Sadly it's not entirely unfounded. SSE on HTTP/1.1 is basically useless due to the connections-per-domain limits implemented in browsers. So WebSockets got a lot of mindshare while we waited for HTTP/2.
But today I always start with plain HTTP, then try SSE, and finally WebSockets if I have to.
Future-proofing is a good use case though. As a developer I don't want to maintain both SSE and WebSockets, since they solve similar problems and WebSockets are a superset of SSE. Even though my WebSockets implementation is currently unidirectional (server to client), I still opted for that over SSE because I'll probably need send data the other way at some point in the future. Why learn two tools when I can just learn one?
If you use nginx, you can use the excellent nchan module to push messages by having your backend make a POST request to nginx. Clients can connect to nchan via websockets, SSE, and few other things like long polling without your app having to support all of them. Been using it for a recent project and really like it.
More overhead, and it doesn't scale. My nodejs websockets server can handle thousands of connections without a problem, but my rails api server allocates a thread per connection so I'm limited to <16 unless I start horizontal scaling.
For infrequent requests everything goes through the api, but for stuff like chat and live-document-editing, nodejs is the better solution.
> You didn't cite bidi as your reason for choosing WS in your last comment, you cited scaling and node vs ruby.
Because I was answering this question: "What's wrong with normal HTTP requests for client->server streams?"
> You can have bidi without WS.
Only by combining HTTP (which doesn't scale because my api server runs rails) and SSE (which does scale). If I want scaling bidirectional communication, I need websockets.
