Wednesday, April 13, 2011

Deleted Discussions, Part II

Ok, what about those images? Are they left behind as detritus somewhere in the bowels of Bb's legacy file system?

Small scale testing on our exploratory server

1. create a post
2. embed an image
3. see what src url is generated


img src="@X@EmbeddedFile.location@X@s%27meeps%20with%20bunnies.jpg"


The @X@EmbeddedFile.location@X@ is a blackboard template variable that's dynamically expanded (http://www.edugarage.com/display/BBDN/Template+variables)

My first attempt was to see if I can get to it from a content item (inserting appropriate code via the VTBE source mode). That did not work.

My second attempt was to see if I can get to it from another discussion posting in the same course (inserting appropriate code via the VTBE source mode). That did not work.

Then I noticed, during expansion, that the path referenced the PK1 of the post itself.

https://BBSERVER/courses/1/COURSEID/db/_MSGPK1_1/embedded/s%27meeps%20with%20bunnies.jpg

My third attempt was to insert the fully expanded code in a new discussion posting, referencing the MSGPK1 of the original post.

Voila! That worked.

Now, the true test. What happens when the original posting is deleted?

The URL still worked!

Could it be cached at the tomcat level? Maybe, so restart the server.

It still worked!

I went looking in the file system for it.

blackboard\content\vi\bb_bb60\courses\1\COURSEID\db\_MSGPK1_1 was blank!! No hidden files, no embedded directory.

The image is obviously there, but where?!

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