»AIOHTTP

Strawberry comes with a basic AIOHTTP integration. It provides a view that you can use to serve your GraphQL schema:

import strawberry
from aiohttp import web
from strawberry.aiohttp.views import GraphQLView


@strawberry.type
class Query:
    pass


schema = strawberry.Schema(query=Query)

app = web.Application()

app.router.add_route("*", "/graphql", GraphQLView(schema=schema))

»Options

The GraphQLView accepts two options at the moment:

  • schema: mandatory, the schema created by strawberry.Schema.
  • graphiql: optional, defaults to True, whether to enable the GraphiQL interface.

»Extending the view

The base GraphQLView class can be extended by overriding the following methods:

»get_context

By overriding GraphQLView.get_context you can provide a custom context object for your resolvers. You can return anything here; by default GraphQLView returns a dictionary with the request.

import strawberry
from aiohttp import web
from strawberry.types import Info
from strawberry.aiohttp.views import GraphQLView


class MyGraphQLView(GraphQLView):
    async def get_context(self, request: web.Request, response: web.StreamResponse):
        return {"request": request, "response": response, "example": 1}


@strawberry.type
class Query:
    @strawberry.field
    def example(self, info: Info) -> str:
        return str(info.context["example"])

Here we are returning a custom context dictionary that contains only one item called "example".

Then we can use the context in a resolver. In this case the resolver will return 1.

»get_root_value

By overriding GraphQLView.get_root_value you can provide a custom root value for your schema. This is probably not used a lot but it might be useful in certain situations.

Here's an example:

import strawberry
from aiohttp import web
from strawberry.aiohttp.views import GraphQLView


class MyGraphQLView(GraphQLView):
    async def get_root_value(self, request: web.Request):
        return Query(name="Patrick")


@strawberry.type
class Query:
    name: str

Here we configure a Query where requesting the name field will return "Patrick" through the custom root value.

»process_result

By overriding GraphQLView.process_result you can customize and/or process results before they are sent to a client. This can be useful for logging errors, or even hiding them (for example to hide internal exceptions).

It needs to return an object of GraphQLHTTPResponse and accepts the request and execution result.

from aiohttp import web
from strawberry.aiohttp.views import GraphQLView
from strawberry.http import GraphQLHTTPResponse
from strawberry.types import ExecutionResult

from graphql.error import format_error as format_graphql_error


class MyGraphQLView(GraphQLView):
    async def process_result(
        self, request: web.Request, result: ExecutionResult
    ) -> GraphQLHTTPResponse:
        data: GraphQLHTTPResponse = {"data": result.data}

        if result.errors:
            data["errors"] = [format_graphql_error(err) for err in result.errors]

        return data

In this case we are doing the default processing of the result, but it can be tweaked based on your needs.

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