The download-message REST endpoint returned 404 [30000] "Original email
content not found" whenever an indexed message's raw content blob was
missing from the blob store, leaving the message permanently
unrecoverable even though it still existed on the IMAP server.
Make the endpoint self-healing: when the content blob is absent, fetch
that one message on demand from the IMAP server via
UID FETCH <uid> (BODY.PEEK[]), repopulate the detached blob, and return
the content. The 404 is now only produced when the on-demand fetch
itself fails (mailbox gone, UID gone, connection failure, or the fetched
bytes no longer match the archived content_hash).
- Add ImapExecutor::fetch_single_message_body: examines the mailbox
read-only and fetches one message by UID, reusing the existing
BODY.PEEK[] fetch command.
- Add reattach_eml_content_self_healing / recover_message_blob in the
envelope extractor: fast-path delegates to reattach_eml_content when
the blob exists; otherwise recovers it via IMAP and re-stores the
stripped EML + attachments through the existing blob queue.
- Make store::blob::get_reader async and route it through the
self-healing path; update the single caller (download_message).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
rustmailer