MatKuhr
commented
2 years ago Hi Mapobo, thanks for reaching out!
You are correct, the SDK filters currently don't support async. You could work around this by writing a custom filter that does it, but it is a lot of custom code and I'm not certain that it will work on Neo.
Code
```Java import com.sap.cloud.sdk.cloudplatform.exception.ShouldNotHappenException; import com.sap.cloud.sdk.cloudplatform.servlet.RequestThreadContextListener; import com.sap.cloud.sdk.cloudplatform.thread.ThreadContext; import com.sap.cloud.sdk.cloudplatform.thread.ThreadContextExecutor; import com.sap.cloud.sdk.cloudplatform.thread.ThreadContextListener; import io.vavr.control.Option; import java.util.List; import javax.annotation.Nonnull; import javax.servlet.Filter; import javax.servlet.FilterChain; import javax.servlet.FilterConfig; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.annotation.WebFilter; import javax.servlet.http.HttpServletRequest; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * Servlet filter for setting the request context for cloud SDK. */ @WebFilter( filterName = "CustomRequestAccessorFilter", urlPatterns = {"/*"}, asyncSupported = true ) public class CustomRequestAccessorFilter implements Filter { private static final Logger log = LoggerFactory.getLogger(CustomRequestAccessorFilter.class); public CustomRequestAccessorFilter() { } public void init(@Nonnull FilterConfig filterConfig) { } /** * Add request to filter chain. */ public void doFilter(@Nonnull ServletRequest request, @Nonnull ServletResponse response, @Nonnull FilterChain filterChain) { if (request instanceof HttpServletRequest) { try { ThreadContextExecutor threadContextExecutor = new ThreadContextExecutor(); ListCould you elaborate on what SDK functionality you want to use inside the async operation? Because currently the SDK context will anyway be destroyed when the initial filter chain ends, i.e. when the initial request is processed & answered. Thus, passing it on to a long-living thread doesn't really work. We are working on an improvement to make this work, but I can't give a timeline yet on when that will be available, and if it will work on Neo..
Mapobo
jensmatw
newtork
Issue Description
Important information:
Hi all! I am trying to create an asynchronous service to generate document's employees with sap cloud sdk for neo environment.
The process is the following:
First an external application sends a post request with a body similar to this:
{ "Empleados": ["XXXX", "YYYY", "EEEEE"], "Secciones": ["1", "2", "3", "4", "5", "6","7","9","10","11","12","13","14","15","16"] }Empleados contains the employees reference and Secciones contains the sections to print.
Then the service returns the following body :
Then, a background process generates documents and saves the json string info and a zip file with documents in two differents attributes of session object to be obtained later (once all documents are generated). Is it correct to save this info in attribute of session Object?
this.session.setAttribute(this.uniqueIdpdf, ByteArrayOutputStream);An UUID is generated by the service to identify the request and other properties (success -> process finished flag, total -> total employee/docs to generate, procesados -> count of documents generated).
In the meantime, the external App call every second the service with the following get request (you can review the UUID parametter to identify the process)
GetCvs?UUID=3315ac6e-fa10-4ccf-a4f6-d6eb7452787aand retrieve the same json info but the property "Procesados" increase while the generator process gen docs.
The only way to make this process works It is adding a new thread to execute it in background.
Rigth now the following code is working correctly.
After I tested a similar code with normal servlet (no created with sdk) and apache tomcat server 7.0 . I could use async support and created a asyncContext similar to this.
` final AsyncContext asyncContext = request.startAsync(request, response);
However, I tried to use asyncContext with sdk servlet and the following error is displayed. com.sap.cloud.sdk.cloudplatform.thread.exception.ThreadContextExecutionException: java.lang.IllegalStateException: A filter or servlet of the current chain does not support asynchronous operations..
I tried to add assync-supported in
@WebServletand in web.xml but always appear this error. Exist some incompatibility with sdk and asynchronous process?I saw Multitenancy, Thread Context and async Operations in the documentation and i tried to implement that but always execute in same thread and the post request return body when all docs are generated.
`ThreadContextExecutor executor = new ThreadContextExecutor(); Callable operationWithContext = () -> executor.execute(() -> operation());
invokeAsynchronously(operationWithContext);`
And I dont find or understand invokeAsyncronously.
What Is the better way to implement this aproach?
Sorry for my java knowledge. I new in that.
Thank you for your help.
Impact / Priority
Affected development phase: e.g. Getting Started, Development, Release, Production
Impact: e.g. No Impact, Inconvenience, Impaired, Blocked
Timeline: e.g. Go-Live is in 12 weeks.
Error Message
Error Output when try used request.startAsync
Project Details
Checklist