Prisma with FastAPI and GraphQL

Following the previous post, we want to continue working on creating graphql resolvers in the current post.

Since FastAPI recommends using Strawberry for using graphql as written in the document, we decided to look into this.

1. Install strawberry-graphql and add directories

pip install 'strawberry-graphql[debug-server]'

We created `models` and `resolvers` folders under `src`.

2. Adding graphql types

You can define the graphql types with Strawberry with decorators. As an example in User.py, the code looks like the one below.

@strawberry.type
class User:
    id: strawberry.ID
    email: str
    name: Optional[str] = None
    nickname: Optional[str] = None
    thumbURL: Optional[str] = None
    photoURL: Optional[str] = None
    birthday: Optional[date] = None
    gender: Optional[Gender] = None
    phone: Optional[str] = None
@strawberry.enum
class Gender(Enum):
    Male = "male"
    Female = "female"

• ID type can be defined as strawberry.ID
• Required type can be defined as str, int
• An optional type can be defined with Optional imported from typing like Optional[str]
• Enum type can be defined with @strawberry.enum as written above
• Date type can be defined from datetime import date

More can be found in Strawberry schema directives.

3. Adding queries

Create queries with Strawberry type.

@strawberry.type
class Query:
    @strawberry.field(permission_classes=[IsAuthenticated])
    def users(self) -> List[User]:
        return prisma.user.find_many()
@strawberry.field(permission_classes=[IsAuthenticated])
    def user(self, id: strawberry.ID) -> User:
        return prisma.user.find_unique(where={"id": id})

• You can see that we are using Prisma Python Client here as described in the previous post.
• The query can be protected with permission_classes as just like graphql shield. See below.

class IsAuthenticated(BasePermission):
    message = "User is not authenticated"
def has_permission(self, source: typing.Any, info: Info, **kwargs) -> bool:
        request: typing.Union[Request, WebSocket] = info.context["request"]
        authorization = request.headers.get("Authorization")
if "Authorization" in request.headers:
            auth = decodeJWT(authorization)
            return auth
return False

4. Adding mutation queries

Creating mutation queries is similar to adding queries.

@strawberry.type
class Mutation:
    @strawberry.mutation
    async def signIn(self, email: str, password: str) -> AuthPayload:
        user = await prisma.user.find_first(
            where={
                "email": email,
            }
        )
validated = validatePassword(password, user.password)
if validated:
            token = signJWT(user.id)
            return AuthPayload(token=token, user=user)
return None

You can define return class like above which is AuthPayload. It looks like the one below.

@strawberry.type
class User:
    id: strawberry.ID
    email: str
    name: Optional[str] = None
    nickname: Optional[str] = None
    thumbURL: Optional[str] = None
    photoURL: Optional[str] = None
    birthday: Optional[date] = None
    gender: Optional[Gender] = None
    phone: Optional[str] = None
@strawberry.type
class AuthPayload:
    token: str
    user: User

5. Adding input types

@strawberry.input
class UserCreateInput:
    email: str
    password: str
    name: Optional[str] = None
    nickname: Optional[str] = None
    birthday: Optional[datetime.date] = None
    gender: Optional[Gender] = None
    phone: Optional[str] = None

6. Define the Strawberry schema altogether in __init__.py

from src.resolvers.users import Query, Mutation
import strawberry
schema = strawberry.Schema(query=Query, mutation=Mutation)

7. Run server

uvicorn main:app --reload

Note: If you want to set Authorization header you might need another graphql tool like Insomnia.