Detecting if an email is a “Delivery Status Notification” and extract information - Python

Question

I\'m using the Python email module to parse emails.

I need to be able to tell if an email is a \"Delivery Status Notification\", find out what the status is

Answer 1

I don't use Python but I suppose Gmail improved its support to DSN because my tests are successfull:

You can see in the sample below this is a multipart message with "Content-Type: multipart/report; report-type=delivery-status".

The way I identify reliably that it is a DSN:

• The first row is "Return-path: <>"
• Content-Type is "multipart/report" with "report-type=delivery-status"

Then, I know that:

• The report content is in the part with Content-Type = "message/delivery-status"
• Status and Action fields are always present in the report content.
• Note the Status field can be less precise than other status eventually present in the Diagnostic-Code field (not mandatory). However, the sample below is good (same status in all fields)
• The original message is in the part with Content-Type = "message/rfc822". Sometimes, MTA returns only original message headers without content. In this case, Content-Type is "text/rfc822-headers".

Sample DSN received after an e-mail sent to test-dsn-failure@gmail.com:

Return-path: <>
Received: from xxx ([xxx])
    by xxx with ESMTP; Fri, 04 May 2012 16:18:13 +0200
From:  (Mail Delivery System)
To: xxx
Subject: Undelivered Mail Returned to Sender
Date: Fri, 04 May 2012 15:25:09 +0200
MIME-Version: 1.0
Content-Type: multipart/report; report-type=delivery-status;
 boundary="HTB3nt3RR7vw/QMPR4kDPbKg+XWjXIKdC/rfHQ=="

This is a MIME-encapsulated message.

--HTB3nt3RR7vw/QMPR4kDPbKg+XWjXIKdC/rfHQ==
Content-Description: Notification
Content-Type: text/plain

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to 

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

: 550-5.1.1 The email account that you tried to reach does not exist. Please try
550-5.1.1 double-checking the recipient's email address for typos or
550-5.1.1 unnecessary spaces. Learn more at
550 5.1.1 http://support.google.com/mail/bin/answer.py?answer=6596 t12si10077186weq.36


--HTB3nt3RR7vw/QMPR4kDPbKg+XWjXIKdC/rfHQ==
Content-Description: Delivery report
Content-Type: message/delivery-status

Reporting-MTA: dns; xxx
Arrival-Date: Fri, 04 May 2012 15:25:09 +0200

Final-Recipient: rfc822; test-dsn-failure@gmail.com
Status: 5.1.1
Action: failed
Last-Attempt-Date: Fri, 04 May 2012 15:25:09 +0200
Diagnostic-Code: smtp; 550-5.1.1 The email account that you tried to reach does not exist. Please try
550-5.1.1 double-checking the recipient's email address for typos or
550-5.1.1 unnecessary spaces. Learn more at
550 5.1.1 http://support.google.com/mail/bin/answer.py?answer=6596 t12si10077186weq.36

--HTB3nt3RR7vw/QMPR4kDPbKg+XWjXIKdC/rfHQ==
Content-Description: Undelivered Message
Content-Type: message/rfc822

[original message...]