Subscriptions

[paralin]

I'm using the library now in my code and quite like how robust it is.

Can we add subscriptions? They are supported in the GraphQL spec and Apollo client.

https://dev-blog.apollodata.com/graphql-subscriptions-in-apollo-client-9a2457f015fb#.lkud9zs7b

subscription comments($repoName: String!) {
  newComments(repoName: $repoName) {
    content
    postedBy {
      username
    }
    postedAt
  }
}

From the article:

Based on the subscription field name “newComments” and a mapping from subscription names to channels, the server subscribes to one or more pub/sub channels. When something is published to one of these channels, the server runs the GraphQL query specified in the subscription and sends a full new result to the client.

My API surface idea for this is:

• Add a net.Context argument to the resolve parameters. Use a context for each request. Similar to how go-grpc does it.
• When a streaming call starts, create a context, and call the resolver functions. If a resolver function needs to return a stream of objects, instead of an array, it can return a chan interface{} channel.
• The call continues to execute and finishes when one of (Context ended/closed, Result channel closed) occurs.

It's a little tough to work around the current pattern of Execute -> return result. I think the best way to handle this is to change the Execute function OR add another function that returns an object instead of a map[string]interface{}, and also accepts a root Context. In this object we can define how the result is shown. If it's a single map[string]interface{} result, set the result field of that object. Otherwise, set the resultChan fields on that object.

[kumarharsh]

@paralin we're ourselves looking to add subscriptions in the near future. We'll keep this issue open, and post updates when we get around to it. @atrniv would be better placed to discuss the technical details of the design.

[smithaitufe]

Attention
@atrniv @kumarharsh

Please what is the current state with Subscription? It's been 11 months now since the last discussion in this thread.

[fungl164]

Any updates on this?