Adding middleware keeps subscriptions events from returning

[justuswilhelm]

I have a middleware that populates info.context with several data loaders that are needed to pull in related objects. When I add the middleware to the GraphQL WS consumer, the subscription stops returning results. If I remove the middleware (by making the middleware list empty), it continues returning results, albeit they are incorrect because of the missing loaders.

My middleware is really simple

def loader_middleware(next, root, info, *args, **kwargs):
    """Add loaders to info.context."""
    info.context.loader = Loader()
    return next(root, info, *args, **kwargs)

and it is added like this

    middleware = [
        middleware.loader_middleware,
    ]

And then, when I trigger a subscription broadcast, it does not return anything when testing the subscription in GraphiQL.

How well tested is the middleware implementation? Is there anything to watch out for?

[justuswilhelm]

I'm willing to put a bounty of 250 USD on this issue. Solving this would very much de-block our project development.

[tony]

Also having this issue

CC'ing other data loader related issues that may be bumping into this, #67 #55.

[justuswilhelm]

So the issue are the data loaders and the resulting promises? Interesting. Perhaps there is a workaround?

[prokher]

The version 1.0.0rc1 is available in PyPI, the middleware-related routines are pretty much different now. Please check whether the issues is still here.