I've been trying to get this right, but after having called with Adobe support and sales, I've turned to the community. My situation is like so: I need to read .indd files (in that format, no .idml) to read the XMP data that's embedded within. My environment is a 64-bit Linux server with Debian 7 running, with Ruby as the language of choice for the project. Any language is OK as long as it runs on this platform. I know, however, that the Adobe InDesign license strictly prohibits reading data explicitly from .indd files and encourages use of ExtendScript. Adobe InDesign Server is a possibility, but the price is too high for our purposes.