Re: Is request.isAsyncStarted() return true after calling asyncContext.dispatch() right in tomcat?

[Mark Thomas <ma...@apache.org>]

On 05/06/2023 10:15, netyeaxi@sina.com wrote:
> According to Servlet Specification Version 3.1, request.isAsyncStarted() should return false after calling asyncContext.dispatch().request.isAsyncStarted() return false in weblogic, but true in tomcat. Is tomcat's action right?

Tomcat is correct. WebLogic is wrong.

The specification states:

<quote>
If any of the dispatch methods are called before the container initiated 
dispatch that called startAsync has returned to the container, the 
following conditions must hold during that time between the invocation 
of dispatch and the return of control to the container:

i. any dispatch invocations invoked during that time will not take 
effect until after the container- initiated dispatch has returned to the 
container.

ii. any AsyncListener.onComplete(AsyncEvent), 
AsyncListener.onTimeout(AsyncEvent) and 
AsyncListener.onError(AsyncEvent) invocations will also be delayed until 
after the container- initiated dispatch has returned to the container.

iii. any calls to request.isAsyncStarted() must return true until after 
the container-initiated dispatch has returned to the container.

</quote>


Point iii is exactly the scenario demonstrated by your sample code.

You should raise a specification compliance bug against WebLogic. You 
might also want to inquire how WebLogic managed to pass the Servlet TCK 
given that there is a test for this specific behavior.

Mark



> Java™ Servlet Specification Version 3.1------------------------------2.3.3.3 Asynchronous processing
> 
>      ServletRequest
> 
>      ■ public boolean isAsyncStarted() - Returns true if async processing has
>      started on this request, and false otherwise. If this request has been
>      dispatched using one of the AsyncContext.dispatch methods since it was put
>      in asynchronous mode, or a call to AsynContext.complete is made, this
>      method returns false.
> test envirment:------------------------------Tomcat 9.0.55
> weblogic 12.2.1.4.0
> JDK 1.8.0_261
> 
> test code:
> ------------------------------
> import java.io.IOException;
> 
> import javax.servlet.AsyncContext;
> import javax.servlet.ServletException;
> import javax.servlet.annotation.WebServlet;
> import javax.servlet.http.HttpServlet;
> import javax.servlet.http.HttpServletRequest;
> import javax.servlet.http.HttpServletResponse;
> 
> @WebServlet(value = "/test", asyncSupported = true)
> public class SimpleIssueServlet extends HttpServlet {
> 
>      private static final long serialVersionUID = -2504425408734161943L;
> 
>      private static final String CTX_RESULT = "CTX_RESULT";
>   
> 
>      @Override
>      protected void doGet(HttpServletRequest request, HttpServletResponse response)
>              throws ServletException, IOException {
>          doPost(request, response);
>      }
> 
>      @Override
>      protected void doPost(HttpServletRequest request, HttpServletResponse response)
>              throws ServletException, IOException {
> 
>          String result = (String) request.getAttribute(CTX_RESULT);
> 
>          if (result != null) {
>              response.getWriter().write(result);
> 
>              return;
>          }
> 
>          AsyncContext asyncContext = request.startAsync();
> 
>          boolean isAsyncStarted01 = request.isAsyncStarted();
>          System.out.println("isAsyncStarted01:" + isAsyncStarted01);
>          // tomcat: isAsyncStarted01 = true;
>          // weblogic: isAsyncStarted01 = true;
> 
>          {
>              // make result
>              String ret = "this is a test";
> 
>              request.setAttribute(CTX_RESULT, ret);
> 
>              asyncContext.dispatch();
>          }
> 
>          boolean isAsyncStarted02 = request.isAsyncStarted();
>          System.out.println("isAsyncStarted02:" + isAsyncStarted02);
>          // tomcat: isAsyncStarted02 = true;
>          // weblogic: isAsyncStarted02 = false;
>      }
> }

---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org