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Posted to dev@tomcat.apache.org by Violeta Georgieva <vi...@apache.org> on 2017/04/12 11:22:13 UTC
ServletOutputStream#isReady throws ISE
Hi,
I have a question about ServletOutputStream#isReady.
I have the following scenario:
- thread A removes the Read/WriteListeners when async timeout/error happens
[1], [2]
- before receiving AsyncListener#onTimeout/onError, thread B checks whether
it is save to perform write invoking ServletOutputStream#isReady. The
exception below happens:
java.lang.IllegalStateException: It is invalid to call isReady() when the
response has not been put into non-blocking mode
at org.apache.coyote.Response.isReady(Response.java:635)
~[tomcat-embed-core-8.5.13.jar!/:8.5.13]
at
org.apache.catalina.connector.OutputBuffer.isReady(OutputBuffer.java:680)
~[tomcat-embed-core-8.5.13.jar!/:8.5.13]
at
org.apache.catalina.connector.CoyoteOutputStream.isReady(CoyoteOutputStream.java:162)
~[tomcat-embed-core-8.5.13.jar!/:8.5.13]
According to javadoc [3] the ServletOutputStream#isReady method does not
throw IllegalStateException.
"This method can be used to determine if data can be written without
blocking."
I also checked the specification and there I did not find the expectation
in such situation.
"
boolean isReady(). This method returns true if a write to the
ServletOutputStream will succeed, otherwise it will return false. If this
method returns true, a write operation can be performed on the
ServletOutputStream. If no further data can be written to the
ServletOutputStream. then this method will return false till the underlying
data is flushed at which point the container will invoke the
onWritePossible method of the WriteListener. A subsequent call to this
method will return true.
"
I think that we should not throw ISE but return "false" in such cases.
What do you think?
Thanks,
Violeta
[1]
https://github.com/apache/tomcat/blob/trunk/java/org/apache/catalina/core/AsyncContextImpl.java#L385
[2]
https://github.com/apache/tomcat/blob/trunk/java/org/apache/coyote/AsyncStateMachine.java#L395
[3]
https://docs.oracle.com/javaee/7/api/javax/servlet/ServletOutputStream.html#isReady--
Re: ServletOutputStream#isReady throws ISE
Posted by Violeta Georgieva <mi...@gmail.com>.
2017-04-12 18:34 GMT+03:00 Mark Thomas <ma...@apache.org>:
>
> On 12/04/17 16:05, Violeta Georgieva wrote:
>
> <snip/>
>
> > Ok
> > I'm going to commit a change.
>
> If you are quick, it will make it in before I tag 9.0.x and 8.5.x.
>
I committed the changes.
Thanks,
Violeta
> Mark
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: dev-unsubscribe@tomcat.apache.org
> For additional commands, e-mail: dev-help@tomcat.apache.org
>
Re: ServletOutputStream#isReady throws ISE
Posted by Mark Thomas <ma...@apache.org>.
On 12/04/17 16:05, Violeta Georgieva wrote:
<snip/>
> Ok
> I'm going to commit a change.
If you are quick, it will make it in before I tag 9.0.x and 8.5.x.
Mark
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Re: ServletOutputStream#isReady throws ISE
Posted by Violeta Georgieva <mi...@gmail.com>.
Hi,
2017-04-12 17:44 GMT+03:00 Mark Thomas <ma...@apache.org>:
>
> On 12/04/17 12:22, Violeta Georgieva wrote:
> > Hi,
> >
> > I have a question about ServletOutputStream#isReady.
> >
> > I have the following scenario:
> > - thread A removes the Read/WriteListeners when async timeout/error
happens
> > [1], [2]
> > - before receiving AsyncListener#onTimeout/onError, thread B checks
whether
> > it is save to perform write invoking ServletOutputStream#isReady. The
> > exception below happens:
> >
> >
> > java.lang.IllegalStateException: It is invalid to call isReady() when
the
> > response has not been put into non-blocking mode
> > at org.apache.coyote.Response.isReady(Response.java:635)
>
> <snip/>
>
> > I think that we should not throw ISE but return "false" in such cases.
> >
> > What do you think?
>
> Seems reasonable to me. I've checked the EG archives and I can't find
> any reference to a discussion that decided otherwise.
Ok
I'm going to commit a change.
Thanks,
Violeta
> Mark
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: dev-unsubscribe@tomcat.apache.org
> For additional commands, e-mail: dev-help@tomcat.apache.org
>
Re: ServletOutputStream#isReady throws ISE
Posted by Mark Thomas <ma...@apache.org>.
On 12/04/17 12:22, Violeta Georgieva wrote:
> Hi,
>
> I have a question about ServletOutputStream#isReady.
>
> I have the following scenario:
> - thread A removes the Read/WriteListeners when async timeout/error happens
> [1], [2]
> - before receiving AsyncListener#onTimeout/onError, thread B checks whether
> it is save to perform write invoking ServletOutputStream#isReady. The
> exception below happens:
>
>
> java.lang.IllegalStateException: It is invalid to call isReady() when the
> response has not been put into non-blocking mode
> at org.apache.coyote.Response.isReady(Response.java:635)
<snip/>
> I think that we should not throw ISE but return "false" in such cases.
>
> What do you think?
Seems reasonable to me. I've checked the EG archives and I can't find
any reference to a discussion that decided otherwise.
Mark
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