typegql 1.0.9

A Python GraphQL library that makes use of type hinting and concurrency support with the new async/await syntax.

TypeGQL

A Python GraphQL library that makes use of type hinting and concurrency support with the new async/await syntax.

DISCLAIMER

This library is still in it’s infancy, so use with caution and feel free to contribute.

Installation

pip install typegql

Usage

The following demonstrates how to use typegql for implementing a GraphQL API for a library of books. The example can be found in typegql/core/examples and you can run it with Sanic by executing python <path_to_example>/server.py

Define your query

from typing import List
from typegql.core.graph import Graph, Connection
from typegql.examples.library.types import Author, Category
from typegql.examples.library.types import Book
from typegql.examples.library import db

class Query(Graph):
    books: List[Book]
    authors: List[Author]
    categories: List[Category]

    books_connection: Connection[Book]

    async def resolve_authors(self, info, **kwargs):
        return db.get('authors')

    async def resolve_books(self, info, **kwargs):
        return db.get('books')

    async def resolve_categories(self, info, **kwargs):
        return db.get('categories')

   async def resolve_books_connection(self, info, **kwargs):
        data = db.get('books')
        return {
            'edges': [{
                'node': node
            } for node in data]}

Define your types

from datetime import datetime
from decimal import Decimal
from enum import Enum
from typing import List

from typegql.core.graph import Graph, ID, GraphInfo
from examples.library import db


class Gender(Enum):
    MALE = 'male'
    FEMALE = 'female'


class GeoLocation:
    latitude: Decimal
    longitude: Decimal

    def __init__(self, latitude, longitude):
        self.latitude = latitude
        self.longitude = longitude


class Author(Graph):
    id: ID
    name: str
    gender: Gender
    geo: GeoLocation


class Category(Graph):
    id: ID
    name: str


class Book(Graph):
    id: ID
    author_id: ID
    title: str
    author: Author
    categories: List[Category]
    published: datetime
    tags: List[str]

    class Meta:
        description = 'Just a book'
        id = GraphInfo(required=True, description='Book unique identifier')

    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        self.published = datetime.strptime(self.published, '%Y-%m-%d %H:%M:%S')

    async def resolve_author(self, info):
        data = filter(lambda x: x['id'] == self.author_id, db.get('authors'))
        data = next(data)
        author = Author(**data)
        author.gender = Gender[author.gender.upper()].value
        if 'geo' in data:
            author.geo = GeoLocation(**data.get('geo'))
        return author

    async def resolve_categories(self, selections, name=None):
        data = filter(lambda x: x['id'] in self.categories, db.get('categories'))
        for d in data:  # showcasing async generator
            yield Category(**d)

    def resolve_tags(self, selections):
        return ['testing', 'purpose']

Using Fields instead

Instead of relying on Meta to define properties you can use the following fields:

Field, InputField, ConnectionField

For example:

from typegql import Field, ConnectionField


class Query(Graph):
    authors: Field[Author]
    categories: Field[Category](description='what\'s this?', required=True)
    books_connection: ConnectionField[Book](connection_class=CustomConnection)

You can also pass arguments either in the Meta or as a Field argument

from typegql import Argument, ArgumentList, Field


class Query(Graph):
    authors: Field[Author](arguments=[
        Argument[ID](name='id', required=True, mutation=True)
    ])
    books: List[Book]

    class Meta:
        books = GraphInfo(mutation=False, arguments=[
            ArgumentList[ID](name='authors')
        ])

Run your query

from typegql.core.schema import Schema
from examples.library.query import Query


schema = Schema(Query)
query = '''
query BooksConnection {
  books_connection {
    edges {
      node {
        id
        title
        published
        author {
          id
          name
        }
      }
    }
  }
}
'''

async def run():
    result = await schema.run(query)

Client

TypeGQL supports DSL client for working with a GraphQL API. The client automatically converts snake to camelcase. set camelcase=False if this is not desired

pip install typegql[client]

For example:

from typegql.client import Client

async with Client(url, camelcase=True) as client:
    await client.introspection()
    dsl = client.dsl
    query = dsl.Query.books_connection.select(dsl.BooksConnection.total_count)
    doc = dsl.query(query)

    status, result = await client.execute(doc)

Change Log

1.0.7 [2018-12-09]

• bug fixing

• adds support for camelcase in Client

1.0.1 [2018-11-19]

• adds support for client DSL

Initial

• added graphql-core-next as a baseline for all GraphQL operations

TODO

• testing

• travis

• more testing

• please help with testing :|