[WIP] Subscriptions

example/api/src/main.py

@@ -1,8 +1,10 @@
 from starlette.responses import JSONResponse
 
-from api.src.queries.cities import CityGraphType, CityFilter, CitySort
-from api.src.queries.hello import UserGraphType#, UserFilter, UserSort, UserGraphType
-from api.src.queries.user import UserFilter, UserSort
+from cpl.dependency.event_bus import EventBusABC
+from cpl.graphql.event_bus.memory import InMemoryEventBus
+from queries.cities import CityGraphType, CityFilter, CitySort
+from queries.hello import UserGraphType  # , UserFilter, UserSort, UserGraphType
+from queries.user import UserFilter, UserSort
 from cpl.api.api_module import ApiModule
 from cpl.application.application_builder import ApplicationBuilder
 from cpl.auth.schema import User, Role
@@ -17,7 +19,7 @@ from cpl.graphql.graphql_module import GraphQLModule
 from model.author_dao import AuthorDao
 from model.author_query import AuthorGraphType, AuthorFilter, AuthorSort
 from model.post_dao import PostDao
-from model.post_query import PostFilter, PostSort, PostGraphType, PostMutation
+from model.post_query import PostFilter, PostSort, PostGraphType, PostMutation, PostSubscription
 from permissions import PostPermissions
 from queries.hello import HelloQuery
 from scoped_service import ScopedService
@@ -41,6 +43,7 @@ def main():
         .add_module(GraphQLModule)
         .add_module(GraphQLAuthModule)
         .add_scoped(ScopedService)
+        .add_singleton(EventBusABC, InMemoryEventBus)
         .add_cache(User)
         .add_cache(Role)
         .add_transient(CityGraphType)
@@ -66,6 +69,7 @@ def main():
         .add_transient(PostFilter)
         .add_transient(PostSort)
         .add_transient(PostMutation)
+        .add_transient(PostSubscription)
     )
 
     app = builder.build()
@@ -96,6 +100,8 @@ def main():
 
     schema.mutation.with_mutation("post", PostMutation).with_public()
 
+    schema.subscription.with_subscription("post", PostSubscription)
+
     app.with_auth_root_queries(True)
     app.with_auth_root_mutations(True)
 

example/api/src/model/post_query.py

@@ -1,3 +1,4 @@
+from cpl.dependency.event_bus import EventBusABC
 from cpl.graphql.query_context import QueryContext
 from cpl.graphql.schema.db_model_graph_type import DbModelGraphType
 from cpl.graphql.schema.filter.db_model_filter import DbModelFilter
@@ -5,6 +6,7 @@ from cpl.graphql.schema.input import Input
 from cpl.graphql.schema.mutation import Mutation
 from cpl.graphql.schema.sort.sort import Sort
 from cpl.graphql.schema.sort.sort_order import SortOrder
+from cpl.graphql.schema.subscription import Subscription
 from model.author_dao import AuthorDao
 from model.author_query import AuthorGraphType, AuthorFilter
 from model.post import Post
@@ -19,6 +21,7 @@ class PostFilter(DbModelFilter[Post]):
         self.string_field("title")
         self.string_field("content")
 
+
 class PostSort(Sort[Post]):
     def __init__(self):
         Sort.__init__(self)
@@ -26,6 +29,7 @@ class PostSort(Sort[Post]):
         self.field("title", SortOrder)
         self.field("content", SortOrder)
 
+
 class PostGraphType(DbModelGraphType[Post]):
 
     def __init__(self, authors: AuthorDao):
@@ -42,7 +46,7 @@ class PostGraphType(DbModelGraphType[Post]):
         def r_name(ctx: QueryContext):
             return ctx.user.username == "admin"
 
-        self.object_field("author", AuthorGraphType, resolver=_a).with_public(True)# .with_require_any([], [r_name]))
+        self.object_field("author", AuthorGraphType, resolver=_a).with_public(True)  # .with_require_any([], [r_name]))
         self.string_field(
             "title",
             resolver=lambda root: root.title,
@@ -64,6 +68,7 @@ class PostCreateInput(Input[Post]):
         self.string_field("content").with_required()
         self.int_field("author_id").with_required()
 
+
 class PostUpdateInput(Input[Post]):
     title: str
     content: str
@@ -75,13 +80,31 @@ class PostUpdateInput(Input[Post]):
         self.string_field("title").with_required(False)
         self.string_field("content").with_required(False)
 
+
+class PostSubscription(Subscription):
+    def __init__(self, bus: EventBusABC):
+        Subscription.__init__(self)
+        self._bus = bus
+
+        async def post_changed():
+            async for event in await self._bus.subscribe("postChange"):
+                print("Event:", event, type(event))
+                yield event
+
+        def selector(event: Post, info) -> bool:
+            return True
+
+        self.subscription_field("postChange", PostGraphType, post_changed, selector)
+
+
 class PostMutation(Mutation):
 
-    def __init__(self, posts: PostDao, authors: AuthorDao):
+    def __init__(self, posts: PostDao, authors: AuthorDao, bus: EventBusABC):
         Mutation.__init__(self)
 
         self._posts = posts
         self._authors = authors
+        self._bus = bus
 
         self.field("create", int, resolver=self.create_post).with_public().with_required().with_argument(
             "input",
@@ -112,6 +135,7 @@ class PostMutation(Mutation):
         post.content = input.content if input.content is not None else post.content
 
         await self._posts.update(post)
+        await self._bus.publish("postChange", post)
         return True
 
     async def delete_post(self, id: int) -> bool:
@@ -127,4 +151,3 @@ class PostMutation(Mutation):
             return False
         await self._posts.restore(post)
         return True
-

example/api/src/queries/hello.py

@@ -1,5 +1,5 @@
-from api.src.queries.cities import CityFilter, CitySort, CityGraphType, City
-from api.src.queries.user import User, UserFilter, UserSort, UserGraphType
+from queries.cities import CityFilter, CitySort, CityGraphType, City
+from queries.user import User, UserFilter, UserSort, UserGraphType
 from cpl.api.middleware.request import get_request
 from cpl.auth.schema import UserDao, User
 from cpl.graphql.schema.filter.filter import Filter
@@ -38,6 +38,7 @@ cities = [City(i, f"City {i}") for i in range(1, 101)]
 #             resolver=lambda root: root.username,
 #         )
 
+
 class HelloQuery(Query):
     def __init__(self):
         Query.__init__(self)