Response Caching through @cacheControl directive

Response caching is a technique for reducing server load by caching GraphQL query operation results. For incoming GraphQL Query operations with the same variable values, the same response is returned from a cache instead of executed again.

To set static cache hints within subgraphs, the @cacheControl directive and CacheControlScope enum definitions must be included in the subgraph schema:

enum CacheControlScope {
  PUBLIC
  PRIVATE
}

directive @cacheControl(
  maxAge: Int
  scope: CacheControlScope
  inheritMaxAge: Boolean
) on FIELD_DEFINITION | OBJECT | INTERFACE | UNION

Then in the subgraph schema, you can use the @cacheControl directive to set cache hints on fields, types, and interfaces:

Time-to-live (TTL)

import { cacheControlDirective } from '@graphql-yoga/plugin-response-cache'

const typeDefs = /* GraphQL */ `
  # the directive needs to be defined in the schema
  ${cacheControlDirective}

  type Query {
    # cache operations selecting Query.lazy for 10 seconds
    lazy: Something @cacheControl(maxAge: 10000)
  }

  # only cache query operations containing User for 500ms
  type User @cacheControl(maxAge: 500) {
    #...
  }
`

Enforce session based caching

In some cases, a type or a field should only be cached if their is a session. For this, you can use the scope to indicate that the cache should only be used if a session is present.

type Query {
  me: User @cacheControl(scope: PRIVATE)
}

type User @cacheControl(scope: PRIVATE) {
  #...
}

Any query containing a type or a field with the scope PRIVATE will only be cached if a session is present.