»Extensions

Strawberry provides support for adding extensions. Extensions can be used to hook into different parts of the GraphQL execution and to provide additional results to the GraphQL response.

To enable extensions you can pass them when creating a schema, here's an example that enables the Apollo tracing extension:

from strawberry.extensions.tracing import ApolloTracingExtension
schema = strawberry.Schema(query=Query, extensions=[ApolloTracingExtension])

»Creating custom extensions

To create a custom extensions you can use extend from our Extension base class:

from strawberry.extensions import Extension
class MyExtension(Extension):
    def get_results(self):
        return {
            "example": "this is an example for an extension"
        }
schema = strawberry.Schema(query=Query, extensions=[MyExtension])

»Hooks

»Request

on_request_start and on_request_end can be used to run code when a GraphQL request starts and end, it also allows you to get the execution context

from strawberry.extensions import Extension
class MyExtension(Extension):
    def on_request_start(self, *, execution_context: ExecutionContext):
        print('GraphQL request start')
    def on_request_end(self, *, execution_context: ExecutionContext):
        print('GraphQL request end')

»Resolve

resolve can be used to run code before or after the execution of resolvers, this method must call _next with all the arguments, as they will be needed by the resolvers:

from strawberry.types import Info
from strawberry.extensions import Extension
class MyExtension(Extension):
    def resolve(self, _next, root, info: Info, *args, **kwargs):
        return _next(root, info, *args, **kwargs)

»Get results

get_results allows to return a dictionary of data that will be included in the GraphQL response.

from strawberry.extensions import Extension
class MyExtension(Extension):
    def get_results(self) -> Dict[str, Any]:
        return {}

»Validation

on_validation_start and on_validation_end can be used to run code on the validation step of the GraphQL execution.

from strawberry.extensions import Extension
class MyExtension(Extension):
    def on_validation_start(self):
        print('GraphQL validation start')
    def on_validation_end(self):
        print('GraphQL validation end')

»Parsing

on_validation_start and on_validation_end can be used to run code on the parsing step of the GraphQL execution.

from strawberry.extensions import Extension
class MyExtension(Extension):
    def on_parsing_start(self):
        print('GraphQL parsing start')
    def on_parsing_end(self):
        print('GraphQL parsing end')