How do I get the caption (Description) out of an image's metadata?

Question

Taking a break from a monstrous project that has had me tied up for days, I have embarked upon what I thought would be a bit of light relief (hah!).
A colleague asked me for an easy way to get captions into InDesign. So I started scripting there, asking for the "description of the link xmp".
This was not forthcoming and a search of the InDesign scripting forum yielded the information that in order to get this information it was necessary to open the doc in Photoshop, save it and re-link. This indeed does work, but it is a waste of time in the file-saving stage and also degrades the image, as we have a jpg workflow.
So I thought that if I was going to have to got to Photoshop anyway, why not have the script go straight there, open the doc, ask for the description and close without saving?
Photoshop so far has jealously guarded its XMP information.
In Applescript I ask go "set theData to raw data of XMP metadata of document 1" and there it is in the event log, but in forbidding red type. I try adding "as string" and it appears twice, once in friendly black type, enclosed in quotes, and then the red stuff. However I find myself refused access to the information in the variable.
AS or JS solutions welcome...

Answer 1

tell application "Adobe InDesign CS2"
activate
tell active document
set This_Selection to get selection
try
if This_Selection ≠ {} then
if length of This_Selection ≠ 1 then
display dialog "You have more than 1 item seleted!!!" giving up after 2
else
if class of item 1 of This_Selection is image then
set This_Image to item 1 of This_Selection
end if
if class of item 1 of This_Selection is rectangle then
set This_Image to image 1 of item 1 of This_Selection
end if
set Image_Path to file path of item link of (item 1 of This_Image)
set MDLS_Result to my Get_XMP_Description(Image_Path)
set {ASTID, AppleScript's text item delimiters} to {AppleScript's text item delimiters, " = "}
set Image_Desc to text item 2 of MDLS_Result
set AppleScript's text item delimiters to ASTID
display dialog Image_Desc giving up after 2
end if
else
display dialog "You have 0 items seleted!!!" giving up after 2
end if
on error
display dialog "This rectange contains NO image!!!" giving up after 2
end try
end tell
end tell
on Get_XMP_Description(File_Path)
try
do shell script "/usr/bin/mdls -name kMDItemDescription " & quoted form of POSIX path of File_Path
return the result
on error
return false
end try
end Get_XMP_Description