Http server api

[gobengo]

Adds support for two new library APIs to add graphql-ws over WebSocket-Over-Http support to a broader class of node.js projects, not just those using express.

• http-request-listener-api - Operates on http.RequestListener and returns the same type, but one that will do graphl-ws over WebSocket-Over-Http before deferring to the provided RequestListener. This example uses apollo-server-micro to produce the logic used by the sample RequestListener, but any RequestListener would work (e.g. those in the node http docs)
  • Makes use of new constructor GraphqlWsOverWebSocketOverHttpRequestListener
• http-server-api Operates on http.Servers (which can be created from an http.RequestListener, but some libraries only make servers and not RequestListeners), patching it to intercept requests and first run them through GraphqlWsOverWebSocketOverHttpExpressMiddleware
  • Makes use of new object GraphqlWsOverWebSocketOverHttpSubscriptionHandlerInstaller
  • This functionality is similar to how subscription-transport-ws SubscriptionServer.create takes an http.Server and adds WebSocket listeners to it

Note that the interface of micro's default export is going to change in 9.3.5 (next release) to return an http.RequestListener whereas historically it has returned an http.Server (vercel/micro#399).
Pretty big change. Hopefully they do it as a major semver bump since it seems like it will be backward incompatible).