Extracting metadata or renaming .emlx files

Question

Hi,
I work for an archivist, and we are for the first time attempting to process a person's email as a collection. I have all of the messages (50,000+) as .emlx, but in Finder it only shows only the 6-digit file name. However, when I search spotlight by one of those 6-digit numbers, it turns up the relevant file -- except it looks as though it is named by the subject (within the email) not the number. Does anyone know why it does this or if I could make it display the name of the file as the subject when not searching?
In addition, from an archival perspective, it would be helpful to a) be able to name the files descriptively, such as with subject, sender email address, or date created (which, fyi, would need to be extracted from within the email too, because Finder currently says the date created is when they were backed up into mboxes) or b) extract the metadata, which Spotlight clearly has indexed, into a database, so we have an index that we can reference.
Any chance anyone has thoughts on how to do this?

Answer 1

Let me preface by pointing out that I do not know the constraints of your profession. I imagine that there's a priority on preserving details, but beyond that...
The files you find in ~/Library/Mail (where Mail.app stores most of its data) are intended for internal use by Mail.app. The human-readable message (the thing actually shown on the computer screen) is compiled and processed by Mail.app before display. There are ways of connecting the stored data with the actual human-readable message. I could write an applescript, for instance, that would start with the message and trace back to each stored piece (or start with a stored piece and discover what message it's part of). But doing so doesn't make a lot of sense from any perspective I know of.
The best approach to preserving the email collection as a whole is to duplicate and zip the ~/Library/Mail folder. That way you can always have the original material to refer to. Changing the file names in the Finder will break the whole system, so you definitely don't want to do that. If you want an archive that's meaningful outside of Spotlight you'd have to do something tricky (e.g. copy the folder hierarchy, replace each file in the copy with an alias to the original, then rename the alias as you see fit), but given the peculiar way that Mail.app stores data I'm not sure I see the advantages of doing that either. In fact, I'd prefer to know more precisely what your goal is before offering more advice: how exactly do you want the data structured, and how do you anticipate it will be used?