Support Apollo Cache Control Specification

[ttyniwa]

Support Apollo Cache Control Specification

Apollo Cache Control exposes cache control hints for an individual request under a cacheControl key in extensions.
graphql-java already implements this feature as CacheControl class.
I'd like to use this feature, so can I implement it?

code

This can be easily implemented by modifying line 45 of GraphQLRequestHandler as follows.

+            var executionResult = graphQL.executeAsync(executionInput).await()
+            executionResult = executionInput.cacheControl.addTo(executionResult)
+            executionResult.toGraphQLResponse()

How to use

Call below code at resolver.

    fun books(
        env: DataFetchingEnvironment,
    ): List<Content> {
+        env.cacheControl.hint(env, 60, CacheControl.Scope.PUBLIC)
...

response sample

  "extensions": {
    "cacheControl": {
      "version": 1,
      "hints": [
        {
          "path": [
            "books"
          ],
          "maxAge": 60,
          "scope": "PUBLIC"
        }
      ]
    }
  }

Caution

If any resolver doesn't call the cacheControl.hint() function, the cacheControl will still appear in the response as following.

  "extensions": {
    "cacheControl": {
      "version": 1,
      "hints": []
    }
  }

This is a specification of CacheControl in graphql-java.
If we don't want them to appear, we need to modify the CacheControl class.

[dariuszkuc]

Hello 👋
GraphQLRequestHandler is an open class so you can easily extend it and implement the cache control logic above.

[ttyniwa]

Thanks for reply.
Graphql-java provides the CacheControl impl, and DataFetchingEnvironment.cacheControl is also initialized by default.
Therefore, i think it would be better if graphql-kotlin also supports this feature by default.

[dariuszkuc]

Apollo Cache Control as the name implies is specific to Apollo and not part of the GraphQL spec. While it is pretty popular it should not be the global default.