automatically handles all queries without custom loader classes
Applications using ORMs other than ActiveRecord without existing adapter support

Pros & Cons

Pros

Efficient Batch Loading

Groups multiple data requests into single database queries, eliminating the N+1 problem as described in the README's basic usage with RecordLoader examples.

Flexible Custom Loaders

Allows creation of reusable loader classes with custom grouping logic, evidenced by the need to define a perform method for different data models.

Promise-based API

Uses promise.rb for chaining and transforming results with methods like .then and Promise.all, shown in the promises section for dependent queries.

ActiveRecord Integration

Includes examples for ActiveRecord with edge case handling, such as type casting IDs, as mentioned in the README for real-world use.

Cons

Manual Loader Implementation

Requires writing custom loader classes for each data model, which can be boilerplate-heavy and time-consuming, as seen in the need to define initialize and perform methods.

Limited to graphql-ruby

Only works with the graphql-ruby gem, making it incompatible with other GraphQL frameworks in Ruby or other languages, as it's a plugin for that specific library.

ActiveRecord-Centric Examples

While not dependent on ActiveRecord, the provided examples focus on it, potentially requiring additional effort for other database layers or ORMs, as acknowledged in the README.

Frequently Asked Questions

graphql-batch

What is graphql-batch?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?

graphql-batch

What is graphql-batch?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?