Abstract thenables (promise, coroutine) out of relay

.travis.yml

@@ -1,20 +1,20 @@
 language: python
 matrix:
   include:
-    -  env: TOXENV=py27
-       python: 2.7
-    -  env: TOXENV=py34
-       python: 3.4
-    -  env: TOXENV=py35
-       python: 3.5
-    -  env: TOXENV=py36
-       python: 3.6
-    -  env: TOXENV=pypy
-       python: pypy-5.7.1
-    -  env: TOXENV=pre-commit
-       python: 3.6
-    -  env: TOXENV=mypy
-       python: 3.6
+    - env: TOXENV=py27
+      python: 2.7
+    - env: TOXENV=py34
+      python: 3.4
+    - env: TOXENV=py35
+      python: 3.5
+    - env: TOXENV=py36
+      python: 3.6
+    - env: TOXENV=pypy
+      python: pypy-5.7.1
+    - env: TOXENV=pre-commit
+      python: 3.6
+    - env: TOXENV=mypy
+      python: 3.6
 install:
   - pip install coveralls tox
 script: tox

graphene/relay/connection.py

@@ -3,11 +3,11 @@
 from functools import partial
 
 from graphql_relay import connection_from_list
-from promise import Promise, is_thenable
 
 from ..types import Boolean, Enum, Int, Interface, List, NonNull, Scalar, String, Union
 from ..types.field import Field
 from ..types.objecttype import ObjectType, ObjectTypeOptions
+from ..utils.thenables import maybe_thenable
 from .node import is_node
 
 
@@ -139,10 +139,7 @@ def connection_resolver(cls, resolver, connection_type, root, info, **args):
             connection_type = connection_type.of_type
 
         on_resolve = partial(cls.resolve_connection, connection_type, args)
-        if is_thenable(resolved):
-            return Promise.resolve(resolved).then(on_resolve)
-
-        return on_resolve(resolved)
+        return maybe_thenable(resolved, on_resolve)
 
     def get_resolver(self, parent_resolver):
         resolver = super(IterableConnectionField, self).get_resolver(parent_resolver)

graphene/relay/mutation.py

@@ -1,10 +1,9 @@
 import re
 from collections import OrderedDict
 
-from promise import Promise, is_thenable
-
 from ..types import Field, InputObjectType, String
 from ..types.mutation import Mutation
+from ..utils.thenables import maybe_thenable
 
 
 class ClientIDMutation(Mutation):
@@ -69,7 +68,4 @@ def on_resolve(payload):
             return payload
 
         result = cls.mutate_and_get_payload(root, info, **input)
-        if is_thenable(result):
-            return Promise.resolve(result).then(on_resolve)
-
-        return on_resolve(result)
+        return maybe_thenable(result, on_resolve)

graphene/utils/thenables.py

@@ -0,0 +1,42 @@
+"""
+This file is used mainly as a bridge for thenable abstractions.
+This includes:
+- Promises
+- Asyncio Coroutines
+"""
+
+try:
+    from promise import Promise, is_thenable  # type: ignore
+except ImportError:
+
+    class Promise(object):  # type: ignore
+        pass
+
+    def is_thenable(obj):  # type: ignore
+        return False
+
+
+try:
+    from inspect import isawaitable
+    from .thenables_asyncio import await_and_execute
+except ImportError:
+
+    def isawaitable(obj):  # type: ignore
+        return False
+
+
+def maybe_thenable(obj, on_resolve):
+    """
+    Execute a on_resolve function once the thenable is resolved,
+    returning the same type of object inputed.
+    If the object is not thenable, it should return on_resolve(obj)
+    """
+    if isawaitable(obj) and not isinstance(obj, Promise):
+        return await_and_execute(obj, on_resolve)
+
+    if is_thenable(obj):
+        return Promise.resolve(obj).then(on_resolve)
+
+    # If it's not awaitable not a Promise, return
+    # the function executed over the object
+    return on_resolve(obj)

graphene/utils/thenables_asyncio.py

@@ -0,0 +1,5 @@
+def await_and_execute(obj, on_resolve):
+    async def build_resolve_async():
+        return on_resolve(await obj)
+
+    return build_resolve_async()

setup.py

@@ -50,6 +50,7 @@ def run_tests(self):
     "pytest-mock",
     "snapshottest",
     "coveralls",
+    "promise",
     "six",
     "mock",
     "pytz",
@@ -84,7 +85,6 @@ def run_tests(self):
         "six>=1.10.0,<2",
         "graphql-core>=2.1,<3",
         "graphql-relay>=0.4.5,<1",
-        "promise>=2.1,<3",
         "aniso8601>=3,<4",
     ],
     tests_require=tests_require,

tests_asyncio/test_relay_connection.py

@@ -0,0 +1,128 @@
+import pytest
+
+from collections import OrderedDict
+from graphql.execution.executors.asyncio import AsyncioExecutor
+
+from graphql_relay.utils import base64
+
+from graphene.types import ObjectType, Schema, String
+from graphene.relay.connection import Connection, ConnectionField, PageInfo
+from graphene.relay.node import Node
+
+letter_chars = ["A", "B", "C", "D", "E"]
+
+
+class Letter(ObjectType):
+    class Meta:
+        interfaces = (Node,)
+
+    letter = String()
+
+
+class LetterConnection(Connection):
+    class Meta:
+        node = Letter
+
+
+class Query(ObjectType):
+    letters = ConnectionField(LetterConnection)
+    connection_letters = ConnectionField(LetterConnection)
+    promise_letters = ConnectionField(LetterConnection)
+
+    node = Node.Field()
+
+    def resolve_letters(self, info, **args):
+        return list(letters.values())
+
+    async def resolve_promise_letters(self, info, **args):
+        return list(letters.values())
+
+    def resolve_connection_letters(self, info, **args):
+        return LetterConnection(
+            page_info=PageInfo(has_next_page=True, has_previous_page=False),
+            edges=[
+                LetterConnection.Edge(node=Letter(id=0, letter="A"), cursor="a-cursor")
+            ],
+        )
+
+
+schema = Schema(Query)
+
+letters = OrderedDict()
+for i, letter in enumerate(letter_chars):
+    letters[letter] = Letter(id=i, letter=letter)
+
+
+def edges(selected_letters):
+    return [
+        {
+            "node": {"id": base64("Letter:%s" % l.id), "letter": l.letter},
+            "cursor": base64("arrayconnection:%s" % l.id),
+        }
+        for l in [letters[i] for i in selected_letters]
+    ]
+
+
+def cursor_for(ltr):
+    letter = letters[ltr]
+    return base64("arrayconnection:%s" % letter.id)
+
+
+def execute(args=""):
+    if args:
+        args = "(" + args + ")"
+
+    return schema.execute(
+        """
+    {
+        letters%s {
+            edges {
+                node {
+                    id
+                    letter
+                }
+                cursor
+            }
+            pageInfo {
+                hasPreviousPage
+                hasNextPage
+                startCursor
+                endCursor
+            }
+        }
+    }
+    """
+        % args
+    )
+
+
+@pytest.mark.asyncio
+async def test_connection_promise():
+    result = await schema.execute(
+        """
+    {
+        promiseLetters(first:1) {
+            edges {
+                node {
+                    id
+                    letter
+                }
+            }
+            pageInfo {
+                hasPreviousPage
+                hasNextPage
+            }
+        }
+    }
+    """,
+        executor=AsyncioExecutor(),
+        return_promise=True,
+    )
+
+    assert not result.errors
+    assert result.data == {
+        "promiseLetters": {
+            "edges": [{"node": {"id": "TGV0dGVyOjA=", "letter": "A"}}],
+            "pageInfo": {"hasPreviousPage": False, "hasNextPage": True},
+        }
+    }

tests_asyncio/test_relay_mutation.py

@@ -0,0 +1,91 @@
+import pytest
+from graphql.execution.executors.asyncio import AsyncioExecutor
+
+from graphene.types import ID, Field, ObjectType, Schema
+from graphene.types.scalars import String
+from graphene.relay.mutation import ClientIDMutation
+
+
+class SharedFields(object):
+    shared = String()
+
+
+class MyNode(ObjectType):
+    # class Meta:
+    #     interfaces = (Node, )
+    id = ID()
+    name = String()
+
+
+class SaySomethingAsync(ClientIDMutation):
+    class Input:
+        what = String()
+
+    phrase = String()
+
+    @staticmethod
+    async def mutate_and_get_payload(self, info, what, client_mutation_id=None):
+        return SaySomethingAsync(phrase=str(what))
+
+
+# MyEdge = MyNode.Connection.Edge
+class MyEdge(ObjectType):
+    node = Field(MyNode)
+    cursor = String()
+
+
+class OtherMutation(ClientIDMutation):
+    class Input(SharedFields):
+        additional_field = String()
+
+    name = String()
+    my_node_edge = Field(MyEdge)
+
+    @staticmethod
+    def mutate_and_get_payload(
+        self, info, shared="", additional_field="", client_mutation_id=None
+    ):
+        edge_type = MyEdge
+        return OtherMutation(
+            name=shared + additional_field,
+            my_node_edge=edge_type(cursor="1", node=MyNode(name="name")),
+        )
+
+
+class RootQuery(ObjectType):
+    something = String()
+
+
+class Mutation(ObjectType):
+    say_promise = SaySomethingAsync.Field()
+    other = OtherMutation.Field()
+
+
+schema = Schema(query=RootQuery, mutation=Mutation)
+
+
+@pytest.mark.asyncio
+async def test_node_query_promise():
+    executed = await schema.execute(
+        'mutation a { sayPromise(input: {what:"hello", clientMutationId:"1"}) { phrase } }',
+        executor=AsyncioExecutor(),
+        return_promise=True,
+    )
+    assert not executed.errors
+    assert executed.data == {"sayPromise": {"phrase": "hello"}}
+
+
+@pytest.mark.asyncio
+async def test_edge_query():
+    executed = await schema.execute(
+        'mutation a { other(input: {clientMutationId:"1"}) { clientMutationId, myNodeEdge { cursor node { name }} } }',
+        executor=AsyncioExecutor(),
+        return_promise=True,
+    )
+    assert not executed.errors
+    assert dict(executed.data) == {
+        "other": {
+            "clientMutationId": "1",
+            "myNodeEdge": {"cursor": "1", "node": {"name": "name"}},
+        }
+    }

tox.ini

@@ -1,13 +1,16 @@
 [tox]
-envlist = flake8,py27,py33,py34,py35,py36,pre-commit,pypy,mypy
+envlist = flake8,py27,py34,py35,py36,py37,pre-commit,pypy,mypy
 skipsdist = true
 
 [testenv]
-deps = .[test]
+deps =
+    .[test]
+    py{35,36,37}: pytest-asyncio
 setenv =
      PYTHONPATH = .:{envdir}
-commands=
-    py.test --cov=graphene graphene examples
+commands =
+    py{27,34,py}: py.test --cov=graphene graphene examples {posargs}
+    py{35,36,37}: py.test --cov=graphene graphene examples tests_asyncio {posargs}
 
 [testenv:pre-commit]
 basepython=python3.6