Generating GraphQL Context

graphql-kotlin-spring-server provides a simple mechanism to build a GraphQL context per query execution through GraphQLContextFactory. Once a context factory bean is available, it will then be used in ContextWebFilter to populate the GraphQL context based on the incoming request and make it available during query execution.

For example if we define our custom context as follows:

class MyGraphQLContext(val myCustomValue: String) : GraphQLContext

We can generate the corresponding GraphQLContextFactory bean:

@Component
class MyGraphQLContextFactory: GraphQLContextFactory<MyGraphQLContext> {
    override suspend fun generateContext(
        request: ServerHttpRequest,
        response: ServerHttpResponse
    ): MyGraphQLContext = MyGraphQLContext(
        myCustomValue = request.headers.getFirst("MyHeader") ?: "defaultValue"
    )
}

Once your application is configured to build your custom MyGraphQLContext, we can then specify it as function argument but it will not be included in the schema. While executing the query, the corresponding GraphQL context will be read from the environment and automatically injected to the function input arguments.

For more details see the Contextual Data documentation.