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From "Oleg Kalnichevski (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HTTPCORE-200) ContentLengthInputStream.close() is not interruptible and may take an arbitrarily long time to complete
Date Wed, 15 Jul 2009 14:16:14 GMT

    [ https://issues.apache.org/jira/browse/HTTPCORE-200?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12731450#action_12731450

Oleg Kalnichevski commented on HTTPCORE-200:


Thread#isInterrupted() is less of a problem compared to Thread#currentThread(), which as far
as I understand can behave differently depending on the execution environment. Low level components
simply ought not meddle with threads. Calling Thread.currentThread().isInterrputed()  from
a low level component of a _generic_ library seems semantically wrong to me.


HttpClient aborts requests by shutting down the underlying socket, which basically ensures
the execution flow gets interrupted by an IOException no matter what.

There are several possible extension points one could use to introduce such a check, both
AbstractSessionInputBuffer and SocketInputStream being reasonable candidates. I still contend,
though, Thread.currentThread() checks do not really belong to the stock version of HttpCore


> ContentLengthInputStream.close() is not interruptible and may take an arbitrarily long
time to complete
> -------------------------------------------------------------------------------------------------------
>                 Key: HTTPCORE-200
>                 URL: https://issues.apache.org/jira/browse/HTTPCORE-200
>             Project: HttpComponents HttpCore
>          Issue Type: Bug
>          Components: HttpCore
>    Affects Versions: 4.0
>            Reporter: Eugene Kirpichov
> The method ContentLengthInputStream.close() reads the entity content to end.
> It does so in a non-interruptible fashion, and thus, if the entity content is too long
(or even infinite), the method may take too much time or not terminate at all.
> I have actually observed this behavior: my program does a time-limited web crawl and,
after the time limit is exceeded, interrupts the crawler thread and expects it to finish soon.
The thread didn't finish in several minutes after the interrupt, because it was stuck in consumeContent()
for some very large entity.
> Actually, execution time of this method for an entity of size N is limited by soTimeout
* N / ContentLengthInputStream.BUFFER_SIZE for the worst case where each call to read() in
the close() method almost causes a socket timeout. This upper limit is definitely too large,
especially for a method that is supposed to release resources.
> It would of course be best if interrupting the thread just caused an IOException in the
underlying SocketInputStream.read(), but I know that this functionality is not implemented
in the JVM (and probably not going to be), so we need a workaround.
> I suggest that ContentLengthInputStream.close() (or someone down its call stack) check
for Thread.currentThread.isInterrputed() between reads from the socket and throw an InterruptedIOException
if it returns true. Probably, this might be done in AbstractSessionInputBuffer.fillBuffer().
> If done so, execution time of this method will be limited by 2*soTimeout, which is already
acceptable and at least predictable.

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