Details
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Bug
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Status: Resolved
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Major
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Resolution: Fixed
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jax-rs-whiteboard-1.0.5, jax-rs-whiteboard-1.0.7, jax-rs-whiteboard-1.0.6
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None
Description
The JAX-RS Specification 2.1 contains the chapter 9 for "Server-Sent Events".
The chapter 9.5 "Pipeline Processing" declares:
For compatibility purposes, implementations MUST initiate processing of an SSE response when either the first message is sent or when the resource method returns, whichever happens first. The initial SSE response, which may only include the HTTP headers, is processed using the standard JAX-RS pipeline as described in Appendix C. Each subsequent SSE event may include a different payload and thus require the use of a specific message body writer. Note that since this use case differs slightly from the normal JAX-RS pipeline, implementations SHOULD NOT call entity interceptors on each individual event (1).
So, the initial SSE response is processes using the standard JAX-RS pipeline (Appendix C).
Appendix C indicates that in front of the method invocation the "Container Request Chain" is handled and after the method invocation the "Container Response Chain" is handled.
The container response chain is currently not handled for the first response!
It is also not handled for the other reponses, but this is expected.
I checked v1.0.5, v1.0.6 and v1.0.7 all seems to be broken for me.
Test code:
@Component(service = Application.class) @JaxrsName("rest") @JaxrsApplicationBase("rest") public class RESTApplicationImpl extends Application { }
@Component(service = { RESTResource.class })
@JaxrsResource
@JaxrsName("foo")
@JaxrsApplicationSelect("(" + JaxrsWhiteboardConstants.JAX_RS_NAME + "=rest)")
@Path("/foo")
public class RESTResource {
@GET
@Path("normal")
public Response normal() {
System.out.println("handle endpoint \"normal\"");
return Response.ok().build();
}
@GET
@Path("sse")
@Produces(MediaType.SERVER_SENT_EVENTS)
public void sse(@Context final SseEventSink eventSink, @Context final Sse sse) {
System.out.println("handle endpoint \"sse\"");
final ExecutorService executor = Executors.newSingleThreadExecutor();
executor.execute(() -> {
try (SseEventSink sink = eventSink) {
eventSink.send(sse.newEvent("event1"));
eventSink.send(sse.newEvent("event2"));
}
});
executor.shutdown();
}
}
@Component @JaxrsExtension @JaxrsApplicationSelect("(" + JaxrsWhiteboardConstants.JAX_RS_NAME + "=rest)") public class SimpleRequestFilter implements ContainerRequestFilter { @Override public void filter(final ContainerRequestContext context) { System.out.println("simple request filter"); } }
@Component @JaxrsExtension @JaxrsApplicationSelect("(" + JaxrsWhiteboardConstants.JAX_RS_NAME + "=rest)") public class SimpleResponseFilter implements ContainerResponseFilter { @Override public void filter(final ContainerRequestContext requestContext, final ContainerResponseContext responseContext) throws IOException { System.out.println("simple response filter"); } }
Test:
On a GET request to "http://127.0.0.1:8080/rest/foo/normal" is see (on the server console):
simple request filter handle endpoint "normal" simple response filter
On a GET request to "http://127.0.0.1:8080/rest/foo/sse" is see (on the server console):
simple request filter handle endpoint "sse"
As the normal processing pipeline must be applied for the first SSE reponse I would expect "simple response filter" is shown once, too.
In my application there is a ContainerResponseFilter to allow (configurable) CORS. If it is enabled, the headers that allow the cross-origin access are added.
This needs to be added to the initial header (first response) of the SSE connection, too.