GraphQL-core-next 1.1.1
GraphQL-core-next is a Python port of GraphQL.js, the JavaScript reference implementation for GraphQL.
License: MIT license
Requires Python: >=3.6,<4
Keywords: graphql

# GraphQL-core-next

GraphQL-core-next is a Python 3.6+ port of [GraphQL.js](https://github.com/graphql/graphql-js),
the JavaScript reference implementation for [GraphQL](https://graphql.org/),
a query language for APIs created by Facebook.

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The current version 1.1.1 of GraphQL-core-next is up-to-date with GraphQL.js version
14.4.0. All parts of the API are covered by an extensive test suite of currently 1885
unit tests.

Development will be continued with the new distribution name GraphQL-core from now on.


## GraphQL-core-next is now GraphQL-core 3

GraphQL-core-next has been discontinued as a separate Python distribution.
Instead, it is now released as GraphQL-core version 3 and newer, replacing
the existing GraphQL-core distribution. The old versions of GraphQL-core,
which also support older Python versions, are still available.


## Documentation

A more detailed documentation for GraphQL-core-next can be found at
[graphql-core-next.readthedocs.io](https://graphql-core-next.readthedocs.io/).

The documentation for GraphQL.js can be found at [graphql.org/graphql-js/](https://graphql.org/graphql-js/).

The documentation for GraphQL itself can be found at [graphql.org](https://graphql.org/).


There will be also [blog articles](https://cito.github.io/tags/graphql/) with more usage
examples.


## Getting started

An overview of GraphQL in general is available in the
[README](https://github.com/graphql/graphql-spec/blob/master/README.md) for the
[Specification for GraphQL](https://github.com/graphql/graphql-spec). That overview
describes a simple set of GraphQL examples that exist as [tests](tests) in this
repository. A good way to get started with this repository is to walk through that
README and the corresponding tests in parallel.


## Installation

GraphQL-core-next can be installed from PyPI using the built-in pip command:

    python -m pip install graphql-core-next

Alternatively, you can also use [pipenv](https://docs.pipenv.org/) for installation in a
virtual environment:

    pipenv install graphql-core-next


## Usage

GraphQL-core-next provides two important capabilities: building a type schema, and
serving queries against that type schema.

First, build a GraphQL type schema which maps to your code base:

```python
from graphql import (
    GraphQLSchema, GraphQLObjectType, GraphQLField, GraphQLString)

schema = GraphQLSchema(
    query=GraphQLObjectType(
        name='RootQueryType',
        fields={
            'hello': GraphQLField(
                GraphQLString,
                resolve=lambda obj, info: 'world')
        }))
```

This defines a simple schema with one type and one field, that resolves to a fixed
value. The `resolve` function can return a value, a co-routine object or a list of
these. It takes two positional arguments; the first one provides the root or the
resolved parent field, the second one provides a `GraphQLResolveInfo` object which
contains information about the execution state of the query, including a `context`
attribute holding per-request state such as authentication information or database
session. Any GraphQL arguments are passed to the `resolve` functions as individual
keyword arguments.

Note that the signature of the resolver functions is a bit different in GraphQL.js,
where the context is passed separately and arguments are passed as a single object.
Also note that GraphQL fields must be passed as a `GraphQLField` object explicitly.
Similarly, GraphQL arguments must be passed as `GraphQLArgument` objects.

A more complex example is included in the top level [tests](tests) directory.

Then, serve the result of a query against that type schema.

```python
from graphql import graphql_sync

query = '{ hello }'

print(graphql_sync(schema, query))
```

This runs a query fetching the one field defined, and then prints the result:

```python
ExecutionResult(data={'hello': 'world'}, errors=None)
```

The `graphql_sync` function will first ensure the query is syntactically and
semantically valid before executing it, reporting errors otherwise.

```python
from graphql import graphql_sync

query = '{ boyhowdy }'

print(graphql_sync(schema, query))
```

Because we queried a non-existing field, we will get the following result:

```python
ExecutionResult(data=None, errors=[GraphQLError(
    "Cannot query field 'boyhowdy' on type 'RootQueryType'.",
    locations=[SourceLocation(line=1, column=3)])])
```

The `graphql_sync` function assumes that all resolvers return values synchronously. By
using coroutines as resolvers, you can also create results in an asynchronous fashion
with the `graphql` function.

```python
import asyncio
from graphql import (
    graphql, GraphQLSchema, GraphQLObjectType, GraphQLField, GraphQLString)


async def resolve_hello(obj, info):
    await asyncio.sleep(3)
    return 'world'

schema = GraphQLSchema(
    query=GraphQLObjectType(
        name='RootQueryType',
        fields={
            'hello': GraphQLField(
                GraphQLString,
                resolve=resolve_hello)
        }))


async def main():
    query = '{ hello }'
    print('Fetching the result...')
    result = await graphql(schema, query)
    print(result)


loop = asyncio.get_event_loop()
try:
    loop.run_until_complete(main())
finally:
    loop.close()
```


## Goals and restrictions

GraphQL-core-next tries to reproduce the code of the reference implementation GraphQL.js
in Python as closely as possible and to stay up-to-date with the latest development of
GraphQL.js.

It has been created as a modern alternative to
[GraphQL-core](https://github.com/graphql-python/graphql-core), a prior work
by Syrus Akbary, based on an older version of GraphQL.js and also targeting
older Python versions. Some parts of GraphQL-core-next have been inspired by
GraphQL-core or directly taken over with only slight modifications, but most of the code
has been re-implemented from scratch, replicating the latest code in GraphQL.js very
closely and adding type hints for Python.

Design goals for the GraphQL-core-next library are:

* to be a simple, cruft-free, state-of-the-art implementation of GraphQL using current
  library and language versions
* to be very close to the GraphQL.js reference implementation, while still using a
  Pythonic API and code style
* to make extensive use of Python type hints, similar to how GraphQL.js makes use of Flow
* to use [black](https://github.com/ambv/black) for automatic code formatting
* to replicate the complete Mocha-based test suite of GraphQL.js using
  [pytest](https://docs.pytest.org/)

Some restrictions (mostly in line with the design goals):

* requires Python 3.6 or 3.7
* does not support some already deprecated methods and options of GraphQL.js
* supports asynchronous operations only via async.io
  (does not support the additional executors in GraphQL-core)
* the benchmarks have not yet been ported to Python


## Integration with other libraries and roadmap

* [Graphene](http://graphene-python.org/) is a more high-level framework for building
  GraphQL APIs in Python, and there is already a whole ecosystem of libraries, server
  integrations and tools built on top of Graphene. Most of this Graphene ecosystem has
  also been created by Syrus Akbary, who meanwhile has handed over the maintenance
  and future development to members of the GraphQL-Python community.

  The current version 2 of Graphene is using Graphql-core as core library for much of
  the heavy lifting. Note that Graphene 2 is not compatible with GraphQL-core-next.
  The  new version 3 of Graphene however is planned to use GraphQL-core-next instead of
  GraphQL-core, and GraphQL-core-next will be renamed to Graphql-core 3.

* [Ariadne](https://github.com/mirumee/ariadne) is a Python library for implementing
  GraphQL servers using schema-first approach created by Mirumee Software.

  Ariadne is already using GraphQL-core-next as its GraphQL implementation.

* [Strawberry](https://github.com/strawberry-graphql/strawberry), created by Patrick
  Arminio, is a new GraphQL library for Python 3, inspired by dataclasses,
  that is also using GraphQL-core-next as underpinning.


## Changelog

Changes are tracked as
[GitHub releases](https://github.com/graphql-python/graphql-core-next/releases).


## Credits and history

The GraphQL-core-next library
* has been created and is maintained by Christoph Zwerschke
* uses ideas and code from GraphQL-core, a prior work by Syrus Akbary
* is a Python port of GraphQL.js which has been developed by Lee Byron and others
  at Facebook, Inc. and is now maintained
  by the [GraphQL foundation](https://gql.foundation/join/)

Please watch the recording of Lee Byron's short keynote on the
[history of GraphQL](https://www.youtube.com/watch?v=VjHWkBr3tjI) 
at the open source leadership summit 2019 to better understand
how and why GraphQL was created at Facebook and then became open sourced
and ported to many different programming languages. 


## License

GraphQL-core-next is
[MIT-licensed](https://github.com/graphql-python/graphql-core-next/blob/master/LICENSE),
just like GraphQL.js.