websocket messages interception & manipulation

[w0aw]

Describe the feature you'd love to see

can we intercept each and every incoming or outgoing websocket messages & manipulate like normal http responses?

use case -
ie. use this proxy as gateway & inspect all graphql subscription messages.( so we can double check user is subscribed to his data only)

let me know if i am at wrong place

Additional context (optional)

existing resource - https://wundergraph.com/blog/quirks_of_graphql_subscriptions_sse_websockets_hasura_apollo_federation_supergraph#manipulating/filtering-graphql-subscription-messages

[EvgeniyaGorobets]

Want the same feature but for different reasons. I'm trying to build a local dev environment that (unfortunately) integrates with an external service.

Current the flow for my http requsts is: local client --> local proxy --> external service --> local server
I'm trying to emulate the same thing with websockets. The external service allows me to pass an argument that redirects my ws request to my local server. I want to have my proxy intercept websocket messages and add that argument before sending it to the external service. I currently do this in the web app code but I'd much rather have it in the proxy