`GraphQLTransportWSHandler` only supports one connection

Once a client has connected to Ariadne through the GraphQLTransportWSHandler (the newer GraphQL WebSocket protocol), all future attempts to connect by another client will fail, even if the first client has disconnected.

I believe this issue is caused by this section in the code:

https://github.com/mirumee/ariadne/blob/86a87efd9e3714a39f4da97cce92db6748331f2e/ariadne/asgi/handlers/graphql_transport_ws.py#L111-L116

It looks like the transport gets tagged as having received an “init” message, even though it seems like the client should be tagged.

Steps to reproduce

I came up with the following sample GraphQL server to demonstrate this issue (using Ariadne v0.16) as a minimal test case:

import asyncio
from ariadne import gql, make_executable_schema, ObjectType, SubscriptionType
from ariadne.asgi import GraphQL
from ariadne.asgi.handlers import GraphQLTransportWSHandler
from starlette.applications import Starlette
from starlette.routing import Route, WebSocketRoute
import uvicorn

type_defs = gql("""
    type Query {
        hello: String!
    }

    type Subscription {
        counter: Int!
    }
""")

query = ObjectType("Query")

@query.field("hello")
def hello_resolver(*_):
    return "Hello world"

subscription = SubscriptionType()

@subscription.source("counter")
async def counter_generator(*_):
    for i in range(5):
        await asyncio.sleep(1)
        yield i

@subscription.field("counter")
def counter_resolver(count, *_):
    return count

schema = make_executable_schema(type_defs, subscription)
graphql_app = GraphQL(
    schema,
    debug=True,
    websocket_handler=GraphQLTransportWSHandler(),
)
routes = [
    Route("/graphql", graphql_app, methods=["GET", "POST"]),
    WebSocketRoute("/graphql", endpoint=graphql_app),
]
app = Starlette(debug=True, routes=routes)

if __name__ == "__main__":
    uvicorn.run(app, host='0.0.0.0', port=4444)

After creating a file with that script and starting the server with main.py, I then used websocat to manually trigger the error. First, I connected to the server, manually sent the “connection init” message, then pressed Ctrl-D to disconnect after receiving a “connection ack” message:

$ websocat --protocol 'graphql-ws' 'ws://localhost:4444/graphql'
{"type": "connection_init"}
{"type": "connection_ack"}
^D

Then, I did the same thing as a new client, but did not get the “connection ack”, indicating that the connection was rejected:

$ websocat --protocol 'graphql-ws' 'ws://localhost:4444/graphql'
{"type": "connection_init"}

Running websocat -vv ... will also show that an error code of 4429 was returned, which lines up with the error code from the graphql_transport_ws.py file linked above.

[rafalp]

I’m releasing a fix as 0.16.1, thanks everyone!

[kylewlacy]

@kylewlacy I’ve released 0.16.1.b1 with changes that should fix this. Can you please verify when you have time and let me know? Thanks!

Sure thing, I just tried out the v0.16.1.b1 release from PyPI and from all my testing, it looks like I am able to connect with multiple different clients now! So from my perspective, that release resolves my issue.

Thanks for coming to such a quick resolution for this issue @rafalp and @pigletto!