Can't get ActionCable subscriptions to work

[fazo96]

Describe the bug

There's two issues:

1. the browser fails to connect to the websocket semi-randomly. This happens almost always on firefox and sometimes on chrome. The WS connection shows up in the Network tab devtools but no messages are exchanged. This might not be a Graphql-ruby bug but I thought I'd mention it. I am still trying to figure this one out
2. ActionCable internally logs a cryptic error

Issue 2 I think is most likely a bug in graphql-ruby

The error message is: [GraphqlChannel] Unable to process GraphqlChannel#send({"variables"=>{"userId"=>nil}, "operationName"=>"useWorkspaceLoader_Subscription", - I cut off the rest which isn't important

I traced it here in the rails source code: https://github.com/rails/rails/blob/21eceb7db26b724d1f7a824d4cc04ddeba44244b/actioncable/lib/action_cable/channel/base.rb#L176

I think the issue is that the graphql client will try to perform a "send" operation but the channel on the ruby code only has a handler for the "execute" operation, see here:

graphql-ruby/javascript_client/src/subscriptions/createActionCableHandler.ts

Lines 47 to 48 in 85e7117

	channel.perform('send', channelParams)
	channel.perform("execute", channelParams)

Versions

graphql version: 2.2.4
rails (or other framework): 7.1

GraphQL schema

I don't think it's relevant

GraphQL query

I don't think it's relevant

Steps to reproduce

Setting up a project with Relay on the frontend and ActionCable on the backend and trying to run subscriptions

Expected behavior

Subscriptions work fine

Actual behavior

I can't get them to actually work even though there is no exception with stack trace anywhere

Additional context

The project is a Next.js app using the "pages" folder for setting up routes

[rmosolgo]

Hey, thanks for reporting this. It certainly sounds possible that the perform("send", ...) call doesn't belong. Somehow it snuck in there three years ago: cf0a3fe#diff-9957e220f3cd45075c8bd11a71aa74970869a76e46eaff6007685295c806c6fdR45

I've worked up a patch to remove that call here: #4793

If you add a dummy def send(_data); end in your ActionCable channel, does that make the error go away? (I think that would make the perform("send", ...) call "work"....)