How to Read SSE event stream at server side instead of browser

Question

I am creating an application to read Event Stream and keeps the information on my database.

I have an URL: http://xx.xx.xx.xx:8080/restconf/streams/mno-vnf-event/json headers required: Accept:text/event-stream, Authorization:Basic YWRtaW46o99RtaW4-, Content-Type:application/yang-data+json

Now I want to fetch stream from above API using java (not javascript code), anyone has the idea to accomplish this.

score 2 · Answer 1 · answered Oct 23 '18 at 07:46

2

You can use some Java libraries that supports SSE:

Jersey: https://jersey.github.io/documentation/latest/sse.html#sse-client-jaxrs
Micronaut: https://dzone.com/articles/micronaut-mastery-consuming-server-sent-events-sse
Spring WebClient: https://www.baeldung.com/spring-server-sent-events (Consuming the Server-Sent Events with a WebClient)

These are the first that come to my mind, but there are undoubtedly more.

answered Oct 23 '18 at 07:46

ctranxuan

785
5
9

Didn't find any option to add custom headers to make SSE request from Jersey or Spring WebClient. Want to add the following headers in the request: `Authorization:Basic YWRtaW46o99RtaW4-` `Accept:text/event-stream` `Content-Type:application/yang-data+json` – Abhishek Mishra Oct 23 '18 at 14:09

score 1 · Answer 2 · answered Oct 23 '18 at 15:07

If the SSE server follows strictly the SSE spec, you can't add any custom headers.

Nonetheless, if it does, have you tried something like that with Spring WebFlux Client:

ResolvableType type = forClassWithGenerics(ServerSentEvent.class, String.class);

WebClient client = WebClient.create();
client.get()
      .uri("http://localhost:8080/sse")
      .accept(TEXT_EVENT_STREAM)
      .header("MyHeader", "Foo") // Add your headers here.
      .exchange()
      .flatMapMany(response -> response.body(toFlux(type)))
      .subscribe(System.out::println,
                 Throwable::printStackTrace);

I have tested this piece of code against a SSE Undertow server. It seems to work: Undertow is able to get the custom header that has been sent.

How to Read SSE event stream at server side instead of browser

2 Answers2