eml1.3 KB

EML — DSN Returning the Original Message in Full

A bounce whose third part is the complete original message — headers and body — as message/rfc822. Paired with the headers-only twin beside it, it shows whether a bounce processor can recover the original Message-ID from either shape.

Email parsing Conversion testing

Preview — first 39 lineseml

From: Mail Delivery Subsystem <MAILER-DAEMON@mx1.meridiansupply.example>
To: Maya Chen <maya@brightside.example>
Subject: Delivery Status Notification (failure) SAMPLE
Date: Mon, 16 Feb 2026 07:47:00 -0800
Message-ID: <p7-dsn-orig@mx1.meridiansupply.example>
Auto-Submitted: auto-replied
MIME-Version: 1.0
Content-Type: multipart/report; report-type=delivery-status; boundary="=_p7_dsn_p7-dsn-orig"

--=_p7_dsn_p7-dsn-orig
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit

Your message could not be delivered. The original message is attached in full.
--=_p7_dsn_p7-dsn-orig
Content-Type: message/delivery-status

Reporting-MTA: dns; mx1.meridiansupply.example
Arrival-Date: Mon, 16 Feb 2026 07:45:12 -0800

Final-Recipient: rfc822; dana@nonexistent.example
Action: failed
Status: 5.1.1
Diagnostic-Code: smtp; 550 5.1.1 SAMPLE - no such user
--=_p7_dsn_p7-dsn-orig
Content-Type: message/rfc822

From: Maya Chen <maya@brightside.example>
To: Sam Rivera <sam@meridiansupply.example>
Subject: Standing order for Q1 (SAMPLE)
Date: Mon, 16 Feb 2026 07:45:00 -0800
Message-ID: <p7-dsn-original@brightside.example>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit

Confirming the Q1 standing order as quoted.
--=_p7_dsn_p7-dsn-orig--

Specifications

Wave: p7
Seed: 20260807
Report Type: delivery-status
Third Part Type: message/rfc822
Returns Body: true
Status: 5.1.1
Line Endings: CRLF (RFC 5322)

Testing contract

Expected to pass

Scenario: Recover the original message's identity and content from a DSN that returns it as a full message/rfc822 part.
Expected result: The original Message-ID <p7-dsn-original@brightside.example> and its body text are both recoverable from the third part.

What is a .eml file?

An EML file is a single email message stored in the RFC 822 / MIME format — plain-text headers (From, To, Subject, Date, Message-ID) followed by the body, which may be plain text, HTML, or a multipart structure with alternative bodies and file attachments encoded in base64.

How to use this file

Use an example EML to test email header parsing, MIME decoding, HTML-part handling, attachment extraction, and EML-to-other-format conversion.

How to use this file for testing

“EML — DSN Returning the Original Message in Full” is a deterministic Novus Examples fixture for Email parsing, Conversion testing. Standards-compliant RFC 822 messages — plain, multipart text+HTML, and with an attachment — plus an MBOX mailbox, for testing header parsing, MIME decoding, attachment extraction, and mailbox splitting.

Documented properties for this file: seed 20260807 · CRLF (RFC 5322). Compare results against paired or grouped companions on this page when present (clean↔damaged, searchable↔scanned, or format twins) so scores stay reproducible across runs.

Download the file once, keep the path stable in CI or local scripts, and treat the spec table as the contract: dimensions, seeds, field lists, and roles are intentional. Corrupt or invalid samples are labelled as such — expect parsers to fail loudly rather than silently accept them.

Email fixtures use fixed dates, message IDs, and MIME boundaries so runs are reproducible, and every address is fictional. Test header parsing, MIME decoding, attachment extraction, and EML/MBOX conversion against the documented structure.

Code examples

from email import policy
from email.parser import BytesParser

msg = BytesParser(policy=policy.default).parse(open("p7-dsn-original-message.eml", "rb"))
print(msg["subject"], msg["from"])