GraphQL::PersistedQueries

GraphQL::PersistedQueries is the implementation of persisted queries for graphql-ruby. With this plugin your backend will cache all the queries, while frontend will send the full query only when it's not found at the backend storage.

• 🗑Heavy query parameter will be omitted in most of cases – network requests will become less heavy
• 🤝Clients share cached queries – it's enough to miss cache only once for each unique query
• 🎅Works for clients without persisted query support

Installation

1. Add the gem to your Gemfile gem 'graphql-persisted_queries'

2. Install and configure apollo-link-persisted-queries:

import { createPersistedQueryLink } from "apollo-link-persisted-queries";
import { createHttpLink } from "apollo-link-http";
import { InMemoryCache } from "apollo-cache-inmemory";
import ApolloClient from "apollo-client";


// use this with Apollo Client
const link = createPersistedQueryLink().concat(createHttpLink({ uri: "/graphql" }));
const client = new ApolloClient({
  cache: new InMemoryCache(),
  link: link,
});

1. Add plugin to the schema:

class GraphqlSchema < GraphQL::Schema
  use GraphQL::PersistedQueries
end

1. Pass :extensions argument to all calls of GraphqlSchema#execute (start with GraphqlController and GraphqlChannel)

GraphqlSchema.execute(
  params[:query],
  variables: ensure_hash(params[:variables]),
  context: {},
  operation_name: params[:operationName],
  extensions: ensure_hash(params[:extensions])
)

1. Run the app! 🔥

Alternative stores

All the queries are stored in memory by default, but you can easily switch to redis:

class GraphqlSchema < GraphQL::Schema
  use GraphQL::PersistedQueries, store: :redis, redis_url: ENV["MY_REDIS_URL"]
end

If you have ENV["REDIS_URL"] configured – you don't need to pass it explicitly. Also, you can pass :redis_host, :redis_port and :redis_db_name to build the URL from scratch or configure Redis client as you want and pass it as the :client option.

Alternative hash functions

apollo-link-persisted-queries uses SHA256 by default so this gem uses it as a default too, but if you want to override it – you can use :hash_generator option:

class GraphqlSchema < GraphQL::Schema
  use GraphQL::PersistedQueries, hash_generator: :md5
end

If string or symbol is passed – the gem would try to find the class in the Digest namespace. Altenatively, you can pass a lambda, e.g.:

class GraphqlSchema < GraphQL::Schema
  use GraphQL::PersistedQueries, hash_generator: proc { |_value| "super_safe_hash!!!" }
end

GET requests and HTTP cache

Using GET requests for persisted queries allows you to enable HTTP caching (e.g., turn on CDN). In order to make it work you should change the way link is initialized on front-end side (createPersistedQueryLink({ useGETForHashedQueries: true })) and register a new route get "/graphql", to: "graphql#execute".

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/DmitryTsepelev/graphql-persisted_queries.

License

The gem is available as open source under the terms of the MIT License.