Flask

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

from flask import Flask
from strawberry.flask.views import GraphQLView

from api.schema import schema

app = Flask(__name__)

app.add_url_rule(
    "/graphql",
    view_func=GraphQLView.as_view("graphql_view", schema=schema),
)

if __name__ == "__main__":
    app.run()  

If you’d prefer to use an asynchronous view you can instead use the following import which has the same interface as GraphQLView . This is helpful if using a dataloader.

from strawberry.flask.views import AsyncGraphQLView  

Options

The GraphQLView accepts the following options at the moment:

• schema : mandatory, the schema created by strawberry.Schema .
• graphql_ide : optional, defaults to "graphiql" , allows to choose the GraphQL IDE interface (one of graphiql , apollo-sandbox or pathfinder ) or to disable it by passing None .
• allow_queries_via_get : optional, defaults to True , whether to enable queries via GET requests
• multipart_uploads_enabled : optional, defaults to False , controls whether to enable multipart uploads. Please make sure to consider the security implications mentioned in the GraphQL Multipart Request Specification when enabling this feature.

Extending the view

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

• def get_context(self, request: Request, response: Response) -> Context
• def get_root_value(self, request: Request) -> Optional[RootValue]
• def process_result(self, request: Request, result: ExecutionResult) -> GraphQLHTTPResponse
• def decode_json(self, data: Union[str, bytes]) -> object
• def encode_json(self, data: object) -> str
• def render_graphql_ide(self, request: Request) -> Response

get_context

get_context allows to provide a custom context object that can be used in your resolver. You can return anything here, by default we return a dictionary with the request. By default; the Response object from flask is injected via the parameters.

import strawberry
from strawberry.flask.views import GraphQLView
from flask import Request, Response


class MyGraphQLView(GraphQLView):
    def get_context(self, request: Request, response: Response):
        return {"example": 1}


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

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

Then we use the context in a resolver, the resolver will return “1” in this case.

get_root_value

get_root_value allows to 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 strawberry.flask.views import GraphQLView
from flask import Request


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


@strawberry.type
class Query:
    name: str  

Here we are returning a Query where the name is “Patrick”, so we when requesting the field name we’ll return “Patrick” in this case.

process_result

process_result allows to customize and/or process results before they are sent to the clients. This can be useful logging errors or hiding them (for example to hide internal exceptions).

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

from strawberry.flask.views import GraphQLView
from strawberry.http import GraphQLHTTPResponse
from strawberry.types import ExecutionResult


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

        if result.errors:
            data["errors"] = [err.formatted 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.

decode_json

decode_json allows to customize the decoding of HTTP JSON requests. By default we use json.loads but you can override this method to use a different decoder.

from strawberry.flask.views import GraphQLView
from typing import Union
import orjson


class MyGraphQLView(GraphQLView):
    def decode_json(self, data: Union[str, bytes]) -> object:
        return orjson.loads(data)  

Make sure your code raises json.JSONDecodeError or a subclass of it if the JSON cannot be decoded. The library shown in the example above, orjson , does this by default.

encode_json

encode_json allows to customize the encoding of HTTP and WebSocket JSON responses. By default we use json.dumps but you can override this method to use a different encoder.

import json
from strawberry.flask.views import GraphQLView


class MyGraphQLView(GraphQLView):
    def encode_json(self, data: object) -> str:
        return json.dumps(data, indent=2)  

render_graphql_ide

In case you need more control over the rendering of the GraphQL IDE than the graphql_ide option provides, you can override the render_graphql_ide method.

from strawberry.flask.views import GraphQLView
from flask import Request, Response


class MyGraphQLView(GraphQLView):
    def render_graphql_ide(self, request: Request) -> Response:
        custom_html = """<html><body><h1>Custom GraphQL IDE</h1></body></html>"""

        return Response(custom_html, status=200, content_type="text/html")