Chalice

Strawberry comes with an AWS Chalice integration. It provides a view that you can use to serve your GraphQL schema:

Use the Chalice CLI to create a new project

chalice new-project badger-project
cd badger-project  

Replace the contents of app.py with the following:

from chalice import Chalice
from chalice.app import Request, Response

import strawberry
from strawberry.chalice.views import GraphQLView

app = Chalice(app_name="BadgerProject")


@strawberry.type
class Query:
    @strawberry.field
    def greetings(self) -> str:
        return "hello from the illustrious stack badger"


@strawberry.type
class Mutation:
    @strawberry.mutation
    def echo(self, string_to_echo: str) -> str:
        return string_to_echo


schema = strawberry.Schema(query=Query, mutation=Mutation)
view = GraphQLView(schema=schema)


@app.route("/graphql", methods=["GET", "POST"], content_types=["application/json"])
def handle_graphql() -> Response:
    request: Request = app.current_request
    result = view.execute_request(request)
    return result  

And then run chalice local to start the localhost

chalice local  

The GraphiQL interface can then be opened in your browser on http://localhost:8000/graphql

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

We allow to extend the base GraphQLView , by overriding the following methods:

• get_context(self, request: Request, response: TemporalResponse) -> Any
• get_root_value(self, request: Request) -> Any
• process_result(self, request: Request, result: ExecutionResult) -> GraphQLHTTPResponse
• encode_json(self, response_data: GraphQLHTTPResponse) -> str

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.

class MyGraphQLView(GraphQLView):
    def get_context(self, response: Response) -> Any:
        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:

class MyGraphQLView(GraphQLView):
    def get_root_value(self) -> Any:
        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.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.

encode_json

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

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