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Server Sent Events delaying 200 response
See original GitHub issueDescribe the bug
I am on 2.6.1.Final. I have an endpoint that is an SSE endpoint. The status code is only returned after the first element is produced.
This was not the case in 1.x and can lead to timeouts on clients.
Expected behavior
I would expect a 200 to be returned immediately (provided everything worked as expected).
Actual behavior
The status code, headers, etc. is not returned until the moment the first item is produced.
How to Reproduce?
Output of uname -a or ver
Linux jose-buguroo 5.11.0-41-generic #45-Ubuntu SMP Fri Nov 5 11:37:01 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
Output of java -version
openjdk version “14.0.2” 2020-07-14 OpenJDK Runtime Environment (build 14.0.2+12-46) OpenJDK 64-Bit Server VM (build 14.0.2+12-46, mixed mode, sharing)
GraalVM version (if different from Java)
No response
Quarkus version or git rev
2.6.1.Final
Build tool (ie. output of mvnw --version or gradlew --version)
Apache Maven 3.6.3 (cecedd343002696d0abb50b32b541b8a6ba2883f) Maven home: /home/jose/.m2/wrapper/dists/apache-maven-3.6.3-bin/1iopthnavndlasol9gbrbg6bf2/apache-maven-3.6.3 Java version: 14.0.2, vendor: Oracle Corporation, runtime: /home/jose/.sdkman/candidates/java/14.0.2-open Default locale: en_US, platform encoding: UTF-8 OS name: “linux”, version: “5.11.0-41-generic”, arch: “amd64”, family: “unix”
Additional information
From what I see SseUtil.send is producing the response the first time an element is produced. Therefore, until the first element is generated, no call to it happens and no response is flushed. I see this could have to do with PublisherResponseHandler suspending the context. I wonder if an option could be to have that class handle SSE slightly different and generate a status code.
I see that adding:
requestContext.serverResponse().setStatusCode(200)
requestContext.serverResponse().setChunked(true)
requestContext.serverResponse().write(new byte[]{})
to PublisherResponseHandler works as expected (i.e. we get the status code, headers, etc. and then the events get produced as they come). Any reason you can think of not to do that?
Issue Analytics
- State:
- Created 2 years ago
- Reactions:2
- Comments:29 (28 by maintainers)
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I’m no SSE expert, just a user, but as a user I would expect the 200 to come right away and then receive the events.
Maybe @cescoffier has an opinion too as he played quite a lot with this.
I’m only ever referring to RestEasy server here. By “client” in the above quote I meant an
EventSourceas defined by the WHATWG Spec.