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https://issues.apache.org/jira/browse/WW-3526?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Lukasz Lenart updated WW-3526:
------------------------------
    Fix Version/s: 6.2.0
                       (was: 6.1.0)

> Augment JakartaMultiPartRequest to include optional progress listener
> ---------------------------------------------------------------------
>
>                 Key: WW-3526
>                 URL: https://issues.apache.org/jira/browse/WW-3526
>             Project: Struts 2
>          Issue Type: New Feature
>          Components: Dispatch Filter
>    Affects Versions: 6.1.0
>         Environment: N/A
>            Reporter: Bob Glamm
>            Priority: Minor
>             Fix For: 6.2.0
>
>         Attachments: upload-listener.tar.gz
>
>
> Original concept from David Casserly: see 
> http://www.devedup.com/ajaxfileupload/
> The basic idea is to augment JakartaMultiPartRequest to allow users to 
> specify a file upload progress listener (see Commons FileUpload 
> ServletFileUpload.setProgressListener()).  The original concept by Casserly 
> references a specific ProgressMonitor class that implements FileUpload's 
> ProgressListener interface.  I'd propose an alternate solution: allow the 
> user to configure the fully-qualified name of an optional listener class via 
> @Inject("struts.multipart.monitor"), then:
>   o  require the listener class to also implement an interface that specifies 
> public void abort(); as its only method;
>   o  in JakartaMultiPartRequest.parseRequest(), attempting to instantiate the 
> specified listener class via Class.forName().newInstance();
>   o  store the instantiated listener in the session, as per Casserly's 
> example;
>   o  in JakartaMultiPartRequest.parse(), in the catch(FileUploadException) 
> block, calling the abort() method on the listener class if it is in the 
> session.
> Users can then implement an action that retrieves the upload status (via AJAX 
> or some other mechanism) by retrieving their listener object from the session 
> (as per Casserly's example.)  AJAX retrieval allows implementation of file 
> upload progress bars, a la GMail's attachment upload mechanism.
> One possible issue I see with this is: what happens if multiple file upload 
> requests happen simultaneously for a user session?
> I have a partial implementation but I'm not familiar with the Struts 
> development process or philosophies, so I'm throwing this out there for 
> review.  If there are better ways to do this, let me know.  I can 
> (eventually) provide a patch to 2.2.1 or HEAD with a little assistance, I 
> think.



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