Version: Tomcat 9.0.35 (embedded in Spring Boot 2.3.0.RELEASE) Use case / problem:
The frontend is doing requests that trigger heavy calculations in the backend. Often these requests get cancelled by the frontend before the backend has finished doing the calculations. The cancellation of the requests is done by using an AbortController (https://developer.mozilla.org/en-US/docs/Web/API/AbortController) to abort the fetch (similar to this example https://developer.mozilla.org/en-US/docs/Web/API/AbortController/abort#examples). When aborting a fetch that happens over HTTP2, an RST_FRAME is send to the server. I'm trying to figure out how to detect in the backend that such an RST_FRAME has been received, and stop doing my calculation. This is done in a Spring Boot Application using the embedded Tomcat webserver, but I would already be glad if I can get a pointer on how to get this information in Tomcat through public apis. I'm hopeful I can figure out the integration with Spring myself. Investigation: What I already found is that the RST_FRAME is received in the backend, at which point the state in the org.apache.coyote.http2.StreamStateMachine switches to CLOSED_RST_TX. After that state switch, the org.apache.coyote.http2.StreamStateMachine#canWrite method returns false which I think is the information I need. After all, if the result of my calculation cannot be written to the stream, there is no point in doing it. The problem is that this information is hidden behind a bunch of package visible/protected classes and methods so I cannot access it without relying on reflection and implementation details. And I couldn't find anything in the source code that exposes this information publicly. So I'm not even sure I'm on the right track here. Does anybody has a pointer on how to obtain this info through official APIs, or to some documentation related to this that I might have missed ? Thanks, Robin --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
