Currently EXPERIMENTAL.
gqltype is a GraphQL schema generator from python type annotations.
- simple definition of GraphQL schema via python type annotations
- builds schema based on
graphql-core>=3.0library - asgi friendly
Using pip
$ pip install gqltypeUsing poetry
$ poetry add gqltypeLet's say we want to model the schema mentioned at the beginning of https://graphql.org/learn/schema/ tutorial.
from dataclasses import dataclass
from enum import Enum
from typing import List
import gqltype
class Episode(Enum):
"""Codename for the episodes"""
NEWHOPE = "new hope"
EMPIRE = "empire"
JEDI = "jedi"
@dataclass
class Character:
"""An individual person within the Star Wars universe"""
name: str
appears_in: List[Episode]
class LengthUnit(Enum):
"""Measure of length"""
METER = "meter"
INCH = "inch"
@dataclass
class Starship:
"""A single transport craft that has hyperdrive capability"""
id: str
name: str
length: float
def resolve_length(self, unit: LengthUnit = LengthUnit.METER) -> float:
if unit == LengthUnit.INCH:
return self.length / 0.0254
return self.length
def get_character() -> Character:
return Character(name="R2D2", appears_in=[Episode.JEDI, Episode.NEWHOPE])
async def get_starship() -> Starship:
return Starship(id="F1000", name="Millennium Falcon", length=34.75)
def add_character(name: str, appears_in: List[Episode]) -> Character:
return Character(name=name, appears_in=appears_in)
schema = gqltype.Schema(
queries=[get_character, get_starship],
mutations=[add_character]
)
from graphql.utilities import print_schema
print(print_schema(schema.build()))It'll produce the following output
type Query {
getCharacter: Character!
getStarship: Starship!
}
"""An individual person within the Star Wars universe"""
type Character {
appearsIn: [Episode!]!
name: String!
}
"""Codename for the episodes"""
enum Episode {
NEWHOPE
EMPIRE
JEDI
}
"""A single transport craft that has hyperdrive capability"""
type Starship {
length(unit: LengthUnit! = METER): Float!
id: ID!
name: String!
}
"""Measure of length"""
enum LengthUnit {
METER
INCH
}
type Mutation {
addCharacter(name: String!, appearsIn: [Episode!]!): Character!
}In order to run server with this schema we can use Starlette
if __name__ == "__main__":
import uvicorn
from gqltype.contrib.starlette import GraphQLApp
from starlette.applications import Starlette
from starlette.routing import Route
app = Starlette(routes=[Route("/graphql", GraphQLApp(schema=schema))])
uvicorn.run(app)Executing
{
getCharacter {
name
appearsIn
}
getStarship {
id
name
length(unit: INCH)
}
}gives
{
"data": {
"getCharacter": {
"name": "R2D2",
"appearsIn": [
"JEDI",
"NEWHOPE"
]
},
"getStarship": {
"id": "F1000",
"name": "Millennium Falcon",
"length": 1368.1102362204724
}
}
}-
sanity checks
- warn if class and resolve method specify different types
-
generic resolvers for certain types?
-
gqltype.F ? -- field definition
-
core part and high level part
-
business level
- validation for input values
- serialization of output values