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Version: 7.x.x

GraphQLContextFactory

note

If you are using graphql-kotlin-spring-server, see the Spring specific documentation.

GraphQLContextFactory provides a generic mechanism for generating a GraphQL context for each request.

interface GraphQLContextFactory<Request> {
    suspend fun generateContext(request: Request): GraphQLContext =
        emptyMap<Any, Any>().toGraphQLContext()
}

Given the generic server request, the interface should attempt to create a GraphQLContext to be used for every new operation. interface from graphql-kotlin-schema-generator. See execution context for more info on how the context can be used in the schema functions.

Coroutine Context​

By default, graphql-kotlin-server creates a supervisor scope with currently available coroutine context. You can provide additional context elements using GraphQLContextFactory by populating CoroutineContext::class entry in the context map or by implementing graphQLCoroutineContext() (deprecated) on a custom context object.

@Component
class MyCustomContextFactory : GraphQLContextFactory() {
    override suspend fun generateContext(request: ServerRequest): GraphQLContext =
        mapOf(
            CoroutineContext::class to MDCContext()
        ).toGraphQLContext()
}

GraphQLServer will then attempt to create supervisor coroutine scope by combining current coroutine context with custom coroutine context provided by the GraphQLContextFactory. This scope will then be used by FunctionDataFetcher to execute all suspendable functions.

Suspendable Factory​

The interface is marked as a suspend function to allow the asynchronous fetching of context data. This may be helpful if you need to call some other services to calculate a context value.

Server-Specific Abstractions​

A specific graphql-kotlin-*-server library may provide an abstract class on top of this interface so users only have to be concerned with the context class and not the server class type. For example the graphql-kotlin-spring-server provides the following class, which sets the request type:

abstract class SpringGraphQLContextFactory : GraphQLContextFactory<ServerRequest>

HTTP Headers and Cookies​

For common use cases around authorization, authentication, or tracing you may need to read HTTP headers and cookies. This should be done in the GraphQLContextFactory and relevant data should be added to the context to be accessible during schema execution.

Federated Tracing​

See federation tracing support documentation for details.

The reference server implementation graphql-kotlin-spring-server supports federated tracing in the context.