How to use dataloaders with graphql-ws subscriptions?

[97amarnathk]

I am trying to use dataloaders for caching execution result of my subscription.
However I am not able to find a way to invalidate the dataloader cache after each execution of graphql.

I was planning to write a custom execute hook, where I will invalidate dataloader in the end.

I noticed that graphql-ws does not call execute for each subscription, and instead it uses subscribe provided by graphql-js, which uses the default execute.

Is there an alternative to defining my on subscribe method ? That would be a little complicated, and not useful since I just need to replace the execute method being used.

I see that graphql/graphql-js#3071 tries to do the same. Any other alternatives till this is merged ?

[n1ru4l]

You can provide a custom subscribe function as an option.

graphql-ws/src/server.ts

Lines 162 to 170 in 784ea15

	/**
	* Is the `subscribe` function from GraphQL which is
	* used to execute the subscription operation.
	*
	* Throwing an error from within this function will
	* close the socket with the `Error` message
	* in the close event reason.
	*/
	subscribe?: (args: ExecutionArgs) => OperationResult;

Right now execute function is an implementation detail of subscribe and thus there is no option to replace it. However, writing your own is pretty straight-forward: https://github.com/dotansimha/envelop/pull/183/files#diff-8172edfaa44ae919cd25a7283b36668248f1484041827d70e66da3aacccde461R7-R49