[jira] [Commented] (ISIS-2119) Increase timeout to avoid occasional exceptions when download Blobs

["ASF subversion and git services (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/ISIS-2119?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16841020#comment-16841020 ] 

ASF subversion and git services commented on ISIS-2119:
-------------------------------------------------------

Commit e7a4c8eabb10cdd5a0796205f998a0397bcc39a8 in isis's branch refs/heads/ISIS-538 from danhaywood
[ https://gitbox.apache.org/repos/asf?p=isis.git;h=e7a4c8e ]

ISIS-2119: increases the timeout for downloading blobs to 250ms

... to avoid, I hope, the occasional InvalidBehaviourIdException .


> Increase timeout to avoid occasional exceptions when download Blobs
> -------------------------------------------------------------------
>
>                 Key: ISIS-2119
>                 URL: https://issues.apache.org/jira/browse/ISIS-2119
>             Project: Isis
>          Issue Type: Bug
>    Affects Versions: 1.17.0
>            Reporter: Dan Haywood
>            Assignee: Dan Haywood
>            Priority: Minor
>             Fix For: 1.18.0
>
>
> On a slow connection, can get occasional exceptions when downloading a blob... that the behaviour cannot be found on the entity.  There's not a lot to go on.
> Inspecting the returned payload though, I discovered at the end:
> {code}
> <evaluate><![CDATA[(function(){setTimeout("window.location.href='./orders.Order:7975?24-1.IBehaviorListener.0-'", 10);})();]]></evaluate>
> {code}
> which gave me the clue.  The relevant code is in ActionResultResponseHandlingStrategy:
> {code}
>     SCHEDULE_HANDLER {
>         @Override
>         public void handleResults(
>                 final ActionResultResponse resultResponse,
>                 final IsisSessionFactory isisSessionFactory) {
>             final RequestCycle requestCycle = RequestCycle.get();
>             AjaxRequestTarget target = requestCycle.find(AjaxRequestTarget.class);
>             if (target == null) {
>                 // non-Ajax request => just stream the Lob to the browser
>                 // or if this is a no-arg action, there also will be no parent for the component
>                 requestCycle.scheduleRequestHandlerAfterCurrent(resultResponse.getHandler());
>             } else {
>                 // otherwise,
>                 // Ajax request => respond with a redirect to be able to stream the Lob to the client
>                 ResourceStreamRequestHandler scheduledHandler = (ResourceStreamRequestHandler) resultResponse.getHandler();
>                 StreamAfterAjaxResponseBehavior streamingBehavior = new StreamAfterAjaxResponseBehavior(scheduledHandler);
>                 final Page page = target.getPage();
>                 page.add(streamingBehavior);
>                 String callbackUrl = streamingBehavior.getCallbackUrl().toString();
>                 target.appendJavaScript("setTimeout(\"window.location.href='" + callbackUrl + "'\", 10);");
>             }
>         }
>     },
> {code}
> What's happening here is that response from the ajax call to invoke the button is the fragments to rebuild the page ... it's not possible to also return the BLOB.  So the Ajax instead sets a timeout to download that Blob as a separate web call.
> Experimenting with this code, if the behaviour is stripped off (everything after the "?") then the download doesn't occur; so this is needed.
> Since I've seen the problem mostly with large docs and on a slow connection, my guess is that this is some sort of race condition.  Since we can wait a bit more than 10ms, my suggestion is to increase the timeout to 250ms.



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)