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jakarta-mailmimerfc822

Emails with empty content-id

I sometimes recieve e-mails with empty CONTENT-ID.

Exemple:

Empty content-id, Content-Disposition: attachement

In most cases, the empty content-id belongs to an attachement, that is added to the email two times, once as correct inline attachement with a content ID, in the second, the content-disposition is : attachement instead and the content ID is empty.

Content-Disposition: inline

Is this a mail client bug ?

Solution

  • According to the MIME RFC a Content-ID is optional, but if present should be "world-unique" (which an empty string certainly isn't).

    Personally I'd treat empty Content-ID to be identical to a missing Content-ID.