[jira] Updated: (GERONIMO-1705) Use AJAX to provide for a progress bar when downloading a JDBC jar

["Paul McMahan (JIRA)" <de...@geronimo.apache.org>]

     [ http://issues.apache.org/jira/browse/GERONIMO-1705?page=all ]

Paul McMahan updated GERONIMO-1705:
-----------------------------------

    Attachment: GERONIMO-1705.patch
                downloadProgress2.png

Attaching a patch that provides an AJAX enabled progress bar on the JDBC driver download page. See the attached screenshot (downloadProgress.2png) for a preview.

The progress bar is implemented as follows :
When the download form in the selectDownload.jsp portlet is submitted a request is sent to the console application to begin downloading the driver from the remote location (this is unchanged).  An object on the server (i.e. DownloadInfo) is updated while the download progresses and is stored in the portlet's session.  An onsubmit javascript listener attached to the download form periodically accesses the server via DWR to query the download progress stored in the DownloadInfo object.  This javascript uses DHTML to update a progress bar underneath the form as the download progresses. If the remote server provides the total download size (some don't, e.g. postgres) then the progress bar shows % complete. Otherwise it just shows total Kb downoaded.  As before, when the download completes the user is returned to the parameter collection screen.

Note:
1.)  As mentioned above a session object is used to pass information between the download portlet and the DWR servlet. The JSR 168 Portlet Specification (PLT.15.4) states that Portlets are supposed to be able to communicate information with other Servlets and JSPs that are part of the same Portlet Application via their session. Pluto running on Jetty passes the information as expected but Pluto running on tomcat does not. The workaround provided by tomcat is to set "emptySessionPath=true" on the web container.  However, IMHO this workaround is not acceptable because it is a server-wide setting that forces all webapps deployed in G to share the same context for their sessions ("/").  i.e. the console should not require a specialized configuration of the web container, especially one like this which could affect cross-context security and complicate session usage.  Therefore, the best alternative is to tunnel requests for the DWR servlet through a servlet in the portal application.  Turns out that this was the exact approach taken in the patch provided for GERONIMO-973 where the security context established by the console-framework application is passed to the console-standard application via such a tunnel. Therefore the patch attached to GERONIMO-973 is a prerequisite of this patch. My understanding was that GERONIMO-973 would be applied at some point in the future - if that's not the case then I can attach the relevant parts of it to this JIRA.  See the following JIRA for more information about this limitation in tomcat:  http://issues.apache.org/jira/browse/PLUTO-53

2.)  If this approach for providing progress indication is found acceptable then it can be readily adapted to work in other parts of the console as well, such as uploading applications or the recently added feature for downloading configurations.

3.)  While downloading the jar the Next and Cancel buttons are disabled.  If we want to leave these buttons enabled during the download then the code running on the server should be enhanced to support interrupted downloads (not hard to do, just didn't want to overload the first iteration of this new function).

4.)  There are various existing issues in the database pool portlet that are not addressed by this patch (errors from download timeouts, error if file already exists in repository, etc).  Again, didn't want to overload this patch so we can address those issues in a separate JIRA.

> Use AJAX to provide for a progress bar when downloading a JDBC jar
> ------------------------------------------------------------------
>
>          Key: GERONIMO-1705
>          URL: http://issues.apache.org/jira/browse/GERONIMO-1705
>      Project: Geronimo
>         Type: Improvement
>   Components: console
>     Versions: 1.0
>     Reporter: Jeff Genender
>  Attachments: GERONIMO-1705.patch, downloadProgress2.png
>
> Use AJAX to provide for a progress bar when downloading a JDBC jar for the Download Drivers portlet.  As it stands, for people who have slower connections, it currently can make them think something is wrong with Geronimo because web page refresh takes too long.  A progrss bar using AJAX can help keep the user up to date on the downloading progress.

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