Allow copying attachments from non-default location

[unitof]

iMessage Exporter 1.6.0

When --copy-method is specified, it appears to look for attachments in the default ~/Library/Messages/Attachments/ directory, even if --db-path is specified, leading to a series of errors such as:

Attachment not found at specified path: "/Users/jacob/Library/Messages/Attachments/db/11/EF5FD3A3-7766-4CB4-91E6-BD1F23D1B382/IMG_3522.jpeg"
Attachment not found at specified path: "/Users/jacob/Library/Messages/Attachments/9d/13/280D341B-60CB-42C7-8175-33C57A4D2832/IMG_3523.jpeg"
Attachment not found at specified path: "/Users/jacob/Library/Messages/Attachments/73/03/BC4F65D1-9D59-4998-9CF1-C53CBC0FC848/image_1.jpg"
Attachment not found at specified path: "/Users/jacob/Library/Messages/Attachments/ee/14/476BC0FC-4B85-4C7F-86B7-77CD83802609/Screenshot 2022-09-13 at 12.26.12 PM.jpeg"
Attachment not found at specified path: "/Users/jacob/Library/Messages/Attachments/42/02/07EC0108-5F60-43E7-A8E0-84A3ECF6AD3D/IMG_4066.mov"

and render in the exported HTML as

<div class="message_part">
<span class="attachment_error">Unable to locate attachment: D6ED891F-6210-4EBF-9AA9-BBECF0F212EFIMG_4845.heic</span>
</div>

I suppose this might be by design, but my use case is archiving iMessage databases (including Attachments directories) from complete backups on external hard drives.

Would love if --copy-method looked relative to --db-path if set, or if there were an additional flag for specifying a custom Attachments directory location.

[ReagentX]

The attachment paths are stored in the database, how would a custom attachment path work?

[unitof]

Ah, I see. Didn't realize the database specified absolute paths. In my ideal world, it'd substitute all database-coded locations with the specified path, for use cases like mine where you have a fully intact Attachments folder from a complete backup, but not in its expected home directory location.

How I imagine it would work:

If I run imessages-exporter with --attachments-path /Volumes/Backblaze_MacEx1TB89963677/Backblaze Restore/Bicycle HD/Users/jacob/Library/Messages/Attachments:

Any time the database specifies an Attachment in ~/Library/Messages/Attachments, imessage-exporter would instead look in (and copy from) /Volumes/Backblaze_MacEx1TB89963677/Backblaze Restore/Bicycle HD/Users/jacob/Library/Messages/Attachments.

[ReagentX]

Sounds reasonable!