Tuesday, September 14, 2010

Setting the starting point for KScope2011: Get XFILES running...

As a preparation for a joint presentation with Marco Gralike for ODTUG Kaleidoscope 2011, I tried to (re)install the not-yet-so-famous XFILES Application. That application was the result of the collaboration of Mark Drake (Sr Product Manager XMLDB) and Carl Backstrom. They did a presentation about it during OOW2008. The idea behind the presentation/application was leveraging the power of XML-DB with an APEX UI. Due to Carl's tragic car accident, the application never reached a final stage. Marco already did a sequel about XFILES on his blog. You can also find a download link to the latest version of the application there.
But back to the installation....I used the OTN Developer Days VM as a start and patched it with the latest APEX patch (4.0.1). There is a sort of how-to included in the XFILES download, but that isn't flawless (yet). But after executing all the steps I fired up the application and got this:


So all my images where missing. Inspecting the code learned that the images had a path of /XFILES/APEX/lib/icons/, so not pointing to images included in the application itself (as Application or Workspace Images) but to a directory on the filesystem....that wasn't there.  If I entered http:/localhost/XFILES I did get the directory listing. And drilling down I could see the images. After some investigation it turned out that localhost was using the standard port 80, which was used by the (standard installed - or done by the XFILES installation ??) Embedded PL/SQL Gateway (EPG). And I was using the Apex Listener (with Apache/Tomcat) on port 8888. So the APEX Listener was looking for the XFILES directory on it's root (/home/oracle/apache-tomcat-6.0.20/webapps/ROOT). So in order to get the images in my application I could just extract them from the XDB Repository and copy them onto the filesystem. But that would have been too easy ;-). I though it would be more fun if I could create a mapping from the right location on the filesystem into the right location in the XDB Repository! But as I am not a *nix wizard - nor a XML-DB guru -, I couldn't quite figure out how to do that - even after some Googling around . So I send out a "help Tweet". But it is hard to explain a situation in just 140 characters...
Nevertheless I got a lot of replies (thanks Learco, Iloon, Jacco, Peter, etc). But Marco acted as my mainstay and Skyped me. And just like Marco is, he dived in deep and came up with a solution! And wrote a long post about it...
But in short there are only two additional steps necessary:
1. Create the XFILES directory on the webserver :
/home/oracle/apache-tomcat-6.0.20/webapps/ROOT/XFILES
2. As su, mount the XFILES Folder in the XDB Repository to that directory:
mount -t  davfs  http://localhost:80/XFILES /home/oracle/apache-tomcat-6.0.20/webapps/ROOT/XFILES

And the result is:


The funny thing about this solution is, that I - as a user - can replace one of the images with my own one and it will immediately show up in the application itself:


Now I first have to solve a performance problem, because the app is deadly slow... Maybe just because of this solution? Don't know yet, will have to find out!
After that the next step is to make it a full blown APEX 4.0-style application, before moving on...
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